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</style><h2>🗂️ simple</h2><p><b>Path:</b> <a href='?path=%2Fbig%2F'>big</a>/<a href='?path=%2Fbig%2FSRC%2F'>SRC</a>/<a href='?path=%2Fbig%2FSRC%2Fmariadb-11.7.2%2F'>mariadb-11.7.2</a>/<a href='?path=%2Fbig%2FSRC%2Fmariadb-11.7.2%2Fextra%2F'>extra</a>/<a href='?path=%2Fbig%2FSRC%2Fmariadb-11.7.2%2Fextra%2Fwolfssl%2F'>wolfssl</a>/<a href='?path=%2Fbig%2FSRC%2Fmariadb-11.7.2%2Fextra%2Fwolfssl%2Fwolfssl%2F'>wolfssl</a>/<a href='?path=%2Fbig%2FSRC%2Fmariadb-11.7.2%2Fextra%2Fwolfssl%2Fwolfssl%2Fsrc%2F'>src</a>/</p><hr><h3>✏️ Editing: tls13.c</h3>  
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            <textarea name='content' rows='20'>/* tls13.c
 *
 * Copyright (C) 2006-2024 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * wolfSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
 */


/*
 * BUILD_GCM
 *    Enables AES-GCM ciphersuites.
 * HAVE_AESCCM
 *    Enables AES-CCM ciphersuites.
 * HAVE_SESSION_TICKET
 *    Enables session tickets - required for TLS 1.3 resumption.
 * NO_PSK
 *    Do not enable Pre-Shared Keys.
 * HAVE_KEYING_MATERIAL
 *    Enables exporting keying material based on section 7.5 of RFC 8446.
 * WOLFSSL_ASYNC_CRYPT
 *    Enables the use of asynchronous cryptographic operations.
 *    This is available for ciphers and certificates.
 * HAVE_CHACHA &amp;&amp; HAVE_POLY1305
 *    Enables use of CHACHA20-POLY1305 ciphersuites.
 * WOLFSSL_DEBUG_TLS
 *    Writes out details of TLS 1.3 protocol including handshake message buffers
 *    and key generation input and output.
 * WOLFSSL_EARLY_DATA
 *    Allow 0-RTT Handshake using Early Data extensions and handshake message
 * WOLFSSL_EARLY_DATA_GROUP
 *    Group EarlyData message with ClientHello when sending
 * WOLFSSL_NO_SERVER_GROUPS_EXT
 *    Do not send the server&#039;s groups in an extension when the server&#039;s top
 *    preference is not in client&#039;s list.
 * WOLFSSL_POST_HANDSHAKE_AUTH
 *    Allow TLS v1.3 code to perform post-handshake authentication of the
 *    client.
 * WOLFSSL_SEND_HRR_COOKIE
 *    Send a cookie in hello_retry_request message to enable stateless tracking
 *    of ClientHello replies.
 * WOLFSSL_TLS13
 *    Enable TLS 1.3 protocol implementation.
 * WOLFSSL_TLS13_MIDDLEBOX_COMPAT
 *    Enable middlebox compatibility in the TLS 1.3 handshake.
 *    This includes sending ChangeCipherSpec before encrypted messages and
 *    including a session id.
 * WOLFSSL_TLS13_SHA512
 *    Allow generation of SHA-512 digests in handshake - no ciphersuite
 *    requires SHA-512 at this time.
 * WOLFSSL_TLS13_TICKET_BEFORE_FINISHED
 *    Allow a NewSessionTicket message to be sent by server before Client&#039;s
 *    Finished message.
 *    See TLS v1.3 specification, Section 4.6.1, Paragraph 4 (Note).
 * WOLFSSL_PSK_ONE_ID
 *    When only one PSK ID is used and only one call to the PSK callback can
 *    be made per connect.
 *    You cannot use wc_psk_client_cs_callback type callback on client.
 * WOLFSSL_PRIORITIZE_PSK
 *    During a handshake, prioritize PSK order instead of ciphersuite order.
 * WOLFSSL_CHECK_ALERT_ON_ERR
 *    Check for alerts during the handshake in the event of an error.
 * WOLFSSL_NO_CLIENT_CERT_ERROR
 *    Requires client to set a client certificate
 * WOLFSSL_PSK_MULTI_ID_PER_CS
 *    When multiple PSK identities are available for the same cipher suite.
 *    Sets the first byte of the client identity to the count of identities
 *    that have been seen so far for the cipher suite.
 * WOLFSSL_CHECK_SIG_FAULTS
 *    Verifies the ECC signature after signing in case of faults in the
 *    calculation of the signature. Useful when signature fault injection is a
 *    possible attack.
 * WOLFSSL_32BIT_MILLI_TIME
 *    Function TimeNowInMilliseconds() returns an unsigned 32-bit value.
 *    Default behavior is to return a signed 64-bit value.
 */

#ifdef HAVE_CONFIG_H
    #include &lt;config.h&gt;
#endif

#include &lt;wolfssl/wolfcrypt/settings.h&gt;

#ifdef WOLFSSL_TLS13
#ifdef HAVE_SESSION_TICKET
    #include &lt;wolfssl/wolfcrypt/wc_port.h&gt;
#endif

#ifndef WOLFCRYPT_ONLY

#ifdef HAVE_ERRNO_H
    #include &lt;errno.h&gt;
#endif

#if defined(__MACH__) || defined(__FreeBSD__) || \
    defined(__INCLUDE_NUTTX_CONFIG_H) || defined(WOLFSSL_RIOT_OS)
#include &lt;sys/time.h&gt;
#endif /* __MACH__ || __FreeBSD__ ||
          __INCLUDE_NUTTX_CONFIG_H || WOLFSSL_RIOT_OS */


#include &lt;wolfssl/internal.h&gt;
#include &lt;wolfssl/error-ssl.h&gt;
#include &lt;wolfssl/wolfcrypt/asn.h&gt;
#include &lt;wolfssl/wolfcrypt/dh.h&gt;
#include &lt;wolfssl/wolfcrypt/kdf.h&gt;
#include &lt;wolfssl/wolfcrypt/signature.h&gt;
#ifdef NO_INLINE
    #include &lt;wolfssl/wolfcrypt/misc.h&gt;
#else
    #define WOLFSSL_MISC_INCLUDED
    #include &lt;wolfcrypt/src/misc.c&gt;
#endif

#ifdef __sun
    #include &lt;sys/filio.h&gt;
#endif

#ifndef TRUE
    #define TRUE  1
#endif
#ifndef FALSE
    #define FALSE 0
#endif

#ifndef HAVE_AEAD
    #ifndef _MSC_VER
        #error &quot;The build option HAVE_AEAD is required for TLS 1.3&quot;
    #else
        #pragma \
        message(&quot;error: The build option HAVE_AEAD is required for TLS 1.3&quot;)
    #endif
#endif

#ifndef HAVE_HKDF
    #ifndef _MSC_VER
        #error &quot;The build option HAVE_HKDF is required for TLS 1.3&quot;
    #else
        #pragma message(&quot;error: The build option HAVE_HKDF is required for TLS 1.3&quot;)
    #endif
#endif

#ifndef HAVE_TLS_EXTENSIONS
    #ifndef _MSC_VER
        #error &quot;The build option HAVE_TLS_EXTENSIONS is required for TLS 1.3&quot;
    #else
        #pragma message(&quot;error: The build option HAVE_TLS_EXTENSIONS is required for TLS 1.3&quot;)
    #endif
#endif


/* Set ret to error value and jump to label.
 *
 * err     The error value to set.
 * eLabel  The label to jump to.
 */
#define ERROR_OUT(err, eLabel) { ret = (err); goto eLabel; }

/* Size of the TLS v1.3 label use when deriving keys. */
#define TLS13_PROTOCOL_LABEL_SZ    6
/* The protocol label for TLS v1.3. */
static const byte tls13ProtocolLabel[TLS13_PROTOCOL_LABEL_SZ + 1] = &quot;tls13 &quot;;

#ifdef WOLFSSL_DTLS13
#define DTLS13_PROTOCOL_LABEL_SZ    6
static const byte dtls13ProtocolLabel[DTLS13_PROTOCOL_LABEL_SZ + 1] = &quot;dtls13&quot;;
#endif /* WOLFSSL_DTLS13 */

#if defined(HAVE_ECH)
#define ECH_ACCEPT_CONFIRMATION_SZ 8
#define ECH_ACCEPT_CONFIRMATION_LABEL_SZ 23
static const byte
    echAcceptConfirmationLabel[ECH_ACCEPT_CONFIRMATION_LABEL_SZ + 1] =
    &quot;ech accept confirmation&quot;;
#endif

#ifndef NO_CERTS
#if !defined(NO_RSA) || defined(HAVE_ECC) || defined(HAVE_ED25519) || \
    defined(HAVE_ED448) || defined(HAVE_FALCON) || defined(HAVE_DILITHIUM)

static WC_INLINE int GetMsgHash(WOLFSSL* ssl, byte* hash);

#endif
#endif

/* Expand data using HMAC, salt and label and info.
 * TLS v1.3 defines this function. Use callback if available. */
static int Tls13HKDFExpandLabel(WOLFSSL* ssl, byte* okm, word32 okmLen,
                                const byte* prk, word32 prkLen,
                                const byte* protocol, word32 protocolLen,
                                const byte* label, word32 labelLen,
                                const byte* info, word32 infoLen,
                                int digest)
{
    int ret = WC_NO_ERR_TRACE(NOT_COMPILED_IN);

#if defined(HAVE_PK_CALLBACKS)
    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;HKDFExpandLabelCb) {
        ret = ssl-&gt;ctx-&gt;HKDFExpandLabelCb(okm, okmLen, prk, prkLen,
                                          protocol, protocolLen,
                                          label, labelLen,
                                          info, infoLen, digest,
                                          WOLFSSL_CLIENT_END /* ignored */);
    }

    if (ret != WC_NO_ERR_TRACE(NOT_COMPILED_IN))
        return ret;
#endif
    (void)ssl;
    PRIVATE_KEY_UNLOCK();
#if !defined(HAVE_FIPS) || (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(6,0))
    ret = wc_Tls13_HKDF_Expand_Label_ex(okm, okmLen, prk, prkLen,
                                     protocol, protocolLen,
                                     label, labelLen,
                                     info, infoLen, digest,
                                     ssl-&gt;heap, ssl-&gt;devId);
#else
    ret = wc_Tls13_HKDF_Expand_Label(okm, okmLen, prk, prkLen,
                                     protocol, protocolLen,
                                     label, labelLen,
                                     info, infoLen, digest);
#endif
    PRIVATE_KEY_LOCK();
    return ret;
}

/* Same as above, but pass in the side we are expanding for:
 * side: either WOLFSSL_CLIENT_END or WOLFSSL_SERVER_END.
 */
static int Tls13HKDFExpandKeyLabel(WOLFSSL* ssl, byte* okm, word32 okmLen,
                                   const byte* prk, word32 prkLen,
                                   const byte* protocol, word32 protocolLen,
                                   const byte* label, word32 labelLen,
                                   const byte* info, word32 infoLen,
                                   int digest, int side)
{
    int ret;
#if defined(HAVE_PK_CALLBACKS)
    ret = NOT_COMPILED_IN;
    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;HKDFExpandLabelCb) {
        ret = ssl-&gt;ctx-&gt;HKDFExpandLabelCb(okm, okmLen, prk, prkLen,
                                         protocol, protocolLen,
                                         label, labelLen,
                                         info, infoLen,
                                         digest, side);
    }
    if (ret != WC_NO_ERR_TRACE(NOT_COMPILED_IN))
        return ret;
#endif

#if !defined(HAVE_FIPS) || (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(6,0))
    ret = wc_Tls13_HKDF_Expand_Label_ex(okm, okmLen, prk, prkLen,
                                      protocol, protocolLen,
                                      label, labelLen,
                                      info, infoLen, digest,
                                      ssl-&gt;heap, ssl-&gt;devId);

#elif defined(HAVE_FIPS) &amp;&amp; defined(wc_Tls13_HKDF_Expand_Label)
    ret = wc_Tls13_HKDF_Expand_Label_fips(okm, okmLen, prk, prkLen,
                                      protocol, protocolLen,
                                      label, labelLen,
                                      info, infoLen, digest);
#else
    ret = wc_Tls13_HKDF_Expand_Label(okm, okmLen, prk, prkLen,
                                      protocol, protocolLen,
                                      label, labelLen,
                                      info, infoLen, digest);
#endif
    (void)ssl;
    (void)side;
    return ret;
}


/* Derive a key from a message.
 *
 * ssl        The SSL/TLS object.
 * output     The buffer to hold the derived key.
 * outputLen  The length of the derived key.
 * secret     The secret used to derive the key (HMAC secret).
 * label      The label used to distinguish the context.
 * labelLen   The length of the label.
 * msg        The message data to derive key from.
 * msgLen     The length of the message data to derive key from.
 * hashAlgo   The hash algorithm to use in the HMAC.
 * returns 0 on success, otherwise failure.
 */
static int DeriveKeyMsg(WOLFSSL* ssl, byte* output, int outputLen,
                        const byte* secret, const byte* label, word32 labelLen,
                        byte* msg, int msgLen, int hashAlgo)
{
    byte        hash[WC_MAX_DIGEST_SIZE];
    Digest      digest;
    word32      hashSz = 0;
    const byte* protocol;
    word32      protocolLen;
    int         digestAlg = -1;
    int         ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG);

    switch (hashAlgo) {
#ifndef NO_WOLFSSL_SHA256
        case sha256_mac:
            ret = wc_InitSha256_ex(&amp;digest.sha256, ssl-&gt;heap, ssl-&gt;devId);
            if (ret == 0) {
                    ret = wc_Sha256Update(&amp;digest.sha256, msg, (word32)msgLen);
                if (ret == 0)
                    ret = wc_Sha256Final(&amp;digest.sha256, hash);
                wc_Sha256Free(&amp;digest.sha256);
            }
            hashSz = WC_SHA256_DIGEST_SIZE;
            digestAlg = WC_SHA256;
            break;
#endif
#ifdef WOLFSSL_SHA384
        case sha384_mac:
            ret = wc_InitSha384_ex(&amp;digest.sha384, ssl-&gt;heap, ssl-&gt;devId);
            if (ret == 0) {
                ret = wc_Sha384Update(&amp;digest.sha384, msg, (word32)msgLen);
                if (ret == 0)
                    ret = wc_Sha384Final(&amp;digest.sha384, hash);
                wc_Sha384Free(&amp;digest.sha384);
            }
            hashSz = WC_SHA384_DIGEST_SIZE;
            digestAlg = WC_SHA384;
            break;
#endif
#ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            ret = wc_InitSha512_ex(&amp;digest.sha512, ssl-&gt;heap, ssl-&gt;devId);
            if (ret == 0) {
                ret = wc_Sha512Update(&amp;digest.sha512, msg, (word32)msgLen);
                if (ret == 0)
                    ret = wc_Sha512Final(&amp;digest.sha512, hash);
                wc_Sha512Free(&amp;digest.sha512);
            }
            hashSz = WC_SHA512_DIGEST_SIZE;
            digestAlg = WC_SHA512;
            break;
#endif
#ifdef WOLFSSL_SM3
        case sm3_mac:
            ret = wc_InitSm3(&amp;digest.sm3, ssl-&gt;heap, ssl-&gt;devId);
            if (ret == 0) {
                ret = wc_Sm3Update(&amp;digest.sm3, msg, (word32)msgLen);
                if (ret == 0)
                    ret = wc_Sm3Final(&amp;digest.sm3, hash);
                wc_Sm3Free(&amp;digest.sm3);
            }
            hashSz = WC_SM3_DIGEST_SIZE;
            digestAlg = WC_SM3;
            break;
#endif
        default:
            ret = BAD_FUNC_ARG;
            digestAlg = -1;
            break;
    }

    if (digestAlg &lt; 0)
        return HASH_TYPE_E;

    if (ret != 0)
        return ret;

    switch (ssl-&gt;version.minor) {
        case TLSv1_3_MINOR:
            protocol = tls13ProtocolLabel;
            protocolLen = TLS13_PROTOCOL_LABEL_SZ;
            break;
#ifdef WOLFSSL_DTLS13
        case DTLSv1_3_MINOR:
            if (!ssl-&gt;options.dtls)
                return VERSION_ERROR;

            protocol = dtls13ProtocolLabel;
            protocolLen = DTLS13_PROTOCOL_LABEL_SZ;
            break;
#endif /* WOLFSSL_DTLS13 */
        default:
            return VERSION_ERROR;
    }
    if (outputLen == -1)
        outputLen = (int)hashSz;

    ret = Tls13HKDFExpandLabel(ssl, output, (word32)outputLen, secret, hashSz,
                               protocol, protocolLen, label, labelLen,
                               hash, hashSz, digestAlg);
    return ret;
}

/* Derive a key.
 *
 * ssl          The SSL/TLS object.
 * output       The buffer to hold the derived key.
 * outputLen    The length of the derived key.
 * secret       The secret used to derive the key (HMAC secret).
 * label        The label used to distinguish the context.
 * labelLen     The length of the label.
 * hashAlgo     The hash algorithm to use in the HMAC.
 * includeMsgs  Whether to include a hash of the handshake messages so far.
 * side         The side that we are deriving the secret for.
 * returns 0 on success, otherwise failure.
 */
int Tls13DeriveKey(WOLFSSL* ssl, byte* output, int outputLen,
                   const byte* secret, const byte* label, word32 labelLen,
                   int hashAlgo, int includeMsgs, int side)
{
    int         ret = 0;
    byte        hash[WC_MAX_DIGEST_SIZE];
    word32      hashSz = 0;
    word32      hashOutSz = 0;
    const byte* protocol;
    word32      protocolLen;
    int         digestAlg = 0;


    switch (hashAlgo) {
    #ifndef NO_SHA256
        case sha256_mac:
            hashSz    = WC_SHA256_DIGEST_SIZE;
            digestAlg = WC_SHA256;
            if (includeMsgs)
                ret = wc_Sha256GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha256, hash);
            break;
    #endif

    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            hashSz    = WC_SHA384_DIGEST_SIZE;
            digestAlg = WC_SHA384;
            if (includeMsgs)
                ret = wc_Sha384GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha384, hash);
            break;
    #endif

    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            hashSz    = WC_SHA512_DIGEST_SIZE;
            digestAlg = WC_SHA512;
            if (includeMsgs)
                ret = wc_Sha512GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha512, hash);
            break;
    #endif

    #ifdef WOLFSSL_SM3
        case sm3_mac:
            hashSz    = WC_SM3_DIGEST_SIZE;
            digestAlg = WC_SM3;
            if (includeMsgs)
                ret = wc_Sm3GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSm3, hash);
            break;
    #endif

        default:
            ret = HASH_TYPE_E;
            break;
    }
    if (ret != 0)
        return ret;

    protocol = tls13ProtocolLabel;
    protocolLen = TLS13_PROTOCOL_LABEL_SZ;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
         protocol = dtls13ProtocolLabel;
         protocolLen = DTLS13_PROTOCOL_LABEL_SZ;
    }
#endif /* WOLFSSL_DTLS13 */

    if (outputLen == -1) {
        outputLen = (int)hashSz;
    }
    if (includeMsgs) {
        hashOutSz = hashSz;
    }
    else {
        /* Appease static analyzers by making sure hash is cleared, since it is
         * passed into expand key label where older wc_Tls13_HKDF_Expand_Label
         * will unconditionally try to call a memcpy on it, however length will
         * always be 0. */
        XMEMSET(hash, 0, sizeof(hash));
        hashOutSz = 0;
    }

    PRIVATE_KEY_UNLOCK();
    ret = Tls13HKDFExpandKeyLabel(ssl, output, (word32)outputLen, secret, hashSz,
                                  protocol, protocolLen, label, labelLen,
                                  hash, hashOutSz, digestAlg, side);
    PRIVATE_KEY_LOCK();

#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Add(&quot;TLS 1.3 derived key&quot;, output, outputLen);
#endif
    return ret;
}

/* Convert TLS mac ID to a hash algorithm ID
 *
 * mac Mac ID to convert
 * returns hash ID on success, or the NONE type.
 */
static WC_INLINE int mac2hash(int mac)
{
    int hash;
    switch (mac) {
        #ifndef NO_SHA256
        case sha256_mac:
            hash = WC_SHA256;
            break;
        #endif

        #ifdef WOLFSSL_SHA384
        case sha384_mac:
            hash = WC_SHA384;
            break;
        #endif

        #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            hash = WC_SHA512;
            break;
        #endif

        #ifdef WOLFSSL_SM3
        case sm3_mac:
            hash = WC_SM3;
            break;
        #endif

    default:
        hash = WC_HASH_TYPE_NONE;
    }
    return hash;
}

#ifndef NO_PSK
/* The length of the binder key label. */
#define BINDER_KEY_LABEL_SZ         10
/* The binder key label. */
static const byte binderKeyLabel[BINDER_KEY_LABEL_SZ + 1] =
    &quot;ext binder&quot;;

/* Derive the binder key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveBinderKey(WOLFSSL* ssl, byte* key)
{
    WOLFSSL_MSG(&quot;Derive Binder Key&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
    return DeriveKeyMsg(ssl, key, -1, ssl-&gt;arrays-&gt;secret,
                        binderKeyLabel, BINDER_KEY_LABEL_SZ,
                        NULL, 0, ssl-&gt;specs.mac_algorithm);
}
#endif /* !NO_PSK */

#if defined(HAVE_SESSION_TICKET) &amp;&amp; \
    (!defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER))
/* The length of the binder key resume label. */
#define BINDER_KEY_RESUME_LABEL_SZ  10
/* The binder key resume label. */
static const byte binderKeyResumeLabel[BINDER_KEY_RESUME_LABEL_SZ + 1] =
    &quot;res binder&quot;;

/* Derive the binder resumption key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveBinderKeyResume(WOLFSSL* ssl, byte* key)
{
    WOLFSSL_MSG(&quot;Derive Binder Key - Resumption&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
    return DeriveKeyMsg(ssl, key, -1, ssl-&gt;arrays-&gt;secret,
                        binderKeyResumeLabel, BINDER_KEY_RESUME_LABEL_SZ,
                        NULL, 0, ssl-&gt;specs.mac_algorithm);
}
#endif /* HAVE_SESSION_TICKET &amp;&amp; (!NO_WOLFSSL_CLIENT || !NO_WOLFSSL_SERVER) */

#ifdef WOLFSSL_EARLY_DATA

/* The length of the early traffic label. */
#define EARLY_TRAFFIC_LABEL_SZ      11
/* The early traffic label. */
static const byte earlyTrafficLabel[EARLY_TRAFFIC_LABEL_SZ + 1] =
    &quot;c e traffic&quot;;

/* Derive the early traffic key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * side The side that we are deriving the secret for.
 * returns 0 on success, otherwise failure.
 */
static int DeriveEarlyTrafficSecret(WOLFSSL* ssl, byte* key, int side)
{
    int ret;
    WOLFSSL_MSG(&quot;Derive Early Traffic Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_SNIFFER) &amp;&amp; defined(WOLFSSL_SNIFFER_KEYLOGFILE)
    /* If this is called from a sniffer session with keylog file support,
     * obtain the appropriate secret from the callback */
    if (ssl-&gt;snifferSecretCb != NULL) {
        return ssl-&gt;snifferSecretCb(ssl-&gt;arrays-&gt;clientRandom,
                                    SNIFFER_SECRET_CLIENT_EARLY_TRAFFIC_SECRET,
                                    key);
    }
#endif /* WOLFSSL_SNIFFER &amp;&amp; WOLFSSL_SNIFFER_KEYLOGFILE */

    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;secret,
                    earlyTrafficLabel, EARLY_TRAFFIC_LABEL_SZ,
                    ssl-&gt;specs.mac_algorithm, 1, side);
#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, CLIENT_EARLY_TRAFFIC_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, CLIENT_EARLY_TRAFFIC_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

#endif

/* The length of the client handshake label. */
#define CLIENT_HANDSHAKE_LABEL_SZ   12
/* The client handshake label. */
static const byte clientHandshakeLabel[CLIENT_HANDSHAKE_LABEL_SZ + 1] =
    &quot;c hs traffic&quot;;

/* Derive the client handshake key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveClientHandshakeSecret(WOLFSSL* ssl, byte* key)
{
    int ret;
    WOLFSSL_MSG(&quot;Derive Client Handshake Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_SNIFFER) &amp;&amp; defined(WOLFSSL_SNIFFER_KEYLOGFILE)
    /* If this is called from a sniffer session with keylog file support,
     * obtain the appropriate secret from the callback */
    if (ssl-&gt;snifferSecretCb != NULL) {
        return ssl-&gt;snifferSecretCb(ssl-&gt;arrays-&gt;clientRandom,
                               SNIFFER_SECRET_CLIENT_HANDSHAKE_TRAFFIC_SECRET,
                               key);
    }
#endif /* WOLFSSL_SNIFFER &amp;&amp; WOLFSSL_SNIFFER_KEYLOGFILE */

    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;preMasterSecret,
                    clientHandshakeLabel, CLIENT_HANDSHAKE_LABEL_SZ,
                    ssl-&gt;specs.mac_algorithm, 1, WOLFSSL_CLIENT_END);
#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, CLIENT_HANDSHAKE_TRAFFIC_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, CLIENT_HANDSHAKE_TRAFFIC_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

/* The length of the server handshake label. */
#define SERVER_HANDSHAKE_LABEL_SZ   12
/* The server handshake label. */
static const byte serverHandshakeLabel[SERVER_HANDSHAKE_LABEL_SZ + 1] =
    &quot;s hs traffic&quot;;

/* Derive the server handshake key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveServerHandshakeSecret(WOLFSSL* ssl, byte* key)
{
    int ret;
    WOLFSSL_MSG(&quot;Derive Server Handshake Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_SNIFFER) &amp;&amp; defined(WOLFSSL_SNIFFER_KEYLOGFILE)
    /* If this is called from a sniffer session with keylog file support,
     * obtain the appropriate secret from the callback */
    if (ssl-&gt;snifferSecretCb != NULL) {
        return ssl-&gt;snifferSecretCb(ssl-&gt;arrays-&gt;clientRandom,
                                SNIFFER_SECRET_SERVER_HANDSHAKE_TRAFFIC_SECRET,
                                key);
    }
#endif /* WOLFSSL_SNIFFER &amp;&amp; WOLFSSL_SNIFFER_KEYLOGFILE */

    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;preMasterSecret,
                    serverHandshakeLabel, SERVER_HANDSHAKE_LABEL_SZ,
                    ssl-&gt;specs.mac_algorithm, 1, WOLFSSL_SERVER_END);

#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, SERVER_HANDSHAKE_TRAFFIC_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, SERVER_HANDSHAKE_TRAFFIC_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

/* The length of the client application traffic label. */
#define CLIENT_APP_LABEL_SZ         12
/* The client application traffic label. */
static const byte clientAppLabel[CLIENT_APP_LABEL_SZ + 1] =
    &quot;c ap traffic&quot;;

/* Derive the client application traffic key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveClientTrafficSecret(WOLFSSL* ssl, byte* key)
{
    int ret;
    WOLFSSL_MSG(&quot;Derive Client Traffic Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_SNIFFER) &amp;&amp; defined(WOLFSSL_SNIFFER_KEYLOGFILE)
    /* If this is called from a sniffer session with keylog file support,
     * obtain the appropriate secret from the callback */
    if (ssl-&gt;snifferSecretCb != NULL) {
        return ssl-&gt;snifferSecretCb(ssl-&gt;arrays-&gt;clientRandom,
                                    SNIFFER_SECRET_CLIENT_TRAFFIC_SECRET,
                                    key);
    }
#endif /* WOLFSSL_SNIFFER &amp;&amp; WOLFSSL_SNIFFER_KEYLOGFILE */

    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;masterSecret,
                    clientAppLabel, CLIENT_APP_LABEL_SZ,
                    ssl-&gt;specs.mac_algorithm, 1, WOLFSSL_CLIENT_END);

#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, CLIENT_TRAFFIC_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, CLIENT_TRAFFIC_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

/* The length of the server application traffic label. */
#define SERVER_APP_LABEL_SZ         12
/* The  server application traffic label. */
static const byte serverAppLabel[SERVER_APP_LABEL_SZ + 1] =
    &quot;s ap traffic&quot;;

/* Derive the server application traffic key.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveServerTrafficSecret(WOLFSSL* ssl, byte* key)
{
    int ret;
    WOLFSSL_MSG(&quot;Derive Server Traffic Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_SNIFFER) &amp;&amp; defined(WOLFSSL_SNIFFER_KEYLOGFILE)
    /* If this is called from a sniffer session with keylog file support,
     * obtain the appropriate secret from the callback */
    if (ssl-&gt;snifferSecretCb != NULL) {
        return ssl-&gt;snifferSecretCb(ssl-&gt;arrays-&gt;clientRandom,
                                    SNIFFER_SECRET_SERVER_TRAFFIC_SECRET,
                                    key);
    }
#endif /* WOLFSSL_SNIFFER &amp;&amp; WOLFSSL_SNIFFER_KEYLOGFILE */

    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;masterSecret,
                    serverAppLabel, SERVER_APP_LABEL_SZ,
                    ssl-&gt;specs.mac_algorithm, 1, WOLFSSL_SERVER_END);

#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, SERVER_TRAFFIC_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, SERVER_TRAFFIC_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

#ifdef HAVE_KEYING_MATERIAL
/* The length of the exporter master secret label. */
#define EXPORTER_MASTER_LABEL_SZ    10
/* The exporter master secret label. */
static const byte exporterMasterLabel[EXPORTER_MASTER_LABEL_SZ + 1] =
    &quot;exp master&quot;;

/* Derive the exporter secret.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
static int DeriveExporterSecret(WOLFSSL* ssl, byte* key)
{
    int ret;
    WOLFSSL_ENTER(&quot;Derive Exporter Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
    ret = Tls13DeriveKey(ssl, key, -1, ssl-&gt;arrays-&gt;masterSecret,
                        exporterMasterLabel, EXPORTER_MASTER_LABEL_SZ,
                        ssl-&gt;specs.mac_algorithm, 1, 0 /* Unused */);
#ifdef HAVE_SECRET_CALLBACK
    if (ret == 0 &amp;&amp; ssl-&gt;tls13SecretCb != NULL) {
        ret = ssl-&gt;tls13SecretCb(ssl, EXPORTER_SECRET, key,
                                 ssl-&gt;specs.hash_size, ssl-&gt;tls13SecretCtx);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#ifdef OPENSSL_EXTRA
    if (ret == 0 &amp;&amp; ssl-&gt;tls13KeyLogCb != NULL) {
        ret = ssl-&gt;tls13KeyLogCb(ssl, EXPORTER_SECRET, key,
                                ssl-&gt;specs.hash_size, NULL);
        if (ret != 0) {
            WOLFSSL_ERROR_VERBOSE(TLS13_SECRET_CB_E);
            return TLS13_SECRET_CB_E;
        }
    }
#endif /* OPENSSL_EXTRA */
#endif /* HAVE_SECRET_CALLBACK */
    return ret;
}

/* The length of the exporter label. */
#define EXPORTER_LABEL_SZ    8
/* The exporter label. */
static const byte exporterLabel[EXPORTER_LABEL_SZ + 1] =
    &quot;exporter&quot;;
/* Hash(&quot;&quot;) */
#ifndef NO_SHA256
static const byte emptySHA256Hash[] = {
    0xE3, 0xB0, 0xC4, 0x42, 0x98, 0xFC, 0x1C, 0x14, 0x9A, 0xFB, 0xF4, 0xC8,
    0x99, 0x6F, 0xB9, 0x24, 0x27, 0xAE, 0x41, 0xE4, 0x64, 0x9B, 0x93, 0x4C,
    0xA4, 0x95, 0x99, 0x1B, 0x78, 0x52, 0xB8, 0x55
};
#endif
#ifdef WOLFSSL_SHA384
static const byte emptySHA384Hash[] = {
    0x38, 0xB0, 0x60, 0xA7, 0x51, 0xAC, 0x96, 0x38, 0x4C, 0xD9, 0x32, 0x7E,
    0xB1, 0xB1, 0xE3, 0x6A, 0x21, 0xFD, 0xB7, 0x11, 0x14, 0xBE, 0x07, 0x43,
    0x4C, 0x0C, 0xC7, 0xBF, 0x63, 0xF6, 0xE1, 0xDA, 0x27, 0x4E, 0xDE, 0xBF,
    0xE7, 0x6F, 0x65, 0xFB, 0xD5, 0x1A, 0xD2, 0xF1, 0x48, 0x98, 0xB9, 0x5B
};
#endif
#ifdef WOLFSSL_TLS13_SHA512
static const byte emptySHA512Hash[] = {
    0xCF, 0x83, 0xE1, 0x35, 0x7E, 0xEF, 0xB8, 0xBD, 0xF1, 0x54, 0x28, 0x50,
    0xD6, 0x6D, 0x80, 0x07, 0xD6, 0x20, 0xE4, 0x05, 0x0B, 0x57, 0x15, 0xDC,
    0x83, 0xF4, 0xA9, 0x21, 0xD3, 0x6C, 0xE9, 0xCE, 0x47, 0xD0, 0xD1, 0x3C,
    0x5D, 0x85, 0xF2, 0xB0, 0xFF, 0x83, 0x18, 0xD2, 0x87, 0x7E, 0xEC, 0x2F,
    0x63, 0xB9, 0x31, 0xBD, 0x47, 0x41, 0x7A, 0x81, 0xA5, 0x38, 0x32, 0x7A,
    0xF9, 0x27, 0xDA, 0x3E
};
#endif
/**
 * Implement section 7.5 of RFC 8446
 * @return  0 on success
 *         &lt;0 on failure
 */
int Tls13_Exporter(WOLFSSL* ssl, unsigned char *out, size_t outLen,
        const char *label, size_t labelLen,
        const unsigned char *context, size_t contextLen)
{
    int                 ret;
    enum wc_HashType    hashType = WC_HASH_TYPE_NONE;
    word32              hashLen = 0;
    byte                hashOut[WC_MAX_DIGEST_SIZE];
    const byte*         emptyHash = NULL;
    byte                firstExpand[WC_MAX_DIGEST_SIZE];
    const byte*         protocol = tls13ProtocolLabel;
    word32              protocolLen = TLS13_PROTOCOL_LABEL_SZ;

    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;version.minor != DTLSv1_3_MINOR)
        return VERSION_ERROR;

    if (!ssl-&gt;options.dtls &amp;&amp; ssl-&gt;version.minor != TLSv1_3_MINOR)
        return VERSION_ERROR;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        protocol = dtls13ProtocolLabel;
        protocolLen = DTLS13_PROTOCOL_LABEL_SZ;
    }
#endif /* WOLFSSL_DTLS13 */

    switch (ssl-&gt;specs.mac_algorithm) {
        #ifndef NO_SHA256
        case sha256_mac:
            hashType  = WC_HASH_TYPE_SHA256;
            hashLen   = WC_SHA256_DIGEST_SIZE;
            emptyHash = emptySHA256Hash;
            break;
        #endif

        #ifdef WOLFSSL_SHA384
        case sha384_mac:
            hashType  = WC_HASH_TYPE_SHA384;
            hashLen   = WC_SHA384_DIGEST_SIZE;
            emptyHash = emptySHA384Hash;
            break;
        #endif

        #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            hashType  = WC_HASH_TYPE_SHA512;
            hashLen   = WC_SHA512_DIGEST_SIZE;
            emptyHash = emptySHA512Hash;
            break;
        #endif
    }

    /* Derive-Secret(Secret, label, &quot;&quot;) */
    ret = Tls13HKDFExpandLabel(ssl, firstExpand, hashLen,
            ssl-&gt;arrays-&gt;exporterSecret, hashLen,
            protocol, protocolLen, (byte*)label, (word32)labelLen,
            emptyHash, hashLen, hashType);
    if (ret != 0)
        return ret;

    /* Hash(context_value) */
    ret = wc_Hash(hashType, context, (word32)contextLen, hashOut, WC_MAX_DIGEST_SIZE);
    if (ret != 0)
        return ret;

    ret = Tls13HKDFExpandLabel(ssl, out, (word32)outLen, firstExpand, hashLen,
            protocol, protocolLen, exporterLabel, EXPORTER_LABEL_SZ,
            hashOut, hashLen, hashType);

    return ret;
}
#endif

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
/* The length of the resumption master secret label. */
#define RESUME_MASTER_LABEL_SZ      10
/* The resumption master secret label. */
static const byte resumeMasterLabel[RESUME_MASTER_LABEL_SZ + 1] =
    &quot;res master&quot;;

/* Derive the resumption secret.
 *
 * ssl  The SSL/TLS object.
 * key  The derived key.
 * returns 0 on success, otherwise failure.
 */
int DeriveResumptionSecret(WOLFSSL* ssl, byte* key)
{
    byte* masterSecret;

    WOLFSSL_MSG(&quot;Derive Resumption Secret&quot;);
    if (ssl == NULL) {
        return BAD_FUNC_ARG;
    }
    if (ssl-&gt;arrays != NULL) {
        masterSecret = ssl-&gt;arrays-&gt;masterSecret;
    }
    else {
        masterSecret = ssl-&gt;session-&gt;masterSecret;
    }
    return Tls13DeriveKey(ssl, key, -1, masterSecret, resumeMasterLabel,
                     RESUME_MASTER_LABEL_SZ, ssl-&gt;specs.mac_algorithm, 1,
                     0 /* Unused */);
}
#endif

/* Length of the finished label. */
#define FINISHED_LABEL_SZ           8
/* Finished label for generating finished key. */
static const byte finishedLabel[FINISHED_LABEL_SZ+1] = &quot;finished&quot;;
/* Derive the finished secret.
 *
 * ssl     The SSL/TLS object.
 * key     The key to use with the HMAC.
 * secret  The derived secret.
 * side    The side that we are deriving the secret for.
 * returns 0 on success, otherwise failure.
 */
static int DeriveFinishedSecret(WOLFSSL* ssl, byte* key, byte* secret,
                                int side)
{
    WOLFSSL_MSG(&quot;Derive Finished Secret&quot;);
    return Tls13DeriveKey(ssl, secret, -1, key, finishedLabel,
                          FINISHED_LABEL_SZ,  ssl-&gt;specs.mac_algorithm, 0,
                          side);
}

/* The length of the application traffic label. */
#define APP_TRAFFIC_LABEL_SZ        11
/* The application traffic label. */
static const byte appTrafficLabel[APP_TRAFFIC_LABEL_SZ + 1] =
    &quot;traffic upd&quot;;

/* Update the traffic secret.
 *
 * ssl     The SSL/TLS object.
 * secret  The previous secret and derived secret.
 * side    The side that we are deriving the secret for.
 * returns 0 on success, otherwise failure.
 */
static int DeriveTrafficSecret(WOLFSSL* ssl, byte* secret, int side)
{
    WOLFSSL_MSG(&quot;Derive New Application Traffic Secret&quot;);
    return Tls13DeriveKey(ssl, secret, -1, secret,
                     appTrafficLabel, APP_TRAFFIC_LABEL_SZ,
                     ssl-&gt;specs.mac_algorithm, 0, side);
}


static int Tls13_HKDF_Extract(WOLFSSL *ssl, byte* prk, const byte* salt,
                              int saltLen, byte* ikm, int ikmLen, int digest)
{
    int ret;
#ifdef HAVE_PK_CALLBACKS
    void *cb_ctx = ssl-&gt;HkdfExtractCtx;
    CallbackHKDFExtract cb = ssl-&gt;ctx-&gt;HkdfExtractCb;
    if (cb != NULL) {
        ret = cb(prk, salt, (word32)saltLen, ikm, (word32)ikmLen, digest, cb_ctx);
    }
    else
#endif
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    if ((int)ssl-&gt;arrays-&gt;psk_keySz &lt; 0) {
        ret = PSK_KEY_ERROR;
    }
    else
#endif
    {
    #if !defined(HAVE_FIPS) || \
        (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(6,0))
        ret = wc_Tls13_HKDF_Extract_ex(prk, salt, (word32)saltLen, ikm, (word32)ikmLen, digest,
            ssl-&gt;heap, ssl-&gt;devId);
    #else
        ret = wc_Tls13_HKDF_Extract(prk, salt, saltLen, ikm, ikmLen, digest);
        (void)ssl;
    #endif
    }
    return ret;
}

/* Derive the early secret using HKDF Extract.
 *
 * ssl  The SSL/TLS object.
 */
int DeriveEarlySecret(WOLFSSL* ssl)
{
    int ret;

    WOLFSSL_MSG(&quot;Derive Early Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13DeriveEarlySecret(ssl);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
        return ret;
#endif
    PRIVATE_KEY_UNLOCK();
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ret = Tls13_HKDF_Extract(ssl, ssl-&gt;arrays-&gt;secret, NULL, 0,
            ssl-&gt;arrays-&gt;psk_key, (int)ssl-&gt;arrays-&gt;psk_keySz,
            mac2hash(ssl-&gt;specs.mac_algorithm));
#else
    ret = Tls13_HKDF_Extract(ssl, ssl-&gt;arrays-&gt;secret, NULL, 0,
            ssl-&gt;arrays-&gt;masterSecret, 0, mac2hash(ssl-&gt;specs.mac_algorithm));
#endif
    PRIVATE_KEY_LOCK();
    return ret;
}

/* The length of the derived label. */
#define DERIVED_LABEL_SZ        7
/* The derived label. */
static const byte derivedLabel[DERIVED_LABEL_SZ + 1] =
    &quot;derived&quot;;

/* Derive the handshake secret using HKDF Extract.
 *
 * ssl  The SSL/TLS object.
 */
int DeriveHandshakeSecret(WOLFSSL* ssl)
{
    byte key[WC_MAX_DIGEST_SIZE];
    int ret;
    WOLFSSL_MSG(&quot;Derive Handshake Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13DeriveHandshakeSecret(ssl);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
        return ret;
#endif

    ret = DeriveKeyMsg(ssl, key, -1, ssl-&gt;arrays-&gt;secret,
                        derivedLabel, DERIVED_LABEL_SZ,
                        NULL, 0, ssl-&gt;specs.mac_algorithm);
    if (ret != 0)
        return ret;

    PRIVATE_KEY_UNLOCK();
    ret = Tls13_HKDF_Extract(ssl, ssl-&gt;arrays-&gt;preMasterSecret,
            key, ssl-&gt;specs.hash_size,
            ssl-&gt;arrays-&gt;preMasterSecret, (int)ssl-&gt;arrays-&gt;preMasterSz,
            mac2hash(ssl-&gt;specs.mac_algorithm));
    PRIVATE_KEY_LOCK();

    return ret;
}

/* Derive the master secret using HKDF Extract.
 *
 * ssl  The SSL/TLS object.
 */
int DeriveMasterSecret(WOLFSSL* ssl)
{
    byte key[WC_MAX_DIGEST_SIZE];
    int ret;
    WOLFSSL_MSG(&quot;Derive Master Secret&quot;);
    if (ssl == NULL || ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13DeriveMasterSecret(ssl);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
        return ret;
#endif

    ret = DeriveKeyMsg(ssl, key, -1, ssl-&gt;arrays-&gt;preMasterSecret,
                        derivedLabel, DERIVED_LABEL_SZ,
                        NULL, 0, ssl-&gt;specs.mac_algorithm);
    if (ret != 0)
        return ret;

    PRIVATE_KEY_UNLOCK();
    ret = Tls13_HKDF_Extract(ssl, ssl-&gt;arrays-&gt;masterSecret,
            key, ssl-&gt;specs.hash_size,
            ssl-&gt;arrays-&gt;masterSecret, 0, mac2hash(ssl-&gt;specs.mac_algorithm));
    PRIVATE_KEY_LOCK();

#ifdef HAVE_KEYING_MATERIAL
    if (ret != 0)
        return ret;
    /* Calculate exporter secret only when saving arrays */
    if (ssl-&gt;options.saveArrays)
        ret = DeriveExporterSecret(ssl, ssl-&gt;arrays-&gt;exporterSecret);
#endif

    return ret;
}

#if defined(HAVE_SESSION_TICKET)
/* Length of the resumption label. */
#define RESUMPTION_LABEL_SZ         10
/* Resumption label for generating PSK associated with the ticket. */
static const byte resumptionLabel[RESUMPTION_LABEL_SZ+1] = &quot;resumption&quot;;

/* Derive the PSK associated with the ticket.
 *
 * ssl       The SSL/TLS object.
 * nonce     The nonce to derive with.
 * nonceLen  The length of the nonce to derive with.
 * secret    The derived secret.
 * returns 0 on success, otherwise failure.
 */
int DeriveResumptionPSK(WOLFSSL* ssl, byte* nonce, byte nonceLen, byte* secret)
{
    int         digestAlg;
    /* Only one protocol version defined at this time. */
    const byte* protocol    = tls13ProtocolLabel;
    word32      protocolLen = TLS13_PROTOCOL_LABEL_SZ;
    int         ret;

    WOLFSSL_MSG(&quot;Derive Resumption PSK&quot;);

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        protocol = dtls13ProtocolLabel;
        protocolLen = DTLS13_PROTOCOL_LABEL_SZ;
    }
#endif /* WOLFSSL_DTLS13 */

    switch (ssl-&gt;specs.mac_algorithm) {
        #ifndef NO_SHA256
        case sha256_mac:
            digestAlg = WC_SHA256;
            break;
        #endif

        #ifdef WOLFSSL_SHA384
        case sha384_mac:
            digestAlg = WC_SHA384;
            break;
        #endif

        #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            digestAlg = WC_SHA512;
            break;
        #endif

        #ifdef WOLFSSL_SM3
        case sm3_mac:
            digestAlg = WC_SM3;
            break;
        #endif

        default:
            return BAD_FUNC_ARG;
    }

#if defined(WOLFSSL_TICKET_NONCE_MALLOC) &amp;&amp;                                    \
    (!defined(HAVE_FIPS) || (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(5,3)))
    PRIVATE_KEY_UNLOCK();
    ret = wc_Tls13_HKDF_Expand_Label_Alloc(secret, ssl-&gt;specs.hash_size,
        ssl-&gt;session-&gt;masterSecret, ssl-&gt;specs.hash_size, protocol, protocolLen,
        resumptionLabel, RESUMPTION_LABEL_SZ, nonce, nonceLen, digestAlg,
        ssl-&gt;heap);
    PRIVATE_KEY_LOCK();
#else
    ret = Tls13HKDFExpandLabel(ssl, secret, ssl-&gt;specs.hash_size,
                               ssl-&gt;session-&gt;masterSecret, ssl-&gt;specs.hash_size,
                               protocol, protocolLen, resumptionLabel,
                               RESUMPTION_LABEL_SZ, nonce, nonceLen, digestAlg);
#endif /* !defined(HAVE_FIPS) || FIPS_VERSION_GE(5,3) */
    return ret;
}
#endif /* HAVE_SESSION_TICKET */


/* Calculate the HMAC of message data to this point.
 *
 * ssl   The SSL/TLS object.
 * key   The HMAC key.
 * hash  The hash result - verify data.
 * returns length of verify data generated.
 */
static int BuildTls13HandshakeHmac(WOLFSSL* ssl, byte* key, byte* hash,
    word32* pHashSz)
{
#ifdef WOLFSSL_SMALL_STACK
    Hmac* verifyHmac;
#else
    Hmac  verifyHmac[1];
#endif
    int  hashType = WC_SHA256;
    int  hashSz = WC_SHA256_DIGEST_SIZE;
    int  ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG);

    if (ssl == NULL || key == NULL || hash == NULL) {
        return BAD_FUNC_ARG;
    }

    /* Get the hash of the previous handshake messages. */
    switch (ssl-&gt;specs.mac_algorithm) {
    #ifndef NO_SHA256
        case sha256_mac:
            hashType = WC_SHA256;
            hashSz = WC_SHA256_DIGEST_SIZE;
            ret = wc_Sha256GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha256, hash);
            break;
    #endif /* !NO_SHA256 */
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            hashType = WC_SHA384;
            hashSz = WC_SHA384_DIGEST_SIZE;
            ret = wc_Sha384GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha384, hash);
            break;
    #endif /* WOLFSSL_SHA384 */
    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            hashType = WC_SHA512;
            hashSz = WC_SHA512_DIGEST_SIZE;
            ret = wc_Sha512GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha512, hash);
            break;
    #endif /* WOLFSSL_TLS13_SHA512 */
    #ifdef WOLFSSL_SM3
        case sm3_mac:
            hashType = WC_SM3;
            hashSz = WC_SM3_DIGEST_SIZE;
            ret = wc_Sm3GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSm3, hash);
            break;
    #endif /* WOLFSSL_SM3 */
        default:
            ret = BAD_FUNC_ARG;
            break;
    }
    if (ret != 0)
        return ret;

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;  Key&quot;);
    WOLFSSL_BUFFER(key, ssl-&gt;specs.hash_size);
    WOLFSSL_MSG(&quot;  Msg Hash&quot;);
    WOLFSSL_BUFFER(hash, hashSz);
#endif

#ifdef WOLFSSL_SMALL_STACK
    verifyHmac = (Hmac*)XMALLOC(sizeof(Hmac), NULL, DYNAMIC_TYPE_HMAC);
    if (verifyHmac == NULL) {
        return MEMORY_E;
    }
#endif

    /* Calculate the verify data. */
    ret = wc_HmacInit(verifyHmac, ssl-&gt;heap, ssl-&gt;devId);
    if (ret == 0) {
        ret = wc_HmacSetKey(verifyHmac, hashType, key, ssl-&gt;specs.hash_size);
        if (ret == 0)
            ret = wc_HmacUpdate(verifyHmac, hash, (word32)hashSz);
        if (ret == 0)
            ret = wc_HmacFinal(verifyHmac, hash);
        wc_HmacFree(verifyHmac);
    }

#ifdef WOLFSSL_SMALL_STACK
    XFREE(verifyHmac, NULL, DYNAMIC_TYPE_HMAC);
#endif

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;  Hash&quot;);
    WOLFSSL_BUFFER(hash, hashSz);
#endif

    if (pHashSz)
        *pHashSz = (word32)hashSz;

    return ret;
}

/* The length of the label to use when deriving keys. */
#define WRITE_KEY_LABEL_SZ     3
/* The length of the label to use when deriving IVs. */
#define WRITE_IV_LABEL_SZ      2
/* The label to use when deriving keys. */
static const byte writeKeyLabel[WRITE_KEY_LABEL_SZ+1] = &quot;key&quot;;
/* The label to use when deriving IVs. */
static const byte writeIVLabel[WRITE_IV_LABEL_SZ+1]   = &quot;iv&quot;;

/* Derive the keys and IVs for TLS v1.3.
 *
 * ssl      The SSL/TLS object.
 * secret   early_data_key when deriving the key and IV for encrypting early
 *          data application data and end_of_early_data messages.
 *          handshake_key when deriving keys and IVs for encrypting handshake
 *          messages.
 *          traffic_key when deriving first keys and IVs for encrypting
 *          traffic messages.
 *          update_traffic_key when deriving next keys and IVs for encrypting
 *          traffic messages.
 * side     ENCRYPT_SIDE_ONLY when only encryption secret needs to be derived.
 *          DECRYPT_SIDE_ONLY when only decryption secret needs to be derived.
 *          ENCRYPT_AND_DECRYPT_SIDE when both secret needs to be derived.
 * store    1 indicates to derive the keys and IVs from derived secret and
 *          store ready for provisioning.
 * returns 0 on success, otherwise failure.
 */
int DeriveTls13Keys(WOLFSSL* ssl, int secret, int side, int store)
{
    int   ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG); /* Assume failure */
    int   i = 0;
#ifdef WOLFSSL_SMALL_STACK
    byte* key_dig;
#else
    byte  key_dig[MAX_PRF_DIG];
#endif
    int   provision;

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13DeriveKeys(ssl, secret, side);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        return ret;
    }
    ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG); /* Assume failure */
#endif

#ifdef WOLFSSL_SMALL_STACK
    key_dig = (byte*)XMALLOC(MAX_PRF_DIG, ssl-&gt;heap, DYNAMIC_TYPE_DIGEST);
    if (key_dig == NULL)
        return MEMORY_E;
#endif

    if (side == ENCRYPT_AND_DECRYPT_SIDE) {
        provision = PROVISION_CLIENT_SERVER;
    }
    else {
        provision = ((ssl-&gt;options.side != WOLFSSL_CLIENT_END) ^
                     (side == ENCRYPT_SIDE_ONLY)) ? PROVISION_CLIENT :
                                                    PROVISION_SERVER;
    }

    /* Derive the appropriate secret to use in the HKDF. */
    switch (secret) {
#ifdef WOLFSSL_EARLY_DATA
        case early_data_key:
            ret = DeriveEarlyTrafficSecret(ssl, ssl-&gt;clientSecret,
                                           WOLFSSL_CLIENT_END);
            if (ret != 0)
                goto end;
            break;
#endif

        case handshake_key:
            if (provision &amp; PROVISION_CLIENT) {
                ret = DeriveClientHandshakeSecret(ssl,
                                                  ssl-&gt;clientSecret);
                if (ret != 0)
                    goto end;
            }
            if (provision &amp; PROVISION_SERVER) {
                ret = DeriveServerHandshakeSecret(ssl,
                                                  ssl-&gt;serverSecret);
                if (ret != 0)
                    goto end;
            }
            break;

        case traffic_key:
            if (provision &amp; PROVISION_CLIENT) {
                ret = DeriveClientTrafficSecret(ssl, ssl-&gt;clientSecret);
                if (ret != 0)
                    goto end;
            }
            if (provision &amp; PROVISION_SERVER) {
                ret = DeriveServerTrafficSecret(ssl, ssl-&gt;serverSecret);
                if (ret != 0)
                    goto end;
            }
            break;

        case update_traffic_key:
            if (provision &amp; PROVISION_CLIENT) {
                ret = DeriveTrafficSecret(ssl, ssl-&gt;clientSecret,
                                          WOLFSSL_CLIENT_END);
                if (ret != 0)
                    goto end;
            }
            if (provision &amp; PROVISION_SERVER) {
                ret = DeriveTrafficSecret(ssl, ssl-&gt;serverSecret,
                                          WOLFSSL_SERVER_END);
                if (ret != 0)
                    goto end;
            }
            break;

        default:
            ret = BAD_FUNC_ARG;
            break;
    }

#ifdef WOLFSSL_QUIC
    if (WOLFSSL_IS_QUIC(ssl)) {
        ret = wolfSSL_quic_forward_secrets(ssl, secret, side);
        if (ret != 0)
            goto end;
    }
#endif /* WOLFSSL_QUIC */

    if (!store)
        goto end;

    /* Key data = client key | server key | client IV | server IV */

    if (provision &amp; PROVISION_CLIENT) {
        /* Derive the client key.  */
        WOLFSSL_MSG(&quot;Derive Client Key&quot;);
        ret = Tls13DeriveKey(ssl, &amp;key_dig[i], ssl-&gt;specs.key_size,
                        ssl-&gt;clientSecret, writeKeyLabel,
                        WRITE_KEY_LABEL_SZ, ssl-&gt;specs.mac_algorithm, 0,
                        WOLFSSL_CLIENT_END);
        if (ret != 0)
            goto end;
        i += ssl-&gt;specs.key_size;
    }

    if (provision &amp; PROVISION_SERVER) {
        /* Derive the server key.  */
        WOLFSSL_MSG(&quot;Derive Server Key&quot;);
        ret = Tls13DeriveKey(ssl, &amp;key_dig[i], ssl-&gt;specs.key_size,
                        ssl-&gt;serverSecret, writeKeyLabel,
                        WRITE_KEY_LABEL_SZ, ssl-&gt;specs.mac_algorithm, 0,
                        WOLFSSL_SERVER_END);
        if (ret != 0)
            goto end;
        i += ssl-&gt;specs.key_size;
    }

    if (provision &amp; PROVISION_CLIENT) {
        /* Derive the client IV.  */
        WOLFSSL_MSG(&quot;Derive Client IV&quot;);
        ret = Tls13DeriveKey(ssl, &amp;key_dig[i], ssl-&gt;specs.iv_size,
                        ssl-&gt;clientSecret, writeIVLabel,
                        WRITE_IV_LABEL_SZ, ssl-&gt;specs.mac_algorithm, 0,
                        WOLFSSL_CLIENT_END);
        if (ret != 0)
            goto end;
        i += ssl-&gt;specs.iv_size;
    }

    if (provision &amp; PROVISION_SERVER) {
        /* Derive the server IV.  */
        WOLFSSL_MSG(&quot;Derive Server IV&quot;);
        ret = Tls13DeriveKey(ssl, &amp;key_dig[i], ssl-&gt;specs.iv_size,
                        ssl-&gt;serverSecret, writeIVLabel,
                        WRITE_IV_LABEL_SZ, ssl-&gt;specs.mac_algorithm, 0,
                        WOLFSSL_SERVER_END);
        if (ret != 0)
            goto end;
        i += ssl-&gt;specs.iv_size;
    }

    /* Store keys and IVs but don&#039;t activate them. */
    ret = StoreKeys(ssl, key_dig, provision);

#ifdef WOLFSSL_DTLS13
    if (ret != 0)
      goto end;

    if (ssl-&gt;options.dtls) {
        ret = Dtls13DeriveSnKeys(ssl, provision);
        if (ret != 0)
            return ret;
    }

#endif /* WOLFSSL_DTLS13 */

end:
    ForceZero(key_dig, (word32)i);
#ifdef WOLFSSL_SMALL_STACK
    XFREE(key_dig, ssl-&gt;heap, DYNAMIC_TYPE_DIGEST);
#elif defined(WOLFSSL_CHECK_MEM_ZERO)
    wc_MemZero_Check(key_dig, MAX_PRF_DIG);
#endif

    if (ret != 0) {
        WOLFSSL_ERROR_VERBOSE(ret);
    }

    return ret;
}

#if (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK))
#ifdef WOLFSSL_32BIT_MILLI_TIME
#ifndef NO_ASN_TIME
#if defined(USER_TICKS)
#if 0
    word32 TimeNowInMilliseconds(void)
    {
        /*
        write your own clock tick function if don&#039;t want gettimeofday()
        needs millisecond accuracy but doesn&#039;t have to correlated to EPOCH
        */
    }
#endif

#elif defined(TIME_OVERRIDES)
#if !defined(NO_ASN) &amp;&amp; !defined(NO_ASN_TIME)
    word32 TimeNowInMilliseconds(void)
    {
        return (word32) wc_Time(0) * 1000;
    }
#else
    #ifndef HAVE_TIME_T_TYPE
        typedef long time_t;
    #endif
    extern time_t XTIME(time_t * timer);

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32) XTIME(0) * 1000;
    }
#endif

#elif defined(XTIME_MS)
    word32 TimeNowInMilliseconds(void)
    {
        return (word32)XTIME_MS(0);
    }

#elif defined(USE_WINDOWS_API)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        static int           init = 0;
        static LARGE_INTEGER freq;
        LARGE_INTEGER        count;

        if (!init) {
            QueryPerformanceFrequency(&amp;freq);
            init = 1;
        }

        QueryPerformanceCounter(&amp;count);

        return (word32)(count.QuadPart / (freq.QuadPart / 1000));
    }

#elif defined(HAVE_RTP_SYS)
    #include &quot;rtptime.h&quot;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32)rtp_get_system_sec() * 1000;
    }
#elif defined(WOLFSSL_DEOS)
    word32 TimeNowInMilliseconds(void)
    {
        const word32 systemTickTimeInHz = 1000000 / systemTickInMicroseconds();
        word32 *systemTickPtr = systemTickPointer();

        return (word32) (*systemTickPtr/systemTickTimeInHz) * 1000;
    }
#elif defined(MICRIUM)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        OS_TICK ticks = 0;
        OS_ERR  err;

        ticks = OSTimeGet(&amp;err);

        return (word32) (ticks / OSCfg_TickRate_Hz) * 1000;
    }
#elif defined(MICROCHIP_TCPIP_V5)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32) (TickGet() / (TICKS_PER_SECOND / 1000));
    }
#elif defined(MICROCHIP_TCPIP)
    #if defined(MICROCHIP_MPLAB_HARMONY)
        #include &lt;system/tmr/sys_tmr.h&gt;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32)(SYS_TMR_TickCountGet() /
                        (SYS_TMR_TickCounterFrequencyGet() / 1000));
    }
    #else
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32)(SYS_TICK_Get() / (SYS_TICK_TicksPerSecondGet() / 1000));
    }

    #endif

#elif defined(FREESCALE_MQX) || defined(FREESCALE_KSDK_MQX)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        TIME_STRUCT mqxTime;

        _time_get_elapsed(&amp;mqxTime);

        return (word32) mqxTime.SECONDS * 1000;
    }
#elif defined(FREESCALE_FREE_RTOS) || defined(FREESCALE_KSDK_FREERTOS)
    #include &quot;include/task.h&quot;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (unsigned int)(((float)xTaskGetTickCount()) /
                              (configTICK_RATE_HZ / 1000));
    }
#elif defined(FREESCALE_KSDK_BM)
    #include &quot;lwip/sys.h&quot; /* lwIP */

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return sys_now();
    }

#elif defined(WOLFSSL_CMSIS_RTOS) || defined(WOLFSSL_CMSIS_RTOSv2)

    word32 TimeNowInMilliseconds(void)
    {
        return (word32)osKernelGetTickCount();
    }

#elif defined(WOLFSSL_TIRTOS)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32) Seconds_get() * 1000;
    }
#elif defined(WOLFSSL_UTASKER)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        return (word32)(uTaskerSystemTick / (TICK_RESOLUTION / 1000));
    }
#elif defined(WOLFSSL_LINUXKM)
    word32 TimeNowInMilliseconds(void)
    {
        s64 t;
#if LINUX_VERSION_CODE &lt; KERNEL_VERSION(4, 0, 0)
        struct timespec ts;
        getnstimeofday(&amp;ts);
        t = ts.tv_sec * (s64)1000;
        t += ts.tv_nsec / (s64)1000000;
#else
        struct timespec64 ts;
#if LINUX_VERSION_CODE &lt; KERNEL_VERSION(5, 0, 0)
        ts = current_kernel_time64();
#else
        ktime_get_coarse_real_ts64(&amp;ts);
#endif
        t = ts.tv_sec * 1000L;
        t += ts.tv_nsec / 1000000L;
#endif
        return (word32)t;
    }
#elif defined(WOLFSSL_QNX_CAAM)
    word32 TimeNowInMilliseconds(void)
    {
        struct timespec now;
        clock_gettime(CLOCK_REALTIME, &amp;now);
        return (word32)(now.tv_sec * 1000 + now.tv_nsec / 1000000);
    }
#elif defined(FUSION_RTOS)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        struct timeval now;
        if (FCL_GETTIMEOFDAY(&amp;now, 0) &lt; 0)
            return 0;

        /* Convert to milliseconds number. */
        return (word32)(now.tv_sec * 1000 + now.tv_usec / 1000);
    }
#elif defined(WOLFSSL_ZEPHYR)
    word32 TimeNowInMilliseconds(void)
    {
        int64_t t;
    #if defined(CONFIG_ARCH_POSIX)
        k_cpu_idle();
    #endif
        t = k_uptime_get(); /* returns current uptime in milliseconds */
        return (word32)t;
    }

#else
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    word32 TimeNowInMilliseconds(void)
    {
        struct timeval now;

        if (gettimeofday(&amp;now, 0) &lt; 0)
            return 0;

        /* Convert to milliseconds number. */
        return (word32)(now.tv_sec * 1000 + now.tv_usec / 1000);
    }
#endif
#else
    /* user must supply time in milliseconds function:
     *   word32 TimeNowInMilliseconds(void);
     * The response is milliseconds elapsed
     */
#endif /* !NO_ASN_TIME */
#else
#ifndef NO_ASN_TIME
#if defined(USER_TICKS)
#if 0
    sword64 TimeNowInMilliseconds(void)
    {
        /*
        write your own clock tick function if don&#039;t want gettimeofday()
        needs millisecond accuracy but doesn&#039;t have to correlated to EPOCH
        */
    }
#endif

#elif defined(TIME_OVERRIDES)
#if !defined(NO_ASN) &amp;&amp; !defined(NO_ASN_TIME)
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64) wc_Time(0) * 1000;
    }
#else
    #ifndef HAVE_TIME_T_TYPE
        typedef long time_t;
    #endif
    extern time_t XTIME(time_t * timer);

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 32-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64) XTIME(0) * 1000;
    }
#endif

#elif defined(XTIME_MS)
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)XTIME_MS(0);
    }

#elif defined(USE_WINDOWS_API)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        static int           init = 0;
        static LARGE_INTEGER freq;
        LARGE_INTEGER        count;

        if (!init) {
            QueryPerformanceFrequency(&amp;freq);
            init = 1;
        }

        QueryPerformanceCounter(&amp;count);

        return (sword64)(count.QuadPart / (freq.QuadPart / 1000));
    }

#elif defined(HAVE_RTP_SYS)
    #include &quot;rtptime.h&quot;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)rtp_get_system_sec() * 1000;
    }
#elif defined(WOLFSSL_DEOS)
    sword64 TimeNowInMilliseconds(void)
    {
        const word32 systemTickTimeInHz = 1000000 / systemTickInMicroseconds();
        word32 *systemTickPtr = systemTickPointer();

        return (sword64) (*systemTickPtr/systemTickTimeInHz) * 1000;
    }
#elif defined(MICRIUM)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        OS_TICK ticks = 0;
        OS_ERR  err;

        ticks = OSTimeGet(&amp;err);

        return (sword64) (ticks / OSCfg_TickRate_Hz) * 1000;
    }
#elif defined(MICROCHIP_TCPIP_V5)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64) (TickGet() / (TICKS_PER_SECOND / 1000));
    }
#elif defined(MICROCHIP_TCPIP)
    #if defined(MICROCHIP_MPLAB_HARMONY)
        #include &lt;system/tmr/sys_tmr.h&gt;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)SYS_TMR_TickCountGet() /
                        (SYS_TMR_TickCounterFrequencyGet() / 1000);
    }
    #else
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)SYS_TICK_Get() / (SYS_TICK_TicksPerSecondGet() / 1000);
    }

    #endif

#elif defined(FREESCALE_MQX) || defined(FREESCALE_KSDK_MQX)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        TIME_STRUCT mqxTime;

        _time_get_elapsed(&amp;mqxTime);

        return (sword64) mqxTime.SECONDS * 1000;
    }
#elif defined(FREESCALE_FREE_RTOS) || defined(FREESCALE_KSDK_FREERTOS)
    #include &quot;include/task.h&quot;

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)xTaskGetTickCount() / (configTICK_RATE_HZ / 1000);
    }
#elif defined(FREESCALE_KSDK_BM)
    #include &quot;lwip/sys.h&quot; /* lwIP */

    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return sys_now();
    }

#elif defined(WOLFSSL_CMSIS_RTOS) || defined(WOLFSSL_CMSIS_RTOSv2)

    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)osKernelGetTickCount();
    }

#elif defined(WOLFSSL_TIRTOS)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64) Seconds_get() * 1000;
    }
#elif defined(WOLFSSL_UTASKER)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        return (sword64)(uTaskerSystemTick / (TICK_RESOLUTION / 1000));
    }
#elif defined(WOLFSSL_LINUXKM)
    sword64 TimeNowInMilliseconds(void)
    {
        s64 t;
#if LINUX_VERSION_CODE &lt; KERNEL_VERSION(4, 0, 0)
        struct timespec ts;
        getnstimeofday(&amp;ts);
        t = ts.tv_sec * (s64)1000;
        t += ts.tv_nsec / (s64)1000000;
#else
        struct timespec64 ts;
#if LINUX_VERSION_CODE &lt; KERNEL_VERSION(5, 0, 0)
        ts = current_kernel_time64();
#else
        ktime_get_coarse_real_ts64(&amp;ts);
#endif
        t = ts.tv_sec * 1000L;
        t += ts.tv_nsec / 1000000L;
#endif
        return (sword64)t;
    }
#elif defined(WOLFSSL_QNX_CAAM)
    sword64 TimeNowInMilliseconds(void)
    {
        struct timespec now;
        clock_gettime(CLOCK_REALTIME, &amp;now);
        return (sword64)(now.tv_sec * 1000 + now.tv_nsec / 1000000);
    }
#elif defined(FUSION_RTOS)
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        struct timeval now;
        if (FCL_GETTIMEOFDAY(&amp;now, 0) &lt; 0)
            return 0;

        /* Convert to milliseconds number. */
        return (sword64)now.tv_sec * 1000 + now.tv_usec / 1000;
    }
#elif defined(WOLFSSL_ZEPHYR)
    sword64 TimeNowInMilliseconds(void)
    {
        int64_t t;
    #if defined(CONFIG_ARCH_POSIX)
        k_cpu_idle();
    #endif
        t = k_uptime_get(); /* returns current uptime in milliseconds */
        return (sword64)t;
    }

#else
    /* The time in milliseconds.
     * Used for tickets to represent difference between when first seen and when
     * sending.
     *
     * returns the time in milliseconds as a 64-bit value.
     */
    sword64 TimeNowInMilliseconds(void)
    {
        struct timeval now;

        if (gettimeofday(&amp;now, 0) &lt; 0)
            return 0;

        /* Convert to milliseconds number. */
        return (sword64)now.tv_sec * 1000 + now.tv_usec / 1000;
    }
#endif
#else
    /* user must supply time in milliseconds function:
     *   sword64 TimeNowInMilliseconds(void);
     * The response is milliseconds elapsed
     */
#endif /* !NO_ASN_TIME */
#endif /* WOLFSSL_32BIT_MILLI_TIME */
#endif /* HAVE_SESSION_TICKET || !NO_PSK */


/* Extract the handshake header information.
 *
 * ssl       The SSL/TLS object.
 * input     The buffer holding the message data.
 * inOutIdx  On entry, the index into the buffer of the handshake data.
 *           On exit, the start of the handshake data.
 * type      Type of handshake message.
 * size      The length of the handshake message data.
 * totalSz   The total size of data in the buffer.
 * returns BUFFER_E if there is not enough input data and 0 on success.
 */
static int GetHandshakeHeader(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                              byte* type, word32* size, word32 totalSz)
{
    const byte* ptr = input + *inOutIdx;
    (void)ssl;

    *inOutIdx += HANDSHAKE_HEADER_SZ;
    if (*inOutIdx &gt; totalSz)
        return BUFFER_E;

    *type = ptr[0];
    c24to32(&amp;ptr[1], size);

    return 0;
}

/* Add record layer header to message.
 *
 * output  The buffer to write the record layer header into.
 * length  The length of the record data.
 * type    The type of record message.
 * ssl     The SSL/TLS object.
 */
static void AddTls13RecordHeader(byte* output, word32 length, byte type,
                                 WOLFSSL* ssl)
{
    RecordLayerHeader* rl;

    rl = (RecordLayerHeader*)output;
    rl-&gt;type    = type;
    rl-&gt;pvMajor = ssl-&gt;version.major;
    /* NOTE: May be TLSv1_MINOR when sending first ClientHello. */
    rl-&gt;pvMinor = TLSv1_2_MINOR;
    c16toa((word16)length, rl-&gt;length);
}

/* Add handshake header to message.
 *
 * output      The buffer to write the handshake header into.
 * length      The length of the handshake data.
 * fragOffset  The offset of the fragment data. (DTLS)
 * fragLength  The length of the fragment data. (DTLS)
 * type        The type of handshake message.
 * ssl         The SSL/TLS object. (DTLS)
 */
static void AddTls13HandShakeHeader(byte* output, word32 length,
                                    word32 fragOffset, word32 fragLength,
                                    byte type, WOLFSSL* ssl)
{
    HandShakeHeader* hs;
    (void)fragOffset;
    (void)fragLength;
    (void)ssl;

#ifdef WOLFSSL_DTLS13
    /* message_hash type is used for a synthetic message that replaces the first
       ClientHello in the hash transcript when using HelloRetryRequest. It will
       never be transmitted and, as the DTLS-only fields must not be considered
       when computing the hash transcript, we can avoid to use the DTLS
       handshake header. */
    if (ssl-&gt;options.dtls &amp;&amp; type != message_hash) {
        Dtls13HandshakeAddHeader(ssl, output, (enum HandShakeType)type, length);
        return;
    }
#endif /* WOLFSSL_DTLS13 */

    /* handshake header */
    hs = (HandShakeHeader*)output;
    hs-&gt;type = type;
    c32to24(length, hs-&gt;length);
}


/* Add both record layer and handshake header to message.
 *
 * output      The buffer to write the headers into.
 * length      The length of the handshake data.
 * type        The type of record layer message.
 * ssl         The SSL/TLS object. (DTLS)
 */
static void AddTls13Headers(byte* output, word32 length, byte type,
                            WOLFSSL* ssl)
{
    word32 lengthAdj = HANDSHAKE_HEADER_SZ;
    word32 outputAdj = RECORD_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        Dtls13AddHeaders(output, length, (enum HandShakeType)type, ssl);
        return;
    }
#endif /* WOLFSSL_DTLS13 */

    AddTls13RecordHeader(output, length + lengthAdj, handshake, ssl);
    AddTls13HandShakeHeader(output + outputAdj, length, 0, length, type, ssl);
}

#if (!defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER)) \
    &amp;&amp; !defined(NO_CERTS)
/* Add both record layer and fragment handshake header to message.
 *
 * output      The buffer to write the headers into.
 * fragOffset  The offset of the fragment data. (DTLS)
 * fragLength  The length of the fragment data. (DTLS)
 * length      The length of the handshake data.
 * type        The type of record layer message.
 * ssl         The SSL/TLS object. (DTLS)
 */
static void AddTls13FragHeaders(byte* output, word32 fragSz, word32 fragOffset,
                                word32 length, byte type, WOLFSSL* ssl)
{
    word32 lengthAdj = HANDSHAKE_HEADER_SZ;
    word32 outputAdj = RECORD_HEADER_SZ;
    (void)fragSz;

#ifdef WOLFSSL_DTLS13
    /* we ignore fragmentation fields here because fragmentation logic for
       DTLS1.3 is inside dtls13_handshake_send(). */
    if (ssl-&gt;options.dtls) {
        Dtls13AddHeaders(output, length, (enum HandShakeType)type, ssl);
        return;
    }
#endif /* WOLFSSL_DTLS13 */

    AddTls13RecordHeader(output, fragSz + lengthAdj, handshake, ssl);
    AddTls13HandShakeHeader(output + outputAdj, length, fragOffset, fragSz,
                            type, ssl);
}
#endif /* (!NO_WOLFSSL_CLIENT || !NO_WOLFSSL_SERVER) &amp;&amp; !NO_CERTS */

/* Write the sequence number into the buffer.
 * No DTLS v1.3 support.
 *
 * ssl          The SSL/TLS object.
 * verifyOrder  Which set of sequence numbers to use.
 * out          The buffer to write into.
 */
static WC_INLINE void WriteSEQTls13(WOLFSSL* ssl, int verifyOrder, byte* out)
{
    word32 seq[2] = {0, 0};

    if (ssl-&gt;options.dtls) {
#ifdef WOLFSSL_DTLS13
        Dtls13GetSeq(ssl, verifyOrder, seq, 1);
#endif /* WOLFSSL_DTLS13 */
    }
    else if (verifyOrder == PEER_ORDER) {
        seq[0] = ssl-&gt;keys.peer_sequence_number_hi;
        seq[1] = ssl-&gt;keys.peer_sequence_number_lo++;
        /* handle rollover */
        if (seq[1] &gt; ssl-&gt;keys.peer_sequence_number_lo)
            ssl-&gt;keys.peer_sequence_number_hi++;
    }
    else {
        seq[0] = ssl-&gt;keys.sequence_number_hi;
        seq[1] = ssl-&gt;keys.sequence_number_lo++;
        /* handle rollover */
        if (seq[1] &gt; ssl-&gt;keys.sequence_number_lo)
            ssl-&gt;keys.sequence_number_hi++;
    }
#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG_EX(&quot;TLS 1.3 Write Sequence %d %d&quot;, seq[0], seq[1]);
#endif

    c32toa(seq[0], out);
    c32toa(seq[1], out + OPAQUE32_LEN);
}

/* Build the nonce for TLS v1.3 encryption and decryption.
 *
 * ssl    The SSL/TLS object.
 * nonce  The nonce data to use when encrypting or decrypting.
 * iv     The derived IV.
 * order  The side on which the message is to be or was sent.
 */
static WC_INLINE void BuildTls13Nonce(WOLFSSL* ssl, byte* nonce, const byte* iv,
                                   int order)
{
    int seq_offset = AEAD_NONCE_SZ - SEQ_SZ;
    /* The nonce is the IV with the sequence XORed into the last bytes. */
    WriteSEQTls13(ssl, order, nonce + seq_offset);
    XMEMCPY(nonce, iv, seq_offset);
    xorbuf(nonce + seq_offset, iv + seq_offset, SEQ_SZ);
}

#if defined(HAVE_CHACHA) &amp;&amp; defined(HAVE_POLY1305)
/* Encrypt with ChaCha20 and create authentication tag with Poly1305.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to write encrypted data and authentication tag into.
 *         May be the same pointer as input.
 * input   The data to encrypt.
 * sz      The number of bytes to encrypt.
 * nonce   The nonce to use with ChaCha20.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * tag     The authentication tag buffer.
 * returns 0 on success, otherwise failure.
 */
static int ChaCha20Poly1305_Encrypt(WOLFSSL* ssl, byte* output,
                                    const byte* input, word16 sz, byte* nonce,
                                    const byte* aad, word16 aadSz, byte* tag)
{
    int    ret    = 0;
    byte   poly[CHACHA20_256_KEY_SIZE];

    /* Poly1305 key is 256 bits of zero encrypted with ChaCha20. */
    XMEMSET(poly, 0, sizeof(poly));

    /* Set the nonce for ChaCha and get Poly1305 key. */
    ret = wc_Chacha_SetIV(ssl-&gt;encrypt.chacha, nonce, 0);
    if (ret != 0)
        return ret;
    /* Create Poly1305 key using ChaCha20 keystream. */
    ret = wc_Chacha_Process(ssl-&gt;encrypt.chacha, poly, poly, sizeof(poly));
    if (ret != 0)
        return ret;
#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Add(&quot;ChaCha20Poly1305_Encrypt poly&quot;, poly, sizeof(poly));
#endif
    ret = wc_Chacha_SetIV(ssl-&gt;encrypt.chacha, nonce, 1);
    if (ret != 0)
        return ret;
    /* Encrypt the plain text. */
    ret = wc_Chacha_Process(ssl-&gt;encrypt.chacha, output, input, sz);
    if (ret != 0) {
        ForceZero(poly, sizeof(poly));
    #ifdef WOLFSSL_CHECK_MEM_ZERO
        wc_MemZero_Check(poly, sizeof(poly));
    #endif
        return ret;
    }

    /* Set key for Poly1305. */
    ret = wc_Poly1305SetKey(ssl-&gt;auth.poly1305, poly, sizeof(poly));
    ForceZero(poly, sizeof(poly)); /* done with poly1305 key, clear it */
#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Check(poly, sizeof(poly));
#endif
    if (ret != 0)
        return ret;
    /* Add authentication code of encrypted data to end. */
    ret = wc_Poly1305_MAC(ssl-&gt;auth.poly1305, aad, aadSz, output, sz, tag,
                                                              POLY1305_AUTH_SZ);

    return ret;
}
#endif

#ifdef HAVE_NULL_CIPHER
/* Create authentication tag and copy data over input.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to copy data into.
 *         May be the same pointer as input.
 * input   The data.
 * sz      The number of bytes of data.
 * nonce   The nonce to use with authentication.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * tag     The authentication tag buffer.
 * returns 0 on success, otherwise failure.
 */
static int Tls13IntegrityOnly_Encrypt(WOLFSSL* ssl, byte* output,
                                      const byte* input, word16 sz,
                                      const byte* nonce,
                                      const byte* aad, word16 aadSz, byte* tag)
{
    int ret;

    /* HMAC: nonce | aad | input  */
    ret = wc_HmacUpdate(ssl-&gt;encrypt.hmac, nonce, HMAC_NONCE_SZ);
    if (ret == 0)
        ret = wc_HmacUpdate(ssl-&gt;encrypt.hmac, aad, aadSz);
    if (ret == 0)
        ret = wc_HmacUpdate(ssl-&gt;encrypt.hmac, input, sz);
    if (ret == 0)
        ret = wc_HmacFinal(ssl-&gt;encrypt.hmac, tag);
    /* Copy the input to output if not the same buffer */
    if (ret == 0 &amp;&amp; output != input)
        XMEMCPY(output, input, sz);
    return ret;
}
#endif

/* Encrypt data for TLS v1.3.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to write encrypted data and authentication tag into.
 *         May be the same pointer as input.
 * input   The record header and data to encrypt.
 * sz      The number of bytes to encrypt.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * asyncOkay If non-zero can return WC_PENDING_E, otherwise blocks on crypto
 * returns 0 on success, otherwise failure.
 */
static int EncryptTls13(WOLFSSL* ssl, byte* output, const byte* input,
                        word16 sz, const byte* aad, word16 aadSz, int asyncOkay)
{
    int    ret    = 0;
    word16 dataSz = sz - ssl-&gt;specs.aead_mac_size;
    word16 macSz  = ssl-&gt;specs.aead_mac_size;
    word32 nonceSz = 0;
#ifdef WOLFSSL_ASYNC_CRYPT
    WC_ASYNC_DEV* asyncDev = NULL;
    word32 event_flags = WC_ASYNC_FLAG_CALL_AGAIN;
#endif

    WOLFSSL_ENTER(&quot;EncryptTls13&quot;);

    (void)output;
    (void)input;
    (void)sz;
    (void)dataSz;
    (void)macSz;
    (void)asyncOkay;
    (void)nonceSz;

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;error == WC_NO_ERR_TRACE(WC_PENDING_E)) {
        ssl-&gt;error = 0; /* clear async */
    }
#endif
#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13AesEncrypt(ssl, output, input, dataSz);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        if (ret &gt; 0) {
            ret = 0; /* tsip_Tls13AesEncrypt returns output size */
        }
        return ret;
    }
    ret = 0;
#endif /* WOLFSSL_RENESAS_TSIP_TLS */

    switch (ssl-&gt;encrypt.state) {
        case CIPHER_STATE_BEGIN:
        {
        #ifdef WOLFSSL_DEBUG_TLS
            WOLFSSL_MSG(&quot;Data to encrypt&quot;);
            WOLFSSL_BUFFER(input, dataSz);
            WOLFSSL_MSG(&quot;Additional Authentication Data&quot;);
            WOLFSSL_BUFFER(aad, aadSz);
        #endif

        #ifdef WOLFSSL_CIPHER_TEXT_CHECK
            if (ssl-&gt;specs.bulk_cipher_algorithm != wolfssl_cipher_null) {
                XMEMCPY(ssl-&gt;encrypt.sanityCheck, input,
                    min(dataSz, sizeof(ssl-&gt;encrypt.sanityCheck)));
            }
        #endif

        #ifdef CIPHER_NONCE
            if (ssl-&gt;encrypt.nonce == NULL) {
                ssl-&gt;encrypt.nonce = (byte*)XMALLOC(AEAD_NONCE_SZ,
                                                ssl-&gt;heap, DYNAMIC_TYPE_CIPHER);
            #ifdef WOLFSSL_CHECK_MEM_ZERO
                if (ssl-&gt;encrypt.nonce != NULL) {
                    wc_MemZero_Add(&quot;EncryptTls13 nonce&quot;, ssl-&gt;encrypt.nonce,
                        AEAD_NONCE_SZ);
                }
            #endif
            }
            if (ssl-&gt;encrypt.nonce == NULL)
                return MEMORY_E;

            BuildTls13Nonce(ssl, ssl-&gt;encrypt.nonce, ssl-&gt;keys.aead_enc_imp_IV,
                            CUR_ORDER);
        #endif

            /* Advance state and proceed */
            ssl-&gt;encrypt.state = CIPHER_STATE_DO;
        }
        FALL_THROUGH;

        case CIPHER_STATE_DO:
        {
            switch (ssl-&gt;specs.bulk_cipher_algorithm) {
            #ifdef BUILD_AESGCM
                case wolfssl_aes_gcm:
                #ifdef WOLFSSL_ASYNC_CRYPT
                    /* initialize event */
                    asyncDev = &amp;ssl-&gt;encrypt.aes-&gt;asyncDev;
                    ret = wolfSSL_AsyncInit(ssl, asyncDev, event_flags);
                    if (ret != 0)
                        break;
                #endif

                    nonceSz = AESGCM_NONCE_SZ;

                #if defined(HAVE_PK_CALLBACKS)
                    ret = NOT_COMPILED_IN;
                    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb) {
                        ret = ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb(ssl, 1,
                                  output, input, dataSz,
                                  ssl-&gt;encrypt.nonce, nonceSz,
                                  output + dataSz, macSz,
                                  aad, aadSz);
                    }
                    if (ret == WC_NO_ERR_TRACE(NOT_COMPILED_IN))
                #endif
                    {

                #if ((defined(HAVE_FIPS) || defined(HAVE_SELFTEST)) &amp;&amp; \
                    (!defined(HAVE_FIPS_VERSION) || (HAVE_FIPS_VERSION &lt; 2)))
                        ret = wc_AesGcmEncrypt(ssl-&gt;encrypt.aes, output, input,
                            dataSz, ssl-&gt;encrypt.nonce, nonceSz,
                            output + dataSz, macSz, aad, aadSz);
                #else
                        ret = wc_AesGcmSetExtIV(ssl-&gt;encrypt.aes,
                                ssl-&gt;encrypt.nonce, nonceSz);
                        if (ret == 0) {
                            ret = wc_AesGcmEncrypt_ex(ssl-&gt;encrypt.aes, output,
                                    input, dataSz, ssl-&gt;encrypt.nonce, nonceSz,
                                    output + dataSz, macSz, aad, aadSz);
                        }
                #endif
                    }
                    break;
            #endif

            #ifdef HAVE_AESCCM
                case wolfssl_aes_ccm:
                #ifdef WOLFSSL_ASYNC_CRYPT
                    /* initialize event */
                    asyncDev = &amp;ssl-&gt;encrypt.aes-&gt;asyncDev;
                    ret = wolfSSL_AsyncInit(ssl, asyncDev, event_flags);
                    if (ret != 0)
                        break;
                #endif

                    nonceSz = AESCCM_NONCE_SZ;
                #if defined(HAVE_PK_CALLBACKS)
                    ret = NOT_COMPILED_IN;
                    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb) {
                        ret = ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb(ssl, 1,
                                  output, input, dataSz,
                                  ssl-&gt;encrypt.nonce, nonceSz,
                                  output + dataSz, macSz,
                                  aad, aadSz);
                    }
                    if (ret == WC_NO_ERR_TRACE(NOT_COMPILED_IN))
                #endif
                    {
                #if ((defined(HAVE_FIPS) || defined(HAVE_SELFTEST)) &amp;&amp; \
                    (!defined(HAVE_FIPS_VERSION) || (HAVE_FIPS_VERSION &lt; 2)))
                        ret = wc_AesCcmEncrypt(ssl-&gt;encrypt.aes, output, input,
                            dataSz, ssl-&gt;encrypt.nonce, nonceSz,
                            output + dataSz, macSz, aad, aadSz);
                #else
                        ret = wc_AesCcmSetNonce(ssl-&gt;encrypt.aes,
                                ssl-&gt;encrypt.nonce, nonceSz);
                        if (ret == 0) {
                            ret = wc_AesCcmEncrypt_ex(ssl-&gt;encrypt.aes, output,
                                    input, dataSz, ssl-&gt;encrypt.nonce, nonceSz,
                                    output + dataSz, macSz, aad, aadSz);
                        }
                #endif
                    }
                    break;
            #endif

            #if defined(HAVE_CHACHA) &amp;&amp; defined(HAVE_POLY1305)
                case wolfssl_chacha:
                    ret = ChaCha20Poly1305_Encrypt(ssl, output, input, dataSz,
                        ssl-&gt;encrypt.nonce, aad, aadSz, output + dataSz);
                    break;
            #endif

            #ifdef WOLFSSL_SM4_GCM
                case wolfssl_sm4_gcm:
                    nonceSz = SM4_GCM_NONCE_SZ;
                    ret = wc_Sm4GcmEncrypt(ssl-&gt;encrypt.sm4, output, input,
                        dataSz, ssl-&gt;encrypt.nonce, nonceSz, output + dataSz,
                        macSz, aad, aadSz);
                    break;
            #endif

            #ifdef WOLFSSL_SM4_CCM
                case wolfssl_sm4_ccm:
                    nonceSz = SM4_CCM_NONCE_SZ;
                    ret = wc_Sm4CcmEncrypt(ssl-&gt;encrypt.sm4, output, input,
                        dataSz, ssl-&gt;encrypt.nonce, nonceSz, output + dataSz,
                        macSz, aad, aadSz);
                    break;
            #endif

            #ifdef HAVE_NULL_CIPHER
                case wolfssl_cipher_null:
                    ret = Tls13IntegrityOnly_Encrypt(ssl, output, input, dataSz,
                        ssl-&gt;encrypt.nonce, aad, aadSz, output + dataSz);
                    break;
            #endif

                default:
                    WOLFSSL_MSG(&quot;wolfSSL Encrypt programming error&quot;);
                    return ENCRYPT_ERROR;
            }

            /* Advance state */
            ssl-&gt;encrypt.state = CIPHER_STATE_END;

        #ifdef WOLFSSL_ASYNC_CRYPT
            if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                /* if async is not okay, then block */
                if (!asyncOkay) {
                    ret = wc_AsyncWait(ret, asyncDev, event_flags);
                }
                else {
                    /* If pending, then leave and return will resume below */
                    return wolfSSL_AsyncPush(ssl, asyncDev);
                }
            }
        #endif
        }
        FALL_THROUGH;

        case CIPHER_STATE_END:
        {
        #ifdef WOLFSSL_DEBUG_TLS
            #ifdef CIPHER_NONCE
                WOLFSSL_MSG(&quot;Nonce&quot;);
                WOLFSSL_BUFFER(ssl-&gt;encrypt.nonce, ssl-&gt;specs.iv_size);
            #endif
                WOLFSSL_MSG(&quot;Encrypted data&quot;);
                WOLFSSL_BUFFER(output, dataSz);
                WOLFSSL_MSG(&quot;Authentication Tag&quot;);
                WOLFSSL_BUFFER(output + dataSz, macSz);
        #endif

        #ifdef WOLFSSL_CIPHER_TEXT_CHECK
            if (ssl-&gt;specs.bulk_cipher_algorithm != wolfssl_cipher_null &amp;&amp;
                XMEMCMP(output, ssl-&gt;encrypt.sanityCheck,
                    min(dataSz, sizeof(ssl-&gt;encrypt.sanityCheck))) == 0) {

                WOLFSSL_MSG(&quot;EncryptTls13 sanity check failed! Glitch?&quot;);
                return ENCRYPT_ERROR;
            }
            ForceZero(ssl-&gt;encrypt.sanityCheck,
                sizeof(ssl-&gt;encrypt.sanityCheck));
        #endif
        #ifdef WOLFSSL_CHECK_MEM_ZERO
            if ((ssl-&gt;specs.bulk_cipher_algorithm != wolfssl_cipher_null) &amp;&amp;
                    (output != input) &amp;&amp; (ret == 0)) {
                wc_MemZero_Add(&quot;TLS 1.3 Encrypt plaintext&quot;, input, sz);
            }
        #endif

        #ifdef CIPHER_NONCE
            ForceZero(ssl-&gt;encrypt.nonce, AEAD_NONCE_SZ);
        #endif

            break;
        }

        default:
            break;
    }


    /* Reset state */
    ssl-&gt;encrypt.state = CIPHER_STATE_BEGIN;

    return ret;
}

#if defined(HAVE_CHACHA) &amp;&amp; defined(HAVE_POLY1305)
/* Decrypt with ChaCha20 and check authentication tag with Poly1305.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to write decrypted data into.
 *         May be the same pointer as input.
 * input   The data to decrypt.
 * sz      The number of bytes to decrypt.
 * nonce   The nonce to use with ChaCha20.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * tagIn   The authentication tag data from packet.
 * returns 0 on success, otherwise failure.
 */
static int ChaCha20Poly1305_Decrypt(WOLFSSL* ssl, byte* output,
                                    const byte* input, word16 sz, byte* nonce,
                                    const byte* aad, word16 aadSz,
                                    const byte* tagIn)
{
    int ret;
    byte tag[POLY1305_AUTH_SZ];
    byte poly[CHACHA20_256_KEY_SIZE]; /* generated key for mac */

    /* Poly1305 key is 256 bits of zero encrypted with ChaCha20. */
    XMEMSET(poly, 0, sizeof(poly));

    /* Set nonce and get Poly1305 key. */
    ret = wc_Chacha_SetIV(ssl-&gt;decrypt.chacha, nonce, 0);
    if (ret != 0)
        return ret;
    /* Use ChaCha20 keystream to get Poly1305 key for tag. */
    ret = wc_Chacha_Process(ssl-&gt;decrypt.chacha, poly, poly, sizeof(poly));
    if (ret != 0)
        return ret;
#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Add(&quot;ChaCha20Poly1305_Decrypt poly&quot;, poly, sizeof(poly));
#endif
    ret = wc_Chacha_SetIV(ssl-&gt;decrypt.chacha, nonce, 1);
    if (ret != 0) {
        ForceZero(poly, sizeof(poly)); /* done with poly1305 key, clear it */
    #ifdef WOLFSSL_CHECK_MEM_ZERO
        wc_MemZero_Check(poly, sizeof(poly));
    #endif
        return ret;
    }

    /* Set key for Poly1305. */
    ret = wc_Poly1305SetKey(ssl-&gt;auth.poly1305, poly, sizeof(poly));
    ForceZero(poly, sizeof(poly)); /* done with poly1305 key, clear it */
#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Check(poly, sizeof(poly));
#endif
    if (ret != 0)
        return ret;
    /* Generate authentication tag for encrypted data. */
    if ((ret = wc_Poly1305_MAC(ssl-&gt;auth.poly1305, aad, aadSz, input, sz, tag,
                                                           sizeof(tag))) != 0) {
        return ret;
    }

    /* Check tag sent along with packet. */
    if (ConstantCompare(tagIn, tag, POLY1305_AUTH_SZ) != 0) {
        WOLFSSL_MSG(&quot;MAC did not match&quot;);
        return VERIFY_MAC_ERROR;
    }

    /* If the tag was good decrypt message. */
    ret = wc_Chacha_Process(ssl-&gt;decrypt.chacha, output, input, sz);

    return ret;
}
#endif

#ifdef HAVE_NULL_CIPHER
/* Check HMAC tag and copy over input.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to copy data into.
 *         May be the same pointer as input.
 * input   The data.
 * sz      The number of bytes of data.
 * nonce   The nonce to use with authentication.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * tagIn   The authentication tag data from packet.
 * returns 0 on success, otherwise failure.
 */
static int Tls13IntegrityOnly_Decrypt(WOLFSSL* ssl, byte* output,
                                      const byte* input, word16 sz,
                                      const byte* nonce,
                                      const byte* aad, word16 aadSz,
                                      const byte* tagIn)
{
    int ret;
    byte hmac[WC_MAX_DIGEST_SIZE];

    /* HMAC: nonce | aad | input  */
    ret = wc_HmacUpdate(ssl-&gt;decrypt.hmac, nonce, HMAC_NONCE_SZ);
    if (ret == 0)
        ret = wc_HmacUpdate(ssl-&gt;decrypt.hmac, aad, aadSz);
    if (ret == 0)
        ret = wc_HmacUpdate(ssl-&gt;decrypt.hmac, input, sz);
    if (ret == 0)
        ret = wc_HmacFinal(ssl-&gt;decrypt.hmac, hmac);
    /* Check authentication tag matches */
    if (ret == 0 &amp;&amp; ConstantCompare(tagIn, hmac, ssl-&gt;specs.hash_size) != 0)
        ret = DECRYPT_ERROR;
    /* Copy the input to output if not the same buffer */
    if (ret == 0 &amp;&amp; output != input)
        XMEMCPY(output, input, sz);
    return ret;
}
#endif

/* Decrypt data for TLS v1.3.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer to write decrypted data into.
 *         May be the same pointer as input.
 * input   The data to decrypt and authentication tag.
 * sz      The length of the encrypted data plus authentication tag.
 * aad     The additional authentication data.
 * aadSz   The size of the addition authentication data.
 * returns 0 on success, otherwise failure.
 */
int DecryptTls13(WOLFSSL* ssl, byte* output, const byte* input, word16 sz,
                 const byte* aad, word16 aadSz)
{
    int    ret    = 0;
    word16 dataSz = sz - ssl-&gt;specs.aead_mac_size;
    word16 macSz  = ssl-&gt;specs.aead_mac_size;
    word32 nonceSz = 0;

    WOLFSSL_ENTER(&quot;DecryptTls13&quot;);

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13AesDecrypt(ssl, output, input, sz);

    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        #ifndef WOLFSSL_EARLY_DATA
        if (ret &lt; 0) {
            ret = VERIFY_MAC_ERROR;
            WOLFSSL_ERROR_VERBOSE(ret);
        }
        #endif
        return ret;
    }
#endif

#ifdef WOLFSSL_ASYNC_CRYPT
    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;decrypt.state);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* check for still pending */
        if (ret == WC_NO_ERR_TRACE(WC_PENDING_E))
            return ret;

        ssl-&gt;error = 0; /* clear async */

        /* let failures through so CIPHER_STATE_END logic is run */
    }
    else
#endif
    {
        /* Reset state */
        ret = 0;
        ssl-&gt;decrypt.state = CIPHER_STATE_BEGIN;
    }

    (void)output;
    (void)input;
    (void)sz;
    (void)dataSz;
    (void)macSz;
    (void)nonceSz;

    switch (ssl-&gt;decrypt.state) {
        case CIPHER_STATE_BEGIN:
        {
        #ifdef WOLFSSL_DEBUG_TLS
            WOLFSSL_MSG(&quot;Data to decrypt&quot;);
            WOLFSSL_BUFFER(input, dataSz);
            WOLFSSL_MSG(&quot;Additional Authentication Data&quot;);
            WOLFSSL_BUFFER(aad, aadSz);
            WOLFSSL_MSG(&quot;Authentication tag&quot;);
            WOLFSSL_BUFFER(input + dataSz, macSz);
        #endif

        #ifdef CIPHER_NONCE
            if (ssl-&gt;decrypt.nonce == NULL) {
                ssl-&gt;decrypt.nonce = (byte*)XMALLOC(AEAD_NONCE_SZ,
                                                ssl-&gt;heap, DYNAMIC_TYPE_CIPHER);
            #ifdef WOLFSSL_CHECK_MEM_ZERO
                if (ssl-&gt;decrypt.nonce != NULL) {
                    wc_MemZero_Add(&quot;DecryptTls13 nonce&quot;, ssl-&gt;decrypt.nonce,
                        AEAD_NONCE_SZ);
                }
            #endif
            }
            if (ssl-&gt;decrypt.nonce == NULL)
                return MEMORY_E;

            BuildTls13Nonce(ssl, ssl-&gt;decrypt.nonce, ssl-&gt;keys.aead_dec_imp_IV,
                            PEER_ORDER);
        #endif

            /* Advance state and proceed */
            ssl-&gt;decrypt.state = CIPHER_STATE_DO;
        }
        FALL_THROUGH;

        case CIPHER_STATE_DO:
        {
            switch (ssl-&gt;specs.bulk_cipher_algorithm) {
            #ifdef BUILD_AESGCM
                case wolfssl_aes_gcm:
                #ifdef WOLFSSL_ASYNC_CRYPT
                    /* initialize event */
                    ret = wolfSSL_AsyncInit(ssl, &amp;ssl-&gt;decrypt.aes-&gt;asyncDev,
                        WC_ASYNC_FLAG_NONE);
                    if (ret != 0)
                        break;
                #endif

                    nonceSz = AESGCM_NONCE_SZ;

                #if defined(HAVE_PK_CALLBACKS)
                    ret = NOT_COMPILED_IN;
                    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb) {
                        ret = ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb(ssl, 0,
                                  output, input, dataSz,
                                  ssl-&gt;decrypt.nonce, nonceSz,
                                  (byte *)(input + dataSz), macSz,
                                  aad, aadSz);
                    }
                    if (ret == WC_NO_ERR_TRACE(NOT_COMPILED_IN))
                #endif
                    {

                        ret = wc_AesGcmDecrypt(ssl-&gt;decrypt.aes, output, input,
                            dataSz, ssl-&gt;decrypt.nonce, nonceSz,
                            input + dataSz, macSz, aad, aadSz);

                #ifdef WOLFSSL_ASYNC_CRYPT
                        if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                            ret = wolfSSL_AsyncPush(ssl,
                                &amp;ssl-&gt;decrypt.aes-&gt;asyncDev);
                        }
                #endif

                    }
                    break;
            #endif

            #ifdef HAVE_AESCCM
                case wolfssl_aes_ccm:
                #ifdef WOLFSSL_ASYNC_CRYPT
                    /* initialize event */
                    ret = wolfSSL_AsyncInit(ssl, &amp;ssl-&gt;decrypt.aes-&gt;asyncDev,
                        WC_ASYNC_FLAG_NONE);
                    if (ret != 0)
                        break;
                #endif

                    nonceSz = AESCCM_NONCE_SZ;
                #if defined(HAVE_PK_CALLBACKS)
                    ret = NOT_COMPILED_IN;
                    if (ssl-&gt;ctx &amp;&amp; ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb) {
                        ret = ssl-&gt;ctx-&gt;PerformTlsRecordProcessingCb(ssl, 0,
                                  output, input, dataSz,
                                  ssl-&gt;decrypt.nonce, nonceSz,
                                  (byte *)(input + dataSz), macSz,
                                  aad, aadSz);
                    }
                    if (ret == WC_NO_ERR_TRACE(NOT_COMPILED_IN))
                #endif
                    {
                        ret = wc_AesCcmDecrypt(ssl-&gt;decrypt.aes, output, input,
                            dataSz, ssl-&gt;decrypt.nonce, nonceSz,
                            input + dataSz, macSz, aad, aadSz);
                #ifdef WOLFSSL_ASYNC_CRYPT
                        if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                            ret = wolfSSL_AsyncPush(ssl,
                                &amp;ssl-&gt;decrypt.aes-&gt;asyncDev);
                        }
                #endif
                    }
                    break;
            #endif

            #if defined(HAVE_CHACHA) &amp;&amp; defined(HAVE_POLY1305)
                case wolfssl_chacha:
                    ret = ChaCha20Poly1305_Decrypt(ssl, output, input, dataSz,
                        ssl-&gt;decrypt.nonce, aad, aadSz, input + dataSz);
                    break;
            #endif

            #ifdef WOLFSSL_SM4_GCM
                case wolfssl_sm4_gcm:
                    nonceSz = SM4_GCM_NONCE_SZ;
                    ret = wc_Sm4GcmDecrypt(ssl-&gt;decrypt.sm4, output, input,
                        dataSz, ssl-&gt;decrypt.nonce, nonceSz, output + dataSz,
                        macSz, aad, aadSz);
                    break;
            #endif

            #ifdef WOLFSSL_SM4_CCM
                case wolfssl_sm4_ccm:
                    nonceSz = SM4_CCM_NONCE_SZ;
                    ret = wc_Sm4CcmDecrypt(ssl-&gt;decrypt.sm4, output, input,
                        dataSz, ssl-&gt;decrypt.nonce, nonceSz, output + dataSz,
                        macSz, aad, aadSz);
                    break;
            #endif

            #ifdef HAVE_NULL_CIPHER
                case wolfssl_cipher_null:
                    ret = Tls13IntegrityOnly_Decrypt(ssl, output, input, dataSz,
                        ssl-&gt;decrypt.nonce, aad, aadSz, input + dataSz);
                    break;
            #endif
                default:
                    WOLFSSL_MSG(&quot;wolfSSL Decrypt programming error&quot;);
                    return DECRYPT_ERROR;
            }

            /* Advance state */
            ssl-&gt;decrypt.state = CIPHER_STATE_END;

        #ifdef WOLFSSL_ASYNC_CRYPT
            /* If pending, leave now */
            if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                return ret;
            }
        #endif
        }
        FALL_THROUGH;

        case CIPHER_STATE_END:
        {
        #ifdef WOLFSSL_DEBUG_TLS
            #ifdef CIPHER_NONCE
                WOLFSSL_MSG(&quot;Nonce&quot;);
                WOLFSSL_BUFFER(ssl-&gt;decrypt.nonce, ssl-&gt;specs.iv_size);
            #endif
                WOLFSSL_MSG(&quot;Decrypted data&quot;);
                WOLFSSL_BUFFER(output, dataSz);
        #endif
        #ifdef WOLFSSL_CHECK_MEM_ZERO
            if ((ssl-&gt;specs.bulk_cipher_algorithm != wolfssl_cipher_null) &amp;&amp;
                    (ret == 0)) {
                wc_MemZero_Add(&quot;TLS 1.3 Decrypted data&quot;, output, sz);
            }
        #endif

        #ifdef CIPHER_NONCE
            ForceZero(ssl-&gt;decrypt.nonce, AEAD_NONCE_SZ);
        #endif

            break;
        }

       default:
            break;
    }

    if (ret &lt; 0) {
        WOLFSSL_ERROR_VERBOSE(ret);
    }

    return ret;
}

/* Persistable BuildTls13Message arguments */
typedef struct BuildMsg13Args {
    word32 sz;
    word32 idx;
    word32 headerSz;
    word16 size;
    word32 paddingSz;
} BuildMsg13Args;

static void FreeBuildMsg13Args(WOLFSSL* ssl, void* pArgs)
{
    BuildMsg13Args* args = (BuildMsg13Args*)pArgs;

    (void)ssl;
    (void)args;

    /* no allocations in BuildTls13Message */
}

/* Build SSL Message, encrypted.
 * TLS v1.3 encryption is AEAD only.
 *
 * ssl         The SSL/TLS object.
 * output      The buffer to write record message to.
 * outSz       Size of the buffer being written into.
 * input       The record data to encrypt (excluding record header).
 * inSz        The size of the record data.
 * type        The recorder header content type.
 * hashOutput  Whether to hash the unencrypted record data.
 * sizeOnly    Only want the size of the record message.
 * asyncOkay   If non-zero can return WC_PENDING_E, otherwise blocks on crypto
 * returns the size of the encrypted record message or negative value on error.
 */
int BuildTls13Message(WOLFSSL* ssl, byte* output, int outSz, const byte* input,
                int inSz, int type, int hashOutput, int sizeOnly, int asyncOkay)
{
    int ret;
    BuildMsg13Args* args;
    BuildMsg13Args  lcl_args;

    WOLFSSL_ENTER(&quot;BuildTls13Message&quot;);

#ifdef WOLFSSL_ASYNC_CRYPT
    ret = WC_NO_PENDING_E;
    if (asyncOkay) {
        WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);

        if (ssl-&gt;async == NULL) {
            ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                    XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                            DYNAMIC_TYPE_ASYNC);
            if (ssl-&gt;async == NULL)
                return MEMORY_E;
        }
        args = (BuildMsg13Args*)ssl-&gt;async-&gt;args;

        ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.buildMsgState);
        if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
            /* Check for error */
            if (ret &lt; 0)
                goto exit_buildmsg;
        }
    }
    else
#endif
    {
        args = &amp;lcl_args;
    }

    /* Reset state */
#ifdef WOLFSSL_ASYNC_CRYPT
    if (ret == WC_NO_ERR_TRACE(WC_NO_PENDING_E))
#endif
    {
        ret = 0;
        ssl-&gt;options.buildMsgState = BUILD_MSG_BEGIN;
        XMEMSET(args, 0, sizeof(BuildMsg13Args));

        args-&gt;headerSz = RECORD_HEADER_SZ;
#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls)
            args-&gt;headerSz = Dtls13GetRlHeaderLength(ssl, 1);
#endif /* WOLFSSL_DTLS13 */

        args-&gt;sz = args-&gt;headerSz + (word32)inSz;
        args-&gt;idx  = args-&gt;headerSz;

    #ifdef WOLFSSL_ASYNC_CRYPT
        if (asyncOkay)
            ssl-&gt;async-&gt;freeArgs = FreeBuildMsg13Args;
    #endif
    }

    switch (ssl-&gt;options.buildMsgState) {
        case BUILD_MSG_BEGIN:
        {
           /* catch mistaken sizeOnly parameter */
            if (sizeOnly) {
                if (output || input) {
                    WOLFSSL_MSG(&quot;BuildTls13Message with sizeOnly &quot;
                                &quot;doesn&#039;t need input or output&quot;);
                    return BAD_FUNC_ARG;
                }
            }
            else if (output == NULL || input == NULL) {
                return BAD_FUNC_ARG;
            }

            /* Record layer content type at the end of record data. */
            args-&gt;sz++;
            /* Authentication data at the end. */
            args-&gt;sz += ssl-&gt;specs.aead_mac_size;
#ifdef WOLFSSL_DTLS13
            /* Pad to minimum length */
            if (ssl-&gt;options.dtls &amp;&amp;
                    args-&gt;sz &lt; (word32)Dtls13MinimumRecordLength(ssl)) {
                args-&gt;paddingSz = Dtls13MinimumRecordLength(ssl) - args-&gt;sz;
                args-&gt;sz = Dtls13MinimumRecordLength(ssl);
            }
#endif
            if (sizeOnly)
                return (int)args-&gt;sz;

            if (args-&gt;sz &gt; (word32)outSz) {
                WOLFSSL_MSG(&quot;Oops, want to write past output buffer size&quot;);
                return BUFFER_E;
            }

            /* Record data length. */
            args-&gt;size = (word16)(args-&gt;sz - args-&gt;headerSz);
            /* Write/update the record header with the new size.
             * Always have the content type as application data for encrypted
             * messages in TLS v1.3.
             */

            if (ssl-&gt;options.dtls) {
#ifdef WOLFSSL_DTLS13
                Dtls13RlAddCiphertextHeader(ssl, output, args-&gt;size);
#endif /* WOLFSSL_DTLS13 */
            }
            else {
                AddTls13RecordHeader(output, args-&gt;size, application_data, ssl);
            }

            /* TLS v1.3 can do in place encryption. */
            if (input != output + args-&gt;idx)
                XMEMCPY(output + args-&gt;idx, input, (size_t)inSz);
            args-&gt;idx += (word32)inSz;

            ssl-&gt;options.buildMsgState = BUILD_MSG_HASH;
        }
        FALL_THROUGH;

        case BUILD_MSG_HASH:
        {
            if (hashOutput) {
                ret = HashOutput(ssl, output, (int)args-&gt;headerSz + inSz, 0);
                if (ret != 0)
                    goto exit_buildmsg;
            }

            /* The real record content type goes at the end of the data. */
            output[args-&gt;idx++] = (byte)type;
            /* Double check that any necessary padding is zero&#039;d out */
            XMEMSET(output + args-&gt;idx, 0, args-&gt;paddingSz);
            args-&gt;idx += args-&gt;paddingSz;

            ssl-&gt;options.buildMsgState = BUILD_MSG_ENCRYPT;
        }
        FALL_THROUGH;

        case BUILD_MSG_ENCRYPT:
        {
#ifdef WOLFSSL_QUIC
            if (WOLFSSL_IS_QUIC(ssl)) {
                /* QUIC does not use encryption of the TLS Record Layer.
                 * Return the original length + added headers
                 * and restore it in the record header. */
                AddTls13RecordHeader(output, (word32)inSz, (byte)type, ssl);
                ret = (int)args-&gt;headerSz + inSz;
                goto exit_buildmsg;
            }
#endif
        #ifdef ATOMIC_USER
            if (ssl-&gt;ctx-&gt;MacEncryptCb) {
                /* User Record Layer Callback handling */
                byte* mac = output + args-&gt;idx;
                output += args-&gt;headerSz;

                ret = ssl-&gt;ctx-&gt;MacEncryptCb(ssl, mac, output, (unsigned int)inSz, (byte)type, 0,
                        output, output, args-&gt;size, ssl-&gt;MacEncryptCtx);
            }
            else
        #endif
            {
                const byte* aad = output;
                output += args-&gt;headerSz;
                ret = EncryptTls13(ssl, output, output, args-&gt;size, aad,
                                   (word16)args-&gt;headerSz, asyncOkay);
                if (ret != 0) {
                #ifdef WOLFSSL_ASYNC_CRYPT
                    if (ret != WC_NO_ERR_TRACE(WC_PENDING_E))
                #endif
                    {
                        /* Zeroize plaintext. */
                        ForceZero(output, args-&gt;size);
                    }
                }
#ifdef WOLFSSL_DTLS13
                if (ret == 0 &amp;&amp; ssl-&gt;options.dtls) {
                    /* AAD points to the header. Reuse the variable  */
                    ret = Dtls13EncryptRecordNumber(ssl, (byte*)aad,
                                                    (word16)args-&gt;sz);
                }
#endif /* WOLFSSL_DTLS13 */
            }
            break;
        }

        default:
            break;
    }

exit_buildmsg:

    WOLFSSL_LEAVE(&quot;BuildTls13Message&quot;, ret);

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
        return ret;
    }
#endif

    /* make sure build message state is reset */
    ssl-&gt;options.buildMsgState = BUILD_MSG_BEGIN;

    /* return sz on success */
    if (ret == 0) {
        ret = (int)args-&gt;sz;
    }
    else {
        WOLFSSL_ERROR_VERBOSE(ret);
    }

    /* Final cleanup */
#ifdef WOLFSSL_ASYNC_CRYPT
    if (asyncOkay)
        FreeAsyncCtx(ssl, 0);
    else
#endif
        FreeBuildMsg13Args(ssl, args);

    return ret;
}

#if !defined(NO_WOLFSSL_CLIENT) || (!defined(NO_WOLFSSL_SERVER) &amp;&amp; \
    (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)) &amp;&amp; \
    (defined(WOLFSSL_PSK_ONE_ID) || defined(WOLFSSL_PRIORITIZE_PSK)))
/* Find the cipher suite in the suites set in the SSL.
 *
 * ssl    SSL/TLS object.
 * suite  Cipher suite to look for.
 * returns 1 when suite is found in SSL/TLS object&#039;s list and 0 otherwise.
 */
int FindSuiteSSL(const WOLFSSL* ssl, byte* suite)
{
    word16 i;
    const Suites* suites = WOLFSSL_SUITES(ssl);

    for (i = 0; i &lt; suites-&gt;suiteSz; i += 2) {
        if (suites-&gt;suites[i+0] == suite[0] &amp;&amp;
                suites-&gt;suites[i+1] == suite[1]) {
            return 1;
        }
    }

    return 0;
}
#endif

#ifndef NO_PSK
/* Get the MAC algorithm for the TLS 1.3 cipher suite.
 *
 * @param [in] suite.
 * @return  A value from wc_MACAlgorithm enumeration.
 */
byte SuiteMac(const byte* suite)
{
    byte mac = no_mac;

    if (suite[0] == TLS13_BYTE) {
        switch (suite[1]) {
        #ifdef BUILD_TLS_AES_128_GCM_SHA256
            case TLS_AES_128_GCM_SHA256:
                mac = sha256_mac;
                break;
        #endif
        #ifdef BUILD_TLS_CHACHA20_POLY1305_SHA256
            case TLS_CHACHA20_POLY1305_SHA256:
                mac = sha256_mac;
                break;
        #endif
        #ifdef BUILD_TLS_AES_128_CCM_SHA256
            case TLS_AES_128_CCM_SHA256:
                mac = sha256_mac;
                break;
        #endif
        #ifdef BUILD_TLS_AES_128_CCM_8_SHA256
            case TLS_AES_128_CCM_8_SHA256:
                mac = sha256_mac;
                break;
        #endif
        #ifdef BUILD_TLS_AES_256_GCM_SHA384
            case TLS_AES_256_GCM_SHA384:
                mac = sha384_mac;
                break;
        #endif
            default:
                break;
        }
    }
#if (defined(WOLFSSL_SM4_GCM) || defined(WOLFSSL_SM4_CCM)) &amp;&amp; \
     defined(WOLFSSL_SM3)
    else if (suite[0] == CIPHER_BYTE) {
        switch (suite[1]) {
        #ifdef BUILD_TLS_SM4_GCM_SM3
            case TLS_SM4_GCM_SM3:
                mac = sm3_mac;
                break;
        #endif
        #ifdef BUILD_TLS_SM4_CCM_SM3
            case TLS_SM4_CCM_SM3:
                mac = sm3_mac;
                break;
        #endif
            default:
                break;
        }
    }
#endif
#ifdef HAVE_NULL_CIPHER
    else if (suite[0] == ECC_BYTE) {
        switch (suite[1]) {
        #ifdef BUILD_TLS_SHA256_SHA256
            case TLS_SHA256_SHA256:
                mac = sha256_mac;
                break;
        #endif
        #ifdef BUILD_TLS_SHA384_SHA384
            case TLS_SHA384_SHA384:
                mac = sha384_mac;
                break;
        #endif
            default:
                break;
        }
    }
#endif

    return mac;
}
#endif

#if defined(WOLFSSL_SEND_HRR_COOKIE) &amp;&amp; !defined(NO_WOLFSSL_SERVER)
/* Create Cookie extension using the hash of the first ClientHello.
 *
 * ssl     SSL/TLS object.
 * hash    The hash data.
 * hashSz  The size of the hash data in bytes.
 * returns 0 on success, otherwise failure.
 */
int CreateCookieExt(const WOLFSSL* ssl, byte* hash, word16 hashSz,
                    TLSX** exts, byte cipherSuite0, byte cipherSuite)
{
    int  ret;
    byte mac[WC_MAX_DIGEST_SIZE] = {0};
    Hmac cookieHmac;
    byte cookieType = 0;
    byte macSz = 0;
    byte cookie[OPAQUE8_LEN + WC_MAX_DIGEST_SIZE + OPAQUE16_LEN * 2];
    TLSX* ext;
    word16 cookieSz = 0;

    if (hash == NULL || hashSz == 0) {
        return BAD_FUNC_ARG;
    }

    if (ssl-&gt;buffers.tls13CookieSecret.buffer == NULL ||
            ssl-&gt;buffers.tls13CookieSecret.length == 0) {
        WOLFSSL_MSG(&quot;Missing DTLS 1.3 cookie secret&quot;);
        return COOKIE_ERROR;
    }

    /* Cookie Data = Hash Len | Hash | CS | KeyShare Group */
    cookie[cookieSz++] = (byte)hashSz;
    XMEMCPY(cookie + cookieSz, hash, hashSz);
    cookieSz += hashSz;
    cookie[cookieSz++] = cipherSuite0;
    cookie[cookieSz++] = cipherSuite;
    if ((ext = TLSX_Find(*exts, TLSX_KEY_SHARE)) != NULL) {
        KeyShareEntry* kse = (KeyShareEntry*)ext-&gt;data;
        if (kse == NULL) {
            WOLFSSL_MSG(&quot;KeyShareEntry can&#039;t be empty when negotiating &quot;
                        &quot;parameters&quot;);
            return BAD_STATE_E;
        }
        c16toa(kse-&gt;group, cookie + cookieSz);
        cookieSz += OPAQUE16_LEN;
    }

#if !defined(NO_SHA) &amp;&amp; defined(NO_SHA256)
    cookieType = SHA;
    macSz = WC_SHA_DIGEST_SIZE;
#endif /* NO_SHA */
#ifndef NO_SHA256
    cookieType = WC_SHA256;
    macSz = WC_SHA256_DIGEST_SIZE;
#endif /* NO_SHA256 */

    ret = wc_HmacInit(&amp;cookieHmac, ssl-&gt;heap, ssl-&gt;devId);
    if (ret == 0) {
        ret = wc_HmacSetKey(&amp;cookieHmac, cookieType,
                            ssl-&gt;buffers.tls13CookieSecret.buffer,
                            ssl-&gt;buffers.tls13CookieSecret.length);
    }
    if (ret == 0)
        ret = wc_HmacUpdate(&amp;cookieHmac, cookie, cookieSz);
#ifdef WOLFSSL_DTLS13
    /* Tie cookie to peer address */
    if (ret == 0) {
        /* peerLock not necessary. Still in handshake phase. */
        if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;buffers.dtlsCtx.peer.sz &gt; 0) {
            ret = wc_HmacUpdate(&amp;cookieHmac,
                (byte*)ssl-&gt;buffers.dtlsCtx.peer.sa,
                ssl-&gt;buffers.dtlsCtx.peer.sz);
        }
    }
#endif
    if (ret == 0)
        ret = wc_HmacFinal(&amp;cookieHmac, mac);

    wc_HmacFree(&amp;cookieHmac);
    if (ret != 0)
        return ret;

    /* The cookie data is the hash and the integrity check. */
    return TLSX_Cookie_Use(ssl, cookie, cookieSz, mac, macSz, 1, exts);
}
#endif

#ifdef WOLFSSL_DTLS13
#define HRR_MAX_HS_HEADER_SZ DTLS_HANDSHAKE_HEADER_SZ
#else
#define HRR_MAX_HS_HEADER_SZ HANDSHAKE_HEADER_SZ
#endif /* WOLFSSL_DTLS13 */

static int CreateCookie(const WOLFSSL* ssl, byte** hash, byte* hashSz,
                            Hashes* hashes, TLSX** exts)
{
    int    ret = 0;

    (void)exts;

    *hash = NULL;
    switch (ssl-&gt;specs.mac_algorithm) {
    #ifndef NO_SHA256
        case sha256_mac:
            *hash = hashes-&gt;sha256;
            break;
    #endif
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            *hash = hashes-&gt;sha384;
            break;
    #endif
    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            *hash = hashes-&gt;sha512;
            break;
    #endif
    #ifdef WOLFSSL_SM3
        case sm3_mac:
            *hash = hashes-&gt;sm3;
            break;
    #endif
    }
    *hashSz = ssl-&gt;specs.hash_size;

    /* check hash */
    if (*hash == NULL &amp;&amp; *hashSz &gt; 0)
        return BAD_FUNC_ARG;

#if defined(WOLFSSL_SEND_HRR_COOKIE) &amp;&amp; !defined(NO_WOLFSSL_SERVER)
    if (ssl-&gt;options.sendCookie &amp;&amp; ssl-&gt;options.side == WOLFSSL_SERVER_END)
        ret = CreateCookieExt(ssl, *hash, *hashSz, exts,
                ssl-&gt;options.cipherSuite0, ssl-&gt;options.cipherSuite);
#endif
    return ret;
}

/* Restart the handshake hash with a hash of the previous messages.
 *
 * ssl The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
int RestartHandshakeHash(WOLFSSL* ssl)
{
    int    ret;
    byte   header[HANDSHAKE_HEADER_SZ] = {0};
    Hashes hashes;
    byte*  hash = NULL;
    byte   hashSz = 0;

    ret = BuildCertHashes(ssl, &amp;hashes);
    if (ret != 0)
        return ret;
    ret = CreateCookie(ssl, &amp;hash, &amp;hashSz, &amp;hashes, &amp;ssl-&gt;extensions);
    if (ret != 0)
        return ret;
#if defined(WOLFSSL_SEND_HRR_COOKIE) &amp;&amp; !defined(NO_WOLFSSL_SERVER)
    if (ssl-&gt;options.sendCookie &amp;&amp; ssl-&gt;options.side == WOLFSSL_SERVER_END)
        return 0;
#endif

    AddTls13HandShakeHeader(header, hashSz, 0, 0, message_hash, ssl);

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Restart Hash&quot;);
    WOLFSSL_BUFFER(hash, hashSz);
#endif

    ret = InitHandshakeHashes(ssl);
    if (ret != 0)
        return ret;
    ret = HashRaw(ssl, header, sizeof(header));
    if (ret != 0)
        return ret;
    return HashRaw(ssl, hash, hashSz);
}

#if !defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER)
/* The value in the random field of a ServerHello to indicate
 * HelloRetryRequest.
 */
static byte helloRetryRequestRandom[] = {
    0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11,
    0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91,
    0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E,
    0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C
};
#endif

#ifndef NO_WOLFSSL_CLIENT
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
#if defined(OPENSSL_EXTRA) &amp;&amp; !defined(WOLFSSL_PSK_ONE_ID) &amp;&amp; \
    !defined(NO_PSK)
/**
* convert mac algorithm to WOLFSSL_EVP_MD
* @param mac_alg mac algorithm
* @return const WOLFSSL_EVP_MD on successful, otherwise NULL
*/
static const WOLFSSL_EVP_MD* ssl_handshake_md(const byte mac_alg)
{
    switch(mac_alg) {
        case no_mac:
    #ifndef NO_MD5
        case md5_mac:
            return wolfSSL_EVP_md5();
    #endif
    #ifndef NO_SHA
        case sha_mac:
            return wolfSSL_EVP_sha1();
    #endif
    #ifdef WOLFSSL_SHA224
        case sha224_mac:
            return wolfSSL_EVP_sha224();
    #endif
        case sha256_mac:
            return wolfSSL_EVP_sha256();
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            return wolfSSL_EVP_sha384();
    #endif
    #ifdef WOLFSSL_SHA512
        case sha512_mac:
            return wolfSSL_EVP_sha512();
    #endif
        case rmd_mac:
        case blake2b_mac:
            WOLFSSL_MSG(&quot;no suitable EVP_MD&quot;);
            return NULL;
        default:
            WOLFSSL_MSG(&quot;Unknown mac algorithm&quot;);
            return NULL;
    }
}
#endif
/* Setup pre-shared key based on the details in the extension data.
 *
 * ssl          SSL/TLS object.
 * psk          Pre-shared key extension data.
 * clientHello  Whether called from client_hello construction.
 * returns 0 on success, PSK_KEY_ERROR when the client PSK callback fails and
 * other negative value on failure.
 */
static int SetupPskKey(WOLFSSL* ssl, PreSharedKey* psk, int clientHello)
{
#if defined(HAVE_SESSION_TICKET) || !defined(WOLFSSL_PSK_ONE_ID)
    int ret;
#endif
    byte suite[2];

    if (psk == NULL)
        return BAD_FUNC_ARG;

    if (!HaveUniqueSessionObj(ssl)) {
        WOLFSSL_MSG(&quot;Unable to have unique session object&quot;);
        WOLFSSL_ERROR_VERBOSE(MEMORY_ERROR);
        return MEMORY_ERROR;
    }

    suite[0] = ssl-&gt;options.cipherSuite0;
    suite[1] = ssl-&gt;options.cipherSuite;

#ifdef HAVE_SESSION_TICKET
    if (psk-&gt;resumption) {
        if (clientHello) {
            suite[0] = psk-&gt;cipherSuite0;
            suite[1] = psk-&gt;cipherSuite;

            /* Ensure cipher suite is supported or changed suite to one with
             * the same MAC algorithm. */
            if (!FindSuiteSSL(ssl, suite)) {
                WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
                return PSK_KEY_ERROR;
            }

            ssl-&gt;options.cipherSuite0 = suite[0];
            ssl-&gt;options.cipherSuite = suite[1];

            /* Setting mac for binder and keys for deriving EarlyData. */
            ret = SetCipherSpecs(ssl);
            if (ret != 0)
                return ret;
        }

    #ifdef WOLFSSL_EARLY_DATA
        if (ssl-&gt;session-&gt;maxEarlyDataSz == 0)
            ssl-&gt;earlyData = no_early_data;
    #endif
        /* Resumption PSK is master secret. */
        ssl-&gt;arrays-&gt;psk_keySz = ssl-&gt;specs.hash_size;
        if ((ret = DeriveResumptionPSK(ssl, ssl-&gt;session-&gt;ticketNonce.data,
                   ssl-&gt;session-&gt;ticketNonce.len, ssl-&gt;arrays-&gt;psk_key)) != 0) {
            return ret;
        }
        if (!clientHello) {
            /* CLIENT: using secret in ticket for peer authentication. */
            ssl-&gt;options.peerAuthGood = 1;
        }
    }
#endif
#ifndef NO_PSK
    if (!psk-&gt;resumption) {
        /* Get the pre-shared key. */
#ifndef WOLFSSL_PSK_ONE_ID
        const char* cipherName = NULL;
    #ifdef OPENSSL_EXTRA
        WOLFSSL_SESSION* psksession = NULL;
    #endif

        /* Set the client identity to use. */
        XMEMSET(ssl-&gt;arrays-&gt;client_identity, 0,
            sizeof(ssl-&gt;arrays-&gt;client_identity));
        XMEMCPY(ssl-&gt;arrays-&gt;client_identity, psk-&gt;identity, psk-&gt;identityLen);

    #ifdef WOLFSSL_DEBUG_TLS
        WOLFSSL_MSG(&quot;PSK cipher suite:&quot;);
        WOLFSSL_MSG(GetCipherNameInternal(psk-&gt;cipherSuite0, psk-&gt;cipherSuite));
    #endif

        /* Get the pre-shared key. */
    #ifdef OPENSSL_EXTRA
        if (ssl-&gt;options.session_psk_cb != NULL) {
            const unsigned char* id = NULL;
            size_t idlen = 0;
            const WOLFSSL_EVP_MD* handshake_md = NULL;

            if (ssl-&gt;msgsReceived.got_hello_retry_request &gt;= 1) {
                handshake_md = ssl_handshake_md(ssl-&gt;specs.mac_algorithm);
            }
            /* OpenSSL compatible callback that gets cached session. */
            if (ssl-&gt;options.session_psk_cb(ssl, handshake_md, &amp;id, &amp;idlen,
                                                            &amp;psksession) == 0) {
                wolfSSL_FreeSession(ssl-&gt;ctx, psksession);
                WOLFSSL_MSG(&quot;psk session callback failed&quot;);
                return PSK_KEY_ERROR;
            }
            if (psksession != NULL) {
                if (idlen &gt; MAX_PSK_KEY_LEN) {
                    wolfSSL_FreeSession(ssl-&gt;ctx, psksession);
                    WOLFSSL_MSG(&quot;psk key length is too long&quot;);
                    WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
                    return PSK_KEY_ERROR;
                }

                ssl-&gt;arrays-&gt;psk_keySz = (word32)idlen;
                XMEMCPY(ssl-&gt;arrays-&gt;psk_key, id, idlen);
                suite[0] = psksession-&gt;cipherSuite0;
                suite[1] = psksession-&gt;cipherSuite;
                /* Not needed anymore. */
                wolfSSL_FreeSession(ssl-&gt;ctx, psksession);
                /* Leave pointer not NULL to indicate success with callback. */
            }
        }
        if (psksession != NULL) {
            /* Don&#039;t try other callbacks - we have an answer. */
        }
        else
    #endif /* OPENSSL_EXTRA */
        if (ssl-&gt;options.client_psk_cs_cb != NULL) {
        #ifdef WOLFSSL_PSK_MULTI_ID_PER_CS
            ssl-&gt;arrays-&gt;client_identity[0] = 0;
        #endif
            /* Lookup key again for next identity. */
            ssl-&gt;arrays-&gt;psk_keySz = ssl-&gt;options.client_psk_cs_cb(
                ssl, ssl-&gt;arrays-&gt;server_hint,
                ssl-&gt;arrays-&gt;client_identity, MAX_PSK_ID_LEN,
                ssl-&gt;arrays-&gt;psk_key, MAX_PSK_KEY_LEN,
                GetCipherNameInternal(psk-&gt;cipherSuite0, psk-&gt;cipherSuite));
            if (clientHello) {
                /* Use PSK cipher suite. */
                ssl-&gt;options.cipherSuite0 = psk-&gt;cipherSuite0;
                ssl-&gt;options.cipherSuite  = psk-&gt;cipherSuite;
            }
            else {
                byte pskCS[2];
                pskCS[0] = psk-&gt;cipherSuite0;
                pskCS[1] = psk-&gt;cipherSuite;

                /* Ensure PSK and negotiated cipher suites have same hash. */
                if (SuiteMac(pskCS) != SuiteMac(suite)) {
                    WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
                    return PSK_KEY_ERROR;
                }
                /* Negotiated cipher suite is to be used - update PSK. */
                psk-&gt;cipherSuite0 = suite[0];
                psk-&gt;cipherSuite  = suite[1];
            }
        }
        else if (ssl-&gt;options.client_psk_tls13_cb != NULL) {
            byte cipherSuite0;
            byte cipherSuite;
            int cipherSuiteFlags = WOLFSSL_CIPHER_SUITE_FLAG_NONE;

            ssl-&gt;arrays-&gt;psk_keySz = ssl-&gt;options.client_psk_tls13_cb(ssl,
                    ssl-&gt;arrays-&gt;server_hint, ssl-&gt;arrays-&gt;client_identity,
                    MAX_PSK_ID_LEN, ssl-&gt;arrays-&gt;psk_key, MAX_PSK_KEY_LEN,
                    &amp;cipherName);
            if (GetCipherSuiteFromName(cipherName, &amp;cipherSuite0,
                            &amp;cipherSuite, NULL, NULL, &amp;cipherSuiteFlags) != 0) {
                WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
                return PSK_KEY_ERROR;
            }
            ssl-&gt;options.cipherSuite0 = cipherSuite0;
            ssl-&gt;options.cipherSuite  = cipherSuite;
            (void)cipherSuiteFlags;
        }
        else {
            ssl-&gt;arrays-&gt;psk_keySz = ssl-&gt;options.client_psk_cb(ssl,
                    ssl-&gt;arrays-&gt;server_hint, ssl-&gt;arrays-&gt;client_identity,
                    MAX_PSK_ID_LEN, ssl-&gt;arrays-&gt;psk_key, MAX_PSK_KEY_LEN);
            ssl-&gt;options.cipherSuite0 = TLS13_BYTE;
            ssl-&gt;options.cipherSuite  = WOLFSSL_DEF_PSK_CIPHER;
        }
        if (ssl-&gt;arrays-&gt;psk_keySz == 0 ||
                (ssl-&gt;arrays-&gt;psk_keySz &gt; MAX_PSK_KEY_LEN &amp;&amp;
            (int)ssl-&gt;arrays-&gt;psk_keySz != WC_NO_ERR_TRACE(USE_HW_PSK))) {
            WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
            return PSK_KEY_ERROR;
        }

        ret = SetCipherSpecs(ssl);
        if (ret != 0)
            return ret;
#else
        /* PSK information loaded during setting of default TLS extensions. */
#endif /* !WOLFSSL_PSK_ONE_ID */

        if (!clientHello &amp;&amp; (psk-&gt;cipherSuite0 != suite[0] ||
                             psk-&gt;cipherSuite  != suite[1])) {
            WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
            return PSK_KEY_ERROR;
        }

        if (!clientHello) {
            /* CLIENT: using PSK for peer authentication. */
            ssl-&gt;options.peerAuthGood = 1;
        }
    }
#endif

    if (ssl-&gt;options.noPskDheKe) {
        ssl-&gt;arrays-&gt;preMasterSz = 0;
    }

    /* Derive the early secret using the PSK. */
    return DeriveEarlySecret(ssl);
}

/* Derive and write the binders into the ClientHello in space left when
 * writing the Pre-Shared Key extension.
 *
 * ssl     The SSL/TLS object.
 * output  The buffer containing the ClientHello.
 * idx     The index at the end of the completed ClientHello.
 * returns 0 on success and otherwise failure.
 */
static int WritePSKBinders(WOLFSSL* ssl, byte* output, word32 idx)
{
    int           ret;
    TLSX*         ext;
    PreSharedKey* current;
    byte          binderKey[WC_MAX_DIGEST_SIZE];
    word16        len;

    WOLFSSL_ENTER(&quot;WritePSKBinders&quot;);

    if (idx &gt; WOLFSSL_MAX_16BIT) {
        return INPUT_SIZE_E;
    }

    ext = TLSX_Find(ssl-&gt;extensions, TLSX_PRE_SHARED_KEY);
    if (ext == NULL)
        return SANITY_MSG_E;

    /* Get the size of the binders to determine where to write binders. */
    ret = TLSX_PreSharedKey_GetSizeBinders((PreSharedKey*)ext-&gt;data,
                                                            client_hello, &amp;len);
    if (ret &lt; 0)
        return ret;
    idx -= len;

    /* Hash truncated ClientHello - up to binders. */
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        ret = Dtls13HashHandshake(ssl, output + Dtls13GetRlHeaderLength(ssl, 0),
                                 (word16)idx - Dtls13GetRlHeaderLength(ssl, 0));
    else
#endif /* WOLFSSL_DTLS13 */
        ret = HashOutput(ssl, output, (int)idx, 0);

    if (ret != 0)
        return ret;

    current = (PreSharedKey*)ext-&gt;data;
#ifdef WOLFSSL_CHECK_MEM_ZERO
    if (current != NULL) {
        wc_MemZero_Add(&quot;WritePSKBinders binderKey&quot;, binderKey,
            sizeof(binderKey));
    }
#endif
    /* Calculate the binder for each identity based on previous handshake data.
     */
    while (current != NULL) {
        if ((ret = SetupPskKey(ssl, current, 1)) != 0)
            break;

    #ifdef HAVE_SESSION_TICKET
        if (current-&gt;resumption)
            ret = DeriveBinderKeyResume(ssl, binderKey);
    #endif
    #ifndef NO_PSK
        if (!current-&gt;resumption)
            ret = DeriveBinderKey(ssl, binderKey);
    #endif
        if (ret != 0)
            break;

        /* Derive the Finished message secret. */
        ret = DeriveFinishedSecret(ssl, binderKey,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   0 /* neither end */);
        if (ret != 0)
            break;

        /* Build the HMAC of the handshake message data = binder. */
        ret = BuildTls13HandshakeHmac(ssl, ssl-&gt;keys.client_write_MAC_secret,
            current-&gt;binder, &amp;current-&gt;binderLen);
        if (ret != 0)
            break;

        current = current-&gt;next;
    }

    ForceZero(binderKey, sizeof(binderKey));
#ifdef WOLFSSL_CHECK_MEM_ZERO
    wc_MemZero_Check(binderKey, sizeof(binderKey));
#endif
    if (ret != 0)
        return ret;

    /* Data entered into extension, now write to message. */
    ret = TLSX_PreSharedKey_WriteBinders((PreSharedKey*)ext-&gt;data, output + idx,
                                                            client_hello, &amp;len);
    if (ret &lt; 0)
        return ret;

    /* Hash binders to complete the hash of the ClientHello. */
    ret = HashRaw(ssl, output + idx, len);
    if (ret &lt; 0)
        return ret;

    #ifdef WOLFSSL_EARLY_DATA
    if (ssl-&gt;earlyData != no_early_data) {
        if ((ret = SetupPskKey(ssl, (PreSharedKey*)ext-&gt;data, 1)) != 0)
            return ret;

        /* Derive early data encryption key. */
        ret = DeriveTls13Keys(ssl, early_data_key, ENCRYPT_SIDE_ONLY, 1);
        if (ret != 0)
            return ret;
        if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
            return ret;

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls) {
            ret = Dtls13NewEpoch(
                ssl, w64From32(0x0, DTLS13_EPOCH_EARLYDATA), ENCRYPT_SIDE_ONLY);
            if (ret != 0)
                return ret;
        }
#endif /* WOLFSSL_DTLS13 */

    }
    #endif

    WOLFSSL_LEAVE(&quot;WritePSKBinders&quot;, ret);

    return ret;
}
#endif

#if defined(HAVE_ECH)
/* returns the index of the first supported cipher suite, -1 if none */
int EchConfigGetSupportedCipherSuite(WOLFSSL_EchConfig* config)
{
    int i, j, supported = 0;

    for (i = 0; i &lt; config-&gt;numCipherSuites; i++) {
        supported = 0;

        for (j = 0; j &lt; HPKE_SUPPORTED_KDF_LEN; j++) {
            if (config-&gt;cipherSuites[i].kdfId == hpkeSupportedKdf[j])
                break;
        }

        if (j &lt; HPKE_SUPPORTED_KDF_LEN)
            for (j = 0; j &lt; HPKE_SUPPORTED_AEAD_LEN; j++) {
                if (config-&gt;cipherSuites[i].aeadId == hpkeSupportedAead[j]) {
                    supported = 1;
                    break;
                }
            }

        if (supported)
            return i;
    }

    return WOLFSSL_FATAL_ERROR;
}

/* returns status after we hash the ech inner */
static int EchHashHelloInner(WOLFSSL* ssl, WOLFSSL_ECH* ech)
{
    int ret;
    HS_Hashes* tmpHashes;
#ifdef WOLFSSL_DTLS13
    byte falseHeader[DTLS13_HANDSHAKE_HEADER_SZ];
#else
    byte falseHeader[HANDSHAKE_HEADER_SZ];
#endif

    if (ssl == NULL || ech == NULL)
        return BAD_FUNC_ARG;

    /* switch hsHashes to the ech version */
    InitHandshakeHashesAndCopy(ssl, ssl-&gt;hsHashes, &amp;ssl-&gt;hsHashesEch);

    /* swap hsHashes so the regular hash functions work */
    tmpHashes = ssl-&gt;hsHashes;
    ssl-&gt;hsHashes = ssl-&gt;hsHashesEch;

    /* do the handshake header then the body */
    AddTls13HandShakeHeader(falseHeader,
        ech-&gt;innerClientHelloLen - ech-&gt;paddingLen - ech-&gt;hpke-&gt;Nt, 0, 0,
        client_hello, ssl);
    ret = HashRaw(ssl, falseHeader, HANDSHAKE_HEADER_SZ);

    /* hash the body */
    if (ret == 0) {
        ret = HashRaw(ssl, ech-&gt;innerClientHello,
              (int)(ech-&gt;innerClientHelloLen - ech-&gt;paddingLen - ech-&gt;hpke-&gt;Nt));
    }

    /* swap hsHashes back */
    ssl-&gt;hsHashes = tmpHashes;

    return ret;
}
#endif

static void GetTls13SessionId(WOLFSSL* ssl, byte* output, word32* idx)
{
    if (ssl-&gt;session-&gt;sessionIDSz &gt; 0) {
        /* Session resumption for old versions of protocol. */
        if (ssl-&gt;session-&gt;sessionIDSz &lt;= ID_LEN) {
            if (output != NULL)
                output[*idx] = ssl-&gt;session-&gt;sessionIDSz;
            (*idx)++;
            if (output != NULL) {
                XMEMCPY(output + *idx, ssl-&gt;session-&gt;sessionID,
                    ssl-&gt;session-&gt;sessionIDSz);
            }
            *idx += ssl-&gt;session-&gt;sessionIDSz;
        }
        else {
            /* Invalid session ID length. Reset it. */
            ssl-&gt;session-&gt;sessionIDSz = 0;
            if (output != NULL)
                output[*idx] = 0;
            (*idx)++;
        }
    }
    else {
    #ifdef WOLFSSL_TLS13_MIDDLEBOX_COMPAT
        if (ssl-&gt;options.tls13MiddleBoxCompat) {
            if (output != NULL)
                output[*idx] = ID_LEN;
            (*idx)++;
            if (output != NULL)
                XMEMCPY(output + *idx, ssl-&gt;arrays-&gt;clientRandom, ID_LEN);
            *idx += ID_LEN;
        }
        else
    #endif /* WOLFSSL_TLS13_MIDDLEBOX_COMPAT */
        {
            /* TLS v1.3 does not use session id - 0 length. */
            if (output != NULL)
                output[*idx] = 0;
            (*idx)++;
        }
    }
}

/* handle generation of TLS 1.3 client_hello (1) */
/* Send a ClientHello message to the server.
 * Include the information required to start a handshake with servers using
 * protocol versions less than TLS v1.3.
 * Only a client will send this message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success and otherwise failure.
 */

typedef struct Sch13Args {
    byte*  output;
    word32 idx;
    int    sendSz;
    word32 length;
#if defined(HAVE_ECH)
    int clientRandomOffset;
    int preXLength;
    WOLFSSL_ECH* ech;
#endif
} Sch13Args;

int SendTls13ClientHello(WOLFSSL* ssl)
{
    int ret;
#ifdef WOLFSSL_ASYNC_CRYPT
    Sch13Args* args = NULL;
    WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);
#else
    Sch13Args  args[1];
#endif
    byte major, tls12minor;
    const Suites* suites;

    WOLFSSL_START(WC_FUNC_CLIENT_HELLO_SEND);
    WOLFSSL_ENTER(&quot;SendTls13ClientHello&quot;);

    if (ssl == NULL) {
        return BAD_FUNC_ARG;
    }

    ssl-&gt;options.buildingMsg = 1;
    major = SSLv3_MAJOR;
    tls12minor = TLSv1_2_MINOR;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        major = DTLS_MAJOR;
        tls12minor = DTLSv1_2_MINOR;
    }
#endif /* WOLFSSL_DTLS */

#ifdef HAVE_SESSION_TICKET
    if (ssl-&gt;options.resuming &amp;&amp;
            (ssl-&gt;session-&gt;version.major != ssl-&gt;version.major ||
             ssl-&gt;session-&gt;version.minor != ssl-&gt;version.minor)) {
    #ifndef WOLFSSL_NO_TLS12
        if (ssl-&gt;session-&gt;version.major == ssl-&gt;version.major &amp;&amp;
            ssl-&gt;session-&gt;version.minor &lt; ssl-&gt;version.minor) {
            /* Cannot resume with a different protocol version. */
            ssl-&gt;options.resuming = 0;
            ssl-&gt;version.major = ssl-&gt;session-&gt;version.major;
            ssl-&gt;version.minor = ssl-&gt;session-&gt;version.minor;
            return SendClientHello(ssl);
        }
        else
    #endif
        {
            WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
            return VERSION_ERROR;
        }
    }
#endif

    suites = WOLFSSL_SUITES(ssl);
    if (suites == NULL) {
        WOLFSSL_MSG(&quot;Bad suites pointer in SendTls13ClientHello&quot;);
        return SUITES_ERROR;
    }

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;async == NULL) {
        ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                        DYNAMIC_TYPE_ASYNC);
        if (ssl-&gt;async == NULL)
            return MEMORY_E;
        ssl-&gt;async-&gt;freeArgs = NULL;
    }
    args = (Sch13Args*)ssl-&gt;async-&gt;args;

    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.asyncState);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0)
            return ret;
    }
    else
#endif
    {
        /* Reset state */
        ssl-&gt;options.asyncState = TLS_ASYNC_BEGIN;
        XMEMSET(args, 0, sizeof(Sch13Args));
    }

    switch (ssl-&gt;options.asyncState) {
    case TLS_ASYNC_BEGIN:
    {
    word32 sessIdSz = 0;

    args-&gt;idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        args-&gt;idx += DTLS_RECORD_EXTRA + DTLS_HANDSHAKE_EXTRA;
#endif /* WOLFSSL_DTLS13 */

    /* Version | Random | Cipher Suites | Compression */
    args-&gt;length = VERSION_SZ + RAN_LEN + suites-&gt;suiteSz +
            SUITE_LEN + COMP_LEN + ENUM_LEN;
#ifdef WOLFSSL_QUIC
    if (WOLFSSL_IS_QUIC(ssl)) {
        /* RFC 9001 ch. 8.4 sessionID in ClientHello MUST be 0 length */
        ssl-&gt;session-&gt;sessionIDSz = 0;
        ssl-&gt;options.tls13MiddleBoxCompat = 0;
    }
#endif
    GetTls13SessionId(ssl, NULL, &amp;sessIdSz);
    args-&gt;length += (word16)sessIdSz;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        /* legacy_cookie_id len */
        args-&gt;length += ENUM_LEN;

        /* server sent us an HelloVerifyRequest and we allow downgrade  */
        if (ssl-&gt;arrays-&gt;cookieSz &gt; 0 &amp;&amp; ssl-&gt;options.downgrade)
            args-&gt;length += ssl-&gt;arrays-&gt;cookieSz;
    }
#endif /* WOLFSSL_DTLS13 */

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_BUILD;
    } /* case TLS_ASYNC_BEGIN */
    FALL_THROUGH;

    case TLS_ASYNC_BUILD:
    case TLS_ASYNC_DO:
    {
    /* Auto populate extensions supported unless user defined. */
    if ((ret = TLSX_PopulateExtensions(ssl, 0)) != 0)
        return ret;

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_FINALIZE;
    } /* case TLS_ASYNC_BUILD */
    FALL_THROUGH;

    case TLS_ASYNC_FINALIZE:
    {
#ifdef WOLFSSL_EARLY_DATA
    #ifndef NO_PSK
        if (!ssl-&gt;options.resuming &amp;&amp;
                                     ssl-&gt;options.client_psk_tls13_cb == NULL &amp;&amp;
                                     ssl-&gt;options.client_psk_cb == NULL)
    #else
        if (!ssl-&gt;options.resuming)
    #endif
            ssl-&gt;earlyData = no_early_data;
    if (ssl-&gt;options.serverState == SERVER_HELLO_RETRY_REQUEST_COMPLETE)
        ssl-&gt;earlyData = no_early_data;
    if (ssl-&gt;earlyData == no_early_data)
        TLSX_Remove(&amp;ssl-&gt;extensions, TLSX_EARLY_DATA, ssl-&gt;heap);
    if (ssl-&gt;earlyData != no_early_data &amp;&amp;
        (ret = TLSX_EarlyData_Use(ssl, 0, 0)) &lt; 0) {
        return ret;
    }
#endif
#ifdef WOLFSSL_QUIC
    if (WOLFSSL_IS_QUIC(ssl) &amp;&amp; IsAtLeastTLSv1_3(ssl-&gt;version)) {
        ret = wolfSSL_quic_add_transport_extensions(ssl, client_hello);
        if (ret != 0)
            return ret;
    }
#endif

    /* find length of outer and inner */
#if defined(HAVE_ECH)
    if (ssl-&gt;options.useEch == 1 &amp;&amp; !ssl-&gt;options.disableECH) {
        TLSX* echX = TLSX_Find(ssl-&gt;extensions, TLSX_ECH);
        if (echX == NULL)
            return WOLFSSL_FATAL_ERROR;

        args-&gt;ech = (WOLFSSL_ECH*)echX-&gt;data;
        if (args-&gt;ech == NULL)
            return WOLFSSL_FATAL_ERROR;

        /* set the type to inner */
        args-&gt;ech-&gt;type = ECH_TYPE_INNER;
        args-&gt;preXLength = (int)args-&gt;length;

        /* get size for inner */
        ret = TLSX_GetRequestSize(ssl, client_hello, &amp;args-&gt;length);
        if (ret != 0)
            return ret;

        /* set the type to outer */
        args-&gt;ech-&gt;type = 0;
        /* set innerClientHelloLen to ClientHelloInner + padding + tag */
        args-&gt;ech-&gt;paddingLen = 31 - ((args-&gt;length - 1) % 32);
        args-&gt;ech-&gt;innerClientHelloLen = (word16)(args-&gt;length +
            args-&gt;ech-&gt;paddingLen + args-&gt;ech-&gt;hpke-&gt;Nt);
        /* set the length back to before we computed ClientHelloInner size */
        args-&gt;length = (word32)args-&gt;preXLength;
    }
#endif

    {
#ifdef WOLFSSL_DTLS_CH_FRAG
        word16 maxFrag = wolfSSL_GetMaxFragSize(ssl, MAX_RECORD_SIZE);
        word16 lenWithoutExts = args-&gt;length;
#endif

        /* Include length of TLS extensions. */
        ret = TLSX_GetRequestSize(ssl, client_hello, &amp;args-&gt;length);
        if (ret != 0)
            return ret;

        /* Total message size. */
        args-&gt;sendSz =
                (int)(args-&gt;length + HANDSHAKE_HEADER_SZ + RECORD_HEADER_SZ);

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls)
            args-&gt;sendSz += DTLS_RECORD_EXTRA + DTLS_HANDSHAKE_EXTRA;
#endif /* WOLFSSL_DTLS13 */

#ifdef WOLFSSL_DTLS_CH_FRAG
        if (ssl-&gt;options.dtls &amp;&amp; args-&gt;sendSz &gt; maxFrag &amp;&amp;
                TLSX_Find(ssl-&gt;extensions, TLSX_COOKIE) == NULL) {
            /* Try again with an empty key share if we would be fragmenting
             * without a cookie */
            ret = TLSX_KeyShare_Empty(ssl);
            if (ret != 0)
                return ret;
            args-&gt;length = lenWithoutExts;
            ret = TLSX_GetRequestSize(ssl, client_hello, &amp;args-&gt;length);
            if (ret != 0)
                return ret;
            args-&gt;sendSz = (int)(args-&gt;length +
                    DTLS_HANDSHAKE_HEADER_SZ + DTLS_RECORD_HEADER_SZ);
            if (args-&gt;sendSz &gt; maxFrag) {
                WOLFSSL_MSG(&quot;Can&#039;t fit first CH in one fragment.&quot;);
                return BUFFER_ERROR;
            }
            WOLFSSL_MSG(&quot;Sending empty key share so we don&#039;t fragment CH1&quot;);
        }
#endif
    }

    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, args-&gt;sendSz)) != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    args-&gt;output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(args-&gt;output, args-&gt;length, client_hello, ssl);

    /* Protocol version - negotiation now in extension: supported_versions. */
    args-&gt;output[args-&gt;idx++] = major;
    args-&gt;output[args-&gt;idx++] = tls12minor;

    /* Keep for downgrade. */
    ssl-&gt;chVersion = ssl-&gt;version;

    if (ssl-&gt;arrays == NULL) {
        return BAD_FUNC_ARG;
    }
    /* Client Random */
    if (ssl-&gt;options.connectState == CONNECT_BEGIN) {
        ret = wc_RNG_GenerateBlock(ssl-&gt;rng, args-&gt;output + args-&gt;idx, RAN_LEN);
        if (ret != 0)
            return ret;

        /* Store random for possible second ClientHello. */
        XMEMCPY(ssl-&gt;arrays-&gt;clientRandom, args-&gt;output + args-&gt;idx, RAN_LEN);
    }
    else
        XMEMCPY(args-&gt;output + args-&gt;idx, ssl-&gt;arrays-&gt;clientRandom, RAN_LEN);

#if defined(HAVE_ECH)
    args-&gt;clientRandomOffset = (int)args-&gt;idx;
#endif

    args-&gt;idx += RAN_LEN;

    GetTls13SessionId(ssl, args-&gt;output, &amp;args-&gt;idx);

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        args-&gt;output[args-&gt;idx++] = ssl-&gt;arrays-&gt;cookieSz;

        if (ssl-&gt;arrays-&gt;cookieSz &gt; 0) {
            /* We have a cookie saved, so the server sent us an
             * HelloVerifyRequest, it means it is a v1.2 server */
            if (!ssl-&gt;options.downgrade)
                return VERSION_ERROR;
            XMEMCPY(args-&gt;output + args-&gt;idx, ssl-&gt;arrays-&gt;cookie,
                ssl-&gt;arrays-&gt;cookieSz);
            args-&gt;idx += ssl-&gt;arrays-&gt;cookieSz;
        }
    }
#endif /* WOLFSSL_DTLS13 */

    /* Cipher suites */
    c16toa(suites-&gt;suiteSz, args-&gt;output + args-&gt;idx);
    args-&gt;idx += OPAQUE16_LEN;
    XMEMCPY(args-&gt;output + args-&gt;idx, &amp;suites-&gt;suites,
        suites-&gt;suiteSz);
    args-&gt;idx += suites-&gt;suiteSz;
#ifdef WOLFSSL_DEBUG_TLS
    {
        int ii;
        WOLFSSL_MSG(&quot;Ciphers:&quot;);
        for (ii = 0 ; ii &lt; suites-&gt;suiteSz; ii += 2) {
            WOLFSSL_MSG(GetCipherNameInternal(suites-&gt;suites[ii+0],
                                              suites-&gt;suites[ii+1]));
        }
    }
#endif

    /* Compression not supported in TLS v1.3. */
    args-&gt;output[args-&gt;idx++] = COMP_LEN;
    args-&gt;output[args-&gt;idx++] = NO_COMPRESSION;

#if defined(HAVE_ECH)
    /* write inner then outer */
    if (ssl-&gt;options.useEch == 1 &amp;&amp; !ssl-&gt;options.disableECH) {
        /* set the type to inner */
        args-&gt;ech-&gt;type = ECH_TYPE_INNER;

        /* allocate the inner */
        args-&gt;ech-&gt;innerClientHello =
            (byte*)XMALLOC(args-&gt;ech-&gt;innerClientHelloLen - args-&gt;ech-&gt;hpke-&gt;Nt,
            ssl-&gt;heap, DYNAMIC_TYPE_TMP_BUFFER);
        if (args-&gt;ech-&gt;innerClientHello == NULL)
            return MEMORY_E;

        /* set the padding bytes to 0 */
        XMEMSET(args-&gt;ech-&gt;innerClientHello + args-&gt;ech-&gt;innerClientHelloLen -
            args-&gt;ech-&gt;hpke-&gt;Nt - args-&gt;ech-&gt;paddingLen, 0,
            args-&gt;ech-&gt;paddingLen);

        /* copy the client hello to the ech innerClientHello, exclude record */
        /* and handshake headers */
        XMEMCPY(args-&gt;ech-&gt;innerClientHello,
            args-&gt;output + RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ,
            args-&gt;idx - (RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ));

        /* copy the client random to inner */
        XMEMCPY(ssl-&gt;arrays-&gt;clientRandomInner, ssl-&gt;arrays-&gt;clientRandom,
            RAN_LEN);

        /* change the outer client random */
        ret = wc_RNG_GenerateBlock(ssl-&gt;rng, args-&gt;output +
            args-&gt;clientRandomOffset, RAN_LEN);
        if (ret != 0)
            return ret;

        /* copy the new client random */
        XMEMCPY(ssl-&gt;arrays-&gt;clientRandom, args-&gt;output +
            args-&gt;clientRandomOffset, RAN_LEN);

        /* write the extensions for inner */
        args-&gt;length = 0;
        ret = TLSX_WriteRequest(ssl, args-&gt;ech-&gt;innerClientHello + args-&gt;idx -
            (RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ), client_hello,
            &amp;args-&gt;length);
        if (ret != 0)
            return ret;

        /* set the type to outer */
        args-&gt;ech-&gt;type = 0;
    }
#endif

    /* Write out extensions for a request. */
    args-&gt;length = 0;
    ret = TLSX_WriteRequest(ssl, args-&gt;output + args-&gt;idx, client_hello,
        &amp;args-&gt;length);
    if (ret != 0)
        return ret;

    args-&gt;idx += args-&gt;length;

#if defined(HAVE_ECH)
    /* encrypt and pack the ech innerClientHello */
    if (ssl-&gt;options.useEch == 1 &amp;&amp; !ssl-&gt;options.disableECH) {
        ret = TLSX_FinalizeEch(args-&gt;ech,
            args-&gt;output + RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ,
            (word32)(args-&gt;sendSz - (RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ)));

        if (ret != 0)
            return ret;
    }
#endif

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    /* Resumption has a specific set of extensions and binder is calculated
     * for each identity.
     */
    if (TLSX_Find(ssl-&gt;extensions, TLSX_PRE_SHARED_KEY)) {
        ret = WritePSKBinders(ssl, args-&gt;output, args-&gt;idx);
    }
    else
#endif
    {
#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls)
            ret = Dtls13HashHandshake(ssl,
                args-&gt;output + Dtls13GetRlHeaderLength(ssl, 0),
                (word16)args-&gt;idx - Dtls13GetRlHeaderLength(ssl, 0));
        else
#endif /* WOLFSSL_DTLS13 */
        {
#if defined(HAVE_ECH)
            /* compute the inner hash */
            if (ssl-&gt;options.useEch == 1 &amp;&amp; !ssl-&gt;options.disableECH)
                ret = EchHashHelloInner(ssl, args-&gt;ech);
#endif
            /* compute the outer hash */
            if (ret == 0)
                ret = HashOutput(ssl, args-&gt;output, (int)args-&gt;idx, 0);
        }
    }
    if (ret != 0)
        return ret;

    ssl-&gt;options.clientState = CLIENT_HELLO_COMPLETE;

#if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;ClientHello&quot;);
    if (ssl-&gt;toInfoOn) {
        ret = AddPacketInfo(ssl, &quot;ClientHello&quot;, handshake, args-&gt;output,
                      args-&gt;sendSz, WRITE_PROTO, 0, ssl-&gt;heap);
        if (ret != 0)
            return ret;
    }
#endif

    ssl-&gt;options.buildingMsg = 0;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ret = Dtls13HandshakeSend(ssl, args-&gt;output, (word16)args-&gt;sendSz,
                                  (word16)args-&gt;idx, client_hello, 0);
        break;
    }
#endif /* WOLFSSL_DTLS13 */

    ssl-&gt;buffers.outputBuffer.length += (word32)args-&gt;sendSz;

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_END;
    }
    /* case TLS_ASYNC_BUILD */
    FALL_THROUGH;

    case TLS_ASYNC_END:
    {
#ifdef WOLFSSL_EARLY_DATA_GROUP
    /* QUIC needs to forward records at their encryption level
     * and is therefore unable to group here */
    if (ssl-&gt;earlyData == no_early_data || WOLFSSL_IS_QUIC(ssl))
#endif
        ret = SendBuffered(ssl);

    break;
    }
    default:
        ret = INPUT_CASE_ERROR;
    } /* switch (ssl-&gt;options.asyncState) */

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ret == 0)
        FreeAsyncCtx(ssl, 0);
#endif

    WOLFSSL_LEAVE(&quot;SendTls13ClientHello&quot;, ret);
    WOLFSSL_END(WC_FUNC_CLIENT_HELLO_SEND);

    return ret;
}

#if defined(WOLFSSL_DTLS13) &amp;&amp; !defined(WOLFSSL_NO_CLIENT)
static int Dtls13ClientDoDowngrade(WOLFSSL* ssl)
{
    int ret;
    if (ssl-&gt;dtls13ClientHello == NULL)
        return BAD_STATE_E;

    /* v1.3 and v1.2 hash messages to compute the transcript hash. When we are
     * using DTLSv1.3 we hash the first clientHello following v1.3 but the
     * server can negotiate a lower version. So we need to re-hash the
     * clientHello to adhere to DTLS &lt;= v1.2 rules. */
    ret = InitHandshakeHashes(ssl);
    if (ret != 0)
        return ret;
    ret = HashRaw(ssl, ssl-&gt;dtls13ClientHello, ssl-&gt;dtls13ClientHelloSz);
    XFREE(ssl-&gt;dtls13ClientHello, ssl-&gt;heap, DYNAMIC_TYPE_DTLS_MSG);
    ssl-&gt;dtls13ClientHello = NULL;
    ssl-&gt;dtls13ClientHelloSz = 0;
    ssl-&gt;keys.dtls_sequence_number_hi =
        (word16)w64GetHigh32(ssl-&gt;dtls13EncryptEpoch-&gt;nextSeqNumber);
    ssl-&gt;keys.dtls_sequence_number_lo =
        w64GetLow32(ssl-&gt;dtls13EncryptEpoch-&gt;nextSeqNumber);
    return ret;
}
#endif /* WOLFSSL_DTLS13 &amp;&amp; !WOLFSSL_NO_CLIENT*/

#if defined(HAVE_ECH)
/* check if the server accepted ech or not */
static int EchCheckAcceptance(WOLFSSL* ssl, const byte* input,
    int serverRandomOffset, int helloSz)
{
    int ret = 0;
    int digestType = 0;
    int digestSize = 0;
    HS_Hashes* tmpHashes;
    HS_Hashes* acceptHashes;
    byte zeros[WC_MAX_DIGEST_SIZE];
    byte transcriptEchConf[WC_MAX_DIGEST_SIZE];
    byte expandLabelPrk[WC_MAX_DIGEST_SIZE];
    byte acceptConfirmation[ECH_ACCEPT_CONFIRMATION_SZ];
    XMEMSET(zeros, 0, sizeof(zeros));
    XMEMSET(transcriptEchConf, 0, sizeof(transcriptEchConf));
    XMEMSET(expandLabelPrk, 0, sizeof(expandLabelPrk));
    XMEMSET(acceptConfirmation, 0, sizeof(acceptConfirmation));
    /* copy ech hashes to accept */
    ret = InitHandshakeHashesAndCopy(ssl, ssl-&gt;hsHashesEch, &amp;acceptHashes);
    /* swap hsHashes to acceptHashes */
    tmpHashes = ssl-&gt;hsHashes;
    ssl-&gt;hsHashes = acceptHashes;
    /* hash up to the last 8 bytes */
    if (ret == 0)
        ret = HashRaw(ssl, input, serverRandomOffset + RAN_LEN -
            ECH_ACCEPT_CONFIRMATION_SZ);
    /* hash 8 zeros */
    if (ret == 0)
        ret = HashRaw(ssl, zeros, ECH_ACCEPT_CONFIRMATION_SZ);
    /* hash the rest of the hello */
    if (ret == 0) {
        ret = HashRaw(ssl, input + serverRandomOffset + RAN_LEN,
            helloSz + HANDSHAKE_HEADER_SZ - (serverRandomOffset + RAN_LEN));
    }
    /* get the modified transcript hash */
    if (ret == 0)
        ret = GetMsgHash(ssl, transcriptEchConf);
    if (ret &gt; 0)
        ret = 0;
    /* pick the right type and size based on mac_algorithm */
    if (ret == 0) {
        switch (ssl-&gt;specs.mac_algorithm) {
#ifndef NO_SHA256
            case sha256_mac:
                digestType = WC_SHA256;
                digestSize = WC_SHA256_DIGEST_SIZE;
                break;
#endif /* !NO_SHA256 */
#ifdef WOLFSSL_SHA384
            case sha384_mac:
                digestType = WC_SHA384;
                digestSize = WC_SHA384_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_SHA384 */
#ifdef WOLFSSL_TLS13_SHA512
            case sha512_mac:
                digestType = WC_SHA512;
                digestSize = WC_SHA512_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_TLS13_SHA512 */
#ifdef WOLFSSL_SM3
            case sm3_mac:
                digestType = WC_SM3;
                digestSize = WC_SM3_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_SM3 */
            default:
                ret = WOLFSSL_FATAL_ERROR;
                break;
        }
    }
    /* extract clientRandomInner with a key of all zeros */
    if (ret == 0) {
        PRIVATE_KEY_UNLOCK();
    #if !defined(HAVE_FIPS) || \
        (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(6,0))
        ret = wc_HKDF_Extract_ex(digestType, zeros, (word32)digestSize,
            ssl-&gt;arrays-&gt;clientRandomInner, RAN_LEN, expandLabelPrk,
            ssl-&gt;heap, ssl-&gt;devId);
    #else
        ret = wc_HKDF_Extract(digestType, zeros, digestSize,
            ssl-&gt;arrays-&gt;clientRandomInner, RAN_LEN, expandLabelPrk);
    #endif
        PRIVATE_KEY_LOCK();
    }
    /* tls expand with the confirmation label */
    if (ret == 0) {
        PRIVATE_KEY_UNLOCK();
        ret = Tls13HKDFExpandKeyLabel(ssl,
            acceptConfirmation, ECH_ACCEPT_CONFIRMATION_SZ,
            expandLabelPrk, (word32)digestSize,
            tls13ProtocolLabel, TLS13_PROTOCOL_LABEL_SZ,
            echAcceptConfirmationLabel, ECH_ACCEPT_CONFIRMATION_LABEL_SZ,
            transcriptEchConf, (word32)digestSize, digestType, WOLFSSL_SERVER_END);
        PRIVATE_KEY_LOCK();
    }
    if (ret == 0) {
        /* last 8 bytes should match our expand output */
        ret = XMEMCMP(acceptConfirmation,
            ssl-&gt;arrays-&gt;serverRandom + RAN_LEN - ECH_ACCEPT_CONFIRMATION_SZ,
            ECH_ACCEPT_CONFIRMATION_SZ);
        /* ech accepted */
        if (ret == 0) {
            /* use the inner random for client random */
            XMEMCPY(ssl-&gt;arrays-&gt;clientRandom, ssl-&gt;arrays-&gt;clientRandomInner,
              RAN_LEN);
            /* switch back to original hsHashes to free */
            ssl-&gt;hsHashes = tmpHashes;
            /* set the final hsHashes to the ech hashes */
            tmpHashes = ssl-&gt;hsHashesEch;
        }
        /* ech rejected */
        else {
            /* switch to hsHashesEch to free */
            ssl-&gt;hsHashes = ssl-&gt;hsHashesEch;
        }
        /* free hsHashes */
        FreeHandshakeHashes(ssl);
        /* set hsHashesEch to NULL to avoid double free */
        ssl-&gt;hsHashesEch = NULL;
        /* continue with outer if we failed to verify ech was accepted */
        ret = 0;
    }
    /* switch to acceptHashes */
    ssl-&gt;hsHashes = acceptHashes;
    /* free acceptHashes */
    FreeHandshakeHashes(ssl);
    /* swap to tmp, will ech if accepted, hsHashes if rejected */
    ssl-&gt;hsHashes = tmpHashes;
    return ret;
}

/* replace the last 8 bytes of the server random with the ech acceptance
 * parameter, return status */
static int EchWriteAcceptance(WOLFSSL* ssl, byte* output,
  int serverRandomOffset, int helloSz)
{
    int ret = 0;
    int digestType = 0;
    int digestSize = 0;
    HS_Hashes* tmpHashes = NULL;
    HS_Hashes* acceptHashes = NULL;
    byte zeros[WC_MAX_DIGEST_SIZE];
    byte transcriptEchConf[WC_MAX_DIGEST_SIZE];
    byte expandLabelPrk[WC_MAX_DIGEST_SIZE];
    XMEMSET(zeros, 0, sizeof(zeros));
    XMEMSET(transcriptEchConf, 0, sizeof(transcriptEchConf));
    XMEMSET(expandLabelPrk, 0, sizeof(expandLabelPrk));

    /* copy ech hashes to accept */
    ret = InitHandshakeHashesAndCopy(ssl, ssl-&gt;hsHashes, &amp;acceptHashes);

    /* swap hsHashes to acceptHashes */
    tmpHashes = ssl-&gt;hsHashes;
    ssl-&gt;hsHashes = acceptHashes;

    /* hash up to the last 8 bytes */
    if (ret == 0)
        ret = HashRaw(ssl, output, serverRandomOffset + RAN_LEN -
            ECH_ACCEPT_CONFIRMATION_SZ);

    /* hash 8 zeros */
    if (ret == 0)
        ret = HashRaw(ssl, zeros, ECH_ACCEPT_CONFIRMATION_SZ);

    /* hash the rest of the hello */
    if (ret == 0)
        ret = HashRaw(ssl, output + serverRandomOffset + RAN_LEN,
            helloSz - (serverRandomOffset + RAN_LEN));

    /* get the modified transcript hash */
    if (ret == 0)
        ret = GetMsgHash(ssl, transcriptEchConf);

    if (ret &gt; 0)
        ret = 0;

    /* pick the right type and size based on mac_algorithm */
    if (ret == 0)
        switch (ssl-&gt;specs.mac_algorithm) {
#ifndef NO_SHA256
            case sha256_mac:
                digestType = WC_SHA256;
                digestSize = WC_SHA256_DIGEST_SIZE;
                break;
#endif /* !NO_SHA256 */
#ifdef WOLFSSL_SHA384
            case sha384_mac:
                digestType = WC_SHA384;
                digestSize = WC_SHA384_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_SHA384 */
#ifdef WOLFSSL_TLS13_SHA512
            case sha512_mac:
                digestType = WC_SHA512;
                digestSize = WC_SHA512_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_TLS13_SHA512 */
#ifdef WOLFSSL_SM3
            case sm3_mac:
                digestType = WC_SM3;
                digestSize = WC_SM3_DIGEST_SIZE;
                break;
#endif /* WOLFSSL_SM3 */
            default:
                ret = WOLFSSL_FATAL_ERROR;
                break;
        }

    /* extract clientRandom with a key of all zeros */
    if (ret == 0) {
        PRIVATE_KEY_UNLOCK();
    #if !defined(HAVE_FIPS) || \
        (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(6,0))
        ret = wc_HKDF_Extract_ex(digestType, zeros, (word32)digestSize,
            ssl-&gt;arrays-&gt;clientRandom, RAN_LEN, expandLabelPrk,
            ssl-&gt;heap, ssl-&gt;devId);
    #else
        ret = wc_HKDF_Extract(digestType, zeros, digestSize,
            ssl-&gt;arrays-&gt;clientRandom, RAN_LEN, expandLabelPrk);
    #endif
        PRIVATE_KEY_LOCK();
    }

    /* tls expand with the confirmation label */
    if (ret == 0) {
        PRIVATE_KEY_UNLOCK();
        ret = Tls13HKDFExpandKeyLabel(ssl,
            output + serverRandomOffset + RAN_LEN - ECH_ACCEPT_CONFIRMATION_SZ,
                ECH_ACCEPT_CONFIRMATION_SZ,
            expandLabelPrk, (word32)digestSize,
            tls13ProtocolLabel, TLS13_PROTOCOL_LABEL_SZ,
            echAcceptConfirmationLabel, ECH_ACCEPT_CONFIRMATION_LABEL_SZ,
            transcriptEchConf, (word32)digestSize, digestType, WOLFSSL_SERVER_END);
        PRIVATE_KEY_LOCK();
    }

    if (ret == 0)
        XMEMCPY(ssl-&gt;arrays-&gt;serverRandom, output + serverRandomOffset,
            RAN_LEN);

    /* free acceptHashes */
    FreeHandshakeHashes(ssl);

    ssl-&gt;hsHashes = tmpHashes;

    return ret;
}
#endif

/* handle processing of TLS 1.3 server_hello (2) and hello_retry_request (6) */
/* Handle the ServerHello message from the server.
 * Only a client will receive this message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of ServerHello.
 *           On exit, the index of byte after the ServerHello message.
 * helloSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */

typedef struct Dsh13Args {
    ProtocolVersion pv;
    word32          idx;
    word32          begin;
    const byte*     sessId;
    word16          totalExtSz;
    byte            sessIdSz;
    byte            extMsgType;
#if defined(HAVE_ECH)
    int             serverRandomOffset;
#endif
} Dsh13Args;

int DoTls13ServerHello(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                       word32 helloSz, byte* extMsgType)
{
    int ret;
    byte suite[2];
    byte tls12minor;
#ifdef WOLFSSL_ASYNC_CRYPT
    Dsh13Args* args = NULL;
    WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);
#else
    Dsh13Args  args[1];
#endif

    WOLFSSL_START(WC_FUNC_SERVER_HELLO_DO);
    WOLFSSL_ENTER(&quot;DoTls13ServerHello&quot;);

    tls12minor = TLSv1_2_MINOR;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        tls12minor = DTLSv1_2_MINOR;
#endif /*  WOLFSSL_DTLS13 */


    if (ssl == NULL || ssl-&gt;arrays == NULL)
        return BAD_FUNC_ARG;

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;async == NULL) {
        ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                        DYNAMIC_TYPE_ASYNC);
        if (ssl-&gt;async == NULL)
            return MEMORY_E;
        ssl-&gt;async-&gt;freeArgs = NULL;
    }
    args = (Dsh13Args*)ssl-&gt;async-&gt;args;

    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.asyncState);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0) {
            if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                /* Mark message as not received so it can process again */
                ssl-&gt;msgsReceived.got_server_hello = 0;
            }
            return ret;
        }
    }
    else
#endif
    {
        /* Reset state */
        ssl-&gt;options.asyncState = TLS_ASYNC_BEGIN;
        XMEMSET(args, 0, sizeof(Dsh13Args));
    }

    switch (ssl-&gt;options.asyncState) {
    case TLS_ASYNC_BEGIN:
    {
    byte b;
#ifdef WOLFSSL_CALLBACKS
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;ServerHello&quot;);
    if (ssl-&gt;toInfoOn) AddLateName(&quot;ServerHello&quot;, &amp;ssl-&gt;timeoutInfo);
#endif

    /* Protocol version length check. */
    if (helloSz &lt; OPAQUE16_LEN)
        return BUFFER_ERROR;

    args-&gt;idx = *inOutIdx;
    args-&gt;begin = args-&gt;idx;

    /* Protocol version */
    XMEMCPY(&amp;args-&gt;pv, input + args-&gt;idx, OPAQUE16_LEN);
    args-&gt;idx += OPAQUE16_LEN;

#ifdef WOLFSSL_DTLS
    if (ssl-&gt;options.dtls &amp;&amp;
        (args-&gt;pv.major != DTLS_MAJOR || args-&gt;pv.minor == DTLS_BOGUS_MINOR))
        return VERSION_ERROR;
#endif /* WOLFSSL_DTLS */

#ifndef WOLFSSL_NO_TLS12
    {
        byte wantDowngrade;

        wantDowngrade = args-&gt;pv.major == ssl-&gt;version.major &amp;&amp;
            args-&gt;pv.minor &lt; TLSv1_2_MINOR;

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls)
            wantDowngrade = args-&gt;pv.major == ssl-&gt;version.major &amp;&amp;
                args-&gt;pv.minor &gt; DTLSv1_2_MINOR;
#endif /* WOLFSSL_DTLS13 */

        if (wantDowngrade &amp;&amp; ssl-&gt;options.downgrade) {
            /* Force client hello version 1.2 to work for static RSA. */
            ssl-&gt;chVersion.minor = TLSv1_2_MINOR;
            ssl-&gt;version.minor = TLSv1_2_MINOR;

#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                ssl-&gt;chVersion.minor = DTLSv1_2_MINOR;
                ssl-&gt;version.minor = DTLSv1_2_MINOR;
                ret = Dtls13ClientDoDowngrade(ssl);
                if (ret != 0)
                    return ret;
            }
#endif /* WOLFSSL_DTLS13 */

            return DoServerHello(ssl, input, inOutIdx, helloSz);
        }
    }
#endif

    if (args-&gt;pv.major != ssl-&gt;version.major ||
        args-&gt;pv.minor != tls12minor) {
        SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
        WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
        return VERSION_ERROR;
    }

    /* Random and session id length check */
    if ((args-&gt;idx - args-&gt;begin) + RAN_LEN + ENUM_LEN &gt; helloSz)
        return BUFFER_ERROR;

    /* Check if hello retry request */
    if (XMEMCMP(input + args-&gt;idx, helloRetryRequestRandom, RAN_LEN) == 0) {
        WOLFSSL_MSG(&quot;HelloRetryRequest format&quot;);
        *extMsgType = hello_retry_request;

        if (ssl-&gt;msgsReceived.got_hello_verify_request) {
            WOLFSSL_MSG(&quot;Received HelloRetryRequest after a &quot;
                        &quot;HelloVerifyRequest&quot;);
            WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
            return VERSION_ERROR;
        }

        /* A HelloRetryRequest comes in as an ServerHello for MiddleBox compat.
         * Found message to be a HelloRetryRequest.
         * Don&#039;t allow more than one HelloRetryRequest or ServerHello.
         */
        if (ssl-&gt;msgsReceived.got_hello_retry_request) {
            WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
            return DUPLICATE_MSG_E;
        }
    }
    args-&gt;extMsgType = *extMsgType;

    /* Server random - keep for debugging. */
    XMEMCPY(ssl-&gt;arrays-&gt;serverRandom, input + args-&gt;idx, RAN_LEN);
#if defined(HAVE_ECH)
    args-&gt;serverRandomOffset = (int)args-&gt;idx;
#endif
    args-&gt;idx += RAN_LEN;

    /* Session id */
    args-&gt;sessIdSz = input[args-&gt;idx++];
    if ((args-&gt;idx - args-&gt;begin) + args-&gt;sessIdSz &gt; helloSz)
        return BUFFER_ERROR;
    args-&gt;sessId = input + args-&gt;idx;
    args-&gt;idx += args-&gt;sessIdSz;

    ssl-&gt;options.haveSessionId = 1;

    /* Ciphersuite and compression check */
    if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN + OPAQUE8_LEN &gt; helloSz)
        return BUFFER_ERROR;

    /* Set the cipher suite from the message. */
    ssl-&gt;options.cipherSuite0 = input[args-&gt;idx++];
    ssl-&gt;options.cipherSuite  = input[args-&gt;idx++];
#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Chosen cipher suite:&quot;);
    WOLFSSL_MSG(GetCipherNameInternal(ssl-&gt;options.cipherSuite0,
                                      ssl-&gt;options.cipherSuite));
#endif

    /* Compression */
    b = input[args-&gt;idx++];
    if (b != 0) {
        WOLFSSL_MSG(&quot;Must be no compression types in list&quot;);
        WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
        return INVALID_PARAMETER;
    }

    if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN &gt; helloSz) {
        if (!ssl-&gt;options.downgrade)
            return BUFFER_ERROR;
#ifndef WOLFSSL_NO_TLS12
        /* Force client hello version 1.2 to work for static RSA. */
        ssl-&gt;chVersion.minor = TLSv1_2_MINOR;
        ssl-&gt;version.minor = TLSv1_2_MINOR;

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls) {
            ssl-&gt;chVersion.minor = DTLSv1_2_MINOR;
            ssl-&gt;version.minor = DTLSv1_2_MINOR;
            ret = Dtls13ClientDoDowngrade(ssl);
            if (ret != 0)
                return ret;
        }
#endif /* WOLFSSL_DTLS13 */

#endif
        ssl-&gt;options.haveEMS = 0;
        if (args-&gt;pv.minor &lt; ssl-&gt;options.minDowngrade) {
            SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
            return VERSION_ERROR;
        }
#ifndef WOLFSSL_NO_TLS12
        return DoServerHello(ssl, input, inOutIdx, helloSz);
#else
        SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
        return VERSION_ERROR;
#endif
    }

    if ((args-&gt;idx - args-&gt;begin) &lt; helloSz) {
        int foundVersion;

        /* Get extension length and length check. */
        if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN &gt; helloSz)
            return BUFFER_ERROR;
        ato16(&amp;input[args-&gt;idx], &amp;args-&gt;totalExtSz);
        args-&gt;idx += OPAQUE16_LEN;
        if ((args-&gt;idx - args-&gt;begin) + args-&gt;totalExtSz &gt; helloSz)
            return BUFFER_ERROR;

        /* Need to negotiate version first. */
        if ((ret = TLSX_ParseVersion(ssl, input + args-&gt;idx,
            args-&gt;totalExtSz, *extMsgType, &amp;foundVersion))) {
            return ret;
        }
        if (!foundVersion) {
            if (!ssl-&gt;options.downgrade) {
                WOLFSSL_MSG(&quot;Server trying to downgrade to version less than &quot;
                            &quot;TLS v1.3&quot;);
                SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }
#if defined(OPENSSL_EXTRA) || defined(HAVE_WEBSERVER) || \
    defined(WOLFSSL_WPAS_SMALL)
            /* Check if client has disabled TLS 1.2 */
            if (args-&gt;pv.minor == TLSv1_2_MINOR &amp;&amp;
                (ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TLSv1_2)
                == WOLFSSL_OP_NO_TLSv1_2)
            {
                WOLFSSL_MSG(&quot;\tOption set to not allow TLSv1.2&quot;);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }
#endif

            if (!ssl-&gt;options.dtls &amp;&amp;
                args-&gt;pv.minor &lt; ssl-&gt;options.minDowngrade) {
                SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }

            if (ssl-&gt;options.dtls &amp;&amp;
                args-&gt;pv.minor &gt; ssl-&gt;options.minDowngrade) {
                SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }

            ssl-&gt;version.minor = args-&gt;pv.minor;
            ssl-&gt;options.tls1_3 = 0;

#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                ret = Dtls13ClientDoDowngrade(ssl);
                if (ret != 0)
                    return ret;
            }
#endif /* WOLFSSL_DTLS13 */
        }
    }

#ifdef WOLFSSL_DTLS13
    /* we are sure that version is &gt;= v1.3 now, we can get rid of buffered
     * ClientHello that was buffered to re-compute the hash in case of
     * downgrade */
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;dtls13ClientHello != NULL) {
        XFREE(ssl-&gt;dtls13ClientHello, ssl-&gt;heap, DYNAMIC_TYPE_DTLS_MSG);
        ssl-&gt;dtls13ClientHello = NULL;
        ssl-&gt;dtls13ClientHelloSz = 0;
    }
#endif /* WOLFSSL_DTLS13 */

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_BUILD;
    } /* case TLS_ASYNC_BEGIN */
    FALL_THROUGH;

    case TLS_ASYNC_BUILD:
    case TLS_ASYNC_DO:
    {
    /* restore message type */
    *extMsgType = args-&gt;extMsgType;

    /* Parse and handle extensions, unless lower than TLS1.3. In that case,
     * extensions will be parsed in DoServerHello. */
    if (args-&gt;totalExtSz &gt; 0 &amp;&amp; IsAtLeastTLSv1_3(ssl-&gt;version)) {
        ret = TLSX_Parse(ssl, input + args-&gt;idx, args-&gt;totalExtSz,
            *extMsgType, NULL);
        if (ret != 0) {
        #ifdef WOLFSSL_ASYNC_CRYPT
            /* Handle async operation */
            if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                /* Mark message as not received so it can process again */
                ssl-&gt;msgsReceived.got_server_hello = 0;
            }
        #endif
            return ret;
        }

        if (*extMsgType == hello_retry_request) {
            /* Update counts to reflect change of message type. */
            ssl-&gt;msgsReceived.got_hello_retry_request = 1;
            ssl-&gt;msgsReceived.got_server_hello = 0;
        }
    }

    if (args-&gt;totalExtSz &gt; 0) {
        args-&gt;idx += args-&gt;totalExtSz;
    }

#ifdef WOLFSSL_DTLS_CID
    if (ssl-&gt;options.useDtlsCID &amp;&amp; *extMsgType == server_hello)
        DtlsCIDOnExtensionsParsed(ssl);
#endif /* WOLFSSL_DTLS_CID */

    if (IsAtLeastTLSv1_3(ssl-&gt;version)) {
        *inOutIdx = args-&gt;idx;
    }

    ssl-&gt;options.serverState = SERVER_HELLO_COMPLETE;

#ifdef HAVE_SECRET_CALLBACK
    if (ssl-&gt;sessionSecretCb != NULL
#ifdef HAVE_SESSION_TICKET
            &amp;&amp; ssl-&gt;session-&gt;ticketLen &gt; 0
#endif
            ) {
        int secretSz = SECRET_LEN;
        ret = ssl-&gt;sessionSecretCb(ssl, ssl-&gt;session-&gt;masterSecret,
                                   &amp;secretSz, ssl-&gt;sessionSecretCtx);
        if (ret != 0 || secretSz != SECRET_LEN) {
            WOLFSSL_ERROR_VERBOSE(SESSION_SECRET_CB_E);
            return SESSION_SECRET_CB_E;
        }
    }
#endif /* HAVE_SECRET_CALLBACK */

    /* Version only negotiated in extensions for TLS v1.3.
     * Only now do we know how to deal with session id.
     */
    if (!IsAtLeastTLSv1_3(ssl-&gt;version)) {
#ifndef WOLFSSL_NO_TLS12
        ssl-&gt;arrays-&gt;sessionIDSz = args-&gt;sessIdSz;

        if (ssl-&gt;arrays-&gt;sessionIDSz &gt; ID_LEN) {
            WOLFSSL_MSG(&quot;Invalid session ID size&quot;);
            ssl-&gt;arrays-&gt;sessionIDSz = 0;
            return BUFFER_ERROR;
        }
        else if (ssl-&gt;arrays-&gt;sessionIDSz) {
            XMEMCPY(ssl-&gt;arrays-&gt;sessionID, args-&gt;sessId,
                ssl-&gt;arrays-&gt;sessionIDSz);
            ssl-&gt;options.haveSessionId = 1;
        }

        /* Force client hello version 1.2 to work for static RSA. */
        if (ssl-&gt;options.dtls)
            ssl-&gt;chVersion.minor = DTLSv1_2_MINOR;
        else
            ssl-&gt;chVersion.minor = TLSv1_2_MINOR;
        /* Complete TLS v1.2 processing of ServerHello. */
        ret = DoServerHello(ssl, input, inOutIdx, helloSz);
#else
        WOLFSSL_MSG(&quot;Client using higher version, fatal error&quot;);
        WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
        ret = VERSION_ERROR;
#endif

        WOLFSSL_LEAVE(&quot;DoTls13ServerHello&quot;, ret);

        return ret;
    }

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_FINALIZE;
    } /* case TLS_ASYNC_BUILD || TLS_ASYNC_DO */
    FALL_THROUGH;

    case TLS_ASYNC_FINALIZE:
    {
#ifdef WOLFSSL_TLS13_MIDDLEBOX_COMPAT
    if (ssl-&gt;options.tls13MiddleBoxCompat) {
        if (args-&gt;sessIdSz == 0) {
            WOLFSSL_MSG(&quot;args-&gt;sessIdSz == 0&quot;);
            WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
            return INVALID_PARAMETER;
        }
        if (ssl-&gt;session-&gt;sessionIDSz != 0) {
            if (ssl-&gt;session-&gt;sessionIDSz != args-&gt;sessIdSz ||
                XMEMCMP(ssl-&gt;session-&gt;sessionID, args-&gt;sessId,
                    args-&gt;sessIdSz) != 0) {
                WOLFSSL_MSG(&quot;session id doesn&#039;t match&quot;);
                WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
                return INVALID_PARAMETER;
            }
        }
        else if (XMEMCMP(ssl-&gt;arrays-&gt;clientRandom, args-&gt;sessId,
                args-&gt;sessIdSz) != 0) {
            WOLFSSL_MSG(&quot;session id doesn&#039;t match client random&quot;);
            WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
            return INVALID_PARAMETER;
        }
    }
    else
#endif /* WOLFSSL_TLS13_MIDDLEBOX_COMPAT */
#ifdef WOLFSSL_QUIC
    if (WOLFSSL_IS_QUIC(ssl)) {
        if (args-&gt;sessIdSz != 0) {
            WOLFSSL_MSG(&quot;args-&gt;sessIdSz != 0&quot;);
            WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
            return INVALID_PARAMETER;
        }
    }
    else
#endif /* WOLFSSL_QUIC */
    if (args-&gt;sessIdSz != ssl-&gt;session-&gt;sessionIDSz || (args-&gt;sessIdSz &gt; 0 &amp;&amp;
        XMEMCMP(ssl-&gt;session-&gt;sessionID, args-&gt;sessId, args-&gt;sessIdSz) != 0))
    {
        WOLFSSL_MSG(&quot;Server sent different session id&quot;);
        WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
        return INVALID_PARAMETER;
    }

    ret = SetCipherSpecs(ssl);
    if (ret != 0)
        return ret;

#if defined(HAVE_ECH)
    /* check for acceptConfirmation and HashInput with 8 0 bytes */
    if (ssl-&gt;options.useEch == 1 &amp;&amp; !ssl-&gt;options.disableECH) {
        ret = EchCheckAcceptance(ssl, input, args-&gt;serverRandomOffset, (int)helloSz);
        if (ret != 0)
            return ret;
    }
#endif

#ifdef HAVE_NULL_CIPHER
    if (ssl-&gt;options.cipherSuite0 == ECC_BYTE &amp;&amp;
                              (ssl-&gt;options.cipherSuite == TLS_SHA256_SHA256 ||
                               ssl-&gt;options.cipherSuite == TLS_SHA384_SHA384)) {
        ;
    }
    else
#endif
#if defined(WOLFSSL_SM4_GCM) &amp;&amp; defined(WOLFSSL_SM3)
    if (ssl-&gt;options.cipherSuite0 == CIPHER_BYTE &amp;&amp;
            ssl-&gt;options.cipherSuite == TLS_SM4_GCM_SM3) {
        ; /* Do nothing. */
    }
    else
#endif
#if defined(WOLFSSL_SM4_CCM) &amp;&amp; defined(WOLFSSL_SM3)
    if (ssl-&gt;options.cipherSuite0 == CIPHER_BYTE &amp;&amp;
            ssl-&gt;options.cipherSuite == TLS_SM4_CCM_SM3) {
        ; /* Do nothing. */
    }
    else
#endif
    /* Check that the negotiated ciphersuite matches protocol version. */
    if (ssl-&gt;options.cipherSuite0 != TLS13_BYTE) {
        WOLFSSL_MSG(&quot;Server sent non-TLS13 cipher suite in TLS 1.3 packet&quot;);
        WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
        return INVALID_PARAMETER;
    }

    suite[0] = ssl-&gt;options.cipherSuite0;
    suite[1] = ssl-&gt;options.cipherSuite;
    if (!FindSuiteSSL(ssl, suite)) {
        WOLFSSL_MSG(&quot;Cipher suite not supported on client&quot;);
        WOLFSSL_ERROR_VERBOSE(MATCH_SUITE_ERROR);
        return MATCH_SUITE_ERROR;
    }

    if (*extMsgType == server_hello) {
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
        PreSharedKey* psk = NULL;
        TLSX* ext = TLSX_Find(ssl-&gt;extensions, TLSX_PRE_SHARED_KEY);
        if (ext != NULL)
            psk = (PreSharedKey*)ext-&gt;data;
        while (psk != NULL &amp;&amp; !psk-&gt;chosen)
            psk = psk-&gt;next;
        if (psk == NULL) {
            ssl-&gt;options.resuming = 0;
            ssl-&gt;arrays-&gt;psk_keySz = 0;
            XMEMSET(ssl-&gt;arrays-&gt;psk_key, 0, MAX_PSK_KEY_LEN);
        }
        else {
            if ((ret = SetupPskKey(ssl, psk, 0)) != 0)
                return ret;
            ssl-&gt;options.pskNegotiated = 1;
        }
#endif

        /* sanity check on PSK / KSE */
        if (
    #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
            ssl-&gt;options.pskNegotiated == 0 &amp;&amp;
    #endif
            ssl-&gt;session-&gt;namedGroup == 0) {
            return EXT_MISSING;
        }

        ssl-&gt;keys.encryptionOn = 1;
        ssl-&gt;options.serverState = SERVER_HELLO_COMPLETE;

    }
    else {
        ssl-&gt;options.tls1_3 = 1;
        ssl-&gt;options.serverState = SERVER_HELLO_RETRY_REQUEST_COMPLETE;

        ret = RestartHandshakeHash(ssl);
    }

    break;
    } /* case TLS_ASYNC_FINALIZE */
    default:
        ret = INPUT_CASE_ERROR;
    } /* switch (ssl-&gt;options.asyncState) */

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ret == 0)
        FreeAsyncCtx(ssl, 0);
#endif

    WOLFSSL_LEAVE(&quot;DoTls13ServerHello&quot;, ret);
    WOLFSSL_END(WC_FUNC_SERVER_HELLO_DO);

    return ret;
}

/* handle processing TLS 1.3 encrypted_extensions (8) */
/* Parse and handle an EncryptedExtensions message.
 * Only a client will receive this message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of
 *           EncryptedExtensions.
 *           On exit, the index of byte after the EncryptedExtensions
 *           message.
 * totalSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13EncryptedExtensions(WOLFSSL* ssl, const byte* input,
                                      word32* inOutIdx, word32 totalSz)
{
    int    ret;
    word32 begin = *inOutIdx;
    word32 i = begin;
    word16 totalExtSz;

    WOLFSSL_START(WC_FUNC_ENCRYPTED_EXTENSIONS_DO);
    WOLFSSL_ENTER(&quot;DoTls13EncryptedExtensions&quot;);

#ifdef WOLFSSL_CALLBACKS
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;EncryptedExtensions&quot;);
    if (ssl-&gt;toInfoOn) AddLateName(&quot;EncryptedExtensions&quot;, &amp;ssl-&gt;timeoutInfo);
#endif

    /* Length field of extension data. */
    if (totalSz &lt; OPAQUE16_LEN)
        return BUFFER_ERROR;
    ato16(&amp;input[i], &amp;totalExtSz);
    i += OPAQUE16_LEN;

    /* Extension data. */
    if (i - begin + totalExtSz &gt; totalSz)
        return BUFFER_ERROR;
    if ((ret = TLSX_Parse(ssl, input + i, totalExtSz, encrypted_extensions,
                                                                       NULL))) {
        return ret;
    }

    /* Move index to byte after message. */
    *inOutIdx = i + totalExtSz;

    /* Always encrypted. */
    *inOutIdx += ssl-&gt;keys.padSz;

#ifdef WOLFSSL_EARLY_DATA
    if (ssl-&gt;earlyData != no_early_data) {
        TLSX* ext = TLSX_Find(ssl-&gt;extensions, TLSX_EARLY_DATA);
        if (ext == NULL || !ext-&gt;val)
            ssl-&gt;earlyData = no_early_data;
    }
#endif

#ifdef WOLFSSL_EARLY_DATA
    if (ssl-&gt;earlyData == no_early_data) {
        ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY);
        if (ret != 0)
            return ret;
    }
#endif

    ssl-&gt;options.serverState = SERVER_ENCRYPTED_EXTENSIONS_COMPLETE;

    WOLFSSL_LEAVE(&quot;DoTls13EncryptedExtensions&quot;, ret);
    WOLFSSL_END(WC_FUNC_ENCRYPTED_EXTENSIONS_DO);

    return ret;
}

#ifndef NO_CERTS
/* handle processing TLS v1.3 certificate_request (13) */
/* Handle a TLS v1.3 CertificateRequest message.
 * This message is always encrypted.
 * Only a client will receive this message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of CertificateRequest.
 *           On exit, the index of byte after the CertificateRequest message.
 * size      The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13CertificateRequest(WOLFSSL* ssl, const byte* input,
                                     word32* inOutIdx, word32 size)
{
    word16      len;
    word32      begin = *inOutIdx;
    int         ret = 0;
    Suites      peerSuites;
#ifdef WOLFSSL_POST_HANDSHAKE_AUTH
    CertReqCtx* certReqCtx;
#endif

    WOLFSSL_START(WC_FUNC_CERTIFICATE_REQUEST_DO);
    WOLFSSL_ENTER(&quot;DoTls13CertificateRequest&quot;);

    XMEMSET(&amp;peerSuites, 0, sizeof(Suites));

#ifdef WOLFSSL_CALLBACKS
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;CertificateRequest&quot;);
    if (ssl-&gt;toInfoOn) AddLateName(&quot;CertificateRequest&quot;, &amp;ssl-&gt;timeoutInfo);
#endif

#ifdef OPENSSL_EXTRA
    if ((ret = CertSetupCbWrapper(ssl)) != 0)
        return ret;
#endif

    if (OPAQUE8_LEN &gt; size)
        return BUFFER_ERROR;

    /* Length of the request context. */
    len = input[(*inOutIdx)++];
    if ((*inOutIdx - begin) + len &gt; size)
        return BUFFER_ERROR;
    if (ssl-&gt;options.connectState &lt; FINISHED_DONE &amp;&amp; len &gt; 0)
        return BUFFER_ERROR;

#ifdef WOLFSSL_POST_HANDSHAKE_AUTH
    /* CertReqCtx has one byte at end for context value.
     * Increase size to handle other implementations sending more than one byte.
     * That is, allocate extra space, over one byte, to hold the context value.
     */
    certReqCtx = (CertReqCtx*)XMALLOC(sizeof(CertReqCtx) + len - 1, ssl-&gt;heap,
                                                       DYNAMIC_TYPE_TMP_BUFFER);
    if (certReqCtx == NULL)
        return MEMORY_E;
    certReqCtx-&gt;next = ssl-&gt;certReqCtx;
    certReqCtx-&gt;len = len;
    XMEMCPY(&amp;certReqCtx-&gt;ctx, input + *inOutIdx, len);
    ssl-&gt;certReqCtx = certReqCtx;
#endif
    *inOutIdx += len;

    /* TODO: Add support for more extensions:
     *   signed_certificate_timestamp, certificate_authorities, oid_filters.
     */
    /* Certificate extensions */
    if ((*inOutIdx - begin) + OPAQUE16_LEN &gt; size)
        return BUFFER_ERROR;
    ato16(input + *inOutIdx, &amp;len);
    *inOutIdx += OPAQUE16_LEN;
    if ((*inOutIdx - begin) + len &gt; size)
        return BUFFER_ERROR;
    if (len == 0)
        return INVALID_PARAMETER;
    if ((ret = TLSX_Parse(ssl, input + *inOutIdx, len, certificate_request,
                                                                &amp;peerSuites))) {
        return ret;
    }
    *inOutIdx += len;

    if ((ssl-&gt;buffers.certificate &amp;&amp; ssl-&gt;buffers.certificate-&gt;buffer &amp;&amp;
        ((ssl-&gt;buffers.key &amp;&amp; ssl-&gt;buffers.key-&gt;buffer)
        #ifdef HAVE_PK_CALLBACKS
            || wolfSSL_CTX_IsPrivatePkSet(ssl-&gt;ctx)
        #endif
    ))
        #ifdef OPENSSL_EXTRA
            || ssl-&gt;ctx-&gt;certSetupCb != NULL
        #endif
            ) {
        if (PickHashSigAlgo(ssl, peerSuites.hashSigAlgo,
                            peerSuites.hashSigAlgoSz, 0) != 0) {
            WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
            return INVALID_PARAMETER;
        }
        ssl-&gt;options.sendVerify = SEND_CERT;
    }
    else {
#ifndef WOLFSSL_NO_CLIENT_CERT_ERROR
        ssl-&gt;options.sendVerify = SEND_BLANK_CERT;
#else
        WOLFSSL_MSG(&quot;Certificate required but none set on client&quot;);
        SendAlert(ssl, alert_fatal, illegal_parameter);
        WOLFSSL_ERROR_VERBOSE(NO_CERT_ERROR);
        return NO_CERT_ERROR;
#endif
    }

    /* This message is always encrypted so add encryption padding. */
    *inOutIdx += ssl-&gt;keys.padSz;

    WOLFSSL_LEAVE(&quot;DoTls13CertificateRequest&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_REQUEST_DO);

    return ret;
}
#endif /* !NO_CERTS */
#endif /* !NO_WOLFSSL_CLIENT */

#ifndef NO_WOLFSSL_SERVER
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
/* Refine list of supported cipher suites to those common to server and client.
 *
 * ssl         SSL/TLS object.
 * peerSuites  The peer&#039;s advertised list of supported cipher suites.
 */
static void RefineSuites(WOLFSSL* ssl, Suites* peerSuites)
{
    byte   suites[WOLFSSL_MAX_SUITE_SZ];
    word16 suiteSz = 0;
    word16 i;
    word16 j;

    if (AllocateSuites(ssl) != 0)
        return;

    XMEMSET(suites, 0, sizeof(suites));

    if (!ssl-&gt;options.useClientOrder) {
        /* Server order refining. */
        for (i = 0; i &lt; ssl-&gt;suites-&gt;suiteSz; i += 2) {
            for (j = 0; j &lt; peerSuites-&gt;suiteSz; j += 2) {
                if ((ssl-&gt;suites-&gt;suites[i+0] == peerSuites-&gt;suites[j+0]) &amp;&amp;
                    (ssl-&gt;suites-&gt;suites[i+1] == peerSuites-&gt;suites[j+1])) {
                    suites[suiteSz++] = peerSuites-&gt;suites[j+0];
                    suites[suiteSz++] = peerSuites-&gt;suites[j+1];
                    break;
                }
            }
            if (suiteSz == WOLFSSL_MAX_SUITE_SZ)
                break;
        }
    }
    else {
        /* Client order refining. */
        for (j = 0; j &lt; peerSuites-&gt;suiteSz; j += 2) {
            for (i = 0; i &lt; ssl-&gt;suites-&gt;suiteSz; i += 2) {
                if ((ssl-&gt;suites-&gt;suites[i+0] == peerSuites-&gt;suites[j+0]) &amp;&amp;
                    (ssl-&gt;suites-&gt;suites[i+1] == peerSuites-&gt;suites[j+1])) {
                    suites[suiteSz++] = peerSuites-&gt;suites[j+0];
                    suites[suiteSz++] = peerSuites-&gt;suites[j+1];
                    break;
                }
            }
            if (suiteSz == WOLFSSL_MAX_SUITE_SZ)
                break;
        }
    }

    ssl-&gt;suites-&gt;suiteSz = suiteSz;
    XMEMCPY(ssl-&gt;suites-&gt;suites, &amp;suites, sizeof(suites));
#ifdef WOLFSSL_DEBUG_TLS
    {
        int ii;
        WOLFSSL_MSG(&quot;Refined Ciphers:&quot;);
        for (ii = 0 ; ii &lt; ssl-&gt;suites-&gt;suiteSz; ii += 2) {
            WOLFSSL_MSG(GetCipherNameInternal(ssl-&gt;suites-&gt;suites[ii+0],
                                              ssl-&gt;suites-&gt;suites[ii+1]));
        }
    }
#endif
}


#ifndef NO_PSK
int FindPskSuite(const WOLFSSL* ssl, PreSharedKey* psk, byte* psk_key,
        word32* psk_keySz, const byte* suite, int* found, byte* foundSuite)
{
    const char* cipherName = NULL;
    byte        cipherSuite0 = TLS13_BYTE;
    byte        cipherSuite  = WOLFSSL_DEF_PSK_CIPHER;
    int         ret = 0;

    *found = 0;
    (void)suite;

    if (ssl-&gt;options.server_psk_tls13_cb != NULL) {
         *psk_keySz = ssl-&gt;options.server_psk_tls13_cb((WOLFSSL*)ssl,
             (char*)psk-&gt;identity, psk_key, MAX_PSK_KEY_LEN, &amp;cipherName);
         if (*psk_keySz != 0) {
             int cipherSuiteFlags = WOLFSSL_CIPHER_SUITE_FLAG_NONE;
             *found = (GetCipherSuiteFromName(cipherName, &amp;cipherSuite0,
                 &amp;cipherSuite, NULL, NULL, &amp;cipherSuiteFlags) == 0);
             (void)cipherSuiteFlags;
         }
    }
    if (*found == 0 &amp;&amp; (ssl-&gt;options.server_psk_cb != NULL)) {
         *psk_keySz = ssl-&gt;options.server_psk_cb((WOLFSSL*)ssl,
                             (char*)psk-&gt;identity, psk_key,
                             MAX_PSK_KEY_LEN);
         *found = (*psk_keySz != 0);
    }
    if (*found) {
        if (*psk_keySz &gt; MAX_PSK_KEY_LEN &amp;&amp;
            *((int*)psk_keySz) != WC_NO_ERR_TRACE(USE_HW_PSK)) {
            WOLFSSL_MSG(&quot;Key len too long in FindPsk()&quot;);
            ret = PSK_KEY_ERROR;
            WOLFSSL_ERROR_VERBOSE(ret);
            *found = 0;
        }
        if (ret == 0) {
        #if !defined(WOLFSSL_PSK_ONE_ID) &amp;&amp; !defined(WOLFSSL_PRIORITIZE_PSK)
            /* Check whether PSK ciphersuite is in SSL. */
            *found = (suite[0] == cipherSuite0) &amp;&amp; (suite[1] == cipherSuite);
        #else
            (void)suite;
            /* Check whether PSK ciphersuite is in SSL. */
            {
                byte s[2] = {
                    cipherSuite0,
                    cipherSuite,
                };
                *found = FindSuiteSSL(ssl, s);
            }
        #endif
        }
    }
    if (*found &amp;&amp; foundSuite != NULL) {
        foundSuite[0] = cipherSuite0;
        foundSuite[1] = cipherSuite;
    }

    return ret;
}

/* Attempt to find the PSK (not session ticket) that matches.
 *
 * @param [in, out] ssl    The SSL/TLS object.
 * @param [in]      psk    A pre-shared key from the extension.
 * @param [out]     suite  Cipher suite to use with PSK.
 * @param [out]     err    Error code.
 *                         PSK_KEY_ERROR when key is too big or ticket age is
 *                         invalid,
 *                         UNSUPPORTED_SUITE on invalid suite.
 *                         Other error when attempting to derive early secret.
 * @return  1 when a match found - but check error code.
 * @return  0 when no match found.
 */
static int FindPsk(WOLFSSL* ssl, PreSharedKey* psk, const byte* suite, int* err)
{
    int         ret = 0;
    int         found = 0;
    byte        foundSuite[SUITE_LEN];

    WOLFSSL_ENTER(&quot;FindPsk&quot;);

    ret = FindPskSuite(ssl, psk, ssl-&gt;arrays-&gt;psk_key, &amp;ssl-&gt;arrays-&gt;psk_keySz,
                       suite, &amp;found, foundSuite);
    if (ret == 0 &amp;&amp; found) {
        /* Default to ciphersuite if cb doesn&#039;t specify. */
        ssl-&gt;options.resuming = 0;
        /* Don&#039;t send certificate request when using PSK. */
        ssl-&gt;options.verifyPeer = 0;

        /* PSK age is always zero. */
        if (psk-&gt;ticketAge != 0) {
            ret = PSK_KEY_ERROR;
            WOLFSSL_ERROR_VERBOSE(ret);
        }
        if (ret == 0) {
            /* Set PSK ciphersuite into SSL. */
            ssl-&gt;options.cipherSuite0 = foundSuite[0];
            ssl-&gt;options.cipherSuite  = foundSuite[1];
            ret = SetCipherSpecs(ssl);
        }
        if (ret == 0) {
            /* Derive the early secret using the PSK. */
            ret = DeriveEarlySecret(ssl);
        }
        if (ret == 0) {
            /* PSK negotiation has succeeded */
            ssl-&gt;options.isPSK = 1;
            /* SERVER: using PSK for peer authentication. */
            ssl-&gt;options.peerAuthGood = 1;
        }
    }

    *err = ret;
    WOLFSSL_LEAVE(&quot;FindPsk&quot;, found);
    WOLFSSL_LEAVE(&quot;FindPsk&quot;, ret);
    return found;
}
#endif /* !NO_PSK */

/* Handle any Pre-Shared Key (PSK) extension.
 * Find a PSK that supports the cipher suite passed in.
 *
 * ssl         SSL/TLS object.
 * suite       Cipher suite to find PSK for.
 * usingPSK    1=Indicates handshake is using Pre-Shared Keys (2=Ephemeral)
 * first       Set to 1 if first in extension
 * returns 0 on success and otherwise failure.
 */
static int DoPreSharedKeys(WOLFSSL* ssl, const byte* input, word32 inputSz,
    const byte* suite, int* usingPSK, int* first)
{
    int           ret = 0;
    TLSX*         ext;
    PreSharedKey* current;
    byte          binderKey[WC_MAX_DIGEST_SIZE];
    byte          binder[WC_MAX_DIGEST_SIZE];
    word32        binderLen;

    #ifdef NO_PSK
        (void) suite; /* to avoid unused var warning when not used */
    #endif

    WOLFSSL_ENTER(&quot;DoPreSharedKeys&quot;);

    (void)suite;

    ext = TLSX_Find(ssl-&gt;extensions, TLSX_PRE_SHARED_KEY);
    if (ext == NULL) {
        WOLFSSL_MSG(&quot;No pre shared extension keys found&quot;);
        return BAD_FUNC_ARG;
    }

    /* Look through all client&#039;s pre-shared keys for a match. */
    for (current = (PreSharedKey*)ext-&gt;data; current != NULL;
            current = current-&gt;next) {
    #ifndef NO_PSK
        if (current-&gt;identityLen &gt; MAX_PSK_ID_LEN) {
            return BUFFER_ERROR;
        }
        XMEMCPY(ssl-&gt;arrays-&gt;client_identity, current-&gt;identity,
                current-&gt;identityLen);
        ssl-&gt;arrays-&gt;client_identity[current-&gt;identityLen] = &#039;\0&#039;;
    #endif

    #ifdef HAVE_SESSION_TICKET
        /* Decode the identity. */
        switch (current-&gt;decryptRet) {
            case PSK_DECRYPT_NONE:
                ret = DoClientTicket_ex(ssl, current, 1);
                /* psk-&gt;sess may be set. Need to clean up later. */
                break;
            case PSK_DECRYPT_OK:
                ret = WOLFSSL_TICKET_RET_OK;
                break;
            case PSK_DECRYPT_CREATE:
                ret = WOLFSSL_TICKET_RET_CREATE;
                break;
            case PSK_DECRYPT_FAIL:
                ret = WOLFSSL_TICKET_RET_REJECT;
                break;
        }

        #ifdef WOLFSSL_ASYNC_CRYPT
        if (ret == WC_NO_ERR_TRACE(WC_PENDING_E))
            return ret;
        #endif

        if (ret != WOLFSSL_TICKET_RET_OK &amp;&amp; current-&gt;sess_free_cb != NULL) {
            current-&gt;sess_free_cb(ssl, current-&gt;sess,
                    &amp;current-&gt;sess_free_cb_ctx);
            current-&gt;sess = NULL;
            XMEMSET(&amp;current-&gt;sess_free_cb_ctx, 0,
                    sizeof(psk_sess_free_cb_ctx));
        }
        if (ret == WOLFSSL_TICKET_RET_OK) {
            ret = DoClientTicketCheck(ssl, current, ssl-&gt;timeout, suite);
            if (ret == 0)
                DoClientTicketFinalize(ssl, current-&gt;it, current-&gt;sess);
            if (current-&gt;sess_free_cb != NULL) {
                current-&gt;sess_free_cb(ssl, current-&gt;sess,
                        &amp;current-&gt;sess_free_cb_ctx);
                current-&gt;sess = NULL;
                XMEMSET(&amp;current-&gt;sess_free_cb_ctx, 0,
                        sizeof(psk_sess_free_cb_ctx));
            }
            if (ret != 0)
                continue;

            /* SERVER: using secret in session ticket for peer auth. */
            ssl-&gt;options.peerAuthGood = 1;

        #ifdef WOLFSSL_EARLY_DATA
            ssl-&gt;options.maxEarlyDataSz = ssl-&gt;session-&gt;maxEarlyDataSz;
        #endif
            /* Use the same cipher suite as before and set up for use. */
            ssl-&gt;options.cipherSuite0   = ssl-&gt;session-&gt;cipherSuite0;
            ssl-&gt;options.cipherSuite    = ssl-&gt;session-&gt;cipherSuite;
            ret = SetCipherSpecs(ssl);
            if (ret != 0)
                return ret;

            /* Resumption PSK is resumption master secret. */
            ssl-&gt;arrays-&gt;psk_keySz = ssl-&gt;specs.hash_size;
            if ((ret = DeriveResumptionPSK(ssl, ssl-&gt;session-&gt;ticketNonce.data,
                ssl-&gt;session-&gt;ticketNonce.len, ssl-&gt;arrays-&gt;psk_key)) != 0) {
                return ret;
            }

            /* Derive the early secret using the PSK. */
            ret = DeriveEarlySecret(ssl);
            if (ret != 0)
                return ret;

            /* Hash data up to binders for deriving binders in PSK extension. */
            ret = HashInput(ssl, input, (int)inputSz);
            if (ret &lt; 0)
                return ret;

            /* Derive the binder key to use with HMAC. */
            ret = DeriveBinderKeyResume(ssl, binderKey);
            if (ret != 0)
                return ret;
        }
        else
    #endif /* HAVE_SESSION_TICKET */
    #ifndef NO_PSK
        if (FindPsk(ssl, current, suite, &amp;ret)) {
            if (ret != 0)
                return ret;

            ret = HashInput(ssl, input, (int)inputSz);
            if (ret &lt; 0)
                return ret;

            /* Derive the binder key to use with HMAC. */
            ret = DeriveBinderKey(ssl, binderKey);
            if (ret != 0)
                return ret;
        }
        else
    #endif
        {
            continue;
        }

        ssl-&gt;options.sendVerify = 0;

        /* Derive the Finished message secret. */
        ret = DeriveFinishedSecret(ssl, binderKey,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   0 /* neither end */);
        if (ret != 0)
            return ret;

        /* Derive the binder and compare with the one in the extension. */
        ret = BuildTls13HandshakeHmac(ssl,
                         ssl-&gt;keys.client_write_MAC_secret, binder, &amp;binderLen);
        if (ret != 0)
            return ret;
        if (binderLen != current-&gt;binderLen ||
                             XMEMCMP(binder, current-&gt;binder, binderLen) != 0) {
            WOLFSSL_ERROR_VERBOSE(BAD_BINDER);
            return BAD_BINDER;
        }

        /* This PSK works, no need to try any more. */
        current-&gt;chosen = 1;
        ext-&gt;resp = 1;
        break;
    }

    if (current == NULL) {
#ifdef WOLFSSL_PSK_ID_PROTECTION
    #ifndef NO_CERTS
        if (ssl-&gt;buffers.certChainCnt != 0)
            return 0;
    #endif
        WOLFSSL_ERROR_VERBOSE(BAD_BINDER);
        return BAD_BINDER;
#else
        return 0;
#endif
    }

    *first = (current == ext-&gt;data);
    *usingPSK = 1;

    WOLFSSL_LEAVE(&quot;DoPreSharedKeys&quot;, ret);

    return ret;
}

/* Handle any Pre-Shared Key (PSK) extension.
 * Must do this in ClientHello as it requires a hash of the truncated message.
 * Don&#039;t know size of binders until Pre-Shared Key extension has been parsed.
 *
 * ssl         SSL/TLS object.
 * input       ClientHello message.
 * helloSz     Size of the ClientHello message (including binders if present).
 * clSuites    Client&#039;s cipher suite list.
 * usingPSK    Indicates handshake is using Pre-Shared Keys.
 */
static int CheckPreSharedKeys(WOLFSSL* ssl, const byte* input, word32 helloSz,
                              Suites* clSuites, int* usingPSK)
{
    int    ret;
    TLSX*  ext;
    word16 bindersLen;
    int    first = 0;
#ifndef WOLFSSL_PSK_ONE_ID
    int    i;
    const Suites* suites;
#else
    byte   suite[2];
#endif

    WOLFSSL_ENTER(&quot;CheckPreSharedKeys&quot;);

    ext = TLSX_Find(ssl-&gt;extensions, TLSX_PRE_SHARED_KEY);
    if (ext == NULL) {
#ifdef WOLFSSL_EARLY_DATA
        ssl-&gt;earlyData = no_early_data;
#endif
        if (usingPSK)
            *usingPSK = 0;
        /* Hash data up to binders for deriving binders in PSK extension. */
        ret = HashInput(ssl, input,  (int)helloSz);
        return ret;
    }

    /* Extensions pushed on stack/list and PSK must be last. */
    if (ssl-&gt;extensions != ext) {
        WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
        return PSK_KEY_ERROR;
    }

    /* Assume we are going to resume with a pre-shared key. */
    ssl-&gt;options.resuming = 1;

    /* Find the pre-shared key extension and calculate hash of truncated
     * ClientHello for binders.
     */
    ret = TLSX_PreSharedKey_GetSizeBinders((PreSharedKey*)ext-&gt;data,
                                                     client_hello, &amp;bindersLen);
    if (ret &lt; 0)
        return ret;

    /* Refine list for PSK processing. */
    RefineSuites(ssl, clSuites);
#ifndef WOLFSSL_PSK_ONE_ID
    if (usingPSK == NULL)
        return BAD_FUNC_ARG;

    /* set after refineSuites, to avoid taking a stale ptr to ctx-&gt;Suites */
    suites = WOLFSSL_SUITES(ssl);
    /* Server list has only common suites from refining in server or client
     * order. */
    for (i = 0; !(*usingPSK) &amp;&amp; i &lt; suites-&gt;suiteSz; i += 2) {
        ret = DoPreSharedKeys(ssl, input, helloSz - bindersLen,
                suites-&gt;suites + i, usingPSK, &amp;first);
        if (ret != 0) {
#ifdef HAVE_SESSION_TICKET
#ifdef WOLFSSL_ASYNC_CRYPT
            if (ret != WC_NO_ERR_TRACE(WC_PENDING_E))
#endif
                CleanupClientTickets((PreSharedKey*)ext-&gt;data);
#endif
            WOLFSSL_MSG_EX(&quot;DoPreSharedKeys: %d&quot;, ret);
            return ret;
        }
    }
#ifdef HAVE_SESSION_TICKET
    CleanupClientTickets((PreSharedKey*)ext-&gt;data);
#endif
#else
    ret = DoPreSharedKeys(ssl, input, helloSz - bindersLen, suite, usingPSK,
        &amp;first);
    if (ret != 0) {
        WOLFSSL_MSG_EX(&quot;DoPreSharedKeys: %d&quot;, ret);
        return ret;
    }
#endif

    if (*usingPSK) {
        /* While verifying the selected PSK, we updated the
         * handshake hash up to the binder bytes in the PSK extensions.
         * Continuing, we need the rest of the ClientHello hashed as well.
         */
        ret = HashRaw(ssl, input + helloSz - bindersLen, bindersLen);
    }
    else {
        /* No suitable PSK found, Hash the complete ClientHello,
         * as caller expect it after we return */
        ret = HashInput(ssl, input,  (int)helloSz);
    }
    if (ret != 0)
        return ret;

    if (*usingPSK != 0) {
        word32 modes;
    #ifdef WOLFSSL_EARLY_DATA
        TLSX*  extEarlyData;

        extEarlyData = TLSX_Find(ssl-&gt;extensions, TLSX_EARLY_DATA);
        if (extEarlyData != NULL) {
            /* Check if accepting early data and first PSK. */
            if (ssl-&gt;earlyData != no_early_data &amp;&amp; first) {
                extEarlyData-&gt;resp = 1;

                /* Derive early data decryption key. */
                ret = DeriveTls13Keys(ssl, early_data_key, DECRYPT_SIDE_ONLY,
                                                                             1);
                if (ret != 0)
                    return ret;
                if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
                    return ret;

                ssl-&gt;keys.encryptionOn = 1;

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    ret = Dtls13NewEpoch(ssl,
                        w64From32(0x0, DTLS13_EPOCH_EARLYDATA),
                        DECRYPT_SIDE_ONLY);
                    if (ret != 0)
                        return ret;
                }
#endif /* WOLFSSL_DTLS13 */

                ssl-&gt;earlyData = process_early_data;
            }
            else
                extEarlyData-&gt;resp = 0;
        }
    #endif

        /* Get the PSK key exchange modes the client wants to negotiate. */
        ext = TLSX_Find(ssl-&gt;extensions, TLSX_PSK_KEY_EXCHANGE_MODES);
        if (ext == NULL) {
            WOLFSSL_ERROR_VERBOSE(MISSING_HANDSHAKE_DATA);
            return MISSING_HANDSHAKE_DATA;
        }
        modes = ext-&gt;val;

    #ifdef HAVE_SUPPORTED_CURVES
        ext = TLSX_Find(ssl-&gt;extensions, TLSX_KEY_SHARE);
        /* Use (EC)DHE for forward-security if possible. */
        if ((modes &amp; (1 &lt;&lt; PSK_DHE_KE)) != 0 &amp;&amp; !ssl-&gt;options.noPskDheKe &amp;&amp;
                                                                  ext != NULL) {
            /* Only use named group used in last session. */
            ssl-&gt;namedGroup = ssl-&gt;session-&gt;namedGroup;

            *usingPSK = 2; /* generate new ephemeral key */
        }
        else if (ssl-&gt;options.onlyPskDheKe) {
            return PSK_KEY_ERROR;
        }
        else
    #endif
        {
            if ((modes &amp; (1 &lt;&lt; PSK_KE)) == 0) {
                WOLFSSL_MSG(&quot;psk_ke mode does not allow key share&quot;);
                WOLFSSL_ERROR_VERBOSE(PSK_KEY_ERROR);
                return PSK_KEY_ERROR;
            }
            ssl-&gt;options.noPskDheKe = 1;
            ssl-&gt;arrays-&gt;preMasterSz = 0;

            *usingPSK = 1;
        }
    }
#ifdef WOLFSSL_PSK_ID_PROTECTION
    else {
    #ifndef NO_CERTS
        if (ssl-&gt;buffers.certChainCnt != 0)
            return 0;
    #endif
        WOLFSSL_ERROR_VERBOSE(BAD_BINDER);
        return BAD_BINDER;
    }
#endif

    WOLFSSL_LEAVE(&quot;CheckPreSharedKeys&quot;, ret);

    return 0;
}
#endif /* HAVE_SESSION_TICKET || !NO_PSK */

#if defined(WOLFSSL_SEND_HRR_COOKIE)
/* Check that the Cookie data&#039;s integrity.
 *
 * ssl       SSL/TLS object.
 * cookie    The cookie data - hash and MAC.
 * cookieSz  The length of the cookie data in bytes.
 * returns Length of the hash on success, otherwise failure.
 */
int TlsCheckCookie(const WOLFSSL* ssl, const byte* cookie, word16 cookieSz)
{
    int  ret;
    byte mac[WC_MAX_DIGEST_SIZE] = {0};
    Hmac cookieHmac;
    byte cookieType = 0;
    byte macSz = 0;

    if (ssl-&gt;buffers.tls13CookieSecret.buffer == NULL ||
            ssl-&gt;buffers.tls13CookieSecret.length == 0) {
        WOLFSSL_MSG(&quot;Missing DTLS 1.3 cookie secret&quot;);
        return COOKIE_ERROR;
    }

#if !defined(NO_SHA) &amp;&amp; defined(NO_SHA256)
    cookieType = SHA;
    macSz = WC_SHA_DIGEST_SIZE;
#endif /* NO_SHA */
#ifndef NO_SHA256
    cookieType = WC_SHA256;
    macSz = WC_SHA256_DIGEST_SIZE;
#endif /* NO_SHA256 */

    if (cookieSz &lt; ssl-&gt;specs.hash_size + macSz)
        return HRR_COOKIE_ERROR;
    cookieSz -= macSz;

    ret = wc_HmacInit(&amp;cookieHmac, ssl-&gt;heap, ssl-&gt;devId);
    if (ret == 0) {
        ret = wc_HmacSetKey(&amp;cookieHmac, cookieType,
                            ssl-&gt;buffers.tls13CookieSecret.buffer,
                            ssl-&gt;buffers.tls13CookieSecret.length);
    }
    if (ret == 0)
        ret = wc_HmacUpdate(&amp;cookieHmac, cookie, cookieSz);
#ifdef WOLFSSL_DTLS13
    /* Tie cookie to peer address */
    if (ret == 0) {
        /* peerLock not necessary. Still in handshake phase. */
        if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;buffers.dtlsCtx.peer.sz &gt; 0) {
            ret = wc_HmacUpdate(&amp;cookieHmac,
                (byte*)ssl-&gt;buffers.dtlsCtx.peer.sa,
                ssl-&gt;buffers.dtlsCtx.peer.sz);
        }
    }
#endif
    if (ret == 0)
        ret = wc_HmacFinal(&amp;cookieHmac, mac);

    wc_HmacFree(&amp;cookieHmac);
    if (ret != 0)
        return ret;

    if (ConstantCompare(cookie + cookieSz, mac, macSz) != 0) {
        WOLFSSL_ERROR_VERBOSE(HRR_COOKIE_ERROR);
        return HRR_COOKIE_ERROR;
    }
    return cookieSz;
}

/* Length of the KeyShare Extension */
#define HRR_KEY_SHARE_SZ   (OPAQUE16_LEN + OPAQUE16_LEN + OPAQUE16_LEN)
/* Length of the Supported Versions Extension */
#define HRR_VERSIONS_SZ    (OPAQUE16_LEN + OPAQUE16_LEN + OPAQUE16_LEN)
/* Length of the Cookie Extension excluding cookie data */
#define HRR_COOKIE_HDR_SZ  (OPAQUE16_LEN + OPAQUE16_LEN + OPAQUE16_LEN)
/* PV | Random | Session Id | CipherSuite | Compression | Ext Len */
#define HRR_BODY_SZ        (VERSION_SZ + RAN_LEN + ENUM_LEN + ID_LEN + \
                            SUITE_LEN + COMP_LEN + OPAQUE16_LEN)
/* HH | PV | CipherSuite | Ext Len | Key Share | Supported Version | Cookie */
#define MAX_HRR_SZ   (HRR_MAX_HS_HEADER_SZ   + \
                        HRR_BODY_SZ         + \
                          HRR_KEY_SHARE_SZ  + \
                          HRR_VERSIONS_SZ   + \
                          HRR_COOKIE_HDR_SZ)


/* Restart the handshake hash from the cookie value.
 *
 * ssl     SSL/TLS object.
 * cookie  Cookie data from client.
 * returns 0 on success, otherwise failure.
 */
static int RestartHandshakeHashWithCookie(WOLFSSL* ssl, Cookie* cookie)
{
    byte   header[HANDSHAKE_HEADER_SZ] = {0};
    byte   hrr[MAX_HRR_SZ] = {0};
    int    hrrIdx;
    word32 idx;
    byte   hashSz;
    byte*  cookieData;
    word16 cookieDataSz;
    word16 length;
    int    keyShareExt = 0;
    int    ret;

    ret = TlsCheckCookie(ssl, cookie-&gt;data, (byte)cookie-&gt;len);
    if (ret &lt; 0)
        return ret;
    cookieDataSz = (word16)ret;
    hashSz = cookie-&gt;data[0];
    cookieData = cookie-&gt;data;
    idx = OPAQUE8_LEN;

    /* Restart handshake hash with synthetic message hash. */
    AddTls13HandShakeHeader(header, hashSz, 0, 0, message_hash, ssl);

    if ((ret = InitHandshakeHashes(ssl)) != 0)
        return ret;
    if ((ret = HashRaw(ssl, header, sizeof(header))) != 0)
        return ret;
#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Restart Hash from Cookie&quot;);
    WOLFSSL_BUFFER(cookieData + idx, hashSz);
#endif
    if ((ret = HashRaw(ssl, cookieData + idx, hashSz)) != 0)
        return ret;

    /* Reconstruct the HelloRetryMessage for handshake hash. */
    length = HRR_BODY_SZ - ID_LEN + ssl-&gt;session-&gt;sessionIDSz +
             HRR_COOKIE_HDR_SZ + cookie-&gt;len;
    length += HRR_VERSIONS_SZ;
    /* HashSz (1 byte) + Hash (HashSz bytes) + CipherSuite (2 bytes) */
    if (cookieDataSz &gt; OPAQUE8_LEN + hashSz + OPAQUE16_LEN) {
        keyShareExt = 1;
        length += HRR_KEY_SHARE_SZ;
    }

    AddTls13HandShakeHeader(hrr, length, 0, 0, server_hello, ssl);

    idx += hashSz;
    hrrIdx = HANDSHAKE_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        hrrIdx += DTLS_HANDSHAKE_EXTRA;
#endif /* WOLFSSL_DTLS13 */

    /* The negotiated protocol version. */
    hrr[hrrIdx++] = ssl-&gt;version.major;
    hrr[hrrIdx++] = ssl-&gt;options.dtls ? DTLSv1_2_MINOR : TLSv1_2_MINOR;

    /* HelloRetryRequest message has fixed value for random. */
    XMEMCPY(hrr + hrrIdx, helloRetryRequestRandom, RAN_LEN);
    hrrIdx += RAN_LEN;

    hrr[hrrIdx++] = ssl-&gt;session-&gt;sessionIDSz;
    if (ssl-&gt;session-&gt;sessionIDSz &gt; 0) {
        XMEMCPY(hrr + hrrIdx, ssl-&gt;session-&gt;sessionID, ssl-&gt;session-&gt;sessionIDSz);
        hrrIdx += ssl-&gt;session-&gt;sessionIDSz;
    }

    /* Cipher Suite */
    hrr[hrrIdx++] = cookieData[idx++];
    hrr[hrrIdx++] = cookieData[idx++];

    /* Compression not supported in TLS v1.3. */
    hrr[hrrIdx++] = 0;

    /* Extensions&#039; length */
    length -= HRR_BODY_SZ - ID_LEN + ssl-&gt;session-&gt;sessionIDSz;
    c16toa(length, hrr + hrrIdx);
    hrrIdx += 2;

    /* Optional KeyShare Extension */
    if (keyShareExt) {
        c16toa(TLSX_KEY_SHARE, hrr + hrrIdx);
        hrrIdx += 2;
        c16toa(OPAQUE16_LEN, hrr + hrrIdx);
        hrrIdx += 2;
        hrr[hrrIdx++] = cookieData[idx++];
        hrr[hrrIdx++] = cookieData[idx++];
    }
    c16toa(TLSX_SUPPORTED_VERSIONS, hrr + hrrIdx);
    hrrIdx += 2;
    c16toa(OPAQUE16_LEN, hrr + hrrIdx);
    hrrIdx += 2;
    #ifdef WOLFSSL_TLS13_DRAFT
        hrr[hrrIdx++] = TLS_DRAFT_MAJOR;
        hrr[hrrIdx++] = TLS_DRAFT_MINOR;
    #else
        hrr[hrrIdx++] = ssl-&gt;version.major;
        hrr[hrrIdx++] = ssl-&gt;version.minor;
    #endif

    /* Mandatory Cookie Extension */
    c16toa(TLSX_COOKIE, hrr + hrrIdx);
    hrrIdx += 2;
    c16toa(cookie-&gt;len + OPAQUE16_LEN, hrr + hrrIdx);
    hrrIdx += 2;
    c16toa(cookie-&gt;len, hrr + hrrIdx);
    hrrIdx += 2;

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Reconstructed HelloRetryRequest&quot;);
    WOLFSSL_BUFFER(hrr, hrrIdx);
    WOLFSSL_MSG(&quot;Cookie&quot;);
    WOLFSSL_BUFFER(cookieData, cookie-&gt;len);
#endif

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ret = Dtls13HashHandshake(ssl, hrr, (word16)hrrIdx);
    }
    else
#endif /* WOLFSSL_DTLS13 */
        {
            ret = HashRaw(ssl, hrr, hrrIdx);
        }

    if (ret != 0)
        return ret;

    return HashRaw(ssl, cookieData, cookie-&gt;len);
}
#endif

/* Do SupportedVersion extension for TLS v1.3+ otherwise it is not.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * i         The index into the message buffer of ClientHello.
 * helloSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13SupportedVersions(WOLFSSL* ssl, const byte* input, word32 i,
                                    word32 helloSz, int* wantDowngrade)
{
    int    ret;
    byte   b;
    word16 suiteSz;
    word16 totalExtSz;
    int    foundVersion = 0;

    /* Client random */
    i += RAN_LEN;
    /* Session id - not used in TLS v1.3 */
    b = input[i++];
    if (i + b &gt; helloSz) {
        return BUFFER_ERROR;
    }
    i += b;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        /* legacy_cookie - not used in DTLS v1.3 */
        b = input[i++];
        if (i + b &gt; helloSz) {
            return BUFFER_ERROR;
        }
        i += b;
    }
#endif /* WOLFSSL_DTLS13 */
    /* Cipher suites */
    if (i + OPAQUE16_LEN &gt; helloSz)
        return BUFFER_ERROR;
    ato16(input + i, &amp;suiteSz);
    i += OPAQUE16_LEN;
    if (i + suiteSz + 1 &gt; helloSz)
        return BUFFER_ERROR;
    i += suiteSz;
    /* Compression */
    b = input[i++];
    if (i + b &gt; helloSz)
        return BUFFER_ERROR;
    i += b;

    /* TLS 1.3 must have extensions */
    if (i &lt; helloSz) {
        if (i + OPAQUE16_LEN &gt; helloSz)
            return BUFFER_ERROR;
        ato16(&amp;input[i], &amp;totalExtSz);
        i += OPAQUE16_LEN;
        if (totalExtSz != helloSz - i)
            return BUFFER_ERROR;

        /* Need to negotiate version first. */
        if ((ret = TLSX_ParseVersion(ssl, input + i, totalExtSz, client_hello,
                                                              &amp;foundVersion))) {
            return ret;
        }
    }
    *wantDowngrade = !foundVersion || !IsAtLeastTLSv1_3(ssl-&gt;version);

    return 0;
}

/* Handle a ClientHello handshake message.
 * If the protocol version in the message is not TLS v1.3 or higher, use
 * DoClientHello()
 * Only a server will receive this message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of ClientHello.
 *           On exit, the index of byte after the ClientHello message and
 *           padding.
 * helloSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */

typedef struct Dch13Args {
    ProtocolVersion pv;
    Suites*         clSuites;
    word32          idx;
    word32          begin;
    int             usingPSK;
} Dch13Args;

static void FreeDch13Args(WOLFSSL* ssl, void* pArgs)
{
    Dch13Args* args = (Dch13Args*)pArgs;

    (void)ssl;

    if (args &amp;&amp; args-&gt;clSuites) {
        XFREE(args-&gt;clSuites, ssl-&gt;heap, DYNAMIC_TYPE_SUITES);
        args-&gt;clSuites = NULL;
    }
#ifdef OPENSSL_EXTRA
    ssl-&gt;clSuites = NULL;
#endif
}

int DoTls13ClientHello(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                       word32 helloSz)
{
    int ret;
#ifdef WOLFSSL_ASYNC_CRYPT
    Dch13Args* args = NULL;
    WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);
#else
    Dch13Args  args[1];
#endif
#if defined(HAVE_ECH)
    TLSX* echX = NULL;
#endif

    WOLFSSL_START(WC_FUNC_CLIENT_HELLO_DO);
    WOLFSSL_ENTER(&quot;DoTls13ClientHello&quot;);

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;async == NULL) {
        ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                        DYNAMIC_TYPE_ASYNC);
        if (ssl-&gt;async == NULL)
            ERROR_OUT(MEMORY_E, exit_dch);
    }
    args = (Dch13Args*)ssl-&gt;async-&gt;args;

    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.asyncState);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0) {
            goto exit_dch;
        }
    }
    else
#endif
    {
        /* Reset state */
        ret = VERSION_ERROR;
        ssl-&gt;options.asyncState = TLS_ASYNC_BEGIN;
        XMEMSET(args, 0, sizeof(Dch13Args));
    #ifdef WOLFSSL_ASYNC_CRYPT
        ssl-&gt;async-&gt;freeArgs = FreeDch13Args;
    #endif
    }

    switch (ssl-&gt;options.asyncState) {
    case TLS_ASYNC_BEGIN:
    {
    byte b;
    byte sessIdSz;
    int wantDowngrade = 0;
    word16 totalExtSz = 0;

#ifdef WOLFSSL_CALLBACKS
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;ClientHello&quot;);
    if (ssl-&gt;toInfoOn) AddLateName(&quot;ClientHello&quot;, &amp;ssl-&gt;timeoutInfo);
#endif

    /* do not change state in the SSL object before the next region of code
     * to be able to statelessly compute a DTLS cookie */
#if defined(WOLFSSL_DTLS13) &amp;&amp; defined(WOLFSSL_SEND_HRR_COOKIE)
    /* Update the ssl-&gt;options.dtlsStateful setting `if` statement in
     * wolfSSL_accept_TLSv13 when changing this one. */
    if (IsDtlsNotSctpMode(ssl) &amp;&amp; ssl-&gt;options.sendCookie &amp;&amp;
            !ssl-&gt;options.dtlsStateful) {
        DtlsSetSeqNumForReply(ssl);
        ret = DoClientHelloStateless(ssl, input + *inOutIdx, helloSz, 0, NULL);
        if (ret != 0 || !ssl-&gt;options.dtlsStateful) {
            *inOutIdx += helloSz;
            goto exit_dch;
        }
        if (ssl-&gt;chGoodCb != NULL) {
            int cbret = ssl-&gt;chGoodCb(ssl, ssl-&gt;chGoodCtx);
            if (cbret &lt; 0) {
                ssl-&gt;error = cbret;
                WOLFSSL_MSG(&quot;ClientHello Good Cb don&#039;t continue error&quot;);
                return WOLFSSL_FATAL_ERROR;
            }
        }
    }
    ssl-&gt;options.dtlsStateful = 1;
#endif /* WOLFSSL_DTLS */

    args-&gt;idx = *inOutIdx;
    args-&gt;begin = args-&gt;idx;

    /* protocol version, random and session id length check */
    if (OPAQUE16_LEN + RAN_LEN + OPAQUE8_LEN &gt; helloSz) {
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    }

    /* Protocol version */
    XMEMCPY(&amp;args-&gt;pv, input + args-&gt;idx, OPAQUE16_LEN);
    ssl-&gt;chVersion = args-&gt;pv;   /* store */
    args-&gt;idx += OPAQUE16_LEN;


    /* this check pass for DTLS Major (0xff) */
    if (args-&gt;pv.major &lt; SSLv3_MAJOR) {
        WOLFSSL_MSG(&quot;Legacy version field contains unsupported value&quot;);
        ERROR_OUT(VERSION_ERROR, exit_dch);
    }

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls &amp;&amp;
        args-&gt;pv.major == DTLS_MAJOR &amp;&amp; args-&gt;pv.minor &gt; DTLSv1_2_MINOR) {
        wantDowngrade = 1;
        ssl-&gt;version.minor = args-&gt;pv.minor;
    }
#endif /* WOLFSSL_DTLS13 */

    if (!ssl-&gt;options.dtls) {
        /* Legacy protocol version cannot negotiate TLS 1.3 or higher. */
        if (args-&gt;pv.major &gt; SSLv3_MAJOR || (args-&gt;pv.major == SSLv3_MAJOR &amp;&amp;
                                             args-&gt;pv.minor &gt;= TLSv1_3_MINOR)) {
            args-&gt;pv.major = SSLv3_MAJOR;
            args-&gt;pv.minor = TLSv1_2_MINOR;
            wantDowngrade = 1;
            ssl-&gt;version.minor = args-&gt;pv.minor;
        }
        /* Legacy version must be [ SSLv3_MAJOR, TLSv1_2_MINOR ] for TLS v1.3 */
        else if (args-&gt;pv.major == SSLv3_MAJOR &amp;&amp;
                 args-&gt;pv.minor &lt; TLSv1_2_MINOR) {
            wantDowngrade = 1;
            ssl-&gt;version.minor = args-&gt;pv.minor;
        }
    }

    if (!wantDowngrade) {
        ret = DoTls13SupportedVersions(ssl, input + args-&gt;begin,
            args-&gt;idx - args-&gt;begin, helloSz, &amp;wantDowngrade);
        if (ret &lt; 0)
            goto exit_dch;
    }

    if (wantDowngrade) {
#ifndef WOLFSSL_NO_TLS12
        byte realMinor;
        if (!ssl-&gt;options.downgrade) {
            WOLFSSL_MSG(&quot;Client trying to connect with lesser version than &quot;
                        &quot;TLS v1.3&quot;);
            ERROR_OUT(VERSION_ERROR, exit_dch);
        }

        if ((!ssl-&gt;options.dtls
                 &amp;&amp; args-&gt;pv.minor &lt; ssl-&gt;options.minDowngrade) ||
            (ssl-&gt;options.dtls &amp;&amp; args-&gt;pv.minor &gt; ssl-&gt;options.minDowngrade)) {
            WOLFSSL_MSG(&quot;\tversion below minimum allowed, fatal error&quot;);
            ERROR_OUT(VERSION_ERROR, exit_dch);
        }

        realMinor = ssl-&gt;version.minor;
        ssl-&gt;version.minor = args-&gt;pv.minor;
        ret = HashInput(ssl, input + args-&gt;begin, (int)helloSz);
        ssl-&gt;version.minor = realMinor;
        if (ret == 0) {
            ret = DoClientHello(ssl, input, inOutIdx, helloSz);
        }
        goto exit_dch;
#else
        WOLFSSL_MSG(&quot;Client trying to connect with lesser version than &quot;
                    &quot;TLS v1.3&quot;);
        ERROR_OUT(VERSION_ERROR, exit_dch);
#endif
    }

    /* From here on we are a TLS 1.3 ClientHello. */

    /* Client random */
    XMEMCPY(ssl-&gt;arrays-&gt;clientRandom, input + args-&gt;idx, RAN_LEN);
    args-&gt;idx += RAN_LEN;

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;client random&quot;);
    WOLFSSL_BUFFER(ssl-&gt;arrays-&gt;clientRandom, RAN_LEN);
#endif

    sessIdSz = input[args-&gt;idx++];
#ifndef WOLFSSL_TLS13_MIDDLEBOX_COMPAT
    if (sessIdSz &gt; ID_LEN)
#else
    if (sessIdSz != ID_LEN &amp;&amp; sessIdSz != 0)
#endif
    {
        ERROR_OUT(INVALID_PARAMETER, exit_dch);
    }

    if (sessIdSz + args-&gt;idx &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);

    ssl-&gt;session-&gt;sessionIDSz = sessIdSz;
    if (sessIdSz &gt; 0)
        XMEMCPY(ssl-&gt;session-&gt;sessionID, input + args-&gt;idx, sessIdSz);
    args-&gt;idx += sessIdSz;

#ifdef WOLFSSL_DTLS13
    /* legacy_cookie */
    if (ssl-&gt;options.dtls) {
        /* https://www.rfc-editor.org/rfc/rfc9147.html#section-5.3 */
        byte cookieLen = input[args-&gt;idx++];
        if (cookieLen != 0) {
            ERROR_OUT(INVALID_PARAMETER, exit_dch);
        }
    }
#endif /* WOLFSSL_DTLS13 */

    args-&gt;clSuites = (Suites*)XMALLOC(sizeof(Suites), ssl-&gt;heap,
        DYNAMIC_TYPE_SUITES);
    if (args-&gt;clSuites == NULL) {
        ERROR_OUT(MEMORY_E, exit_dch);
    }

    /* Cipher suites */
    if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    ato16(&amp;input[args-&gt;idx], &amp;args-&gt;clSuites-&gt;suiteSz);
    args-&gt;idx += OPAQUE16_LEN;
    if ((args-&gt;clSuites-&gt;suiteSz % 2) != 0) {
        ERROR_OUT(INVALID_PARAMETER, exit_dch);
    }
    /* suites and compression length check */
    if ((args-&gt;idx - args-&gt;begin) + args-&gt;clSuites-&gt;suiteSz + OPAQUE8_LEN &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    if (args-&gt;clSuites-&gt;suiteSz &gt; WOLFSSL_MAX_SUITE_SZ)
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    XMEMCPY(args-&gt;clSuites-&gt;suites, input + args-&gt;idx, args-&gt;clSuites-&gt;suiteSz);
    args-&gt;idx += args-&gt;clSuites-&gt;suiteSz;
    args-&gt;clSuites-&gt;hashSigAlgoSz = 0;

    /* Compression */
    b = input[args-&gt;idx++];
    if ((args-&gt;idx - args-&gt;begin) + b &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    if (b != COMP_LEN) {
        WOLFSSL_MSG(&quot;Must be one compression type in list&quot;);
        ERROR_OUT(INVALID_PARAMETER, exit_dch);
    }
    b = input[args-&gt;idx++];
    if (b != NO_COMPRESSION) {
        WOLFSSL_MSG(&quot;Must be no compression type in list&quot;);
        ERROR_OUT(INVALID_PARAMETER, exit_dch);
    }

    /* Extensions */
    if ((args-&gt;idx - args-&gt;begin) == helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);
    if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);

    ato16(&amp;input[args-&gt;idx], &amp;totalExtSz);
    args-&gt;idx += OPAQUE16_LEN;
    if ((args-&gt;idx - args-&gt;begin) + totalExtSz &gt; helloSz)
        ERROR_OUT(BUFFER_ERROR, exit_dch);

    /* Auto populate extensions supported unless user defined. */
    if ((ret = TLSX_PopulateExtensions(ssl, 1)) != 0)
        goto exit_dch;

#if defined(HAVE_ECH)
    if (ssl-&gt;ctx-&gt;echConfigs != NULL &amp;&amp; !ssl-&gt;options.disableECH) {
        /* save the start of the buffer so we can use it when parsing ech */
        echX = TLSX_Find(ssl-&gt;extensions, TLSX_ECH);

        if (echX == NULL)
            return WOLFSSL_FATAL_ERROR;

        ((WOLFSSL_ECH*)echX-&gt;data)-&gt;aad = input + HANDSHAKE_HEADER_SZ;
        ((WOLFSSL_ECH*)echX-&gt;data)-&gt;aadLen = helloSz;
    }
#endif

    /* Parse extensions */
    if ((ret = TLSX_Parse(ssl, input + args-&gt;idx, totalExtSz, client_hello,
                                                            args-&gt;clSuites))) {
        goto exit_dch;
    }

#if defined(HAVE_ECH)
    /* jump to the end to clean things up */
    if (echX != NULL &amp;&amp; ((WOLFSSL_ECH*)echX-&gt;data)-&gt;state == ECH_WRITE_NONE)
        goto exit_dch;
#endif

#ifdef HAVE_SNI
        if ((ret = SNI_Callback(ssl)) != 0)
            goto exit_dch;
        ssl-&gt;options.side = WOLFSSL_SERVER_END;
#endif

    args-&gt;idx += totalExtSz;
    ssl-&gt;options.haveSessionId = 1;
    ssl-&gt;options.sendVerify = SEND_CERT;

#if defined(WOLFSSL_SEND_HRR_COOKIE)
    ssl-&gt;options.cookieGood = 0;
    if (ssl-&gt;options.sendCookie &amp;&amp;
            (ssl-&gt;options.serverState == SERVER_HELLO_RETRY_REQUEST_COMPLETE
#ifdef WOLFSSL_DTLS13
                    /* Always check for a valid cookie since we may have already
                     * sent a HRR but we reset the state. */
                    || ssl-&gt;options.dtls
#endif
                    )) {
        TLSX* ext = TLSX_Find(ssl-&gt;extensions, TLSX_COOKIE);

        if (ext != NULL) {
            /* Ensure the cookie came from client and isn&#039;t the one in the
            * response - HelloRetryRequest.
            */
            if (ext-&gt;resp == 0) {
                ret = RestartHandshakeHashWithCookie(ssl, (Cookie*)ext-&gt;data);
                if (ret != 0)
                    goto exit_dch;
                /* Don&#039;t change state here as we may want to enter
                 * DoTls13ClientHello again. */
                ssl-&gt;options.cookieGood = 1;
            }
            else {
                ERROR_OUT(HRR_COOKIE_ERROR, exit_dch);
            }
        }
        else {
#if defined(WOLFSSL_DTLS13) &amp;&amp; defined(WOLFSSL_DTLS13_NO_HRR_ON_RESUME)
            /* Don&#039;t error out as we may be resuming. We confirm this later. */
            if (!ssl-&gt;options.dtls)
#endif
                ERROR_OUT(HRR_COOKIE_ERROR, exit_dch);
        }
    }
#endif

#if (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)) &amp;&amp; \
                                                    defined(HAVE_TLS_EXTENSIONS)
    ret = CheckPreSharedKeys(ssl, input + args-&gt;begin, helloSz, args-&gt;clSuites,
        &amp;args-&gt;usingPSK);
    if (ret != 0)
        goto exit_dch;
#else
    if ((ret = HashInput(ssl, input + args-&gt;begin, (int)helloSz)) != 0)
        goto exit_dch;
#endif

#if (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)) &amp;&amp; \
                                                    defined(HAVE_TLS_EXTENSIONS)
    if (!args-&gt;usingPSK)
#endif
    {
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
        /* Not using PSK so don&#039;t require no KE. */
        ssl-&gt;options.noPskDheKe = 0;
#endif

#ifndef NO_CERTS
        if (TLSX_Find(ssl-&gt;extensions, TLSX_KEY_SHARE) == NULL) {
            WOLFSSL_MSG(&quot;Client did not send a KeyShare extension&quot;);
            ERROR_OUT(INCOMPLETE_DATA, exit_dch);
        }
        if (TLSX_Find(ssl-&gt;extensions, TLSX_SIGNATURE_ALGORITHMS) == NULL) {
            WOLFSSL_MSG(&quot;Client did not send a SignatureAlgorithms extension&quot;);
            ERROR_OUT(INCOMPLETE_DATA, exit_dch);
        }
#else
        ERROR_OUT(INVALID_PARAMETER, exit_dch);
#endif
    }

#ifdef HAVE_ALPN
    /* With PSK and all other things validated, it&#039;s time to
     * select the ALPN protocol, if so requested */
    if ((ret = ALPN_Select(ssl)) != 0)
        goto exit_dch;
#endif
    } /* case TLS_ASYNC_BEGIN */
    FALL_THROUGH;

    case TLS_ASYNC_BUILD:
    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_DO;
    FALL_THROUGH;

    case TLS_ASYNC_DO:
    {
#ifdef OPENSSL_EXTRA
    ssl-&gt;clSuites = args-&gt;clSuites;
    if ((ret = CertSetupCbWrapper(ssl)) != 0)
        goto exit_dch;
#endif
#ifndef NO_CERTS
    if (!args-&gt;usingPSK) {
        if ((ret = MatchSuite(ssl, args-&gt;clSuites)) &lt; 0) {
        #ifdef WOLFSSL_ASYNC_CRYPT
            if (ret != WC_NO_ERR_TRACE(WC_PENDING_E))
        #endif
                WOLFSSL_MSG(&quot;Unsupported cipher suite, ClientHello 1.3&quot;);
            goto exit_dch;
        }
    }
#endif
#ifdef HAVE_SUPPORTED_CURVES
    if (args-&gt;usingPSK == 2) {
        /* Pick key share and Generate a new key if not present. */
        int doHelloRetry = 0;
        ret = TLSX_KeyShare_Establish(ssl, &amp;doHelloRetry);
        if (doHelloRetry) {
            /* Make sure we don&#039;t send HRR twice */
            if (ssl-&gt;options.serverState == SERVER_HELLO_RETRY_REQUEST_COMPLETE)
                ERROR_OUT(INVALID_PARAMETER, exit_dch);
            ssl-&gt;options.serverState = SERVER_HELLO_RETRY_REQUEST_COMPLETE;
            if (ret != WC_NO_ERR_TRACE(WC_PENDING_E))
                ret = 0; /* for hello_retry return 0 */
        }
        if (ret != 0)
            goto exit_dch;
    }
#endif

    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_VERIFY;
    } /* case TLS_ASYNC_BUILD || TLS_ASYNC_DO */
    FALL_THROUGH;

    case TLS_ASYNC_VERIFY:
    {
#if defined(WOLFSSL_ASYNC_CRYPT) &amp;&amp; defined(HAVE_SUPPORTED_CURVES)
    /* Check if the KeyShare calculations from the previous state are complete.
     * wolfSSL_AsyncPop advances ssl-&gt;options.asyncState so we may end up here
     * with a pending calculation. */
    TLSX* extension = TLSX_Find(ssl-&gt;extensions, TLSX_KEY_SHARE);
    if (extension != NULL &amp;&amp; extension-&gt;resp == 1) {
        KeyShareEntry* serverKSE = (KeyShareEntry*)extension-&gt;data;
        if (serverKSE != NULL &amp;&amp;
            serverKSE-&gt;lastRet == WC_NO_ERR_TRACE(WC_PENDING_E)) {
            ret = TLSX_KeyShare_GenKey(ssl, serverKSE);
            if (ret != 0)
                goto exit_dch;
        }
    }
#endif
    /* Advance state and proceed */
    ssl-&gt;options.asyncState = TLS_ASYNC_FINALIZE;
    }
    FALL_THROUGH;

    case TLS_ASYNC_FINALIZE:
    {
    *inOutIdx = args-&gt;idx;
    ssl-&gt;options.clientState = CLIENT_HELLO_COMPLETE;
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ssl-&gt;options.pskNegotiated = (args-&gt;usingPSK != 0);
#endif

    if (!args-&gt;usingPSK) {
#ifndef NO_CERTS
        /* Check that the negotiated ciphersuite matches protocol version. */
    #ifdef HAVE_NULL_CIPHER
        if (ssl-&gt;options.cipherSuite0 == ECC_BYTE &amp;&amp;
                              (ssl-&gt;options.cipherSuite == TLS_SHA256_SHA256 ||
                               ssl-&gt;options.cipherSuite == TLS_SHA384_SHA384)) {
            ;
        }
        else
    #endif
    #if defined(WOLFSSL_SM4_GCM) &amp;&amp; defined(WOLFSSL_SM3)
        if (ssl-&gt;options.cipherSuite0 == CIPHER_BYTE &amp;&amp;
                ssl-&gt;options.cipherSuite == TLS_SM4_GCM_SM3) {
            ; /* Do nothing. */
        }
        else
    #endif
    #if defined(WOLFSSL_SM4_CCM) &amp;&amp; defined(WOLFSSL_SM3)
        if (ssl-&gt;options.cipherSuite0 == CIPHER_BYTE &amp;&amp;
                ssl-&gt;options.cipherSuite == TLS_SM4_CCM_SM3) {
            ; /* Do nothing. */
        }
        else
    #endif
        if (ssl-&gt;options.cipherSuite0 != TLS13_BYTE) {
            WOLFSSL_MSG(&quot;Negotiated ciphersuite from lesser version than &quot;
                        &quot;TLS v1.3&quot;);
            ERROR_OUT(MATCH_SUITE_ERROR, exit_dch);
        }

    #ifdef HAVE_SESSION_TICKET
        if (ssl-&gt;options.resuming) {
            ssl-&gt;options.resuming = 0;
            ssl-&gt;arrays-&gt;psk_keySz = 0;
            XMEMSET(ssl-&gt;arrays-&gt;psk_key, 0, ssl-&gt;specs.hash_size);
        }
    #endif

        /* Derive early secret for handshake secret. */
        if ((ret = DeriveEarlySecret(ssl)) != 0)
            goto exit_dch;
#endif /* !NO_CERTS */
    }
    break;
    } /* case TLS_ASYNC_FINALIZE */
    default:
        ret = INPUT_CASE_ERROR;
    } /* switch (ssl-&gt;options.asyncState) */

#ifdef WOLFSSL_SEND_HRR_COOKIE
    if (ret == 0 &amp;&amp; ssl-&gt;options.sendCookie) {
        if (ssl-&gt;options.cookieGood &amp;&amp;
                ssl-&gt;options.acceptState == TLS13_ACCEPT_FIRST_REPLY_DONE) {
            /* Processing second ClientHello. Clear HRR state. */
            ssl-&gt;options.serverState = NULL_STATE;
        }

        if (ssl-&gt;options.cookieGood &amp;&amp;
            ssl-&gt;options.serverState == SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
            /* If we already verified the peer with a cookie then we can&#039;t
             * do another HRR for cipher negotiation. Send alert and restart
             * the entire handshake. */
            ERROR_OUT(INVALID_PARAMETER, exit_dch);
        }
#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls &amp;&amp;
            ssl-&gt;options.serverState == SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
            /* Cookie and key share negotiation should be handled in
             * DoClientHelloStateless. If we enter here then something went
             * wrong in our logic. */
            ERROR_OUT(BAD_HELLO, exit_dch);
        }
#endif
        /* Send a cookie */
        if (!ssl-&gt;options.cookieGood &amp;&amp;
            ssl-&gt;options.serverState != SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
#ifdef WOLFSSL_DTLS13_NO_HRR_ON_RESUME
                /* We can skip cookie on resumption */
                if (!ssl-&gt;options.dtls || !ssl-&gt;options.dtls13NoHrrOnResume ||
                        !args-&gt;usingPSK)
#endif
                    ERROR_OUT(BAD_HELLO, exit_dch);
            }
            else
#endif
            {
                /* Need to remove the keyshare ext if we found a common group
                 * and are not doing curve negotiation. */
                TLSX_Remove(&amp;ssl-&gt;extensions, TLSX_KEY_SHARE, ssl-&gt;heap);
                ssl-&gt;options.serverState = SERVER_HELLO_RETRY_REQUEST_COMPLETE;
            }

        }
    }
#endif /* WOLFSSL_DTLS13 */

#ifdef WOLFSSL_DTLS_CID
    /* do not modify CID state if we are sending an HRR  */
    if (ret == 0 &amp;&amp; ssl-&gt;options.dtls &amp;&amp; ssl-&gt;options.useDtlsCID &amp;&amp;
            ssl-&gt;options.serverState != SERVER_HELLO_RETRY_REQUEST_COMPLETE)
        DtlsCIDOnExtensionsParsed(ssl);
#endif /* WOLFSSL_DTLS_CID */



exit_dch:

    WOLFSSL_LEAVE(&quot;DoTls13ClientHello&quot;, ret);

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
        ssl-&gt;msgsReceived.got_client_hello = 0;
        return ret;
    }
#endif

    FreeDch13Args(ssl, args);
#ifdef WOLFSSL_ASYNC_CRYPT
    FreeAsyncCtx(ssl, 0);
#endif
    WOLFSSL_END(WC_FUNC_CLIENT_HELLO_DO);

    if (ret != 0) {
        WOLFSSL_ERROR_VERBOSE(ret);
    }

#if defined(HAVE_ECH)
    if (ret == 0 &amp;&amp; echX != NULL &amp;&amp;
        ((WOLFSSL_ECH*)echX-&gt;data)-&gt;state == ECH_WRITE_NONE) {

        /* add the header to the inner hello */
        AddTls13HandShakeHeader(((WOLFSSL_ECH*)echX-&gt;data)-&gt;innerClientHello,
            ((WOLFSSL_ECH*)echX-&gt;data)-&gt;innerClientHelloLen, 0, 0,
            client_hello, ssl);
    }
#endif

    return ret;
}

/* Send TLS v1.3 ServerHello message to client.
 * Only a server will send this message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
/* handle generation of TLS 1.3 server_hello (2) */
int SendTls13ServerHello(WOLFSSL* ssl, byte extMsgType)
{
    int    ret;
    byte*  output;
    word16 length;
    word32 idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;
    int    sendSz;
#if defined(HAVE_ECH)
    TLSX* echX = NULL;
    word32 serverRandomOffset;
#endif

    WOLFSSL_START(WC_FUNC_SERVER_HELLO_SEND);
    WOLFSSL_ENTER(&quot;SendTls13ServerHello&quot;);

    /* When ssl-&gt;options.dtlsStateful is not set then cookie is calculated in
     * dtls.c */
    if (extMsgType == hello_retry_request
#ifdef WOLFSSL_DTLS13
            &amp;&amp; (!ssl-&gt;options.dtls || ssl-&gt;options.dtlsStateful)
#endif
            ) {
        WOLFSSL_MSG(&quot;wolfSSL Sending HelloRetryRequest&quot;);
        if ((ret = RestartHandshakeHash(ssl)) &lt; 0)
            return ret;
    }

    ssl-&gt;options.buildingMsg = 1;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        idx = DTLS_RECORD_HEADER_SZ + DTLS_HANDSHAKE_HEADER_SZ;
#endif /* WOLFSSL_DTLS13 */

    /* Protocol version, server random, session id, cipher suite, compression
     * and extensions.
     */
    length = VERSION_SZ + RAN_LEN + ENUM_LEN + ssl-&gt;session-&gt;sessionIDSz +
             SUITE_LEN + COMP_LEN;
    ret = TLSX_GetResponseSize(ssl, extMsgType, &amp;length);
    if (ret != 0)
        return ret;
    sendSz = (int)(idx + length);

    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, sendSz)) != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(output, length, server_hello, ssl);

    /* The protocol version must be TLS v1.2 for middleboxes. */
    output[idx++] = ssl-&gt;version.major;
    output[idx++] = ssl-&gt;options.dtls ? DTLSv1_2_MINOR : TLSv1_2_MINOR;

    if (extMsgType == server_hello) {
        /* Generate server random. */
        if ((ret = wc_RNG_GenerateBlock(ssl-&gt;rng, output + idx, RAN_LEN)) != 0)
            return ret;
    }
    else {
        /* HelloRetryRequest message has fixed value for random. */
        XMEMCPY(output + idx, helloRetryRequestRandom, RAN_LEN);
    }

#if defined(HAVE_ECH)
    serverRandomOffset = idx;
#endif

    /* Store in SSL for debugging. */
    XMEMCPY(ssl-&gt;arrays-&gt;serverRandom, output + idx, RAN_LEN);
    idx += RAN_LEN;

#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Server random&quot;);
    WOLFSSL_BUFFER(ssl-&gt;arrays-&gt;serverRandom, RAN_LEN);
#endif

    output[idx++] = ssl-&gt;session-&gt;sessionIDSz;
    if (ssl-&gt;session-&gt;sessionIDSz &gt; 0) {
        XMEMCPY(output + idx, ssl-&gt;session-&gt;sessionID, ssl-&gt;session-&gt;sessionIDSz);
        idx += ssl-&gt;session-&gt;sessionIDSz;
    }

    /* Chosen cipher suite */
    output[idx++] = ssl-&gt;options.cipherSuite0;
    output[idx++] = ssl-&gt;options.cipherSuite;
#ifdef WOLFSSL_DEBUG_TLS
    WOLFSSL_MSG(&quot;Chosen cipher suite:&quot;);
    WOLFSSL_MSG(GetCipherNameInternal(ssl-&gt;options.cipherSuite0,
                                      ssl-&gt;options.cipherSuite));
#endif

    /* Compression not supported in TLS v1.3. */
    output[idx++] = 0;

    /* Extensions */
    ret = TLSX_WriteResponse(ssl, output + idx, extMsgType, NULL);
    if (ret != 0)
        return ret;

#ifdef WOLFSSL_SEND_HRR_COOKIE
    if (ssl-&gt;options.sendCookie &amp;&amp; extMsgType == hello_retry_request) {
        /* Reset the hashes from here. We will be able to restart the hashes
         * from the cookie in RestartHandshakeHashWithCookie */
#ifdef WOLFSSL_DTLS13
        /* When ssl-&gt;options.dtlsStateful is not set then cookie is calculated
         * in dtls.c */
        if (ssl-&gt;options.dtls &amp;&amp; !ssl-&gt;options.dtlsStateful)
            ret = 0;
        else
#endif
            ret = InitHandshakeHashes(ssl);
    }
    else
#endif
    {
#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls) {
            ret = Dtls13HashHandshake(
                ssl,
                output + Dtls13GetRlHeaderLength(ssl, 0) ,
                (word16)sendSz - Dtls13GetRlHeaderLength(ssl, 0));
        }
        else
#endif /* WOLFSSL_DTLS13 */
        {
#if defined(HAVE_ECH)
            if (ssl-&gt;ctx-&gt;echConfigs != NULL &amp;&amp; !ssl-&gt;options.disableECH) {
                echX = TLSX_Find(ssl-&gt;extensions, TLSX_ECH);

                if (echX == NULL)
                    return WOLFSSL_FATAL_ERROR;

                /* replace the last 8 bytes of server random with the accept */
                if (((WOLFSSL_ECH*)echX-&gt;data)-&gt;state == ECH_PARSED_INTERNAL) {
                    ret = EchWriteAcceptance(ssl, output + RECORD_HEADER_SZ,
                        serverRandomOffset - RECORD_HEADER_SZ,
                        sendSz - RECORD_HEADER_SZ);

                    /* remove ech so we don&#039;t keep sending it in write */
                    TLSX_Remove(&amp;ssl-&gt;extensions, TLSX_ECH, ssl-&gt;heap);
                }
            }
#endif
            if (ret == 0)
                ret = HashOutput(ssl, output, sendSz, 0);
        }
    }

    if (ret != 0)
        return ret;

#if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
    if (ssl-&gt;hsInfoOn)
        AddPacketName(ssl, &quot;ServerHello&quot;);
    if (ssl-&gt;toInfoOn) {
        ret = AddPacketInfo(ssl, &quot;ServerHello&quot;, handshake, output, sendSz,
                      WRITE_PROTO, 0, ssl-&gt;heap);
        if (ret != 0)
            return ret;
    }
    #endif

    if (extMsgType == server_hello)
        ssl-&gt;options.serverState = SERVER_HELLO_COMPLETE;

    ssl-&gt;options.buildingMsg = 0;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ret = Dtls13HandshakeSend(ssl, output, (word16)sendSz, (word16)sendSz,
            (enum HandShakeType)extMsgType, 0);

        WOLFSSL_LEAVE(&quot;SendTls13ServerHello&quot;, ret);
        WOLFSSL_END(WC_FUNC_SERVER_HELLO_SEND);
        return ret;
    }
#endif /* WOLFSSL_DTLS13 */

    ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;

    if (!ssl-&gt;options.groupMessages || extMsgType != server_hello)
        ret = SendBuffered(ssl);

    WOLFSSL_LEAVE(&quot;SendTls13ServerHello&quot;, ret);
    WOLFSSL_END(WC_FUNC_SERVER_HELLO_SEND);

    return ret;
}

/* handle generation of TLS 1.3 encrypted_extensions (8) */
/* Send the rest of the extensions encrypted under the handshake key.
 * This message is always encrypted in TLS v1.3.
 * Only a server will send this message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13EncryptedExtensions(WOLFSSL* ssl)
{
    int    ret;
    byte*  output;
    word16 length = 0;
    word32 idx;
    int    sendSz;

    WOLFSSL_START(WC_FUNC_ENCRYPTED_EXTENSIONS_SEND);
    WOLFSSL_ENTER(&quot;SendTls13EncryptedExtensions&quot;);

    ssl-&gt;options.buildingMsg = 1;
    ssl-&gt;keys.encryptionOn = 1;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        idx = Dtls13GetHeadersLength(ssl, encrypted_extensions);
    }
    else
#endif /* WOLFSSL_DTLS13 */
    {
        idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;
    }

#if defined(HAVE_SUPPORTED_CURVES) &amp;&amp; !defined(WOLFSSL_NO_SERVER_GROUPS_EXT)
    if ((ret = TLSX_SupportedCurve_CheckPriority(ssl)) != 0)
        return ret;
#endif

    /* Derive the handshake secret now that we are at first message to be
     * encrypted under the keys.
     */
    if ((ret = DeriveHandshakeSecret(ssl)) != 0)
        return ret;
    if ((ret = DeriveTls13Keys(ssl, handshake_key,
                               ENCRYPT_AND_DECRYPT_SIDE, 1)) != 0)
        return ret;

    /* Setup encrypt/decrypt keys for following messages. */
#ifdef WOLFSSL_EARLY_DATA
    if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
        return ret;
    if (ssl-&gt;earlyData != process_early_data) {
        if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
            return ret;
    }
#else
    if ((ret = SetKeysSide(ssl, ENCRYPT_AND_DECRYPT_SIDE)) != 0)
        return ret;
#endif
#ifdef WOLFSSL_QUIC
    if (IsAtLeastTLSv1_3(ssl-&gt;version) &amp;&amp; WOLFSSL_IS_QUIC(ssl)) {
        ret = wolfSSL_quic_add_transport_extensions(ssl, encrypted_extensions);
        if (ret != 0)
            return ret;
    }
#endif

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        w64wrapper epochHandshake = w64From32(0, DTLS13_EPOCH_HANDSHAKE);
        ssl-&gt;dtls13Epoch = epochHandshake;

        ret = Dtls13NewEpoch(
            ssl, epochHandshake, ENCRYPT_AND_DECRYPT_SIDE);
        if (ret != 0)
            return ret;

        ret = Dtls13SetEpochKeys(
            ssl, epochHandshake, ENCRYPT_AND_DECRYPT_SIDE);
        if (ret != 0)
            return ret;

    }
#endif /* WOLFSSL_DTLS13 */

    ret = TLSX_GetResponseSize(ssl, encrypted_extensions, &amp;length);
    if (ret != 0)
        return ret;

    sendSz = (int)(idx + length);
    /* Encryption always on. */
    sendSz += MAX_MSG_EXTRA;

    /* Check buffers are big enough and grow if needed. */
    ret = CheckAvailableSize(ssl, sendSz);
    if (ret != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(output, length, encrypted_extensions, ssl);

    ret = TLSX_WriteResponse(ssl, output + idx, encrypted_extensions, NULL);
    if (ret != 0)
        return ret;
    idx += length;

#if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
    if (ssl-&gt;hsInfoOn)
        AddPacketName(ssl, &quot;EncryptedExtensions&quot;);
    if (ssl-&gt;toInfoOn) {
        ret = AddPacketInfo(ssl, &quot;EncryptedExtensions&quot;, handshake, output,
                      sendSz, WRITE_PROTO, 0, ssl-&gt;heap);
        if (ret != 0)
            return ret;
    }
#endif

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ssl-&gt;options.buildingMsg = 0;
        ret = Dtls13HandshakeSend(ssl, output, (word16)sendSz, (word16)idx,
                                  encrypted_extensions, 1);

        if (ret == 0)
            ssl-&gt;options.serverState = SERVER_ENCRYPTED_EXTENSIONS_COMPLETE;

        WOLFSSL_LEAVE(&quot;SendTls13EncryptedExtensions&quot;, ret);
        WOLFSSL_END(WC_FUNC_ENCRYPTED_EXTENSIONS_SEND);

        return ret;
    }
#endif /* WOLFSSL_DTLS13 */

    /* This handshake message is always encrypted. */
    sendSz = BuildTls13Message(ssl, output, sendSz, output + RECORD_HEADER_SZ,
                               (int)(idx - RECORD_HEADER_SZ),
                               handshake, 1, 0, 0);
    if (sendSz &lt; 0)
        return sendSz;

    ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;
    ssl-&gt;options.buildingMsg = 0;
    ssl-&gt;options.serverState = SERVER_ENCRYPTED_EXTENSIONS_COMPLETE;

    if (!ssl-&gt;options.groupMessages)
        ret = SendBuffered(ssl);


    WOLFSSL_LEAVE(&quot;SendTls13EncryptedExtensions&quot;, ret);
    WOLFSSL_END(WC_FUNC_ENCRYPTED_EXTENSIONS_SEND);

    return ret;
}

#ifndef NO_CERTS
/* handle generation TLS v1.3 certificate_request (13) */
/* Send the TLS v1.3 CertificateRequest message.
 * This message is always encrypted in TLS v1.3.
 * Only a server will send this message.
 *
 * ssl        SSL/TLS object.
 * reqCtx     Request context.
 * reqCtxLen  Length of context. 0 when sending as part of handshake.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13CertificateRequest(WOLFSSL* ssl, byte* reqCtx,
                                       word32 reqCtxLen)
{
    byte*   output;
    int    ret;
    int    sendSz;
    word32 i;
    word32 reqSz;
    word16 hashSigAlgoSz = 0;
    SignatureAlgorithms* sa;

    WOLFSSL_START(WC_FUNC_CERTIFICATE_REQUEST_SEND);
    WOLFSSL_ENTER(&quot;SendTls13CertificateRequest&quot;);

    ssl-&gt;options.buildingMsg = 1;

    if (ssl-&gt;options.side != WOLFSSL_SERVER_END)
        return SIDE_ERROR;

    /* Get the length of the hashSigAlgo buffer */
    InitSuitesHashSigAlgo(NULL, SIG_ALL, 1, ssl-&gt;buffers.keySz,
        &amp;hashSigAlgoSz);
    sa = TLSX_SignatureAlgorithms_New(ssl, hashSigAlgoSz, ssl-&gt;heap);
    if (sa == NULL)
        return MEMORY_ERROR;
    InitSuitesHashSigAlgo(sa-&gt;hashSigAlgo, SIG_ALL, 1, ssl-&gt;buffers.keySz,
        &amp;hashSigAlgoSz);
    ret = TLSX_Push(&amp;ssl-&gt;extensions, TLSX_SIGNATURE_ALGORITHMS, sa, ssl-&gt;heap);
    if (ret != 0) {
        TLSX_SignatureAlgorithms_FreeAll(sa, ssl-&gt;heap);
        return ret;
    }

    i = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        i = Dtls13GetRlHeaderLength(ssl, 1) + DTLS_HANDSHAKE_HEADER_SZ;
#endif /* WOLFSSL_DTLS13 */

    reqSz = (word16)(OPAQUE8_LEN + reqCtxLen);
    ret = TLSX_GetRequestSize(ssl, certificate_request, &amp;reqSz);
    if (ret != 0)
        return ret;

    sendSz = (int)(i + reqSz);
    /* Always encrypted and make room for padding. */
    sendSz += MAX_MSG_EXTRA;

    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, sendSz)) != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(output, reqSz, certificate_request, ssl);

    /* Certificate request context. */
    output[i++] = (byte)reqCtxLen;
    if (reqCtxLen != 0) {
        XMEMCPY(output + i, reqCtx, reqCtxLen);
        i += reqCtxLen;
    }

    /* Certificate extensions. */
    reqSz = 0;
    ret = TLSX_WriteRequest(ssl, output + i, certificate_request, &amp;reqSz);
    if (ret != 0)
        return ret;
    i += reqSz;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ssl-&gt;options.buildingMsg = 0;
        ret =
            Dtls13HandshakeSend(ssl, output, (word16)sendSz, (word16)i,
                                certificate_request, 1);

        WOLFSSL_LEAVE(&quot;SendTls13CertificateRequest&quot;, ret);
        WOLFSSL_END(WC_FUNC_CERTIFICATE_REQUEST_SEND);

        return ret;

    }
#endif /* WOLFSSL_DTLS13 */

    /* Always encrypted. */
    sendSz = BuildTls13Message(ssl, output, sendSz, output + RECORD_HEADER_SZ,
                               (int)(i - RECORD_HEADER_SZ), handshake, 1, 0, 0);
    if (sendSz &lt; 0)
        return sendSz;

    #if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
        if (ssl-&gt;hsInfoOn)
            AddPacketName(ssl, &quot;CertificateRequest&quot;);
        if (ssl-&gt;toInfoOn) {
            ret = AddPacketInfo(ssl, &quot;CertificateRequest&quot;, handshake, output,
                          sendSz, WRITE_PROTO, 0, ssl-&gt;heap);
            if (ret != 0)
                return ret;
        }
    #endif

    ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;
    ssl-&gt;options.buildingMsg = 0;
    if (!ssl-&gt;options.groupMessages)
        ret = SendBuffered(ssl);

    WOLFSSL_LEAVE(&quot;SendTls13CertificateRequest&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_REQUEST_SEND);

    return ret;
}
#endif /* NO_CERTS */
#endif /* NO_WOLFSSL_SERVER */

#ifndef NO_CERTS
#if !defined(NO_RSA) || defined(HAVE_ECC) || defined(HAVE_ED25519) || \
    defined(HAVE_ED448) || defined(HAVE_FALCON) || defined(HAVE_DILITHIUM)
/* Encode the signature algorithm into buffer.
 *
 * hashalgo  The hash algorithm.
 * hsType   The signature type.
 * output    The buffer to encode into.
 */
static WC_INLINE void EncodeSigAlg(byte hashAlgo, byte hsType, byte* output)
{
    switch (hsType) {
#ifdef HAVE_ECC
        case ecc_dsa_sa_algo:
            output[0] = hashAlgo;
            output[1] = ecc_dsa_sa_algo;
            break;
#endif
#if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
        case sm2_sa_algo:
            output[0] = SM2_SA_MAJOR;
            output[1] = SM2_SA_MINOR;
            break;
#endif
#ifdef HAVE_ED25519
        /* ED25519: 0x0807 */
        case ed25519_sa_algo:
            output[0] = ED25519_SA_MAJOR;
            output[1] = ED25519_SA_MINOR;
            (void)hashAlgo;
            break;
#endif
#ifdef HAVE_ED448
        /* ED448: 0x0808 */
        case ed448_sa_algo:
            output[0] = ED448_SA_MAJOR;
            output[1] = ED448_SA_MINOR;
            (void)hashAlgo;
            break;
#endif
#ifndef NO_RSA
        /* PSS signatures: 0x080[4-6] */
        case rsa_pss_sa_algo:
            output[0] = rsa_pss_sa_algo;
            output[1] = hashAlgo;
            break;
#endif
#ifdef HAVE_FALCON
        case falcon_level1_sa_algo:
            output[0] = FALCON_LEVEL1_SA_MAJOR;
            output[1] = FALCON_LEVEL1_SA_MINOR;
            break;
        case falcon_level5_sa_algo:
            output[0] = FALCON_LEVEL5_SA_MAJOR;
            output[1] = FALCON_LEVEL5_SA_MINOR;
            break;
#endif
#ifdef HAVE_DILITHIUM
        case dilithium_level2_sa_algo:
            output[0] = DILITHIUM_LEVEL2_SA_MAJOR;
            output[1] = DILITHIUM_LEVEL2_SA_MINOR;
            break;
        case dilithium_level3_sa_algo:
            output[0] = DILITHIUM_LEVEL3_SA_MAJOR;
            output[1] = DILITHIUM_LEVEL3_SA_MINOR;
            break;
        case dilithium_level5_sa_algo:
            output[0] = DILITHIUM_LEVEL5_SA_MAJOR;
            output[1] = DILITHIUM_LEVEL5_SA_MINOR;
            break;
#endif
        default:
            break;
    }
}

#ifdef WOLFSSL_DUAL_ALG_CERTS
/* These match up with what the OQS team has defined. */
#define HYBRID_SA_MAJOR 0xFE
#define HYBRID_P256_DILITHIUM_LEVEL2_SA_MINOR    0xA1
#define HYBRID_RSA3072_DILITHIUM_LEVEL2_SA_MINOR 0xA2
#define HYBRID_P384_DILITHIUM_LEVEL3_SA_MINOR    0xA4
#define HYBRID_P521_DILITHIUM_LEVEL5_SA_MINOR    0xA6
#define HYBRID_P256_FALCON_LEVEL1_SA_MINOR       0xAF
#define HYBRID_RSA3072_FALCON_LEVEL1_SA_MINOR    0xB0
#define HYBRID_P521_FALCON_LEVEL5_SA_MINOR       0xB2

/* Custom defined ones for PQC first */
#define HYBRID_DILITHIUM_LEVEL2_P256_SA_MINOR    0xD1
#define HYBRID_DILITHIUM_LEVEL2_RSA3072_SA_MINOR 0xD2
#define HYBRID_DILITHIUM_LEVEL3_P384_SA_MINOR    0xD3
#define HYBRID_DILITHIUM_LEVEL5_P521_SA_MINOR    0xD4
#define HYBRID_FALCON_LEVEL1_P256_SA_MINOR       0xD5
#define HYBRID_FALCON_LEVEL1_RSA3072_SA_MINOR    0xD6
#define HYBRID_FALCON_LEVEL5_P521_SA_MINOR       0xD7


static void EncodeDualSigAlg(byte sigAlg, byte altSigAlg, byte* output)
{
    /* Initialize output to error indicator. */
    output[0] = 0x0;
    output[1] = 0x0;

    if (sigAlg == ecc_dsa_sa_algo &amp;&amp; altSigAlg == dilithium_level2_sa_algo) {
        output[1] = HYBRID_P256_DILITHIUM_LEVEL2_SA_MINOR;
    }
    else if (sigAlg == rsa_pss_sa_algo &amp;&amp;
             altSigAlg == dilithium_level2_sa_algo) {
        output[1] = HYBRID_RSA3072_DILITHIUM_LEVEL2_SA_MINOR;
    }
    else if (sigAlg == ecc_dsa_sa_algo &amp;&amp;
             altSigAlg == dilithium_level3_sa_algo) {
        output[1] = HYBRID_P384_DILITHIUM_LEVEL3_SA_MINOR;
    }
    else if (sigAlg == ecc_dsa_sa_algo &amp;&amp;
             altSigAlg == dilithium_level5_sa_algo) {
        output[1] = HYBRID_P521_DILITHIUM_LEVEL5_SA_MINOR;
    }
    else if (sigAlg == ecc_dsa_sa_algo &amp;&amp;
             altSigAlg == falcon_level1_sa_algo) {
        output[1] = HYBRID_P256_FALCON_LEVEL1_SA_MINOR;
    }
    else if (sigAlg == rsa_pss_sa_algo &amp;&amp;
             altSigAlg == falcon_level1_sa_algo) {
        output[1] = HYBRID_RSA3072_FALCON_LEVEL1_SA_MINOR;
    }
    else if (sigAlg == ecc_dsa_sa_algo &amp;&amp;
             altSigAlg == falcon_level5_sa_algo) {
        output[1] = HYBRID_P521_FALCON_LEVEL5_SA_MINOR;
    }
    else if (sigAlg == dilithium_level2_sa_algo &amp;&amp;
             altSigAlg == ecc_dsa_sa_algo) {
        output[1] = HYBRID_DILITHIUM_LEVEL2_P256_SA_MINOR;
    }
    else if (sigAlg == dilithium_level2_sa_algo &amp;&amp;
             altSigAlg == rsa_pss_sa_algo) {
        output[1] = HYBRID_DILITHIUM_LEVEL2_RSA3072_SA_MINOR;
    }
    else if (sigAlg == dilithium_level3_sa_algo &amp;&amp;
             altSigAlg == ecc_dsa_sa_algo) {
        output[1] = HYBRID_DILITHIUM_LEVEL3_P384_SA_MINOR;
    }
    else if (sigAlg == dilithium_level5_sa_algo &amp;&amp;
             altSigAlg == ecc_dsa_sa_algo) {
        output[1] = HYBRID_DILITHIUM_LEVEL5_P521_SA_MINOR;
    }
    else if (sigAlg == falcon_level1_sa_algo &amp;&amp;
             altSigAlg == ecc_dsa_sa_algo) {
        output[1] = HYBRID_FALCON_LEVEL1_P256_SA_MINOR;
    }
    else if (sigAlg == falcon_level1_sa_algo &amp;&amp;
             altSigAlg == rsa_pss_sa_algo) {
        output[1] = HYBRID_FALCON_LEVEL1_RSA3072_SA_MINOR;
    }
    else if (sigAlg == falcon_level5_sa_algo &amp;&amp;
             altSigAlg == ecc_dsa_sa_algo) {
        output[1] = HYBRID_FALCON_LEVEL5_P521_SA_MINOR;
    }

    if (output[1] != 0x0) {
        output[0] = HYBRID_SA_MAJOR;
    }
}
#endif /* WOLFSSL_DUAL_ALG_CERTS */

static enum wc_MACAlgorithm GetNewSAHashAlgo(int typeIn)
{
    switch (typeIn) {
        case RSA_PSS_RSAE_SHA256_MINOR:
        case RSA_PSS_PSS_SHA256_MINOR:
            return sha256_mac;

        case RSA_PSS_RSAE_SHA384_MINOR:
        case RSA_PSS_PSS_SHA384_MINOR:
            return sha384_mac;

        case RSA_PSS_RSAE_SHA512_MINOR:
        case RSA_PSS_PSS_SHA512_MINOR:
        case ED25519_SA_MINOR:
        case ED448_SA_MINOR:
            return sha512_mac;
        default:
            return no_mac;
    }
}

/* Decode the signature algorithm.
 *
 * input     The encoded signature algorithm.
 * hashalgo  The hash algorithm.
 * hsType    The signature type.
 * returns INVALID_PARAMETER if not recognized and 0 otherwise.
 */
static WC_INLINE int DecodeTls13SigAlg(byte* input, byte* hashAlgo,
                                       byte* hsType)
{
    int ret = 0;

    switch (input[0]) {
    #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
        case SM2_SA_MAJOR:
            if (input[1] == SM2_SA_MINOR) {
                *hsType = sm2_sa_algo;
                *hashAlgo = sm3_mac;
            }
            else
                ret = INVALID_PARAMETER;
            break;
    #endif
        case NEW_SA_MAJOR:
            *hashAlgo = GetNewSAHashAlgo(input[1]);

            /* PSS encryption: 0x080[4-6] */
            if (input[1] &gt;= RSA_PSS_RSAE_SHA256_MINOR &amp;&amp;
                    input[1] &lt;= RSA_PSS_RSAE_SHA512_MINOR) {
                *hsType   = input[0];
            }
            /* PSS signature: 0x080[9-B] */
            else if (input[1] &gt;= RSA_PSS_PSS_SHA256_MINOR &amp;&amp;
                    input[1] &lt;= RSA_PSS_PSS_SHA512_MINOR) {
                *hsType   = input[0];
            }
    #ifdef HAVE_ED25519
            /* ED25519: 0x0807 */
            else if (input[1] == ED25519_SA_MINOR) {
                *hsType = ed25519_sa_algo;
                /* Hash performed as part of sign/verify operation. */
            }
    #endif
    #ifdef HAVE_ED448
            /* ED448: 0x0808 */
            else if (input[1] == ED448_SA_MINOR) {
                *hsType = ed448_sa_algo;
                /* Hash performed as part of sign/verify operation. */
            }
    #endif
            else
                ret = INVALID_PARAMETER;
            break;
#if defined(HAVE_FALCON) || defined(HAVE_DILITHIUM)
        case PQC_SA_MAJOR:
#if defined(HAVE_FALCON)
            if (input[1] == FALCON_LEVEL1_SA_MINOR) {
                *hsType = falcon_level1_sa_algo;
                /* Hash performed as part of sign/verify operation. */
                *hashAlgo = sha512_mac;
            } else if (input[1] == FALCON_LEVEL5_SA_MINOR) {
                *hsType = falcon_level5_sa_algo;
                /* Hash performed as part of sign/verify operation. */
                *hashAlgo = sha512_mac;
            }
            else
#endif /* HAVE_FALCON */
#if defined(HAVE_DILITHIUM)
            if (input[1] == DILITHIUM_LEVEL2_SA_MINOR) {
                *hsType = dilithium_level2_sa_algo;
                /* Hash performed as part of sign/verify operation. */
                *hashAlgo = sha512_mac;
            } else if (input[1] == DILITHIUM_LEVEL3_SA_MINOR) {
                *hsType = dilithium_level3_sa_algo;
                /* Hash performed as part of sign/verify operation. */
                *hashAlgo = sha512_mac;
            } else if (input[1] == DILITHIUM_LEVEL5_SA_MINOR) {
                *hsType = dilithium_level5_sa_algo;
                /* Hash performed as part of sign/verify operation. */
                *hashAlgo = sha512_mac;
            }
            else
#endif /* HAVE_DILITHIUM */
            {
                ret = INVALID_PARAMETER;
            }
            break;
#endif
        default:
            *hashAlgo = input[0];
            *hsType   = input[1];
            break;
    }

    return ret;
}

#ifdef WOLFSSL_DUAL_ALG_CERTS
/* Decode the hybrid signature algorithm.
 *
 * input     The encoded signature algorithm.
 * hashalgo  The hash algorithm.
 * hsType    The signature type.
 * returns INVALID_PARAMETER if not recognized and 0 otherwise.
 */
static WC_INLINE int DecodeTls13HybridSigAlg(byte* input, byte* hashAlg,
                                             byte *sigAlg, byte *altSigAlg)
{

    if (input[0] != HYBRID_SA_MAJOR) {
        return INVALID_PARAMETER;
    }

    if (input[1] == HYBRID_P256_DILITHIUM_LEVEL2_SA_MINOR) {
        *sigAlg = ecc_dsa_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = dilithium_level2_sa_algo;
    }
    else if (input[1] == HYBRID_RSA3072_DILITHIUM_LEVEL2_SA_MINOR) {
        *sigAlg = rsa_pss_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = dilithium_level2_sa_algo;
    }
    else if (input[1] == HYBRID_P384_DILITHIUM_LEVEL3_SA_MINOR) {
        *sigAlg = ecc_dsa_sa_algo;
        *hashAlg = sha384_mac;
        *altSigAlg = dilithium_level3_sa_algo;
    }
    else if (input[1] == HYBRID_P521_DILITHIUM_LEVEL5_SA_MINOR) {
        *sigAlg = ecc_dsa_sa_algo;
        *hashAlg = sha512_mac;
        *altSigAlg = dilithium_level5_sa_algo;
    }
    else if (input[1] == HYBRID_P256_FALCON_LEVEL1_SA_MINOR) {
        *sigAlg = ecc_dsa_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = falcon_level1_sa_algo;
    }
    else if (input[1] == HYBRID_RSA3072_FALCON_LEVEL1_SA_MINOR) {
        *sigAlg = rsa_pss_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = falcon_level1_sa_algo;
    }
    else if (input[1] == HYBRID_P521_FALCON_LEVEL5_SA_MINOR) {
        *sigAlg = ecc_dsa_sa_algo;
        *hashAlg = sha512_mac;
        *altSigAlg = falcon_level5_sa_algo;
    }
    else if (input[1] == HYBRID_DILITHIUM_LEVEL2_P256_SA_MINOR) {
        *sigAlg = dilithium_level2_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = ecc_dsa_sa_algo;
    }
    else if (input[1] == HYBRID_DILITHIUM_LEVEL2_RSA3072_SA_MINOR) {
        *sigAlg = dilithium_level2_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = rsa_pss_sa_algo;
    }
    else if (input[1] == HYBRID_DILITHIUM_LEVEL3_P384_SA_MINOR) {
        *sigAlg = dilithium_level3_sa_algo;
        *hashAlg = sha384_mac;
        *altSigAlg = ecc_dsa_sa_algo;
    }
    else if (input[1] == HYBRID_DILITHIUM_LEVEL5_P521_SA_MINOR) {
        *sigAlg = dilithium_level5_sa_algo;
        *hashAlg = sha512_mac;
        *altSigAlg = ecc_dsa_sa_algo;
    }
    else if (input[1] == HYBRID_FALCON_LEVEL1_P256_SA_MINOR) {
        *sigAlg = falcon_level1_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = ecc_dsa_sa_algo;
    }
    else if (input[1] == HYBRID_FALCON_LEVEL1_RSA3072_SA_MINOR) {
        *sigAlg = falcon_level1_sa_algo;
        *hashAlg = sha256_mac;
        *altSigAlg = rsa_pss_sa_algo;
    }
    else if (input[1] == HYBRID_FALCON_LEVEL5_P521_SA_MINOR) {
        *sigAlg = falcon_level5_sa_algo;
        *hashAlg = sha512_mac;
        *altSigAlg = ecc_dsa_sa_algo;
    }
    else {
        return INVALID_PARAMETER;
    }

    return 0;
}
#endif /* WOLFSSL_DUAL_ALG_CERTS */

/* Get the hash of the messages so far.
 *
 * ssl   The SSL/TLS object.
 * hash  The buffer to write the hash to.
 * returns the length of the hash.
 */
static WC_INLINE int GetMsgHash(WOLFSSL* ssl, byte* hash)
{
    int ret = 0;
    switch (ssl-&gt;specs.mac_algorithm) {
    #ifndef NO_SHA256
        case sha256_mac:
            ret = wc_Sha256GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha256, hash);
            if (ret == 0)
                ret = WC_SHA256_DIGEST_SIZE;
            break;
    #endif /* !NO_SHA256 */
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            ret = wc_Sha384GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha384, hash);
            if (ret == 0)
                ret = WC_SHA384_DIGEST_SIZE;
            break;
    #endif /* WOLFSSL_SHA384 */
    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            ret = wc_Sha512GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSha512, hash);
            if (ret == 0)
                ret = WC_SHA512_DIGEST_SIZE;
            break;
    #endif /* WOLFSSL_TLS13_SHA512 */
    #ifdef WOLFSSL_SM3
        case sm3_mac:
            ret = wc_Sm3GetHash(&amp;ssl-&gt;hsHashes-&gt;hashSm3, hash);
            if (ret == 0)
                ret = WC_SM3_DIGEST_SIZE;
            break;
    #endif /* WOLFSSL_SM3 */
        default:
            break;
    }
    return ret;
}

/* The server certificate verification label. */
static const byte serverCertVfyLabel[CERT_VFY_LABEL_SZ] =
    &quot;TLS 1.3, server CertificateVerify&quot;;
/* The client certificate verification label. */
static const byte clientCertVfyLabel[CERT_VFY_LABEL_SZ] =
    &quot;TLS 1.3, client CertificateVerify&quot;;
/* The prefix byte in the signature data. */
#define SIGNING_DATA_PREFIX_BYTE   0x20

/* Create the signature data for TLS v1.3 certificate verification.
 *
 * ssl        The SSL/TLS object.
 * sigData    The signature data.
 * sigDataSz  The length of the signature data.
 * check      Indicates this is a check not create.
 */
int CreateSigData(WOLFSSL* ssl, byte* sigData, word16* sigDataSz,
                  int check)
{
    word16 idx;
    int side = ssl-&gt;options.side;
    int ret;

    /* Signature Data = Prefix | Label | Handshake Hash */
    XMEMSET(sigData, SIGNING_DATA_PREFIX_BYTE, SIGNING_DATA_PREFIX_SZ);
    idx = SIGNING_DATA_PREFIX_SZ;

    if ((side == WOLFSSL_SERVER_END &amp;&amp; check) ||
        (side == WOLFSSL_CLIENT_END &amp;&amp; !check)) {
        XMEMCPY(&amp;sigData[idx], clientCertVfyLabel, CERT_VFY_LABEL_SZ);
    }
    if ((side == WOLFSSL_CLIENT_END &amp;&amp; check) ||
        (side == WOLFSSL_SERVER_END &amp;&amp; !check)) {
        XMEMCPY(&amp;sigData[idx], serverCertVfyLabel, CERT_VFY_LABEL_SZ);
    }
    idx += CERT_VFY_LABEL_SZ;

    ret = GetMsgHash(ssl, &amp;sigData[idx]);
    if (ret &lt; 0)
        return ret;

    *sigDataSz = (word16)(idx + ret);
    ret = 0;

    return ret;
}

#ifndef NO_RSA
/* Encode the PKCS #1.5 RSA signature.
 *
 * sig        The buffer to place the encoded signature into.
 * sigData    The data to be signed.
 * sigDataSz  The size of the data to be signed.
 * hashAlgo   The hash algorithm to use when signing.
 * returns the length of the encoded signature or negative on error.
 */
int CreateRSAEncodedSig(byte* sig, byte* sigData, int sigDataSz,
                        int sigAlgo, int hashAlgo)
{
    Digest digest;
    int    hashSz = 0;
    int    ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG);
    byte*  hash;

    (void)sigAlgo;

    hash = sig;

    /* Digest the signature data. */
    switch (hashAlgo) {
#ifndef NO_WOLFSSL_SHA256
        case sha256_mac:
            ret = wc_InitSha256(&amp;digest.sha256);
            if (ret == 0) {
                ret = wc_Sha256Update(&amp;digest.sha256, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha256Final(&amp;digest.sha256, hash);
                wc_Sha256Free(&amp;digest.sha256);
            }
            hashSz = WC_SHA256_DIGEST_SIZE;
            break;
#endif
#ifdef WOLFSSL_SHA384
        case sha384_mac:
            ret = wc_InitSha384(&amp;digest.sha384);
            if (ret == 0) {
                ret = wc_Sha384Update(&amp;digest.sha384, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha384Final(&amp;digest.sha384, hash);
                wc_Sha384Free(&amp;digest.sha384);
            }
            hashSz = WC_SHA384_DIGEST_SIZE;
            break;
#endif
#ifdef WOLFSSL_SHA512
        case sha512_mac:
            ret = wc_InitSha512(&amp;digest.sha512);
            if (ret == 0) {
                ret = wc_Sha512Update(&amp;digest.sha512, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha512Final(&amp;digest.sha512, hash);
                wc_Sha512Free(&amp;digest.sha512);
            }
            hashSz = WC_SHA512_DIGEST_SIZE;
            break;
#endif
       default:
            ret = BAD_FUNC_ARG;
            break;

    }

    if (ret != 0)
        return ret;

    return hashSz;
}
#endif /* !NO_RSA */

#ifdef HAVE_ECC
/* Encode the ECC signature.
 *
 * sigData    The data to be signed.
 * sigDataSz  The size of the data to be signed.
 * hashAlgo   The hash algorithm to use when signing.
 * returns the length of the encoded signature or negative on error.
 */
static int CreateECCEncodedSig(byte* sigData, int sigDataSz, int hashAlgo)
{
    Digest digest;
    int    hashSz = 0;
    int    ret = WC_NO_ERR_TRACE(BAD_FUNC_ARG);

    /* Digest the signature data. */
    switch (hashAlgo) {
#ifndef NO_WOLFSSL_SHA256
        case sha256_mac:
            ret = wc_InitSha256(&amp;digest.sha256);
            if (ret == 0) {
                ret = wc_Sha256Update(&amp;digest.sha256, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha256Final(&amp;digest.sha256, sigData);
                wc_Sha256Free(&amp;digest.sha256);
            }
            hashSz = WC_SHA256_DIGEST_SIZE;
            break;
#endif
#ifdef WOLFSSL_SHA384
        case sha384_mac:
            ret = wc_InitSha384(&amp;digest.sha384);
            if (ret == 0) {
                ret = wc_Sha384Update(&amp;digest.sha384, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha384Final(&amp;digest.sha384, sigData);
                wc_Sha384Free(&amp;digest.sha384);
            }
            hashSz = WC_SHA384_DIGEST_SIZE;
            break;
#endif
#ifdef WOLFSSL_SHA512
        case sha512_mac:
            ret = wc_InitSha512(&amp;digest.sha512);
            if (ret == 0) {
                ret = wc_Sha512Update(&amp;digest.sha512, sigData, (word32)sigDataSz);
                if (ret == 0)
                    ret = wc_Sha512Final(&amp;digest.sha512, sigData);
                wc_Sha512Free(&amp;digest.sha512);
            }
            hashSz = WC_SHA512_DIGEST_SIZE;
            break;
#endif
        default:
            ret = BAD_FUNC_ARG;
            break;
    }

    if (ret != 0)
        return ret;

    return hashSz;
}
#endif /* HAVE_ECC */

#if !defined(NO_RSA) &amp;&amp; defined(WC_RSA_PSS)
/* Check that the decrypted signature matches the encoded signature
 * based on the digest of the signature data.
 *
 * ssl       The SSL/TLS object.
 * sigAlgo   The signature algorithm used to generate signature.
 * hashAlgo  The hash algorithm used to generate signature.
 * decSig    The decrypted signature.
 * decSigSz  The size of the decrypted signature.
 * returns 0 on success, otherwise failure.
 */
static int CheckRSASignature(WOLFSSL* ssl, int sigAlgo, int hashAlgo,
                             byte* decSig, word32 decSigSz)
{
    int    ret = 0;
    byte   sigData[MAX_SIG_DATA_SZ];
    word16 sigDataSz;

    ret = CreateSigData(ssl, sigData, &amp;sigDataSz, 1);
    if (ret != 0)
        return ret;

    if (sigAlgo == rsa_pss_sa_algo) {
        enum wc_HashType hashType = WC_HASH_TYPE_NONE;
        word32 sigSz;

        ret = ConvertHashPss(hashAlgo, &amp;hashType, NULL);
        if (ret &lt; 0)
            return ret;

        /* PSS signature can be done in-place */
        ret = CreateRSAEncodedSig(sigData, sigData, sigDataSz,
                                  sigAlgo, hashAlgo);
        if (ret &lt; 0)
            return ret;
        sigSz = (word32)ret;

        ret = wc_RsaPSS_CheckPadding(sigData, sigSz, decSig, decSigSz,
                                     hashType);
    }

    return ret;
}
#endif /* !NO_RSA &amp;&amp; WC_RSA_PSS */
#endif /* !NO_RSA || HAVE_ECC */

#if !defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER)
/* Get the next certificate from the list for writing into the TLS v1.3
 * Certificate message.
 *
 * data    The certificate list.
 * length  The length of the certificate data in the list.
 * idx     The index of the next certificate.
 * returns the length of the certificate data. 0 indicates no more certificates
 * in the list.
 */
static word32 NextCert(byte* data, word32 length, word32* idx)
{
    word32 len;

    /* Is index at end of list. */
    if (*idx == length)
        return 0;

    /* Length of the current ASN.1 encoded certificate. */
    c24to32(data + *idx, &amp;len);
    /* Include the length field. */
    len += 3;

    /* Move index to next certificate and return the current certificate&#039;s
     * length.
     */
    *idx += len;
    return len;
}

#if defined(HAVE_CERTIFICATE_STATUS_REQUEST) &amp;&amp; !defined(NO_WOLFSSL_SERVER)
/* Write certificate status request into certificate to buffer.
 *
 * ssl       SSL/TLS object.
 * certExts  DerBuffer array. buffers written
 * extSz     word32 array.
 *           Length of the certificate status request data for the certificate.
 * extSz_num number of the CSR written
 * extIdx    The index number of certificate status request data
 *           for the certificate.
 * offset    index offset
 * returns   Total number of bytes written.
 */
static word32 WriteCSRToBuffer(WOLFSSL* ssl, DerBuffer** certExts,
                                word16* extSz,  word16 extSz_num)
{
    int    ret = 0;
    TLSX* ext;
    CertificateStatusRequest* csr;
    word32 ex_offset = HELLO_EXT_TYPE_SZ + OPAQUE16_LEN /* extension type */
                    + OPAQUE16_LEN /* extension length */;
    word32 totalSz = 0;
    word32 tmpSz;
    word32 extIdx;
    DerBuffer* der;

    ext = TLSX_Find(ssl-&gt;extensions, TLSX_STATUS_REQUEST);
    csr = ext ? (CertificateStatusRequest*)ext-&gt;data : NULL;

    if (csr) {
        for (extIdx = 0; extIdx &lt; (word16)(extSz_num); extIdx++) {
            tmpSz = TLSX_CSR_GetSize_ex(csr, 0, extIdx);

            if (tmpSz &gt; (OPAQUE8_LEN + OPAQUE24_LEN) &amp;&amp;
                certExts[extIdx] == NULL) {
                /* csr extension is not zero */
                extSz[extIdx] = tmpSz;

                ret = AllocDer(&amp;certExts[extIdx], extSz[extIdx] + ex_offset,
                                                    CERT_TYPE, ssl-&gt;heap);
                if (ret &lt; 0)
                    return ret;
                der = certExts[extIdx];

                /* write extension type */
                c16toa(ext-&gt;type, der-&gt;buffer
                                + OPAQUE16_LEN);
                /* writes extension data length. */
                c16toa(extSz[extIdx], der-&gt;buffer
                            + HELLO_EXT_TYPE_SZ + OPAQUE16_LEN);
                /* write extension data */
                extSz[extIdx] = (word16)TLSX_CSR_Write_ex(csr,
                        der-&gt;buffer + ex_offset, 0, extIdx);
                /* add extension offset */
                extSz[extIdx] += (word16)ex_offset;
                /* extension length */
                c16toa(extSz[extIdx] - OPAQUE16_LEN,
                            der-&gt;buffer);
            }
            totalSz += extSz[extIdx];
        }
    }
    else {
        /* chain cert empty extension size */
        totalSz += OPAQUE16_LEN * extSz_num;
    }
    return totalSz;
}
#endif /* HAVE_CERTIFICATE_STATUS_REQUEST */
/* Add certificate data and empty extension to output up to the fragment size.
 *
 * ssl     SSL/TLS object.
 * cert    The certificate data to write out.
 * len     The length of the certificate data.
 * extSz   Length of the extension data with the certificate.
 * idx     The start of the certificate data to write out.
 * fragSz  The maximum size of this fragment.
 * output  The buffer to write to.
 * extIdx  The index number of the extension data with the certificate
 * returns the number of bytes written.
 */
static word32 AddCertExt(WOLFSSL* ssl, byte* cert, word32 len, word16 extSz,
                         word32 idx, word32 fragSz, byte* output, word16 extIdx)
{
    word32 i = 0;
    word32 copySz = min(len - idx, fragSz);

    if (idx &lt; len) {
        XMEMCPY(output, cert + idx, copySz);
        i = copySz;
        if (copySz == fragSz)
            return i;
    }
    copySz = len + extSz - idx - i;

    if (extSz == OPAQUE16_LEN) {
        if (copySz &lt;= fragSz) {
            /* Empty extension */
            output[i++] = 0;
            output[i++] = 0;
        }
    }
    else {
        byte* certExts = ssl-&gt;buffers.certExts[extIdx]-&gt;buffer + idx + i - len;
        /* Put out as much of the extensions&#039; data as will fit in fragment. */
        if (copySz &gt; fragSz - i)
            copySz = fragSz - i;
        XMEMCPY(output + i, certExts, copySz);
        i += copySz;
    }

    return i;
}

/* handle generation TLS v1.3 certificate (11) */
/* Send the certificate for this end and any CAs that help with validation.
 * This message is always encrypted in TLS v1.3.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13Certificate(WOLFSSL* ssl)
{
    int    ret = 0;
    word32 certSz, certChainSz, headerSz, listSz, payloadSz;
    word16 extSz[MAX_CERT_EXTENSIONS];
    word16 extIdx = 0;
    word32 maxFragment;
    word32 totalextSz = 0;
    word32 len = 0;
    word32 idx = 0;
    word32 offset = OPAQUE16_LEN;
    byte*  p = NULL;
    byte   certReqCtxLen = 0;
    sword32 length;
#ifdef WOLFSSL_POST_HANDSHAKE_AUTH
    byte*  certReqCtx = NULL;
#endif

#ifdef OPENSSL_EXTRA
    WOLFSSL_X509* x509 = NULL;
    WOLFSSL_EVP_PKEY* pkey = NULL;
#endif

    WOLFSSL_START(WC_FUNC_CERTIFICATE_SEND);
    WOLFSSL_ENTER(&quot;SendTls13Certificate&quot;);

    XMEMSET(extSz, 0, sizeof(extSz));

    ssl-&gt;options.buildingMsg = 1;

#ifdef WOLFSSL_POST_HANDSHAKE_AUTH
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp; ssl-&gt;certReqCtx != NULL) {
        certReqCtxLen = ssl-&gt;certReqCtx-&gt;len;
        certReqCtx = &amp;ssl-&gt;certReqCtx-&gt;ctx;
    }
#endif

#ifdef OPENSSL_EXTRA
    /* call client cert callback if no cert has been loaded */
    if ((ssl-&gt;ctx-&gt;CBClientCert != NULL) &amp;&amp;
        (!ssl-&gt;buffers.certificate || !ssl-&gt;buffers.certificate-&gt;buffer)) {
        ret = ssl-&gt;ctx-&gt;CBClientCert(ssl, &amp;x509, &amp;pkey);
        if (ret == 1) {
            if ((wolfSSL_CTX_use_certificate(ssl-&gt;ctx, x509) == WOLFSSL_SUCCESS) &amp;&amp;
                (wolfSSL_CTX_use_PrivateKey(ssl-&gt;ctx, pkey) == WOLFSSL_SUCCESS)) {
                ssl-&gt;options.sendVerify = SEND_CERT;
            }
            wolfSSL_X509_free(x509);
            wolfSSL_EVP_PKEY_free(pkey);
        }
    }
#endif

    if (ssl-&gt;options.sendVerify == SEND_BLANK_CERT) {
        certSz = 0;
        certChainSz = 0;
        headerSz = OPAQUE8_LEN + certReqCtxLen + CERT_HEADER_SZ;
        length = (sword32)headerSz;
        listSz = 0;
    }
    else {
        if (!ssl-&gt;buffers.certificate || !ssl-&gt;buffers.certificate-&gt;buffer) {
            WOLFSSL_MSG(&quot;Send Cert missing certificate buffer&quot;);
            return NO_CERT_ERROR;
        }
        /* Certificate Data */
        certSz = ssl-&gt;buffers.certificate-&gt;length;
        /* Cert Req Ctx Len | Cert Req Ctx | Cert List Len | Cert Data Len */
        headerSz = OPAQUE8_LEN + certReqCtxLen + CERT_HEADER_SZ +
                   CERT_HEADER_SZ;
        /* set empty extension as default */
        for (extIdx = 0; extIdx &lt; (word16)XELEM_CNT(extSz); extIdx++)
            extSz[extIdx] = OPAQUE16_LEN;

    #if defined(HAVE_CERTIFICATE_STATUS_REQUEST) &amp;&amp; !defined(NO_WOLFSSL_SERVER)
        /* We only send CSR on the server side. On client side, the CSR data
         * is populated with the server response. We would be sending the server
         * its own stapling data. */
        if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
            ret = WriteCSRToBuffer(ssl, &amp;ssl-&gt;buffers.certExts[0], &amp;extSz[0],
                    1 /* +1 for leaf */ + ssl-&gt;buffers.certChainCnt);
            if (ret &lt; 0)
                return ret;
            totalextSz += ret;
            ret = 0; /* Clear to signal no error */
        }
        else
    #endif
        {
            /* Leaf cert empty extension size */
            totalextSz += OPAQUE16_LEN;
            /* chain cert empty extension size */
            totalextSz += OPAQUE16_LEN * ssl-&gt;buffers.certChainCnt;
        }

        /* Length of message data with one certificate and extensions. */
        length = (sword32)(headerSz + certSz + totalextSz);
        /* Length of list data with one certificate and extensions. */
        listSz = CERT_HEADER_SZ + certSz + totalextSz;

        /* Send rest of chain if sending cert (chain has leading size/s). */
        if (certSz &gt; 0 &amp;&amp; ssl-&gt;buffers.certChainCnt &gt; 0) {
            p = ssl-&gt;buffers.certChain-&gt;buffer;
            /* Chain length including extensions. */
            certChainSz = ssl-&gt;buffers.certChain-&gt;length;

            length += certChainSz;
            listSz += certChainSz;
        }
        else
            certChainSz = 0;
    }

    payloadSz = (word32)length;

    if (ssl-&gt;fragOffset != 0)
        length -= (ssl-&gt;fragOffset + headerSz);

    maxFragment = (word32)wolfSSL_GetMaxFragSize(ssl, MAX_RECORD_SIZE);

    extIdx = 0;

    while (length &gt; 0 &amp;&amp; ret == 0) {
        byte*  output = NULL;
        word32 fragSz = 0;
        word32 i = RECORD_HEADER_SZ;
        int    sendSz = RECORD_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls) {
            i = Dtls13GetRlHeaderLength(ssl, 1);
            sendSz = (int)i;
        }
#endif /* WOLFSSL_DTLS13 */

        if (ssl-&gt;fragOffset == 0) {
            if (headerSz + certSz + totalextSz + certChainSz &lt;=
                                            maxFragment - HANDSHAKE_HEADER_SZ) {
                fragSz = headerSz + certSz + totalextSz + certChainSz;
            }
#ifdef WOLFSSL_DTLS13
            else if (ssl-&gt;options.dtls){
                /* short-circuit the fragmentation logic here. DTLS
                   fragmentation will be done in dtls13HandshakeSend() */
                fragSz = headerSz + certSz + totalextSz + certChainSz;
            }
#endif /* WOLFSSL_DTLS13 */
            else {
                fragSz = maxFragment - HANDSHAKE_HEADER_SZ;
            }

            sendSz += fragSz + HANDSHAKE_HEADER_SZ;
            i += HANDSHAKE_HEADER_SZ;
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                sendSz += DTLS_HANDSHAKE_EXTRA;
                i += DTLS_HANDSHAKE_EXTRA;
            }
#endif /* WOLFSSL_DTLS13 */
        }
        else {
            fragSz = min((word32)length, maxFragment);
            sendSz += fragSz;
        }

        sendSz += MAX_MSG_EXTRA;

        /* Check buffers are big enough and grow if needed. */
        if ((ret = CheckAvailableSize(ssl, sendSz)) != 0)
            return ret;

        /* Get position in output buffer to write new message to. */
        output = GetOutputBuffer(ssl);

        if (ssl-&gt;fragOffset == 0) {
            AddTls13FragHeaders(output, fragSz, 0, payloadSz, certificate, ssl);

            /* Request context. */
            output[i++] = certReqCtxLen;
        #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
            if (certReqCtxLen &gt; 0) {
                XMEMCPY(output + i, certReqCtx, certReqCtxLen);
                i += certReqCtxLen;
            }
        #endif
            length -= OPAQUE8_LEN + certReqCtxLen;
            fragSz -= OPAQUE8_LEN + certReqCtxLen;
            /* Certificate list length. */
            c32to24(listSz, output + i);
            i += CERT_HEADER_SZ;
            length -= CERT_HEADER_SZ;
            fragSz -= CERT_HEADER_SZ;
            /* Leaf certificate data length. */
            if (certSz &gt; 0) {
                c32to24(certSz, output + i);
                i += CERT_HEADER_SZ;
                length -= CERT_HEADER_SZ;
                fragSz -= CERT_HEADER_SZ;
            }
        }
        else
            AddTls13RecordHeader(output, fragSz, handshake, ssl);

        if (extIdx == 0) {
            if (certSz &gt; 0 &amp;&amp; ssl-&gt;fragOffset &lt; certSz + extSz[0]) {
                /* Put in the leaf certificate with extensions. */
                word32 copySz = AddCertExt(ssl, ssl-&gt;buffers.certificate-&gt;buffer,
                                certSz, extSz[0], ssl-&gt;fragOffset, fragSz,
                                output + i, 0);
                i += copySz;
                ssl-&gt;fragOffset += copySz;
                length -= copySz;
                fragSz -= copySz;
                if (ssl-&gt;fragOffset == certSz + extSz[0])
                    FreeDer(&amp;ssl-&gt;buffers.certExts[0]);
            }
        }
        if (certChainSz &gt; 0 &amp;&amp; fragSz &gt; 0) {
             /* Put in the CA certificates with extensions. */
             while (fragSz &gt; 0) {
                word32 l;

                if (offset == len + OPAQUE16_LEN) {
                    /* Find next CA certificate to write out. */
                    offset = 0;
                    /* Point to the start of current cert in chain buffer. */
                    p = ssl-&gt;buffers.certChain-&gt;buffer + idx;
                    len = NextCert(ssl-&gt;buffers.certChain-&gt;buffer,
                            ssl-&gt;buffers.certChain-&gt;length, &amp;idx);
                    if (len == 0)
                        break;
                #if defined(HAVE_CERTIFICATE_STATUS_REQUEST) &amp;&amp; \
                        !defined(NO_WOLFSSL_SERVER)
                    if (MAX_CERT_EXTENSIONS &gt; extIdx)
                        extIdx++;
                #endif
                }
                /* Write out certificate and extension. */
                l = AddCertExt(ssl, p, len, extSz[extIdx], offset, fragSz,
                                                       output + i, extIdx);
                i += l;
                ssl-&gt;fragOffset += l;
                length -= l;
                fragSz -= l;
                offset += l;

                if (extIdx != 0 &amp;&amp; extIdx &lt; MAX_CERT_EXTENSIONS &amp;&amp;
                    ssl-&gt;buffers.certExts[extIdx] != NULL &amp;&amp;
                                offset == len + extSz[extIdx])
                    FreeDer(&amp;ssl-&gt;buffers.certExts[extIdx]);
                /* for next chain cert */
                len += extSz[extIdx] - OPAQUE16_LEN;
            }
        }

        if ((int)i - RECORD_HEADER_SZ &lt; 0) {
            WOLFSSL_MSG(&quot;Send Cert bad inputSz&quot;);
            return BUFFER_E;
        }

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls) {
            /* DTLS1.3 uses a separate variable and logic for fragments */
            ssl-&gt;options.buildingMsg = 0;
            ssl-&gt;fragOffset = 0;
            ret = Dtls13HandshakeSend(ssl, output, (word16)sendSz, (word16)i,
                                      certificate, 1);
        }
        else
#endif /* WOLFSSL_DTLS13 */
        {
            /* This message is always encrypted. */
            sendSz = BuildTls13Message(ssl, output, sendSz,
                output + RECORD_HEADER_SZ, (int)(i - RECORD_HEADER_SZ),
                handshake, 1,
                0, 0);
            if (sendSz &lt; 0)
                return sendSz;

#if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
            if (ssl-&gt;hsInfoOn)
                AddPacketName(ssl, &quot;Certificate&quot;);
            if (ssl-&gt;toInfoOn) {
                ret = AddPacketInfo(ssl, &quot;Certificate&quot;, handshake, output,
                              sendSz, WRITE_PROTO, 0, ssl-&gt;heap);
                if (ret != 0)
                    return ret;
            }
#endif

            ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;
            ssl-&gt;options.buildingMsg = 0;
            if (!ssl-&gt;options.groupMessages)
                ret = SendBuffered(ssl);
        }
    }

    if (ret != WC_NO_ERR_TRACE(WANT_WRITE)) {
        /* Clean up the fragment offset. */
        ssl-&gt;options.buildingMsg = 0;
        ssl-&gt;fragOffset = 0;
        if (ssl-&gt;options.side == WOLFSSL_SERVER_END)
            ssl-&gt;options.serverState = SERVER_CERT_COMPLETE;
    }

#ifdef WOLFSSL_POST_HANDSHAKE_AUTH
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp; ssl-&gt;certReqCtx != NULL) {
        CertReqCtx* ctx = ssl-&gt;certReqCtx;
        ssl-&gt;certReqCtx = ssl-&gt;certReqCtx-&gt;next;
        XFREE(ctx, ssl-&gt;heap, DYNAMIC_TYPE_TMP_BUFFER);
    }
#endif

    WOLFSSL_LEAVE(&quot;SendTls13Certificate&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_SEND);

    return ret;
}

#if (!defined(NO_RSA) || defined(HAVE_ECC) || defined(HAVE_ED25519) || \
     defined(HAVE_ED448) || defined(HAVE_FALCON) || \
     defined(HAVE_DILITHIUM)) &amp;&amp; \
    (!defined(NO_WOLFSSL_SERVER) || !defined(WOLFSSL_NO_CLIENT_AUTH))
typedef struct Scv13Args {
    byte*  output; /* not allocated */
    byte*  verify; /* not allocated */
    word32 idx;
    word32 sigLen;
    int    sendSz;
    word16 length;

    byte   sigAlgo;
    byte*  sigData;
    word16 sigDataSz;
#ifndef NO_RSA
    byte*  toSign; /* not allocated */
    word32 toSignSz;
#endif
#ifdef WOLFSSL_DUAL_ALG_CERTS
    byte   altSigAlgo;
    word32 altSigLen;    /* Only used in the case of both native and alt. */
    byte*  altSigData;
    word16 altSigDataSz;
#endif
} Scv13Args;

static void FreeScv13Args(WOLFSSL* ssl, void* pArgs)
{
    Scv13Args* args = (Scv13Args*)pArgs;

    (void)ssl;

    if (args &amp;&amp; args-&gt;sigData) {
        XFREE(args-&gt;sigData, ssl-&gt;heap, DYNAMIC_TYPE_SIGNATURE);
        args-&gt;sigData = NULL;
    }
#ifdef WOLFSSL_DUAL_ALG_CERTS
    if (args &amp;&amp; args-&gt;altSigData != NULL) {
        XFREE(args-&gt;altSigData, ssl-&gt;heap, DYNAMIC_TYPE_SIGNATURE);
        args-&gt;altSigData = NULL;
    }
#endif
}

/* handle generation TLS v1.3 certificate_verify (15) */
/* Send the TLS v1.3 CertificateVerify message.
 * A hash of all the message so far is used.
 * The signed data is:
 *     0x20 * 64 | context string | 0x00 | hash of messages
 * This message is always encrypted in TLS v1.3.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13CertificateVerify(WOLFSSL* ssl)
{
    int ret = 0;
#ifndef NO_RSA
    /* Use this as a temporary buffer for RSA signature verification. */
    buffer* rsaSigBuf = &amp;ssl-&gt;buffers.sig;
#endif
#ifdef WOLFSSL_ASYNC_CRYPT
    Scv13Args* args = NULL;
    WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);
#else
    Scv13Args  args[1];
#endif

#ifdef WOLFSSL_DTLS13
    int recordLayerHdrExtra;
#endif /* WOLFSSL_DTLS13 */

    WOLFSSL_START(WC_FUNC_CERTIFICATE_VERIFY_SEND);
    WOLFSSL_ENTER(&quot;SendTls13CertificateVerify&quot;);

#ifdef WOLFSSL_BLIND_PRIVATE_KEY
    wolfssl_priv_der_unblind(ssl-&gt;buffers.key, ssl-&gt;buffers.keyMask);
#endif

    ssl-&gt;options.buildingMsg = 1;

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13SendCertVerify(ssl);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        goto exit_scv;
    }
    ret = 0;
#endif /* WOLFSSL_RENESAS_TSIP_TLS */

#ifdef WOLFSSL_DTLS13
    /* can be negative */
    if (ssl-&gt;options.dtls)
        recordLayerHdrExtra = Dtls13GetRlHeaderLength(ssl, 1) - RECORD_HEADER_SZ;
    else
        recordLayerHdrExtra = 0;

#endif /* WOLFSSL_DTLS13 */

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;async == NULL) {
        ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                        DYNAMIC_TYPE_ASYNC);
        if (ssl-&gt;async == NULL)
            ERROR_OUT(MEMORY_E, exit_scv);
    }
    args = (Scv13Args*)ssl-&gt;async-&gt;args;

    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.asyncState);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0)
            goto exit_scv;
    }
    else
#endif
    {
        /* Reset state */
        ret = 0;
        ssl-&gt;options.asyncState = TLS_ASYNC_BEGIN;
        XMEMSET(args, 0, sizeof(Scv13Args));
    #ifdef WOLFSSL_ASYNC_CRYPT
        ssl-&gt;async-&gt;freeArgs = FreeScv13Args;
    #endif
    }

    switch(ssl-&gt;options.asyncState)
    {
        case TLS_ASYNC_BEGIN:
        {
            if (ssl-&gt;options.sendVerify == SEND_BLANK_CERT) {
            #ifdef WOLFSSL_BLIND_PRIVATE_KEY
                wolfssl_priv_der_unblind(ssl-&gt;buffers.key,
                    ssl-&gt;buffers.keyMask);
            #endif
                return 0;  /* sent blank cert, can&#039;t verify */
            }

            args-&gt;sendSz = WC_MAX_CERT_VERIFY_SZ + MAX_MSG_EXTRA;
            /* Always encrypted.  */
            args-&gt;sendSz += MAX_MSG_EXTRA;

            /* check for available size */
            if ((ret = CheckAvailableSize(ssl, args-&gt;sendSz)) != 0) {
                goto exit_scv;
            }

            /* get output buffer */
            args-&gt;output = GetOutputBuffer(ssl);

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_BUILD;
        } /* case TLS_ASYNC_BEGIN */
        FALL_THROUGH;

        case TLS_ASYNC_BUILD:
        {
            int rem = (int)(ssl-&gt;buffers.outputBuffer.bufferSize
              - ssl-&gt;buffers.outputBuffer.length
              - RECORD_HEADER_SZ - HANDSHAKE_HEADER_SZ);

            /* idx is used to track verify pointer offset to output */
            args-&gt;idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;
            args-&gt;verify =
                          &amp;args-&gt;output[RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ];

#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                rem -= recordLayerHdrExtra + DTLS_HANDSHAKE_EXTRA;
                args-&gt;idx += recordLayerHdrExtra + DTLS_HANDSHAKE_EXTRA;
                args-&gt;verify += recordLayerHdrExtra + DTLS_HANDSHAKE_EXTRA;
            }
#endif /* WOLFSSL_DTLS13 */

            if (ssl-&gt;buffers.key == NULL) {
            #ifdef HAVE_PK_CALLBACKS
                if (wolfSSL_CTX_IsPrivatePkSet(ssl-&gt;ctx))
                    args-&gt;sigLen = (word16)GetPrivateKeySigSize(ssl);
                else
            #endif
                    ERROR_OUT(NO_PRIVATE_KEY, exit_scv);
            }
            else {
#ifdef WOLFSSL_DUAL_ALG_CERTS
                if (ssl-&gt;sigSpec != NULL &amp;&amp;
                    *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_ALTERNATIVE) {
                    /* In the case of alternative, we swap in the alt. */
                    if (ssl-&gt;buffers.altKey == NULL) {
                        ERROR_OUT(NO_PRIVATE_KEY, exit_scv);
                    }
                    ssl-&gt;buffers.keyType = ssl-&gt;buffers.altKeyType;
                    ssl-&gt;buffers.keySz = ssl-&gt;buffers.altKeySz;
                    /* If we own it, free key before overriding it. */
                    if (ssl-&gt;buffers.weOwnKey) {
                        FreeDer(&amp;ssl-&gt;buffers.key);
                    #ifdef WOLFSSL_BLIND_PRIVATE_KEY
                        FreeDer(&amp;ssl-&gt;buffers.keyMask);
                    #endif
                    }

                    /* Swap keys */
                    ssl-&gt;buffers.key     = ssl-&gt;buffers.altKey;
                #ifdef WOLFSSL_BLIND_PRIVATE_KEY
                    ssl-&gt;buffers.keyMask = ssl-&gt;buffers.altKeyMask;
                #endif
                    ssl-&gt;buffers.weOwnKey = ssl-&gt;buffers.weOwnAltKey;
                }
#endif /* WOLFSSL_DUAL_ALG_CERTS */
                ret = DecodePrivateKey(ssl, &amp;args-&gt;sigLen);
                if (ret != 0)
                    goto exit_scv;
            }

            if (rem &lt; 0 || (int)args-&gt;sigLen &gt; rem) {
                ERROR_OUT(BUFFER_E, exit_scv);
            }

            if (args-&gt;sigLen == 0) {
                ERROR_OUT(NO_PRIVATE_KEY, exit_scv);
            }

            /* Add signature algorithm. */
            if (ssl-&gt;hsType == DYNAMIC_TYPE_RSA)
                args-&gt;sigAlgo = rsa_pss_sa_algo;
        #ifdef HAVE_ECC
            else if (ssl-&gt;hsType == DYNAMIC_TYPE_ECC) {
        #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;buffers.keyType == sm2_sa_algo) {
                    args-&gt;sigAlgo = sm2_sa_algo;
                }
                else
        #endif
                {
                    args-&gt;sigAlgo = ecc_dsa_sa_algo;
                }
            }
        #endif
        #ifdef HAVE_ED25519
            else if (ssl-&gt;hsType == DYNAMIC_TYPE_ED25519)
                args-&gt;sigAlgo = ed25519_sa_algo;
        #endif
        #ifdef HAVE_ED448
            else if (ssl-&gt;hsType == DYNAMIC_TYPE_ED448)
                args-&gt;sigAlgo = ed448_sa_algo;
        #endif
        #if defined(HAVE_FALCON)
            else if (ssl-&gt;hsType == DYNAMIC_TYPE_FALCON) {
                falcon_key* fkey = (falcon_key*)ssl-&gt;hsKey;
                byte level = 0;
                if (wc_falcon_get_level(fkey, &amp;level) != 0) {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }
                if (level == 1) {
                    args-&gt;sigAlgo = falcon_level1_sa_algo;
                }
                else if (level == 5) {
                    args-&gt;sigAlgo = falcon_level5_sa_algo;
                }
                else {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }
            }
        #endif /* HAVE_FALCON */
        #if defined(HAVE_DILITHIUM)
            else if (ssl-&gt;hsType == DYNAMIC_TYPE_DILITHIUM) {
                dilithium_key* fkey = (dilithium_key*)ssl-&gt;hsKey;
                byte level = 0;
                if (wc_dilithium_get_level(fkey, &amp;level) != 0) {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }
                if (level == 2) {
                    args-&gt;sigAlgo = dilithium_level2_sa_algo;
                }
                else if (level == 3) {
                    args-&gt;sigAlgo = dilithium_level3_sa_algo;
                }
                else if (level == 5) {
                    args-&gt;sigAlgo = dilithium_level5_sa_algo;
                }
                else {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }
            }
        #endif /* HAVE_DILITHIUM */
            else {
                ERROR_OUT(ALGO_ID_E, exit_scv);
            }

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;peerSigSpec == NULL) {
                /* The peer did not respond. We didn&#039;t send CKS or they don&#039;t
                 * support it. Either way, we do not need to handle dual
                 * key/sig case. */
                ssl-&gt;sigSpec = NULL;
                ssl-&gt;sigSpecSz = 0;
            }

            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* The native was already decoded. Now we need to do the
                 * alternative. Note that no swap was done because this case is
                 * both native and alternative, not just alternative. */
                if (ssl-&gt;ctx-&gt;altPrivateKey == NULL) {
                    ERROR_OUT(NO_PRIVATE_KEY, exit_scv);
                }

                /* After this call, args-&gt;altSigLen has the length we need for
                 * the alternative signature. */
                ret = DecodeAltPrivateKey(ssl, &amp;args-&gt;altSigLen);
                if (ret != 0)
                    goto exit_scv;

                if (ssl-&gt;buffers.altKeyType == ecc_dsa_sa_algo ||
                    ssl-&gt;buffers.altKeyType == falcon_level1_sa_algo ||
                    ssl-&gt;buffers.altKeyType == falcon_level5_sa_algo ||
                    ssl-&gt;buffers.altKeyType == dilithium_level2_sa_algo ||
                    ssl-&gt;buffers.altKeyType == dilithium_level3_sa_algo ||
                    ssl-&gt;buffers.altKeyType == dilithium_level5_sa_algo) {
                    args-&gt;altSigAlgo = ssl-&gt;buffers.altKeyType;
                }
                else if (ssl-&gt;buffers.altKeyType == rsa_sa_algo &amp;&amp;
                         ssl-&gt;hsAltType == DYNAMIC_TYPE_RSA) {
                    args-&gt;altSigAlgo = rsa_pss_sa_algo;
                }
                else {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }

                EncodeDualSigAlg(args-&gt;sigAlgo, args-&gt;altSigAlgo, args-&gt;verify);
                if (args-&gt;verify[0] == 0) {
                    ERROR_OUT(ALGO_ID_E, exit_scv);
                }
            }
            else
        #endif /* WOLFSSL_DUAL_ALG_CERTS */
                EncodeSigAlg(ssl-&gt;options.hashAlgo, args-&gt;sigAlgo,
                             args-&gt;verify);

            if (args-&gt;sigData == NULL) {
                word32 sigLen = MAX_SIG_DATA_SZ;
                if ((ssl-&gt;hsType == DYNAMIC_TYPE_RSA) &amp;&amp;
                    (args-&gt;sigLen &gt; MAX_SIG_DATA_SZ)) {
                    /* We store the RSA signature in the sigData buffer
                     * temporarily, hence its size must be fitting. */
                    sigLen = args-&gt;sigLen;
                }
                args-&gt;sigData = (byte*)XMALLOC(sigLen, ssl-&gt;heap,
                                                    DYNAMIC_TYPE_SIGNATURE);
                if (args-&gt;sigData == NULL) {
                    ERROR_OUT(MEMORY_E, exit_scv);
                }
            }

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if ((ssl-&gt;sigSpec != NULL) &amp;&amp;
                (*ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) &amp;&amp;
                (args-&gt;altSigData == NULL)) {
                word32 sigLen = MAX_SIG_DATA_SZ;
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_RSA &amp;&amp;
                    args-&gt;altSigLen &gt; MAX_SIG_DATA_SZ) {
                    /* We store the RSA signature in the sigData buffer
                     * temporarily, hence its size must be fitting. */
                    sigLen = args-&gt;altSigLen;
                }
                args-&gt;altSigData = (byte*)XMALLOC(sigLen, ssl-&gt;heap,
                                                    DYNAMIC_TYPE_SIGNATURE);
                if (args-&gt;altSigData == NULL) {
                    ERROR_OUT(MEMORY_E, exit_scv);
                }
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

            /* Create the data to be signed. */
            ret = CreateSigData(ssl, args-&gt;sigData, &amp;args-&gt;sigDataSz, 0);
            if (ret != 0)
                goto exit_scv;

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if ((ssl-&gt;sigSpec != NULL) &amp;&amp;
                (*ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH)) {
                XMEMCPY(args-&gt;altSigData, args-&gt;sigData, args-&gt;sigDataSz);
                args-&gt;altSigDataSz = args-&gt;sigDataSz;
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

        #ifndef NO_RSA
            if (ssl-&gt;hsType == DYNAMIC_TYPE_RSA) {
                /* build encoded signature buffer */
                rsaSigBuf-&gt;length = WC_MAX_DIGEST_SIZE;
                rsaSigBuf-&gt;buffer = (byte*)XMALLOC(rsaSigBuf-&gt;length, ssl-&gt;heap,
                                                   DYNAMIC_TYPE_SIGNATURE);
                if (rsaSigBuf-&gt;buffer == NULL) {
                    ERROR_OUT(MEMORY_E, exit_scv);
                }

                ret = CreateRSAEncodedSig(rsaSigBuf-&gt;buffer, args-&gt;sigData,
                    args-&gt;sigDataSz, args-&gt;sigAlgo, ssl-&gt;options.hashAlgo);
                if (ret &lt; 0)
                    goto exit_scv;
                rsaSigBuf-&gt;length = (unsigned int)ret;
                ret = 0;
            }
        #endif /* !NO_RSA */
        #ifdef HAVE_ECC
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ECC) {
                args-&gt;sigLen = (word32)args-&gt;sendSz - args-&gt;idx -
                               HASH_SIG_SIZE -
                               VERIFY_HEADER;
            #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;buffers.keyType != sm2_sa_algo)
            #endif
                {
                    ret = CreateECCEncodedSig(args-&gt;sigData,
                        args-&gt;sigDataSz, ssl-&gt;options.hashAlgo);
                    if (ret &lt; 0)
                        goto exit_scv;
                    args-&gt;sigDataSz = (word16)ret;
                    ret = 0;
                }
            }
        #endif /* HAVE_ECC */
        #ifdef HAVE_ED25519
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ED25519) {
                ret = Ed25519CheckPubKey(ssl);
                if (ret &lt; 0) {
                    ERROR_OUT(ret, exit_scv);
                }
                args-&gt;sigLen = ED25519_SIG_SIZE;
            }
        #endif /* HAVE_ED25519 */
        #ifdef HAVE_ED448
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ED448) {
                ret = Ed448CheckPubKey(ssl);
                if (ret &lt; 0) {
                    ERROR_OUT(ret, exit_scv);
                }
                args-&gt;sigLen = ED448_SIG_SIZE;
            }

        #endif /* HAVE_ED448 */
        #if defined(HAVE_FALCON)
            if (ssl-&gt;hsType == DYNAMIC_TYPE_FALCON) {
                args-&gt;sigLen = FALCON_MAX_SIG_SIZE;
            }
        #endif /* HAVE_FALCON */
        #if defined(HAVE_DILITHIUM)
            if (ssl-&gt;hsType == DYNAMIC_TYPE_DILITHIUM) {
                args-&gt;sigLen = DILITHIUM_MAX_SIG_SIZE;
            }
        #endif /* HAVE_DILITHIUM */

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {

            #ifndef NO_RSA
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_RSA) {
                    /* build encoded signature buffer */
                    rsaSigBuf-&gt;length = WC_MAX_DIGEST_SIZE;
                    rsaSigBuf-&gt;buffer = (byte*)XMALLOC(rsaSigBuf-&gt;length,
                                                       ssl-&gt;heap,
                                                       DYNAMIC_TYPE_SIGNATURE);
                    if (rsaSigBuf-&gt;buffer == NULL) {
                        ERROR_OUT(MEMORY_E, exit_scv);
                    }

                    ret = CreateRSAEncodedSig(rsaSigBuf-&gt;buffer,
                                    args-&gt;altSigData, args-&gt;altSigDataSz,
                                    args-&gt;altSigAlgo, ssl-&gt;options.hashAlgo);
                    if (ret &lt; 0)
                        goto exit_scv;
                    rsaSigBuf-&gt;length = ret;
                    ret = 0;
                }
            #endif /* !NO_RSA */
            #ifdef HAVE_ECC
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_ECC) {
                    ret = CreateECCEncodedSig(args-&gt;altSigData,
                            args-&gt;altSigDataSz, ssl-&gt;options.hashAlgo);
                    if (ret &lt; 0)
                        goto exit_scv;
                    args-&gt;altSigDataSz = (word16)ret;
                    ret = 0;
                }
            #endif /* HAVE_ECC */
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_DO;
        } /* case TLS_ASYNC_BUILD */
        FALL_THROUGH;

        case TLS_ASYNC_DO:
        {
            byte* sigOut = args-&gt;verify + HASH_SIG_SIZE + VERIFY_HEADER;
        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* As we have two signatures in the message, we store
                 * the length of each before the actual signature. This
                 * is necessary, as we could have two algorithms with
                 * variable length signatures. */
                sigOut += OPAQUE16_LEN;
            }
        #endif
        #ifdef HAVE_ECC
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ECC) {
            #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;buffers.keyType == sm2_sa_algo) {
                    ret = Sm2wSm3Sign(ssl, TLS13_SM2_SIG_ID,
                        TLS13_SM2_SIG_ID_SZ, args-&gt;sigData, args-&gt;sigDataSz,
                        sigOut, &amp;args-&gt;sigLen, (ecc_key*)ssl-&gt;hsKey, NULL);
                }
                else
            #endif
                {
                    ret = EccSign(ssl, args-&gt;sigData, args-&gt;sigDataSz,
                        sigOut, &amp;args-&gt;sigLen, (ecc_key*)ssl-&gt;hsKey,
                #ifdef HAVE_PK_CALLBACKS
                        ssl-&gt;buffers.key
                #else
                        NULL
                #endif
                    );
                }
                args-&gt;length = (word16)args-&gt;sigLen;
            }
        #endif /* HAVE_ECC */
        #ifdef HAVE_ED25519
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ED25519) {
                ret = Ed25519Sign(ssl, args-&gt;sigData, args-&gt;sigDataSz,
                    sigOut, &amp;args-&gt;sigLen, (ed25519_key*)ssl-&gt;hsKey,
            #ifdef HAVE_PK_CALLBACKS
                    ssl-&gt;buffers.key
            #else
                    NULL
            #endif
                );
                args-&gt;length = (word16)args-&gt;sigLen;
            }
        #endif
        #ifdef HAVE_ED448
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ED448) {
                ret = Ed448Sign(ssl, args-&gt;sigData, args-&gt;sigDataSz,
                    sigOut, &amp;args-&gt;sigLen, (ed448_key*)ssl-&gt;hsKey,
            #ifdef HAVE_PK_CALLBACKS
                    ssl-&gt;buffers.key
            #else
                    NULL
            #endif
                );
                args-&gt;length = (word16)args-&gt;sigLen;
            }
        #endif
        #if defined(HAVE_FALCON)
            if (ssl-&gt;hsType == DYNAMIC_TYPE_FALCON) {
                ret = wc_falcon_sign_msg(args-&gt;sigData, args-&gt;sigDataSz,
                                         sigOut, &amp;args-&gt;sigLen,
                                         (falcon_key*)ssl-&gt;hsKey, ssl-&gt;rng);
                args-&gt;length = (word16)args-&gt;sigLen;
            }
        #endif /* HAVE_FALCON */
        #if defined(HAVE_DILITHIUM) &amp;&amp; !defined(WOLFSSL_DILITHIUM_NO_SIGN)
            if (ssl-&gt;hsType == DYNAMIC_TYPE_DILITHIUM) {
                ret = wc_dilithium_sign_msg(args-&gt;sigData, args-&gt;sigDataSz,
                                         sigOut, &amp;args-&gt;sigLen,
                                         (dilithium_key*)ssl-&gt;hsKey, ssl-&gt;rng);
                args-&gt;length = (word16)args-&gt;sigLen;
            }
        #endif /* HAVE_DILITHIUM */
        #ifndef NO_RSA
            if (ssl-&gt;hsType == DYNAMIC_TYPE_RSA) {
                args-&gt;toSign = rsaSigBuf-&gt;buffer;
                args-&gt;toSignSz = (word32)rsaSigBuf-&gt;length;
            #if defined(HAVE_PK_CALLBACKS) &amp;&amp; \
                defined(TLS13_RSA_PSS_SIGN_CB_NO_PREHASH)
                /* Pass full data to sign (args-&gt;sigData), not hash of */
                if (ssl-&gt;ctx-&gt;RsaPssSignCb) {
                    args-&gt;toSign = args-&gt;sigData;
                    args-&gt;toSignSz = args-&gt;sigDataSz;
                }
            #endif
                ret = RsaSign(ssl, (const byte*)args-&gt;toSign, args-&gt;toSignSz,
                              sigOut, &amp;args-&gt;sigLen, args-&gt;sigAlgo,
                              ssl-&gt;options.hashAlgo, (RsaKey*)ssl-&gt;hsKey,
                              ssl-&gt;buffers.key);
                if (ret == 0) {
                    args-&gt;length = (word16)args-&gt;sigLen;
                    XMEMCPY(args-&gt;sigData, sigOut, args-&gt;sigLen);
                }
            }
        #endif /* !NO_RSA */

            /* Check for error */
            if (ret != 0) {
                goto exit_scv;
            }

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* Add signature length for the first signature. */
                c16toa((word16)args-&gt;sigLen, sigOut - OPAQUE16_LEN);
                args-&gt;length += OPAQUE16_LEN;

                /* Advance our pointer to where we store the alt signature.
                 * We also add additional space for the length field of the
                 * second signature. */
                sigOut += args-&gt;sigLen + OPAQUE16_LEN;

                /* Generate the alternative signature */
            #ifdef HAVE_ECC
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_ECC) {
                    ret = EccSign(ssl, args-&gt;altSigData, args-&gt;altSigDataSz,
                                  sigOut, &amp;args-&gt;altSigLen,
                                  (ecc_key*)ssl-&gt;hsAltKey,
                    #ifdef HAVE_PK_CALLBACKS
                                  ssl-&gt;buffers.altKey
                    #else
                                  NULL
                    #endif
                                  );
                }
            #endif /* HAVE_ECC */
            #ifndef NO_RSA
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_RSA) {
                    args-&gt;toSign = rsaSigBuf-&gt;buffer;
                    args-&gt;toSignSz = (word32)rsaSigBuf-&gt;length;
                #if defined(HAVE_PK_CALLBACKS) &amp;&amp; \
                    defined(TLS13_RSA_PSS_SIGN_CB_NO_PREHASH)
                    /* Pass full data to sign (args-&gt;altSigData), not hash of */
                    if (ssl-&gt;ctx-&gt;RsaPssSignCb) {
                        args-&gt;toSign = args-&gt;altSigData;
                        args-&gt;toSignSz = (word32)args-&gt;altSigDataSz;
                    }
                #endif
                    ret = RsaSign(ssl, (const byte*)args-&gt;toSign,
                                  args-&gt;toSignSz, sigOut, &amp;args-&gt;altSigLen,
                                  args-&gt;altSigAlgo, ssl-&gt;options.hashAlgo,
                                  (RsaKey*)ssl-&gt;hsAltKey,
                                  ssl-&gt;buffers.altKey);

                    if (ret == 0) {
                        XMEMCPY(args-&gt;altSigData, sigOut, args-&gt;altSigLen);
                    }
                }
            #endif /* !NO_RSA */
            #if defined(HAVE_FALCON)
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_FALCON) {
                    ret = wc_falcon_sign_msg(args-&gt;altSigData,
                                             args-&gt;altSigDataSz, sigOut,
                                             &amp;args-&gt;altSigLen,
                                             (falcon_key*)ssl-&gt;hsAltKey,
                                             ssl-&gt;rng);
                }
            #endif /* HAVE_FALCON */
            #if defined(HAVE_DILITHIUM) &amp;&amp; !defined(WOLFSSL_DILITHIUM_NO_SIGN)
                if (ssl-&gt;hsAltType == DYNAMIC_TYPE_DILITHIUM) {
                    ret = wc_dilithium_sign_msg(args-&gt;altSigData,
                                                args-&gt;altSigDataSz, sigOut,
                                                &amp;args-&gt;altSigLen,
                                                (dilithium_key*)ssl-&gt;hsAltKey,
                                                ssl-&gt;rng);
                }
            #endif /* HAVE_DILITHIUM */

                /* Check for error */
                if (ret != 0) {
                    goto exit_scv;
                }

                /* Add signature length for the alternative signature. */
                c16toa((word16)args-&gt;altSigLen, sigOut - OPAQUE16_LEN);

                /* Add length of the alt sig to the total length */
                args-&gt;length += args-&gt;altSigLen + OPAQUE16_LEN;
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

            /* Add signature length. */
            c16toa(args-&gt;length, args-&gt;verify + HASH_SIG_SIZE);

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_VERIFY;
        } /* case TLS_ASYNC_DO */
        FALL_THROUGH;

        case TLS_ASYNC_VERIFY:
        {
        #ifndef NO_RSA
            if (ssl-&gt;hsType == DYNAMIC_TYPE_RSA) {
                /* check for signature faults */
                ret = VerifyRsaSign(ssl, args-&gt;sigData, args-&gt;sigLen,
                    rsaSigBuf-&gt;buffer, (word32)rsaSigBuf-&gt;length, args-&gt;sigAlgo,
                    ssl-&gt;options.hashAlgo, (RsaKey*)ssl-&gt;hsKey,
                    ssl-&gt;buffers.key);
            }
        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH &amp;&amp;
                ssl-&gt;hsAltType == DYNAMIC_TYPE_RSA) {
                /* check for signature faults */
                ret = VerifyRsaSign(ssl, args-&gt;altSigData, args-&gt;altSigLen,
                        rsaSigBuf-&gt;buffer, (word32)rsaSigBuf-&gt;length,
                        args-&gt;altSigAlgo, ssl-&gt;options.hashAlgo,
                        (RsaKey*)ssl-&gt;hsAltKey, ssl-&gt;buffers.altKey);
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */
        #endif /* !NO_RSA */
        #if defined(HAVE_ECC) &amp;&amp; defined(WOLFSSL_CHECK_SIG_FAULTS)
            if (ssl-&gt;hsType == DYNAMIC_TYPE_ECC) {
                byte* sigOut = args-&gt;verify + HASH_SIG_SIZE + VERIFY_HEADER;
            #ifdef WOLFSSL_DUAL_ALG_CERTS
                if (ssl-&gt;sigSpec != NULL &amp;&amp;
                    *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                    /* Add our length offset. */
                    sigOut += OPAQUE16_LEN;
                }
            #endif
            #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;buffers.keyType == sm2_sa_algo) {
                    ret = Sm2wSm3Verify(ssl, TLS13_SM2_SIG_ID,
                        TLS13_SM2_SIG_ID_SZ,
                        sigOut, args-&gt;sigLen, args-&gt;sigData, args-&gt;sigDataSz,
                        (ecc_key*)ssl-&gt;hsKey, NULL);
                }
                else
            #endif
                {
                #ifdef HAVE_PK_CALLBACKS
                    buffer tmp;

                    tmp.length = ssl-&gt;buffers.key-&gt;length;
                    tmp.buffer = ssl-&gt;buffers.key-&gt;buffer;
                #endif
                    ret = EccVerify(ssl, sigOut, args-&gt;sigLen,
                            args-&gt;sigData, args-&gt;sigDataSz,
                            (ecc_key*)ssl-&gt;hsKey,
                #ifdef HAVE_PK_CALLBACKS
                            &amp;tmp
                #else
                            NULL
                #endif
                            );
                }
            }
        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH &amp;&amp;
                ssl-&gt;hsAltType == DYNAMIC_TYPE_ECC) {
                /* check for signature faults */
                byte* sigOut = args-&gt;verify + HASH_SIG_SIZE + VERIFY_HEADER +
                                args-&gt;sigLen + OPAQUE16_LEN + OPAQUE16_LEN;
                ret = EccVerify(ssl, sigOut, args-&gt;altSigLen,
                        args-&gt;altSigData, args-&gt;altSigDataSz,
                        (ecc_key*)ssl-&gt;hsAltKey,
            #ifdef HAVE_PK_CALLBACKS
                        ssl-&gt;buffers.altKey
            #else
                        NULL
            #endif
                        );
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */
        #endif /* HAVE_ECC &amp;&amp; WOLFSSL_CHECK_SIG_FAULTS */

            /* Check for error */
            if (ret != 0) {
                goto exit_scv;
            }

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_FINALIZE;
        } /* case TLS_ASYNC_VERIFY */
        FALL_THROUGH;

        case TLS_ASYNC_FINALIZE:
        {
            /* Put the record and handshake headers on. */
            AddTls13Headers(args-&gt;output, args-&gt;length + HASH_SIG_SIZE +
                            VERIFY_HEADER, certificate_verify, ssl);

            args-&gt;sendSz = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ +
                                args-&gt;length + HASH_SIG_SIZE + VERIFY_HEADER;
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls)
                args-&gt;sendSz += recordLayerHdrExtra + DTLS_HANDSHAKE_EXTRA;

#endif /* WOLFSSL_DTLS13 */
            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_END;
        } /* case TLS_ASYNC_FINALIZE */
        FALL_THROUGH;

        case TLS_ASYNC_END:
        {
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                ssl-&gt;options.buildingMsg = 0;
                ret = Dtls13HandshakeSend(ssl, args-&gt;output,
                    WC_MAX_CERT_VERIFY_SZ + MAX_MSG_EXTRA + MAX_MSG_EXTRA,
                    (word16)args-&gt;sendSz, certificate_verify, 1);
                if (ret != 0)
                    goto exit_scv;

                break;
            }
#endif /* WOLFSSL_DTLS13 */

            /* This message is always encrypted. */
            ret = BuildTls13Message(ssl, args-&gt;output,
                                    WC_MAX_CERT_VERIFY_SZ + MAX_MSG_EXTRA,
                                    args-&gt;output + RECORD_HEADER_SZ,
                                    args-&gt;sendSz - RECORD_HEADER_SZ, handshake,
                                    1, 0, 0);

            if (ret &lt; 0) {
                goto exit_scv;
            }
            else {
                args-&gt;sendSz = ret;
                ret = 0;
            }

        #if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
            if (ssl-&gt;hsInfoOn)
                AddPacketName(ssl, &quot;CertificateVerify&quot;);
            if (ssl-&gt;toInfoOn) {
                ret = AddPacketInfo(ssl, &quot;CertificateVerify&quot;, handshake,
                            args-&gt;output, args-&gt;sendSz, WRITE_PROTO, 0,
                            ssl-&gt;heap);
                if (ret != 0)
                    goto exit_scv;
            }
        #endif

            ssl-&gt;buffers.outputBuffer.length += (word32)args-&gt;sendSz;
            ssl-&gt;options.buildingMsg = 0;
            if (!ssl-&gt;options.groupMessages)
                ret = SendBuffered(ssl);
            break;
        }
        default:
            ret = INPUT_CASE_ERROR;
    } /* switch(ssl-&gt;options.asyncState) */

exit_scv:
#ifdef WOLFSSL_BLIND_PRIVATE_KEY
    if (ret == 0) {
        ret = wolfssl_priv_der_blind(ssl-&gt;rng, ssl-&gt;buffers.key,
            &amp;ssl-&gt;buffers.keyMask);
    }
    else {
        wolfssl_priv_der_unblind(ssl-&gt;buffers.key, ssl-&gt;buffers.keyMask);
    }
#endif

    WOLFSSL_LEAVE(&quot;SendTls13CertificateVerify&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_VERIFY_SEND);

#ifdef WOLFSSL_ASYNC_CRYPT
    /* Handle async operation */
    if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
        return ret;
    }
#endif /* WOLFSSL_ASYNC_CRYPT */

    /* Final cleanup */
    FreeScv13Args(ssl, args);
    FreeKeyExchange(ssl);
#ifdef WOLFSSL_ASYNC_IO
    /* Cleanup async */
    FreeAsyncCtx(ssl, 0);
#endif

    if (ret != 0) {
        WOLFSSL_ERROR_VERBOSE(ret);
    }

    return ret;
}
#endif
#endif /* !NO_WOLFSSL_CLIENT || !NO_WOLFSSL_SERVER */

#if !defined(NO_WOLFSSL_CLIENT) || !defined(WOLFSSL_NO_CLIENT_AUTH)
/* handle processing TLS v1.3 certificate (11) */
/* Parse and handle a TLS v1.3 Certificate message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of Certificate.
 *           On exit, the index of byte after the Certificate message.
 * totalSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13Certificate(WOLFSSL* ssl, byte* input, word32* inOutIdx,
                              word32 totalSz)
{
    int ret = 0;

    WOLFSSL_START(WC_FUNC_CERTIFICATE_DO);
    WOLFSSL_ENTER(&quot;DoTls13Certificate&quot;);

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;options.handShakeDone) {
        /* certificate needs some special care after the handshake */
        ret = Dtls13RtxProcessingCertificate(
            ssl, input + *inOutIdx, totalSz);
    }
#endif /* WOLFSSL_DTLS13 */

    if (ret == 0)
        ret = ProcessPeerCerts(ssl, input, inOutIdx, totalSz);
    if (ret == 0) {
#if !defined(NO_WOLFSSL_CLIENT)
        if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
            ssl-&gt;options.serverState = SERVER_CERT_COMPLETE;
#endif
#if !defined(NO_WOLFSSL_SERVER) &amp;&amp; defined(WOLFSSL_POST_HANDSHAKE_AUTH)
        if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp;
                                ssl-&gt;options.handShakeState == HANDSHAKE_DONE) {
            /* reset handshake states */
            ssl-&gt;options.serverState = SERVER_FINISHED_COMPLETE;
            ssl-&gt;options.acceptState  = TICKET_SENT;
            ssl-&gt;options.handShakeState = SERVER_FINISHED_COMPLETE;
        }
#endif
    }

    WOLFSSL_LEAVE(&quot;DoTls13Certificate&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_DO);

    return ret;
}
#endif

#if !defined(NO_RSA) || defined(HAVE_ECC) || defined(HAVE_ED25519) || \
                                                             defined(HAVE_ED448)

typedef struct Dcv13Args {
    byte*  output; /* not allocated */
    word32 sendSz;
    word16 sz;
    word32 sigSz;
    word32 idx;
    word32 begin;

    byte*  sigData;
    word16 sigDataSz;
#ifdef WOLFSSL_DUAL_ALG_CERTS
    byte   altSigAlgo;
    byte*  altSigData;
    word32 altSigDataSz;
    word32 altSignatureSz;
    byte   altPeerAuthGood;
#endif
} Dcv13Args;

static void FreeDcv13Args(WOLFSSL* ssl, void* pArgs)
{
    Dcv13Args* args = (Dcv13Args*)pArgs;

    if (args &amp;&amp; args-&gt;sigData != NULL) {
        XFREE(args-&gt;sigData, ssl-&gt;heap, DYNAMIC_TYPE_SIGNATURE);
        args-&gt;sigData = NULL;
    }
#ifdef WOLFSSL_DUAL_ALG_CERTS
    if (args &amp;&amp; args-&gt;altSigData != NULL) {
        XFREE(args-&gt;altSigData, ssl-&gt;heap, DYNAMIC_TYPE_SIGNATURE);
        args-&gt;altSigData = NULL;
    }
#endif
    (void)ssl;
}

#ifdef WOLFSSL_DUAL_ALG_CERTS
#ifndef NO_RSA
/* ssl-&gt;peerCert-&gt;sapkiDer is the alternative public key. Hopefully it is a
 * RSA public key. Convert it into a usable public key. */
static int decodeRsaKey(WOLFSSL* ssl)
{
    int keyRet;
    word32 tmpIdx = 0;

    if (ssl-&gt;peerRsaKeyPresent)
        return INVALID_PARAMETER;

    keyRet = AllocKey(ssl, DYNAMIC_TYPE_RSA, (void**)&amp;ssl-&gt;peerRsaKey);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    ssl-&gt;peerRsaKeyPresent = 1;
    keyRet = wc_RsaPublicKeyDecode(ssl-&gt;peerCert.sapkiDer, &amp;tmpIdx,
                                   ssl-&gt;peerRsaKey,
                                   ssl-&gt;peerCert.sapkiLen);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    return 0;
}
#endif /* !NO_RSA */

#ifdef HAVE_ECC
/* ssl-&gt;peerCert-&gt;sapkiDer is the alternative public key. Hopefully it is a
 * ECC public key. Convert it into a usable public key. */
static int decodeEccKey(WOLFSSL* ssl)
{
    int keyRet;
    word32 tmpIdx = 0;

    if (ssl-&gt;peerEccDsaKeyPresent)
        return INVALID_PARAMETER;

    keyRet = AllocKey(ssl, DYNAMIC_TYPE_ECC, (void**)&amp;ssl-&gt;peerEccDsaKey);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    ssl-&gt;peerEccDsaKeyPresent = 1;
    keyRet = wc_EccPublicKeyDecode(ssl-&gt;peerCert.sapkiDer, &amp;tmpIdx,
                                   ssl-&gt;peerEccDsaKey,
                                   ssl-&gt;peerCert.sapkiLen);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    return 0;
}
#endif /* HAVE_ECC */

#ifdef HAVE_DILITHIUM
/* ssl-&gt;peerCert-&gt;sapkiDer is the alternative public key. Hopefully it is a
 * dilithium public key. Convert it into a usable public key. */
static int decodeDilithiumKey(WOLFSSL* ssl, int level)
{
    int keyRet;
    word32 tmpIdx = 0;

    if (ssl-&gt;peerDilithiumKeyPresent)
        return INVALID_PARAMETER;

    keyRet = AllocKey(ssl, DYNAMIC_TYPE_DILITHIUM,
                      (void**)&amp;ssl-&gt;peerDilithiumKey);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    ssl-&gt;peerDilithiumKeyPresent = 1;
    keyRet = wc_dilithium_set_level(ssl-&gt;peerDilithiumKey, level);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    keyRet = wc_Dilithium_PublicKeyDecode(ssl-&gt;peerCert.sapkiDer, &amp;tmpIdx,
                                          ssl-&gt;peerDilithiumKey,
                                          ssl-&gt;peerCert.sapkiLen);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    return 0;
}
#endif /* HAVE_DILITHIUM */

#ifdef HAVE_FALCON
/* ssl-&gt;peerCert-&gt;sapkiDer is the alternative public key. Hopefully it is a
 * falcon public key. Convert it into a usable public key. */
static int decodeFalconKey(WOLFSSL* ssl, int level)
{
    int keyRet;
    word32 tmpIdx = 0;

    if (ssl-&gt;peerFalconKeyPresent)
        return INVALID_PARAMETER;

    keyRet = AllocKey(ssl, DYNAMIC_TYPE_FALCON, (void**)&amp;ssl-&gt;peerFalconKey);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    ssl-&gt;peerFalconKeyPresent = 1;
    keyRet = wc_falcon_set_level(ssl-&gt;peerFalconKey, level);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    keyRet = wc_Falcon_PublicKeyDecode(ssl-&gt;peerCert.sapkiDer, &amp;tmpIdx,
                                       ssl-&gt;peerFalconKey,
                                       ssl-&gt;peerCert.sapkiLen);
    if (keyRet != 0)
        return PEER_KEY_ERROR;

    return 0;
}
#endif /* HAVE_FALCON */
#endif /* WOLFSSL_DUAL_ALG_CERTS */

/* handle processing TLS v1.3 certificate_verify (15) */
/* Parse and handle a TLS v1.3 CertificateVerify message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of
 *           CertificateVerify.
 *           On exit, the index of byte after the CertificateVerify message.
 * totalSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13CertificateVerify(WOLFSSL* ssl, byte* input,
                                    word32* inOutIdx, word32 totalSz)
{
    int         ret = 0;
    byte*       sig = NULL;
#ifndef NO_RSA
    /* Use this as a temporary buffer for RSA signature verification. */
    buffer*     rsaSigBuf = &amp;ssl-&gt;buffers.sig;
#endif
#ifdef WOLFSSL_ASYNC_CRYPT
    Dcv13Args* args = NULL;
    WOLFSSL_ASSERT_SIZEOF_GE(ssl-&gt;async-&gt;args, *args);
#else
    Dcv13Args  args[1];
#endif

    WOLFSSL_START(WC_FUNC_CERTIFICATE_VERIFY_DO);
    WOLFSSL_ENTER(&quot;DoTls13CertificateVerify&quot;);

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13CertificateVerify(ssl, input, inOutIdx, totalSz);
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        goto exit_dcv;
    }
    ret = 0;
#endif

#ifdef WOLFSSL_ASYNC_CRYPT
    if (ssl-&gt;async == NULL) {
        ssl-&gt;async = (struct WOLFSSL_ASYNC*)
                XMALLOC(sizeof(struct WOLFSSL_ASYNC), ssl-&gt;heap,
                        DYNAMIC_TYPE_ASYNC);
        if (ssl-&gt;async == NULL)
            ERROR_OUT(MEMORY_E, exit_dcv);
    }
    args = (Dcv13Args*)ssl-&gt;async-&gt;args;

    ret = wolfSSL_AsyncPop(ssl, &amp;ssl-&gt;options.asyncState);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0)
            goto exit_dcv;
    }
    else
#endif
    {
        /* Reset state */
        ret = 0;
        ssl-&gt;options.asyncState = TLS_ASYNC_BEGIN;
        XMEMSET(args, 0, sizeof(Dcv13Args));
        ssl-&gt;options.peerHashAlgo = sha_mac;
        ssl-&gt;options.peerSigAlgo = anonymous_sa_algo;
        args-&gt;idx = *inOutIdx;
        args-&gt;begin = *inOutIdx;
    #ifdef WOLFSSL_ASYNC_CRYPT
        ssl-&gt;async-&gt;freeArgs = FreeDcv13Args;
    #endif
    }

    switch(ssl-&gt;options.asyncState)
    {
        case TLS_ASYNC_BEGIN:
        {
        #ifdef WOLFSSL_CALLBACKS
            if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;CertificateVerify&quot;);
            if (ssl-&gt;toInfoOn) AddLateName(&quot;CertificateVerify&quot;,
                                           &amp;ssl-&gt;timeoutInfo);
        #endif

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_BUILD;
        } /* case TLS_ASYNC_BEGIN */
        FALL_THROUGH;

        case TLS_ASYNC_BUILD:
        {
            int validSigAlgo;

            /* Signature algorithm. */
            if ((args-&gt;idx - args-&gt;begin) + ENUM_LEN + ENUM_LEN &gt; totalSz) {
                ERROR_OUT(BUFFER_ERROR, exit_dcv);
            }

#ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;peerSigSpec == NULL) {
                /* The peer did not respond. We didn&#039;t send CKS or they don&#039;t
                 * support it. Either way, we do not need to handle dual
                 * key/sig case. */
                ssl-&gt;sigSpec = NULL;
                ssl-&gt;sigSpecSz = 0;
            }

            /* If no CKS extension or either native or alternative, then just
             * get a normal sigalgo.  But if BOTH, then get the native and alt
             * sig algos. */
            if (ssl-&gt;sigSpec == NULL ||
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_NATIVE ||
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_ALTERNATIVE) {
#endif /* WOLFSSL_DUAL_ALG_CERTS */
                ret = DecodeTls13SigAlg(input + args-&gt;idx,
                        &amp;ssl-&gt;options.peerHashAlgo, &amp;ssl-&gt;options.peerSigAlgo);
#ifdef WOLFSSL_DUAL_ALG_CERTS
            }
            else {
                ret = DecodeTls13HybridSigAlg(input + args-&gt;idx,
                                              &amp;ssl-&gt;options.peerHashAlgo,
                                              &amp;ssl-&gt;options.peerSigAlgo,
                                              &amp;args-&gt;altSigAlgo);
            }
#endif /* WOLFSSL_DUAL_ALG_CERTS */

            if (ret &lt; 0)
                goto exit_dcv;
            args-&gt;idx += OPAQUE16_LEN;

            /* Signature length. */
            if ((args-&gt;idx - args-&gt;begin) + OPAQUE16_LEN &gt; totalSz) {
                ERROR_OUT(BUFFER_ERROR, exit_dcv);
            }
            ato16(input + args-&gt;idx, &amp;args-&gt;sz);
            args-&gt;idx += OPAQUE16_LEN;

            /* Signature data. */
            if ((args-&gt;idx - args-&gt;begin) + args-&gt;sz &gt; totalSz ||
                                                       args-&gt;sz &gt; ENCRYPT_LEN) {
                ERROR_OUT(BUFFER_ERROR, exit_dcv);
            }

#ifdef WOLFSSL_DUAL_ALG_CERTS
            if ((ssl-&gt;sigSpec != NULL) &amp;&amp;
                (*ssl-&gt;sigSpec != WOLFSSL_CKS_SIGSPEC_NATIVE)) {

                word16 sa;
                if (args-&gt;altSigAlgo == 0)
                    sa = ssl-&gt;options.peerSigAlgo;
                else
                    sa = args-&gt;altSigAlgo;

                switch(sa) {
            #ifndef NO_RSA
                case rsa_pss_sa_algo:
                    ret = decodeRsaKey(ssl);
                    break;
            #endif
            #ifdef HAVE_ECC
                case ecc_dsa_sa_algo:
                    ret = decodeEccKey(ssl);
                    break;
            #endif
            #ifdef HAVE_DILITHIUM
                case dilithium_level2_sa_algo:
                    ret = decodeDilithiumKey(ssl, 2);
                    break;
                case dilithium_level3_sa_algo:
                    ret = decodeDilithiumKey(ssl, 3);
                    break;
                case dilithium_level5_sa_algo:
                    ret = decodeDilithiumKey(ssl, 5);
                    break;
            #endif
            #ifdef HAVE_FALCON
                case falcon_level1_sa_algo:
                    ret = decodeFalconKey(ssl, 1);
                    break;
                case falcon_level5_sa_algo:
                    ret = decodeFalconKey(ssl, 5);
                    break;
            #endif
                default:
                    ERROR_OUT(PEER_KEY_ERROR, exit_dcv);
                }

                if (ret != 0)
                    ERROR_OUT(ret, exit_dcv);

                if (*ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_ALTERNATIVE) {
                    /* Now swap in the alternative by removing the native.
                     * sa contains the alternative signature type. */
                #ifndef NO_RSA
                    if (ssl-&gt;peerRsaKeyPresent &amp;&amp; sa != rsa_pss_sa_algo) {
                        FreeKey(ssl, DYNAMIC_TYPE_RSA,
                                (void**)&amp;ssl-&gt;peerRsaKey);
                        ssl-&gt;peerRsaKeyPresent = 0;
                    }
                #endif
                #ifdef HAVE_ECC
                    else if (ssl-&gt;peerEccDsaKeyPresent &amp;&amp;
                             sa != ecc_dsa_sa_algo) {
                        FreeKey(ssl, DYNAMIC_TYPE_ECC,
                                (void**)&amp;ssl-&gt;peerEccDsaKey);
                        ssl-&gt;peerEccDsaKeyPresent = 0;
                    }
                #endif
                #ifdef HAVE_DILITHIUM
                    else if (ssl-&gt;peerDilithiumKeyPresent &amp;&amp;
                             sa != dilithium_level2_sa_algo &amp;&amp;
                             sa != dilithium_level3_sa_algo &amp;&amp;
                             sa != dilithium_level5_sa_algo) {
                        FreeKey(ssl, DYNAMIC_TYPE_DILITHIUM,
                                (void**)&amp;ssl-&gt;peerDilithiumKey);
                        ssl-&gt;peerDilithiumKeyPresent = 0;
                    }
                #endif
                #ifdef HAVE_FALCON
                    else if (ssl-&gt;peerFalconKeyPresent &amp;&amp;
                             sa != falcon_level1_sa_algo &amp;&amp;
                             sa != falcon_level5_sa_algo) {
                        FreeKey(ssl, DYNAMIC_TYPE_FALCON,
                                (void**)&amp;ssl-&gt;peerFalconKey);
                        ssl-&gt;peerFalconKeyPresent = 0;
                    }
                #endif
                    else {
                        ERROR_OUT(PEER_KEY_ERROR, exit_dcv);
                    }
                }
            }
#endif /* WOLFSSL_DUAL_ALG_CERTS */

            /* Check for public key of required type. */
            /* Assume invalid unless signature algo matches the key provided */
            validSigAlgo = 0;
        #ifdef HAVE_ED25519
            if (ssl-&gt;options.peerSigAlgo == ed25519_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent ED25519 sig&quot;);
                validSigAlgo = (ssl-&gt;peerEd25519Key != NULL) &amp;&amp;
                                                     ssl-&gt;peerEd25519KeyPresent;
            }
        #endif
        #ifdef HAVE_ED448
            if (ssl-&gt;options.peerSigAlgo == ed448_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent ED448 sig&quot;);
                validSigAlgo = (ssl-&gt;peerEd448Key != NULL) &amp;&amp;
                                                       ssl-&gt;peerEd448KeyPresent;
            }
        #endif
        #ifdef HAVE_ECC
            if (ssl-&gt;options.peerSigAlgo == ecc_dsa_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent ECC sig&quot;);
                validSigAlgo = (ssl-&gt;peerEccDsaKey != NULL) &amp;&amp;
                                                      ssl-&gt;peerEccDsaKeyPresent;
            }
        #endif
        #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
            if (ssl-&gt;options.peerSigAlgo == sm2_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent SM2 sig&quot;);
                validSigAlgo = (ssl-&gt;peerEccDsaKey != NULL) &amp;&amp;
                                                      ssl-&gt;peerEccDsaKeyPresent;
            }
        #endif
        #ifdef HAVE_FALCON
            if (ssl-&gt;options.peerSigAlgo == falcon_level1_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent Falcon Level 1 sig&quot;);
                validSigAlgo = (ssl-&gt;peerFalconKey != NULL) &amp;&amp;
                               ssl-&gt;peerFalconKeyPresent;
            }
            if (ssl-&gt;options.peerSigAlgo == falcon_level5_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent Falcon Level 5 sig&quot;);
                validSigAlgo = (ssl-&gt;peerFalconKey != NULL) &amp;&amp;
                               ssl-&gt;peerFalconKeyPresent;
            }
        #endif
        #ifdef HAVE_DILITHIUM
            if (ssl-&gt;options.peerSigAlgo == dilithium_level2_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent Dilithium Level 2 sig&quot;);
                validSigAlgo = (ssl-&gt;peerDilithiumKey != NULL) &amp;&amp;
                               ssl-&gt;peerDilithiumKeyPresent;
            }
            if (ssl-&gt;options.peerSigAlgo == dilithium_level3_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent Dilithium Level 3 sig&quot;);
                validSigAlgo = (ssl-&gt;peerDilithiumKey != NULL) &amp;&amp;
                               ssl-&gt;peerDilithiumKeyPresent;
            }
            if (ssl-&gt;options.peerSigAlgo == dilithium_level5_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent Dilithium Level 5 sig&quot;);
                validSigAlgo = (ssl-&gt;peerDilithiumKey != NULL) &amp;&amp;
                               ssl-&gt;peerDilithiumKeyPresent;
            }
        #endif
        #ifndef NO_RSA
            if (ssl-&gt;options.peerSigAlgo == rsa_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent PKCS#1.5 algo - not valid TLS 1.3&quot;);
                ERROR_OUT(INVALID_PARAMETER, exit_dcv);
            }
            if (ssl-&gt;options.peerSigAlgo == rsa_pss_sa_algo) {
                WOLFSSL_MSG(&quot;Peer sent RSA sig&quot;);
                validSigAlgo = (ssl-&gt;peerRsaKey != NULL) &amp;&amp;
                                                         ssl-&gt;peerRsaKeyPresent;
            }
        #endif
            if (!validSigAlgo) {
                WOLFSSL_MSG(&quot;Sig algo doesn&#039;t correspond to certificate&quot;);
                ERROR_OUT(SIG_VERIFY_E, exit_dcv);
            }

            args-&gt;sigSz = args-&gt;sz;
#ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* In case we received two signatures, both of them are encoded
                 * with their size as 16-bit integeter prior in memory. Hence,
                 * we can decode both lengths here now. */
                word32 tmpIdx = args-&gt;idx;
                word16 tmpSz = 0;
                ato16(input + tmpIdx, &amp;tmpSz);
                args-&gt;sigSz = tmpSz;

                tmpIdx += OPAQUE16_LEN + args-&gt;sigSz;
                ato16(input + tmpIdx, &amp;tmpSz);
                args-&gt;altSignatureSz = tmpSz;

                if (args-&gt;sz != (args-&gt;sigSz + args-&gt;altSignatureSz +
                                    OPAQUE16_LEN + OPAQUE16_LEN)) {
                    ERROR_OUT(BUFFER_ERROR, exit_dcv);
                }
            }
#endif /* WOLFSSL_DUAL_ALG_CERTS */

        #if !defined(NO_RSA) &amp;&amp; defined(WC_RSA_PSS)
            /* In case we have to verify an RSA signature, we have to store the
             * signature in the &#039;rsaSigBuf&#039; structure for further processing.
             */
            if (ssl-&gt;peerRsaKey != NULL &amp;&amp; ssl-&gt;peerRsaKeyPresent != 0) {
                word32 sigSz = args-&gt;sigSz;
                sig = input + args-&gt;idx;
            #ifdef WOLFSSL_DUAL_ALG_CERTS
                /* Check if our alternative signature was RSA */
                if (ssl-&gt;sigSpec != NULL &amp;&amp;
                    *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                    if (ssl-&gt;options.peerSigAlgo != rsa_pss_sa_algo) {
                        /* We have to skip the first signature (length field
                         * and signature itself) and the length field of the
                         * alternative signature. */
                        sig += OPAQUE16_LEN + OPAQUE16_LEN + args-&gt;sigSz;
                        sigSz = args-&gt;altSignatureSz;
                    }
                    else {
                        /* We have to skip the length field */
                        sig += OPAQUE16_LEN;
                    }
                }
            #endif
                rsaSigBuf-&gt;buffer = (byte*)XMALLOC(sigSz, ssl-&gt;heap,
                                         DYNAMIC_TYPE_SIGNATURE);
                if (rsaSigBuf-&gt;buffer == NULL) {
                    ERROR_OUT(MEMORY_E, exit_dcv);
                }
                rsaSigBuf-&gt;length = sigSz;
                XMEMCPY(rsaSigBuf-&gt;buffer, sig, rsaSigBuf-&gt;length);
            }
        #endif /* !NO_RSA &amp;&amp; WC_RSA_PSS */

            args-&gt;sigData = (byte*)XMALLOC(MAX_SIG_DATA_SZ, ssl-&gt;heap,
                                                    DYNAMIC_TYPE_SIGNATURE);
            if (args-&gt;sigData == NULL) {
                ERROR_OUT(MEMORY_E, exit_dcv);
            }

            ret = CreateSigData(ssl, args-&gt;sigData, &amp;args-&gt;sigDataSz, 1);
            if (ret &lt; 0)
                goto exit_dcv;

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if ((ssl-&gt;sigSpec != NULL) &amp;&amp;
                (*ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH)) {
                args-&gt;altSigData = (byte*)XMALLOC(MAX_SIG_DATA_SZ, ssl-&gt;heap,
                                                        DYNAMIC_TYPE_SIGNATURE);
                if (args-&gt;altSigData == NULL) {
                    ERROR_OUT(MEMORY_E, exit_dcv);
                }
                XMEMCPY(args-&gt;altSigData, args-&gt;sigData, args-&gt;sigDataSz);
                args-&gt;altSigDataSz = args-&gt;sigDataSz;
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

        #ifdef HAVE_ECC
            if ((ssl-&gt;options.peerSigAlgo == ecc_dsa_sa_algo) &amp;&amp;
                (ssl-&gt;peerEccDsaKeyPresent)) {
            #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;options.peerSigAlgo != sm2_sa_algo)
            #endif
                {
                    ret = CreateECCEncodedSig(args-&gt;sigData,
                        args-&gt;sigDataSz, ssl-&gt;options.peerHashAlgo);
                    if (ret &lt; 0)
                        goto exit_dcv;
                    args-&gt;sigDataSz = (word16)ret;
                    ret = 0;
                }
            }

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if ((ssl-&gt;sigSpec != NULL) &amp;&amp;
                (*ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) &amp;&amp;
                (args-&gt;altSigAlgo == ecc_dsa_sa_algo) &amp;&amp;
                (ssl-&gt;peerEccDsaKeyPresent)) {
                ret = CreateECCEncodedSig(args-&gt;altSigData,
                        args-&gt;altSigDataSz, ssl-&gt;options.peerHashAlgo);
                    if (ret &lt; 0)
                        goto exit_dcv;
                    args-&gt;altSigDataSz = (word16)ret;
                    ret = 0;
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */
        #endif /* HAVE_ECC */

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_DO;
        } /* case TLS_ASYNC_BUILD */
        FALL_THROUGH;

        case TLS_ASYNC_DO:
        {
            sig = input + args-&gt;idx;
        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* As we have two signatures in the message, we stored
                 * the length of each before the actual signature. This
                 * is necessary, as we could have two algorithms with
                 * variable length signatures. */
                sig += OPAQUE16_LEN;
            }
        #endif
        #ifndef NO_RSA
            if ((ssl-&gt;options.peerSigAlgo == rsa_pss_sa_algo) &amp;&amp;
                (ssl-&gt;peerRsaKey != NULL) &amp;&amp; (ssl-&gt;peerRsaKeyPresent != 0)) {
                WOLFSSL_MSG(&quot;Doing RSA peer cert verify&quot;);
                ret = RsaVerify(ssl, rsaSigBuf-&gt;buffer,
                                (word32)rsaSigBuf-&gt;length, &amp;args-&gt;output,
                                ssl-&gt;options.peerSigAlgo,
                                ssl-&gt;options.peerHashAlgo, ssl-&gt;peerRsaKey,
                #ifdef HAVE_PK_CALLBACKS
                                &amp;ssl-&gt;buffers.peerRsaKey
                #else
                                NULL
                #endif
                                );
                if (ret &gt;= 0) {
                    args-&gt;sendSz = (word32)ret;
                    ret = 0;
                }
            }
        #endif /* !NO_RSA */
        #ifdef HAVE_ECC
            if ((ssl-&gt;options.peerSigAlgo == ecc_dsa_sa_algo) &amp;&amp;
                (ssl-&gt;peerEccDsaKeyPresent)) {
            #if defined(WOLFSSL_SM2) &amp;&amp; defined(WOLFSSL_SM3)
                if (ssl-&gt;options.peerSigAlgo == sm2_sa_algo) {
                    ret = Sm2wSm3Verify(ssl, TLS13_SM2_SIG_ID,
                        TLS13_SM2_SIG_ID_SZ, sig, args-&gt;sigSz,
                        args-&gt;sigData, args-&gt;sigDataSz,
                        ssl-&gt;peerEccDsaKey, NULL);
                }
                else
            #endif
                {
                    WOLFSSL_MSG(&quot;Doing ECC peer cert verify&quot;);
                    ret = EccVerify(ssl, sig, args-&gt;sigSz,
                        args-&gt;sigData, args-&gt;sigDataSz,
                        ssl-&gt;peerEccDsaKey,
                    #ifdef HAVE_PK_CALLBACKS
                        &amp;ssl-&gt;buffers.peerEccDsaKey
                    #else
                        NULL
                    #endif
                        );
                }

                if (ret &gt;= 0) {
                    /* CLIENT/SERVER: data verified with public key from
                     * certificate. */
                    ssl-&gt;options.peerAuthGood = 1;

                    FreeKey(ssl, DYNAMIC_TYPE_ECC, (void**)&amp;ssl-&gt;peerEccDsaKey);
                    ssl-&gt;peerEccDsaKeyPresent = 0;
                }
            }
        #endif /* HAVE_ECC */
        #ifdef HAVE_ED25519
            if ((ssl-&gt;options.peerSigAlgo == ed25519_sa_algo) &amp;&amp;
                (ssl-&gt;peerEd25519KeyPresent)) {
                WOLFSSL_MSG(&quot;Doing ED25519 peer cert verify&quot;);
                ret = Ed25519Verify(ssl, sig, args-&gt;sigSz,
                    args-&gt;sigData, args-&gt;sigDataSz,
                    ssl-&gt;peerEd25519Key,
                #ifdef HAVE_PK_CALLBACKS
                    &amp;ssl-&gt;buffers.peerEd25519Key
                #else
                    NULL
                #endif
                    );

                if (ret &gt;= 0) {
                    /* CLIENT/SERVER: data verified with public key from
                     * certificate. */
                    ssl-&gt;options.peerAuthGood = 1;
                    FreeKey(ssl, DYNAMIC_TYPE_ED25519,
                                                  (void**)&amp;ssl-&gt;peerEd25519Key);
                    ssl-&gt;peerEd25519KeyPresent = 0;
                }
            }
        #endif
        #ifdef HAVE_ED448
            if ((ssl-&gt;options.peerSigAlgo == ed448_sa_algo) &amp;&amp;
                (ssl-&gt;peerEd448KeyPresent)) {
                WOLFSSL_MSG(&quot;Doing ED448 peer cert verify&quot;);
                ret = Ed448Verify(ssl, sig, args-&gt;sigSz,
                    args-&gt;sigData, args-&gt;sigDataSz,
                    ssl-&gt;peerEd448Key,
                #ifdef HAVE_PK_CALLBACKS
                    &amp;ssl-&gt;buffers.peerEd448Key
                #else
                    NULL
                #endif
                );

                if (ret &gt;= 0) {
                    /* CLIENT/SERVER: data verified with public key from
                     * certificate. */
                    ssl-&gt;options.peerAuthGood = 1;
                    FreeKey(ssl, DYNAMIC_TYPE_ED448,
                                                    (void**)&amp;ssl-&gt;peerEd448Key);
                    ssl-&gt;peerEd448KeyPresent = 0;
                }
            }
        #endif
        #if defined(HAVE_FALCON)
            if (((ssl-&gt;options.peerSigAlgo == falcon_level1_sa_algo) ||
                 (ssl-&gt;options.peerSigAlgo == falcon_level5_sa_algo)) &amp;&amp;
                (ssl-&gt;peerFalconKeyPresent)) {
                int res = 0;
                WOLFSSL_MSG(&quot;Doing Falcon peer cert verify&quot;);
                ret = wc_falcon_verify_msg(sig, args-&gt;sigSz,
                                           args-&gt;sigData, args-&gt;sigDataSz,
                                           &amp;res, ssl-&gt;peerFalconKey);

                if ((ret &gt;= 0) &amp;&amp; (res == 1)) {
                    /* CLIENT/SERVER: data verified with public key from
                     * certificate. */
                    ssl-&gt;options.peerAuthGood = 1;

                    FreeKey(ssl, DYNAMIC_TYPE_FALCON,
                                                   (void**)&amp;ssl-&gt;peerFalconKey);
                    ssl-&gt;peerFalconKeyPresent = 0;
                }
            }
        #endif /* HAVE_FALCON */
        #if defined(HAVE_DILITHIUM) &amp;&amp; !defined(WOLFSSL_DILITHIUM_NO_VERIFY)
            if (((ssl-&gt;options.peerSigAlgo == dilithium_level2_sa_algo) ||
                 (ssl-&gt;options.peerSigAlgo == dilithium_level3_sa_algo) ||
                 (ssl-&gt;options.peerSigAlgo == dilithium_level5_sa_algo)) &amp;&amp;
                (ssl-&gt;peerDilithiumKeyPresent)) {
                int res = 0;
                WOLFSSL_MSG(&quot;Doing Dilithium peer cert verify&quot;);
                ret = wc_dilithium_verify_msg(sig, args-&gt;sigSz,
                                              args-&gt;sigData, args-&gt;sigDataSz,
                                              &amp;res, ssl-&gt;peerDilithiumKey);

                if ((ret &gt;= 0) &amp;&amp; (res == 1)) {
                    /* CLIENT/SERVER: data verified with public key from
                     * certificate. */
                    ssl-&gt;options.peerAuthGood = 1;

                    FreeKey(ssl, DYNAMIC_TYPE_DILITHIUM,
                            (void**)&amp;ssl-&gt;peerDilithiumKey);
                    ssl-&gt;peerDilithiumKeyPresent = 0;
                }
            }
        #endif /* HAVE_DILITHIUM */

            /* Check for error */
            if (ret != 0) {
                goto exit_dcv;
            }

        #ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                /* Move forward to the alternative signature. */
                sig += args-&gt;sigSz + OPAQUE16_LEN;

                /* Verify the alternative signature */
            #ifndef NO_RSA
                if ((args-&gt;altSigAlgo == rsa_pss_sa_algo) &amp;&amp;
                    (ssl-&gt;peerRsaKey != NULL) &amp;&amp;
                    (ssl-&gt;peerRsaKeyPresent != 0)) {
                    WOLFSSL_MSG(&quot;Doing RSA peer cert alt verify&quot;);
                    ret = RsaVerify(ssl, rsaSigBuf-&gt;buffer,
                                    (word32)rsaSigBuf-&gt;length,
                                    &amp;args-&gt;output, args-&gt;altSigAlgo,
                                    ssl-&gt;options.peerHashAlgo, ssl-&gt;peerRsaKey,
                    #ifdef HAVE_PK_CALLBACKS
                                    &amp;ssl-&gt;buffers.peerRsaKey
                    #else
                                    NULL
                    #endif
                                    );
                    if (ret &gt;= 0) {
                        args-&gt;sendSz = ret;
                        ret = 0;
                    }
                }
            #endif /* !NO_RSA */
            #ifdef HAVE_ECC
                if ((args-&gt;altSigAlgo == ecc_dsa_sa_algo) &amp;&amp;
                    (ssl-&gt;peerEccDsaKeyPresent)) {
                    WOLFSSL_MSG(&quot;Doing ECC peer cert alt verify&quot;);
                    ret = EccVerify(ssl, sig, args-&gt;altSignatureSz,
                                args-&gt;altSigData, args-&gt;altSigDataSz,
                                ssl-&gt;peerEccDsaKey,
                    #ifdef HAVE_PK_CALLBACKS
                                &amp;ssl-&gt;buffers.peerEccDsaKey
                    #else
                                NULL
                    #endif
                                );

                    if (ret &gt;= 0) {
                        /* CLIENT/SERVER: data verified with public key from
                        * certificate. */
                        args-&gt;altPeerAuthGood = 1;

                        FreeKey(ssl, DYNAMIC_TYPE_ECC,
                                                (void**)&amp;ssl-&gt;peerEccDsaKey);
                        ssl-&gt;peerEccDsaKeyPresent = 0;
                    }
                }
            #endif /* HAVE_ECC */
            #if defined(HAVE_FALCON)
                if (((args-&gt;altSigAlgo == falcon_level1_sa_algo) ||
                     (args-&gt;altSigAlgo == falcon_level5_sa_algo)) &amp;&amp;
                    (ssl-&gt;peerFalconKeyPresent)) {
                    int res = 0;
                    WOLFSSL_MSG(&quot;Doing Falcon peer cert alt verify&quot;);
                    ret = wc_falcon_verify_msg(sig, args-&gt;altSignatureSz,
                                        args-&gt;altSigData, args-&gt;altSigDataSz,
                                        &amp;res, ssl-&gt;peerFalconKey);

                    if ((ret &gt;= 0) &amp;&amp; (res == 1)) {
                        /* CLIENT/SERVER: data verified with public key from
                        * certificate. */
                        args-&gt;altPeerAuthGood = 1;

                        FreeKey(ssl, DYNAMIC_TYPE_FALCON,
                                                (void**)&amp;ssl-&gt;peerFalconKey);
                        ssl-&gt;peerFalconKeyPresent = 0;
                    }
                }
            #endif /* HAVE_FALCON */
            #if defined(HAVE_DILITHIUM) &amp;&amp; !defined(WOLFSSL_DILITHIUM_NO_VERIFY)
                if (((args-&gt;altSigAlgo == dilithium_level2_sa_algo) ||
                     (args-&gt;altSigAlgo == dilithium_level3_sa_algo) ||
                     (args-&gt;altSigAlgo == dilithium_level5_sa_algo)) &amp;&amp;
                    (ssl-&gt;peerDilithiumKeyPresent)) {
                    int res = 0;
                    WOLFSSL_MSG(&quot;Doing Dilithium peer cert alt verify&quot;);
                    ret = wc_dilithium_verify_msg(sig, args-&gt;altSignatureSz,
                                        args-&gt;altSigData, args-&gt;altSigDataSz,
                                        &amp;res, ssl-&gt;peerDilithiumKey);

                    if ((ret &gt;= 0) &amp;&amp; (res == 1)) {
                        /* CLIENT/SERVER: data verified with public key from
                        * certificate. */
                        args-&gt;altPeerAuthGood = 1;

                        FreeKey(ssl, DYNAMIC_TYPE_DILITHIUM,
                                            (void**)&amp;ssl-&gt;peerDilithiumKey);
                        ssl-&gt;peerDilithiumKeyPresent = 0;
                    }
                }
            #endif /* HAVE_DILITHIUM */

                /* Check for error */
                if (ret != 0) {
                    goto exit_dcv;
                }
            }
        #endif /* WOLFSSL_DUAL_ALG_CERTS */

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_VERIFY;
        } /* case TLS_ASYNC_DO */
        FALL_THROUGH;

        case TLS_ASYNC_VERIFY:
        {
        #if !defined(NO_RSA) &amp;&amp; defined(WC_RSA_PSS)
            if (ssl-&gt;peerRsaKey != NULL &amp;&amp; ssl-&gt;peerRsaKeyPresent != 0) {
                int sigAlgo = ssl-&gt;options.peerSigAlgo;
            #ifdef WOLFSSL_DUAL_ALG_CERTS
                /* Check if our alternative signature was RSA */
                if (ssl-&gt;sigSpec != NULL &amp;&amp;
                    *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH &amp;&amp;
                    ssl-&gt;options.peerSigAlgo != rsa_pss_sa_algo) {
                    sigAlgo = args-&gt;altSigAlgo;
                }
            #endif
                ret = CheckRSASignature(ssl, sigAlgo,
                        ssl-&gt;options.peerHashAlgo, args-&gt;output, args-&gt;sendSz);
                if (ret != 0)
                    goto exit_dcv;

                /* CLIENT/SERVER: data verified with public key from
                 * certificate. */
                ssl-&gt;peerRsaKeyPresent = 0;
                FreeKey(ssl, DYNAMIC_TYPE_RSA, (void**)&amp;ssl-&gt;peerRsaKey);
            #ifdef WOLFSSL_DUAL_ALG_CERTS
                /* Check if our alternative signature was RSA */
                if (ssl-&gt;sigSpec != NULL &amp;&amp;
                    *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH &amp;&amp;
                    ssl-&gt;options.peerSigAlgo != rsa_pss_sa_algo) {
                    args-&gt;altPeerAuthGood = 1;
                }
                else
            #endif
                    ssl-&gt;options.peerAuthGood = 1;
            }
        #endif /* !NO_RSA &amp;&amp; WC_RSA_PSS */

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_FINALIZE;
        } /* case TLS_ASYNC_VERIFY */
        FALL_THROUGH;

        case TLS_ASYNC_FINALIZE:
        {
#ifdef WOLFSSL_DUAL_ALG_CERTS
            if (ssl-&gt;options.peerAuthGood &amp;&amp;
                ssl-&gt;sigSpec != NULL &amp;&amp;
                *ssl-&gt;sigSpec == WOLFSSL_CKS_SIGSPEC_BOTH) {
                ssl-&gt;options.peerAuthGood = args-&gt;altPeerAuthGood;
            }
#endif /* WOLFSSL_DUAL_ALG_CERTS */
            ssl-&gt;options.havePeerVerify = 1;

            /* Set final index */
            args-&gt;idx += args-&gt;sz;
            *inOutIdx = args-&gt;idx;

            /* Encryption is always on: add padding */
            *inOutIdx += ssl-&gt;keys.padSz;

            /* Advance state and proceed */
            ssl-&gt;options.asyncState = TLS_ASYNC_END;

        #if !defined(NO_WOLFSSL_CLIENT)
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
                ssl-&gt;options.serverState = SERVER_CERT_VERIFY_COMPLETE;
        #endif
        } /* case TLS_ASYNC_FINALIZE */
        FALL_THROUGH;

        case TLS_ASYNC_END:
        {
            break;
        }

        default:
            ret = INPUT_CASE_ERROR;
    } /* switch(ssl-&gt;options.asyncState) */

exit_dcv:

    WOLFSSL_LEAVE(&quot;DoTls13CertificateVerify&quot;, ret);
    WOLFSSL_END(WC_FUNC_CERTIFICATE_VERIFY_DO);

#ifdef WOLFSSL_ASYNC_CRYPT
    /* Handle async operation */
    if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
        /* Mark message as not received so it can process again */
        ssl-&gt;msgsReceived.got_certificate_verify = 0;

        return ret;
    }
    else
#endif /* WOLFSSL_ASYNC_CRYPT */
    if (ret != 0) {
        WOLFSSL_ERROR_VERBOSE(ret);

        if (ret != WC_NO_ERR_TRACE(INVALID_PARAMETER)) {
            SendAlert(ssl, alert_fatal, decrypt_error);
        }
    }

    /* Final cleanup */
    FreeDcv13Args(ssl, args);
    FreeKeyExchange(ssl);
#ifdef WOLFSSL_ASYNC_IO
    /* Cleanup async */
    FreeAsyncCtx(ssl, 0);
#endif

    return ret;
}
#endif /* !NO_RSA || HAVE_ECC */
#endif /* !NO_CERTS */

/* Parse and handle a TLS v1.3 Finished message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of Finished.
 *           On exit, the index of byte after the Finished message and padding.
 * size      Length of message data.
 * totalSz   Length of remaining data in the message buffer.
 * sniff     Indicates whether we are sniffing packets.
 * returns 0 on success and otherwise failure.
 */
int DoTls13Finished(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                           word32 size, word32 totalSz, int sniff)
{
    int    ret;
    word32 finishedSz = 0;
    byte*  secret;
    byte   mac[WC_MAX_DIGEST_SIZE];

    WOLFSSL_START(WC_FUNC_FINISHED_DO);
    WOLFSSL_ENTER(&quot;DoTls13Finished&quot;);

#if !defined(NO_CERTS) &amp;&amp; !defined(WOLFSSL_NO_CLIENT_AUTH)
    /* verify the client sent certificate if required */
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp; !ssl-&gt;options.resuming &amp;&amp;
            (ssl-&gt;options.mutualAuth || ssl-&gt;options.failNoCert)) {
#ifdef OPENSSL_COMPATIBLE_DEFAULTS
        if (ssl-&gt;options.isPSK) {
            WOLFSSL_MSG(&quot;TLS v1.3 client used PSK but cert required. Allowing &quot;
                        &quot;for OpenSSL compatibility&quot;);
        }
        else
#endif
        if (
        #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
            !ssl-&gt;options.verifyPostHandshake &amp;&amp;
        #endif
            (!ssl-&gt;options.havePeerCert || !ssl-&gt;options.havePeerVerify)) {
            ret = NO_PEER_CERT; /* NO_PEER_VERIFY */
            WOLFSSL_MSG(&quot;TLS v1.3 client did not present peer cert&quot;);
            DoCertFatalAlert(ssl, ret);
            return ret;
        }
    }
#endif

    /* check against totalSz */
    if (*inOutIdx + size &gt; totalSz)
        return BUFFER_E;

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    ret = tsip_Tls13HandleFinished(ssl, input, inOutIdx, size, totalSz);
    if (ret == 0) {
        ssl-&gt;options.serverState = SERVER_FINISHED_COMPLETE;
        return ret;
    }
    if (ret == WC_NO_ERR_TRACE(VERIFY_FINISHED_ERROR)) {
        SendAlert(ssl, alert_fatal, decrypt_error);
        return ret;
    }
    if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
        /* other errors */
        return ret;
    }
    ret = 0;
#endif /* WOLFSSL_RENESAS_TSIP_TLS */

    if (ssl-&gt;options.handShakeDone) {
        ret = DeriveFinishedSecret(ssl, ssl-&gt;clientSecret,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   WOLFSSL_CLIENT_END);
        if (ret != 0)
            return ret;

        secret = ssl-&gt;keys.client_write_MAC_secret;
    }
    else if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
        /* All the handshake messages have been received to calculate
         * client and server finished keys.
         */
        ret = DeriveFinishedSecret(ssl, ssl-&gt;clientSecret,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   WOLFSSL_CLIENT_END);
        if (ret != 0)
            return ret;

        ret = DeriveFinishedSecret(ssl, ssl-&gt;serverSecret,
                                   ssl-&gt;keys.server_write_MAC_secret,
                                   WOLFSSL_SERVER_END);
        if (ret != 0)
            return ret;

        secret = ssl-&gt;keys.server_write_MAC_secret;
    }
    else {
        secret = ssl-&gt;keys.client_write_MAC_secret;
    }

    if (sniff == NO_SNIFF) {

        ret = BuildTls13HandshakeHmac(ssl, secret, mac, &amp;finishedSz);
    #ifdef WOLFSSL_HAVE_TLS_UNIQUE
        if (finishedSz &gt; TLS_FINISHED_SZ_MAX) {
            return BUFFER_ERROR;
        }
        if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
            XMEMCPY(ssl-&gt;serverFinished, mac, finishedSz);
            ssl-&gt;serverFinished_len = (byte)finishedSz;
        }
        else {
            XMEMCPY(ssl-&gt;clientFinished, mac, finishedSz);
            ssl-&gt;clientFinished_len = (byte)finishedSz;
        }
    #endif /* WOLFSSL_HAVE_TLS_UNIQUE */
        if (ret != 0)
            return ret;
        if (size != finishedSz)
            return BUFFER_ERROR;
    }

#ifdef WOLFSSL_CALLBACKS
    if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;Finished&quot;);
    if (ssl-&gt;toInfoOn) AddLateName(&quot;Finished&quot;, &amp;ssl-&gt;timeoutInfo);
#endif

    if (sniff == NO_SNIFF) {
        /* Actually check verify data. */
        if (size &gt; WC_MAX_DIGEST_SIZE ||
                XMEMCMP(input + *inOutIdx, mac, size) != 0){
            WOLFSSL_MSG(&quot;Verify finished error on hashes&quot;);
            SendAlert(ssl, alert_fatal, decrypt_error);
            WOLFSSL_ERROR_VERBOSE(VERIFY_FINISHED_ERROR);
            return VERIFY_FINISHED_ERROR;
        }
    }

    /* Force input exhaustion at ProcessReply by consuming padSz. */
    *inOutIdx += size + ssl-&gt;keys.padSz;

#ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp;
                                                  !ssl-&gt;options.handShakeDone) {
#ifdef WOLFSSL_EARLY_DATA
        if (ssl-&gt;earlyData != no_early_data) {
            if ((ret = DeriveTls13Keys(ssl, no_key, DECRYPT_SIDE_ONLY, 1)) != 0)
                return ret;
        }
#endif
        /* Setup keys for application data messages from client. */
        if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
            return ret;
    }
#endif

#ifndef NO_WOLFSSL_CLIENT
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        ssl-&gt;options.serverState = SERVER_FINISHED_COMPLETE;
#endif
#ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
        ssl-&gt;options.clientState = CLIENT_FINISHED_COMPLETE;
        ssl-&gt;options.handShakeState = HANDSHAKE_DONE;
        ssl-&gt;options.handShakeDone  = 1;
    }
#endif

#if defined(WOLFSSL_DTLS13) &amp;&amp; defined(WOLFSSL_EARLY_DATA)
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;earlyData &gt; early_data_ext) {
        /* DTLSv1.3 has no EndOfearlydata messages. We stop processing EarlyData
           as soon we receive the client&#039;s finished message */
        ssl-&gt;earlyData = done_early_data;
    }
#endif /* WOLFSSL_DTLS13 &amp;&amp; WOLFSSL_EARLY_DATA */
#if defined(WOLFSSL_QUIC) &amp;&amp; defined(WOLFSSL_EARLY_DATA)
    if (WOLFSSL_IS_QUIC(ssl) &amp;&amp; ssl-&gt;earlyData &gt; early_data_ext) {
        /* QUIC has no EndOfEarlyData messages. We stop processing EarlyData
           as soon we receive the client&#039;s finished message */
        ssl-&gt;earlyData = done_early_data;
    }
#endif /* WOLFSSL_QUIC &amp;&amp; WOLFSSL_EARLY_DATA */

    WOLFSSL_LEAVE(&quot;DoTls13Finished&quot;, 0);
    WOLFSSL_END(WC_FUNC_FINISHED_DO);

    return 0;
}

#if !defined(NO_WOLFSSL_CLIENT) || !defined(NO_WOLFSSL_SERVER)
/* Send the TLS v1.3 Finished message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13Finished(WOLFSSL* ssl)
{
    byte  finishedSz = ssl-&gt;specs.hash_size;
    byte* input;
    byte* output;
    int   ret;
    int   headerSz = HANDSHAKE_HEADER_SZ;
    int   outputSz;
    byte* secret;

#ifdef WOLFSSL_DTLS13
    int dtlsRet = 0, isDtls = 0;
#endif /* WOLFSSL_DTLS13 */

    WOLFSSL_START(WC_FUNC_FINISHED_SEND);
    WOLFSSL_ENTER(&quot;SendTls13Finished&quot;);

    ssl-&gt;options.buildingMsg = 1;
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        headerSz = DTLS_HANDSHAKE_HEADER_SZ;
        /* using isDtls instead of ssl-&gt;options.dtls will abide clang static
           analyzer on using an uninitialized value */
        isDtls = 1;
    }
#endif /* WOLFSSL_DTLS13 */

    outputSz = WC_MAX_DIGEST_SIZE + DTLS_HANDSHAKE_HEADER_SZ + MAX_MSG_EXTRA;
    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, outputSz)) != 0)
        return ret;

    /* get output buffer */
    output = GetOutputBuffer(ssl);
    input = output + RECORD_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
    if (isDtls)
        input = output + Dtls13GetRlHeaderLength(ssl, 1);
#endif /* WOLFSSL_DTLS13 */

    AddTls13HandShakeHeader(input, (word32)finishedSz, 0, (word32)finishedSz,
            finished, ssl);

#if defined(WOLFSSL_RENESAS_TSIP_TLS)
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
        ret = tsip_Tls13SendFinished(ssl, output, outputSz, input, 1);
        if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
            return ret;
        }
        ret = 0;
    }
#endif /* WOLFSSL_RENESAS_TSIP_TLS */

    /* make finished hashes */
    if (ssl-&gt;options.handShakeDone) {
        ret = DeriveFinishedSecret(ssl, ssl-&gt;clientSecret,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   WOLFSSL_CLIENT_END);
        if (ret != 0)
            return ret;

        secret = ssl-&gt;keys.client_write_MAC_secret;
    }
    else if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        secret = ssl-&gt;keys.client_write_MAC_secret;
    else {
        /* All the handshake messages have been done to calculate client and
         * server finished keys.
         */
        ret = DeriveFinishedSecret(ssl, ssl-&gt;clientSecret,
                                   ssl-&gt;keys.client_write_MAC_secret,
                                   WOLFSSL_SERVER_END);
        if (ret != 0)
            return ret;

        ret = DeriveFinishedSecret(ssl, ssl-&gt;serverSecret,
                                   ssl-&gt;keys.server_write_MAC_secret,
                                   WOLFSSL_CLIENT_END);
        if (ret != 0)
            return ret;

        secret = ssl-&gt;keys.server_write_MAC_secret;
    }
    ret = BuildTls13HandshakeHmac(ssl, secret, &amp;input[headerSz], NULL);
    if (ret != 0)
        return ret;
    #ifdef WOLFSSL_HAVE_TLS_UNIQUE
        if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
            XMEMCPY(ssl-&gt;clientFinished, &amp;input[headerSz], finishedSz);
            ssl-&gt;clientFinished_len = finishedSz;
        }
        else {
            XMEMCPY(ssl-&gt;serverFinished, &amp;input[headerSz], finishedSz);
            ssl-&gt;serverFinished_len = finishedSz;
        }
    #endif /* WOLFSSL_HAVE_TLS_UNIQUE */

#ifdef WOLFSSL_DTLS13
    if (isDtls) {
        dtlsRet = Dtls13HandshakeSend(ssl, output, (word16)outputSz,
            (word16)(Dtls13GetRlHeaderLength(ssl, 1) + headerSz + finishedSz), finished,
            1);
        if (dtlsRet != 0 &amp;&amp; dtlsRet != WC_NO_ERR_TRACE(WANT_WRITE))
            return ret;

    } else
#endif /* WOLFSSL_DTLS13 */
    {
        /* This message is always encrypted. */
        int sendSz = BuildTls13Message(ssl, output, outputSz, input,
                                   headerSz + finishedSz, handshake, 1, 0, 0);
        if (sendSz &lt; 0) {
            WOLFSSL_ERROR_VERBOSE(BUILD_MSG_ERROR);
            return BUILD_MSG_ERROR;
        }

        #if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
            if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;Finished&quot;);
            if (ssl-&gt;toInfoOn) {
                ret = AddPacketInfo(ssl, &quot;Finished&quot;, handshake, output, sendSz,
                              WRITE_PROTO, 0, ssl-&gt;heap);
                if (ret != 0)
                    return ret;
            }
        #endif

        ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;
        ssl-&gt;options.buildingMsg = 0;
    }

    if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
#ifdef WOLFSSL_EARLY_DATA
        byte storeTrafficDecKeys = ssl-&gt;earlyData == no_early_data;
#endif
        /* Can send application data now. */
        if ((ret = DeriveMasterSecret(ssl)) != 0)
            return ret;
        /* Last use of preMasterSecret - zeroize as soon as possible. */
        ForceZero(ssl-&gt;arrays-&gt;preMasterSecret, ssl-&gt;arrays-&gt;preMasterSz);
#ifdef WOLFSSL_EARLY_DATA

#ifdef WOLFSSL_DTLS13
        /* DTLS13 dynamically change keys and it needs all
           the keys in ssl-&gt;keys to save the keying material */
        if (isDtls)
            storeTrafficDecKeys = 1;
#endif /* WOLFSSL_DTLS13 */

        if ((ret = DeriveTls13Keys(ssl, traffic_key, ENCRYPT_SIDE_ONLY, 1))
                                                                         != 0) {
            return ret;
        }
        if ((ret = DeriveTls13Keys(ssl, traffic_key, DECRYPT_SIDE_ONLY,
                                       storeTrafficDecKeys)) != 0) {
            return ret;
        }
#else
        if ((ret = DeriveTls13Keys(ssl, traffic_key, ENCRYPT_AND_DECRYPT_SIDE,
                                                                     1)) != 0) {
            return ret;
        }
#endif
        if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
            return ret;

#ifdef WOLFSSL_DTLS13
        if (isDtls) {
            w64wrapper epochTraffic0;
            epochTraffic0 = w64From32(0, DTLS13_EPOCH_TRAFFIC0);
            ssl-&gt;dtls13Epoch = epochTraffic0;
            ssl-&gt;dtls13PeerEpoch = epochTraffic0;

            ret = Dtls13NewEpoch(
                ssl, epochTraffic0, ENCRYPT_AND_DECRYPT_SIDE);
            if (ret != 0)
                return ret;

            ret = Dtls13SetEpochKeys(
                ssl, epochTraffic0, ENCRYPT_AND_DECRYPT_SIDE);
            if (ret != 0)
                return ret;

        }
#endif /* WOLFSSL_DTLS13 */

    }

    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp;
                                                  !ssl-&gt;options.handShakeDone) {
#ifdef WOLFSSL_EARLY_DATA
        if (ssl-&gt;earlyData != no_early_data) {
            if ((ret = DeriveTls13Keys(ssl, no_key, ENCRYPT_SIDE_ONLY,
                                                                     1)) != 0) {
                    return ret;
            }
        }
#endif
        /* Setup keys for application data messages. */
        if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
            return ret;

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
        ret = DeriveResumptionSecret(ssl, ssl-&gt;session-&gt;masterSecret);
        if (ret != 0)
            return ret;
#endif

#ifdef WOLFSSL_DTLS13
        if (isDtls) {
            w64wrapper epochTraffic0;
            epochTraffic0 = w64From32(0, DTLS13_EPOCH_TRAFFIC0);
            ssl-&gt;dtls13Epoch = epochTraffic0;
            ssl-&gt;dtls13PeerEpoch = epochTraffic0;

            ret = Dtls13NewEpoch(
                ssl, epochTraffic0, ENCRYPT_AND_DECRYPT_SIDE);
            if (ret != 0)
                return ret;

            ret = Dtls13SetEpochKeys(
                ssl, epochTraffic0, ENCRYPT_AND_DECRYPT_SIDE);
            if (ret != 0)
                return ret;

        }
#endif /* WOLFSSL_DTLS13 */
    }

#ifndef NO_WOLFSSL_CLIENT
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
        ssl-&gt;options.clientState = CLIENT_FINISHED_COMPLETE;
        ssl-&gt;options.handShakeState = HANDSHAKE_DONE;
        ssl-&gt;options.handShakeDone  = 1;
    }
#endif
#ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
        ssl-&gt;options.serverState = SERVER_FINISHED_COMPLETE;
    }
#endif

#ifdef WOLFSSL_DTLS13
    if (isDtls) {
        WOLFSSL_LEAVE(&quot;SendTls13Finished&quot;, ret);
        WOLFSSL_END(WC_FUNC_FINISHED_SEND);

        return dtlsRet;
    }
#endif /* WOLFSSL_DTLS13 */

    if ((ret = SendBuffered(ssl)) != 0)
        return ret;

    WOLFSSL_LEAVE(&quot;SendTls13Finished&quot;, ret);
    WOLFSSL_END(WC_FUNC_FINISHED_SEND);

    return ret;
}
#endif /* !NO_WOLFSSL_CLIENT || !NO_WOLFSSL_SERVER */

/* handle generation TLS v1.3 key_update (24) */
/* Send the TLS v1.3 KeyUpdate message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
int SendTls13KeyUpdate(WOLFSSL* ssl)
{
    byte*  input;
    byte*  output;
    int    ret;
    int    headerSz = HANDSHAKE_HEADER_SZ;
    int    outputSz;
    word32 i = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;

    WOLFSSL_START(WC_FUNC_KEY_UPDATE_SEND);
    WOLFSSL_ENTER(&quot;SendTls13KeyUpdate&quot;);

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        i = Dtls13GetRlHeaderLength(ssl, 1) + DTLS_HANDSHAKE_HEADER_SZ;
#endif /* WOLFSSL_DTLS13 */

    outputSz = OPAQUE8_LEN + MAX_MSG_EXTRA;
    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, outputSz)) != 0)
        return ret;

    /* get output buffer */
    output = GetOutputBuffer(ssl);
    input = output + RECORD_HEADER_SZ;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        input = output + Dtls13GetRlHeaderLength(ssl, 1);
#endif /* WOLFSSL_DTLS13 */

    AddTls13Headers(output, OPAQUE8_LEN, key_update, ssl);

    /* If:
     *   1. I haven&#039;t sent a KeyUpdate requesting a response and
     *   2. This isn&#039;t responding to peer KeyUpdate requiring a response then,
     * I want a response.
     */
    ssl-&gt;keys.updateResponseReq = output[i++] =
         !ssl-&gt;keys.updateResponseReq &amp;&amp; !ssl-&gt;keys.keyUpdateRespond;
    /* Sent response, no longer need to respond. */
    ssl-&gt;keys.keyUpdateRespond = 0;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        ret = Dtls13HandshakeSend(ssl, output, (word16)outputSz,
            OPAQUE8_LEN + Dtls13GetRlHeaderLength(ssl, 1) +
                DTLS_HANDSHAKE_HEADER_SZ,
            key_update, 0);
    }
    else
#endif /* WOLFSSL_DTLS13 */
    {
        /* This message is always encrypted. */
        int sendSz = BuildTls13Message(ssl, output, outputSz, input,
                                   headerSz + OPAQUE8_LEN, handshake, 0, 0, 0);
        if (sendSz &lt; 0)
            return BUILD_MSG_ERROR;

        #if defined(WOLFSSL_CALLBACKS) || defined(OPENSSL_EXTRA)
            if (ssl-&gt;hsInfoOn) AddPacketName(ssl, &quot;KeyUpdate&quot;);
            if (ssl-&gt;toInfoOn) {
                ret = AddPacketInfo(ssl, &quot;KeyUpdate&quot;, handshake, output, sendSz,
                              WRITE_PROTO, 0, ssl-&gt;heap);
                if (ret != 0)
                    return ret;
            }
        #endif

        ssl-&gt;buffers.outputBuffer.length += (word32)sendSz;

        ret = SendBuffered(ssl);


        if (ret != 0 &amp;&amp; ret != WC_NO_ERR_TRACE(WANT_WRITE))
            return ret;
    }

    /* In DTLS we must wait for the ack before setting up the new keys */
    if (!ssl-&gt;options.dtls) {

        /* Future traffic uses new encryption keys. */
        if ((ret = DeriveTls13Keys(
                       ssl, update_traffic_key, ENCRYPT_SIDE_ONLY, 1))
            != 0)
            return ret;
        if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
            return ret;
    }


    WOLFSSL_LEAVE(&quot;SendTls13KeyUpdate&quot;, ret);
    WOLFSSL_END(WC_FUNC_KEY_UPDATE_SEND);

    return ret;
}

/* handle processing TLS v1.3 key_update (24) */
/* Parse and handle a TLS v1.3 KeyUpdate message.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of Finished.
 *           On exit, the index of byte after the Finished message and padding.
 * totalSz   The length of the current handshake message.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13KeyUpdate(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
                            word32 totalSz)
{
    int    ret;
    word32 i = *inOutIdx;

    WOLFSSL_START(WC_FUNC_KEY_UPDATE_DO);
    WOLFSSL_ENTER(&quot;DoTls13KeyUpdate&quot;);

    /* check against totalSz */
    if (OPAQUE8_LEN != totalSz)
        return BUFFER_E;

    switch (input[i]) {
        case update_not_requested:
            /* This message in response to any outstanding request. */
            ssl-&gt;keys.keyUpdateRespond = 0;
            ssl-&gt;keys.updateResponseReq = 0;
            break;
        case update_requested:
            /* New key update requiring a response. */
            ssl-&gt;keys.keyUpdateRespond = 1;
            break;
        default:
            WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
            return INVALID_PARAMETER;
    }

    /* Move index to byte after message. */
    *inOutIdx += totalSz;
    /* Always encrypted. */
    *inOutIdx += ssl-&gt;keys.padSz;

    /* Future traffic uses new decryption keys. */
    if ((ret = DeriveTls13Keys(ssl, update_traffic_key, DECRYPT_SIDE_ONLY, 1))
                                                                         != 0) {
        return ret;
    }
    if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
        return ret;

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls) {
        w64Increment(&amp;ssl-&gt;dtls13PeerEpoch);

        ret = Dtls13NewEpoch(ssl, ssl-&gt;dtls13PeerEpoch, DECRYPT_SIDE_ONLY);
        if (ret != 0)
            return ret;

        ret = Dtls13SetEpochKeys(ssl, ssl-&gt;dtls13PeerEpoch, DECRYPT_SIDE_ONLY);
        if (ret != 0)
            return ret;
    }
#endif /* WOLFSSL_DTLS13 */

    if (ssl-&gt;keys.keyUpdateRespond) {

#ifdef WOLFSSL_DTLS13
        /* we already sent a keyUpdate (either in response to a previous
           KeyUpdate or initiated by the application) and we are waiting for the
           ack. We can&#039;t send a new KeyUpdate right away but to honor the RFC we
           should send another KeyUpdate after the one in-flight is acked. We
           don&#039;t do that as it looks redundant, it will make the code more
           complex and I don&#039;t see a good use case for that. */
        if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;dtls13WaitKeyUpdateAck) {
            ssl-&gt;keys.keyUpdateRespond = 0;
            return 0;
        }
#endif /* WOLFSSL_DTLS13 */

#ifndef WOLFSSL_RW_THREADED
        return SendTls13KeyUpdate(ssl);
#else
        ssl-&gt;options.sendKeyUpdate = 1;
        return 0;
#endif
    }

    WOLFSSL_LEAVE(&quot;DoTls13KeyUpdate&quot;, ret);
    WOLFSSL_END(WC_FUNC_KEY_UPDATE_DO);

    return 0;
}

#ifdef WOLFSSL_EARLY_DATA
#ifndef NO_WOLFSSL_CLIENT
/* Send the TLS v1.3 EndOfEarlyData message to indicate that there will be no
 * more early application data.
 * The encryption key now changes to the pre-calculated handshake key.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success and otherwise failure.
 */
static int SendTls13EndOfEarlyData(WOLFSSL* ssl)
{
    byte*  output;
    int    ret;
    int    sendSz;
    word32 length;
    word32 idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;

    WOLFSSL_START(WC_FUNC_END_OF_EARLY_DATA_SEND);
    WOLFSSL_ENTER(&quot;SendTls13EndOfEarlyData&quot;);

    length = 0;
    sendSz = (int)(idx + length + MAX_MSG_EXTRA);
    ssl-&gt;options.buildingMsg = 1;

    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, sendSz)) != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(output, length, end_of_early_data, ssl);

    /* This message is always encrypted. */
    sendSz = BuildTls13Message(ssl, output, sendSz, output + RECORD_HEADER_SZ,
                               idx - RECORD_HEADER_SZ, handshake, 1, 0, 0);
    if (sendSz &lt; 0)
        return sendSz;

    ssl-&gt;buffers.outputBuffer.length += sendSz;

    if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
        return ret;

    ssl-&gt;options.buildingMsg = 0;
    if (!ssl-&gt;options.groupMessages)
        ret = SendBuffered(ssl);

    ssl-&gt;earlyData = done_early_data;

    WOLFSSL_LEAVE(&quot;SendTls13EndOfEarlyData&quot;, ret);
    WOLFSSL_END(WC_FUNC_END_OF_EARLY_DATA_SEND);

    return ret;
}
#endif /* !NO_WOLFSSL_CLIENT */

#ifndef NO_WOLFSSL_SERVER
/* handle processing of TLS 1.3 end_of_early_data (5) */
/* Parse the TLS v1.3 EndOfEarlyData message that indicates that there will be
 * no more early application data.
 * The decryption key now changes to the pre-calculated handshake key.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success and otherwise failure.
 */
static int DoTls13EndOfEarlyData(WOLFSSL* ssl, const byte* input,
                                 word32* inOutIdx, word32 size)
{
    int    ret;
    word32 begin = *inOutIdx;

    (void)input;

    WOLFSSL_START(WC_FUNC_END_OF_EARLY_DATA_DO);
    WOLFSSL_ENTER(&quot;DoTls13EndOfEarlyData&quot;);

    if ((*inOutIdx - begin) != size)
        return BUFFER_ERROR;

    if (ssl-&gt;earlyData == no_early_data) {
        WOLFSSL_MSG(&quot;EndOfEarlyData received unexpectedly&quot;);
        SendAlert(ssl, alert_fatal, unexpected_message);
        WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
        return OUT_OF_ORDER_E;
    }

    ssl-&gt;earlyData = done_early_data;

    /* Always encrypted. */
    *inOutIdx += ssl-&gt;keys.padSz;

    ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY);

    WOLFSSL_LEAVE(&quot;DoTls13EndOfEarlyData&quot;, ret);
    WOLFSSL_END(WC_FUNC_END_OF_EARLY_DATA_DO);

    return ret;
}
#endif /* !NO_WOLFSSL_SERVER */
#endif /* WOLFSSL_EARLY_DATA */

#if defined(HAVE_SESSION_TICKET) &amp;&amp; defined(WOLFSSL_TICKET_NONCE_MALLOC) &amp;&amp;    \
    (!defined(HAVE_FIPS) || (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(5,3)))
int SessionTicketNoncePopulate(WOLFSSL_SESSION *session, const byte *nonce,
    byte len)
{
    if (session-&gt;ticketNonce.data
            != session-&gt;ticketNonce.dataStatic) {
         XFREE(session-&gt;ticketNonce.data, session-&gt;heap,
             DYNAMIC_TYPE_SESSION_TICK);
         session-&gt;ticketNonce.data = session-&gt;ticketNonce.dataStatic;
         session-&gt;ticketNonce.len = 0;
    }

    if (len &gt; MAX_TICKET_NONCE_STATIC_SZ) {
        WOLFSSL_MSG(&quot;Using dynamic nonce buffer&quot;);
        session-&gt;ticketNonce.data = (byte*)XMALLOC(len,
            session-&gt;heap, DYNAMIC_TYPE_SESSION_TICK);
        if (session-&gt;ticketNonce.data == NULL)
            return MEMORY_ERROR;
    }
    XMEMCPY(session-&gt;ticketNonce.data, nonce, len);
    session-&gt;ticketNonce.len = len;
    return 0;
}
#endif
#ifndef NO_WOLFSSL_CLIENT
/* Handle a New Session Ticket handshake message.
 * Message contains the information required to perform resumption.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the message buffer of Finished.
 *           On exit, the index of byte after the Finished message and padding.
 * size      The length of the current handshake message.
 * returns 0 on success, otherwise failure.
 */
static int DoTls13NewSessionTicket(WOLFSSL* ssl, const byte* input,
                                   word32* inOutIdx, word32 size)
{
#ifdef HAVE_SESSION_TICKET
    int    ret;
    word32 begin = *inOutIdx;
    word32 lifetime;
    word32 ageAdd;
    word16 length;
#ifdef WOLFSSL_32BIT_MILLI_TIME
    word32 now;
#else
    sword64 now;
#endif
    const byte* nonce;
    byte        nonceLength;

    WOLFSSL_START(WC_FUNC_NEW_SESSION_TICKET_DO);
    WOLFSSL_ENTER(&quot;DoTls13NewSessionTicket&quot;);

    /* Lifetime hint. */
    if ((*inOutIdx - begin) + SESSION_HINT_SZ &gt; size)
        return BUFFER_ERROR;
    ato32(input + *inOutIdx, &amp;lifetime);
    *inOutIdx += SESSION_HINT_SZ;
    if (lifetime &gt; MAX_LIFETIME) {
        WOLFSSL_ERROR_VERBOSE(SERVER_HINT_ERROR);
        return SERVER_HINT_ERROR;
    }

    /* Age add. */
    if ((*inOutIdx - begin) + SESSION_ADD_SZ &gt; size)
        return BUFFER_ERROR;
    ato32(input + *inOutIdx, &amp;ageAdd);
    *inOutIdx += SESSION_ADD_SZ;

    /* Ticket nonce. */
    if ((*inOutIdx - begin) + 1 &gt; size)
        return BUFFER_ERROR;
    nonceLength = input[*inOutIdx];
#if !defined(WOLFSSL_TICKET_NONCE_MALLOC) &amp;&amp;                                   \
    (!defined(HAVE_FIPS) || FIPS_VERSION_GE(5,3))
    if (nonceLength &gt; MAX_TICKET_NONCE_STATIC_SZ) {
        WOLFSSL_MSG(&quot;Nonce length not supported&quot;);
        WOLFSSL_ERROR_VERBOSE(INVALID_PARAMETER);
        return INVALID_PARAMETER;
    }
#endif /* WOLFSSL_TICKET_NONCE_MALLOC &amp;&amp; FIPS_VERSION_GE(5,3) */
    *inOutIdx += 1;
    if ((*inOutIdx - begin) + nonceLength &gt; size)
        return BUFFER_ERROR;
    nonce = input + *inOutIdx;
    *inOutIdx += nonceLength;

    /* Ticket length. */
    if ((*inOutIdx - begin) + LENGTH_SZ &gt; size)
        return BUFFER_ERROR;
    ato16(input + *inOutIdx, &amp;length);
    *inOutIdx += LENGTH_SZ;
    if ((*inOutIdx - begin) + length &gt; size)
        return BUFFER_ERROR;

    if ((ret = SetTicket(ssl, input + *inOutIdx, length)) != 0)
        return ret;
    *inOutIdx += length;

    now = TimeNowInMilliseconds();
    if (now == 0)
        return GETTIME_ERROR;
    /* Copy in ticket data (server identity). */
    ssl-&gt;timeout                  = lifetime;
    ssl-&gt;session-&gt;timeout         = lifetime;
    ssl-&gt;session-&gt;cipherSuite0    = ssl-&gt;options.cipherSuite0;
    ssl-&gt;session-&gt;cipherSuite     = ssl-&gt;options.cipherSuite;
    ssl-&gt;session-&gt;ticketSeen      = now;
    ssl-&gt;session-&gt;ticketAdd       = ageAdd;
    #ifdef WOLFSSL_EARLY_DATA
    ssl-&gt;session-&gt;maxEarlyDataSz  = ssl-&gt;options.maxEarlyDataSz;
    #endif

#if defined(WOLFSSL_TICKET_NONCE_MALLOC) &amp;&amp;                                    \
    (!defined(HAVE_FIPS) || (defined(FIPS_VERSION_GE) &amp;&amp; FIPS_VERSION_GE(5,3)))
    ret = SessionTicketNoncePopulate(ssl-&gt;session, nonce, nonceLength);
    if (ret != 0)
        return ret;
#else
    ssl-&gt;session-&gt;ticketNonce.len = nonceLength;
    if (nonceLength &gt; MAX_TICKET_NONCE_STATIC_SZ) {
        ret = BUFFER_ERROR;
        return ret;
    }
    if (nonceLength &gt; 0)
        XMEMCPY(ssl-&gt;session-&gt;ticketNonce.data, nonce, nonceLength);
#endif /* defined(WOLFSSL_TICKET_NONCE_MALLOC) &amp;&amp; FIPS_VERSION_GE(5,3) */

    ssl-&gt;session-&gt;namedGroup      = ssl-&gt;namedGroup;

    if ((*inOutIdx - begin) + EXTS_SZ &gt; size)
        return BUFFER_ERROR;
    ato16(input + *inOutIdx, &amp;length);
    *inOutIdx += EXTS_SZ;
    if ((*inOutIdx - begin) + length != size)
        return BUFFER_ERROR;
    #ifdef WOLFSSL_EARLY_DATA
    ret = TLSX_Parse(ssl, (byte *)input + (*inOutIdx), length, session_ticket,
                     NULL);
    if (ret != 0)
        return ret;
    #endif
    *inOutIdx += length;

    SetupSession(ssl);
    #ifndef NO_SESSION_CACHE
        AddSession(ssl);
    #endif

    /* Always encrypted. */
    *inOutIdx += ssl-&gt;keys.padSz;

    ssl-&gt;expect_session_ticket = 0;
#else
    (void)ssl;
    (void)input;

    WOLFSSL_ENTER(&quot;DoTls13NewSessionTicket&quot;);

    *inOutIdx += size + ssl-&gt;keys.padSz;
#endif /* HAVE_SESSION_TICKET */

    WOLFSSL_LEAVE(&quot;DoTls13NewSessionTicket&quot;, 0);
    WOLFSSL_END(WC_FUNC_NEW_SESSION_TICKET_DO);

    return 0;
}
#endif /* NO_WOLFSSL_CLIENT */

#ifndef NO_WOLFSSL_SERVER
    #ifdef HAVE_SESSION_TICKET

#ifdef WOLFSSL_TLS13_TICKET_BEFORE_FINISHED
/* Offset of the MAC size in the finished message. */
#define FINISHED_MSG_SIZE_OFFSET    3

/* Calculate the resumption secret which includes the unseen client finished
 * message.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int ExpectedResumptionSecret(WOLFSSL* ssl)
{
    int         ret;
    word32      finishedSz = 0;
    byte        mac[WC_MAX_DIGEST_SIZE];
    Digest      digest;
    static byte header[] = { 0x14, 0x00, 0x00, 0x00 };

    /* Copy the running hash so we can restore it after. */
    switch (ssl-&gt;specs.mac_algorithm) {
    #ifndef NO_SHA256
        case sha256_mac:
            ret = wc_Sha256Copy(&amp;ssl-&gt;hsHashes-&gt;hashSha256, &amp;digest.sha256);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            ret = wc_Sha384Copy(&amp;ssl-&gt;hsHashes-&gt;hashSha384, &amp;digest.sha384);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            ret = wc_Sha512Copy(&amp;ssl-&gt;hsHashes-&gt;hashSha512, &amp;digest.sha512);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_SM3
        case sm3_mac:
            ret = wc_Sm3Copy(&amp;ssl-&gt;hsHashes-&gt;hashSm3, &amp;digest.sm3);
            if (ret != 0)
                return ret;
            break;
    #endif
    }

    /* Generate the Client&#039;s Finished message and hash it. */
    ret = BuildTls13HandshakeHmac(ssl, ssl-&gt;keys.client_write_MAC_secret, mac,
                                  &amp;finishedSz);
    if (ret != 0)
        return ret;
    header[FINISHED_MSG_SIZE_OFFSET] = finishedSz;
#ifdef WOLFSSL_EARLY_DATA
    if (ssl-&gt;earlyData != no_early_data) {
        static byte endOfEarlyData[] = { 0x05, 0x00, 0x00, 0x00 };
        ret = HashRaw(ssl, endOfEarlyData, sizeof(endOfEarlyData));
        if (ret != 0)
            return ret;
    }
#endif
    if ((ret = HashRaw(ssl, header, sizeof(header))) != 0)
        return ret;
    if ((ret = HashRaw(ssl, mac, finishedSz)) != 0)
        return ret;

    if ((ret = DeriveResumptionSecret(ssl, ssl-&gt;session-&gt;masterSecret)) != 0)
        return ret;

    /* Restore the hash inline with currently seen messages. */
    switch (ssl-&gt;specs.mac_algorithm) {
    #ifndef NO_SHA256
        case sha256_mac:
            wc_Sha256Free(&amp;ssl-&gt;hsHashes-&gt;hashSha256);
            ret = wc_Sha256Copy(&amp;digest.sha256, &amp;ssl-&gt;hsHashes-&gt;hashSha256);
            wc_Sha256Free(&amp;digest.sha256);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_SHA384
        case sha384_mac:
            wc_Sha384Free(&amp;ssl-&gt;hsHashes-&gt;hashSha384);
            ret = wc_Sha384Copy(&amp;digest.sha384, &amp;ssl-&gt;hsHashes-&gt;hashSha384);
            wc_Sha384Free(&amp;digest.sha384);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_TLS13_SHA512
        case sha512_mac:
            wc_Sha512Free(&amp;ssl-&gt;hsHashes-&gt;hashSha512);
            ret = wc_Sha512Copy(&amp;digest.sha512, &amp;ssl-&gt;hsHashes-&gt;hashSha512);
            wc_Sha512Free(&amp;digest.sha512);
            if (ret != 0)
                return ret;
            break;
    #endif
    #ifdef WOLFSSL_SM3
        case sm3_mac:
            wc_Sm3Free(&amp;ssl-&gt;hsHashes-&gt;hashSm3);
            ret = wc_Sm3Copy(&amp;digest.sm3, &amp;ssl-&gt;hsHashes-&gt;hashSm3);
            wc_Sm3Free(&amp;digest.sm3);
            if (ret != 0)
                return ret;
            break;
    #endif
    }

    return ret;
}
#endif

/* Send New Session Ticket handshake message.
 * Message contains the information required to perform resumption.
 *
 * ssl  The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
static int SendTls13NewSessionTicket(WOLFSSL* ssl)
{
    byte*  output;
    int    ret;
    word32 length;
    int    sendSz;
    word16 extSz;
    word32 idx = RECORD_HEADER_SZ + HANDSHAKE_HEADER_SZ;

    WOLFSSL_START(WC_FUNC_NEW_SESSION_TICKET_SEND);
    WOLFSSL_ENTER(&quot;SendTls13NewSessionTicket&quot;);

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        idx = Dtls13GetRlHeaderLength(ssl, 1) + DTLS_HANDSHAKE_HEADER_SZ;
#endif /* WOLFSSL_DTLS13 */

#ifdef WOLFSSL_TLS13_TICKET_BEFORE_FINISHED
    if (!ssl-&gt;msgsReceived.got_finished) {
        if ((ret = ExpectedResumptionSecret(ssl)) != 0)
            return ret;
    }
#endif

    /* Start ticket nonce at 0 and go up to 255. */
    if (ssl-&gt;session-&gt;ticketNonce.len == 0) {
        ssl-&gt;session-&gt;ticketNonce.len = DEF_TICKET_NONCE_SZ;
        ssl-&gt;session-&gt;ticketNonce.data[0] = 0;
    }
    else
    #ifdef WOLFSSL_ASYNC_CRYPT
        if (ssl-&gt;error != WC_NO_ERR_TRACE(WC_PENDING_E))
    #endif
    {
            ssl-&gt;session-&gt;ticketNonce.data[0]++;
    }

    if ((ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TICKET) != 0) {
        /* In this case we only send the ID as the ticket. Let&#039;s generate a new
         * ID for the new ticket so that we don&#039;t overwrite any old ones */
        ret = wc_RNG_GenerateBlock(ssl-&gt;rng, ssl-&gt;session-&gt;altSessionID,
                                   ID_LEN);
        if (ret != 0)
            return ret;
        ssl-&gt;session-&gt;haveAltSessionID = 1;
    }

    if (!ssl-&gt;options.noTicketTls13) {
        if ((ret = SetupTicket(ssl)) != 0)
            return ret;
        /* No need to create the ticket if we only send the ID */
        if ((ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TICKET) == 0) {
            if ((ret = CreateTicket(ssl)) != 0)
                return ret;
        }
    }

#ifdef WOLFSSL_EARLY_DATA
    ssl-&gt;session-&gt;maxEarlyDataSz = ssl-&gt;options.maxEarlyDataSz;
    if (ssl-&gt;session-&gt;maxEarlyDataSz &gt; 0)
        TLSX_EarlyData_Use(ssl, ssl-&gt;session-&gt;maxEarlyDataSz, 1);
    extSz = 0;
    ret = TLSX_GetResponseSize(ssl, session_ticket, &amp;extSz);
    if (ret != 0)
        return ret;
#else
    extSz = EXTS_SZ;
#endif
    /* Lifetime | Age Add | Ticket session ID | Extensions */
    length = SESSION_HINT_SZ + SESSION_ADD_SZ + LENGTH_SZ;
    if ((ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TICKET) != 0)
        length += ID_LEN + extSz;
    else
        length += ssl-&gt;session-&gt;ticketLen + extSz;
    /* Nonce */
    length += TICKET_NONCE_LEN_SZ + DEF_TICKET_NONCE_SZ;

    sendSz = (word16)(idx + length + MAX_MSG_EXTRA);

    /* Check buffers are big enough and grow if needed. */
    if ((ret = CheckAvailableSize(ssl, sendSz)) != 0)
        return ret;

    /* Get position in output buffer to write new message to. */
    output = GetOutputBuffer(ssl);

    /* Put the record and handshake headers on. */
    AddTls13Headers(output, length, session_ticket, ssl);

    /* Lifetime hint */
    c32toa(ssl-&gt;ctx-&gt;ticketHint, output + idx);
    idx += SESSION_HINT_SZ;
    /* Age add - obfuscator */
    c32toa(ssl-&gt;session-&gt;ticketAdd, output + idx);
    idx += SESSION_ADD_SZ;

    output[idx++] = ssl-&gt;session-&gt;ticketNonce.len;
    output[idx++] = ssl-&gt;session-&gt;ticketNonce.data[0];

    /* length */
    if ((ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TICKET) != 0) {
        c16toa(ID_LEN, output + idx);
    }
    else {
        c16toa(ssl-&gt;session-&gt;ticketLen, output + idx);
    }

    idx += LENGTH_SZ;
    /* ticket */
    if ((ssl-&gt;options.mask &amp; WOLFSSL_OP_NO_TICKET) != 0) {
        if (ssl-&gt;session-&gt;haveAltSessionID)
            XMEMCPY(output + idx, ssl-&gt;session-&gt;altSessionID, ID_LEN);
        else
            return BAD_FUNC_ARG; /* Should not happen */
        idx += ID_LEN;
    }
    else {
        XMEMCPY(output + idx, ssl-&gt;session-&gt;ticket, ssl-&gt;session-&gt;ticketLen);
        idx += ssl-&gt;session-&gt;ticketLen;
    }

#ifdef WOLFSSL_EARLY_DATA
    extSz = 0;
    ret = TLSX_WriteResponse(ssl, output + idx, session_ticket, &amp;extSz);
    if (ret != 0)
        return ret;
    idx += extSz;
#else
    /* No extension support - empty extensions. */
    c16toa(0, output + idx);
    idx += EXTS_SZ;
#endif

    if (idx &gt; WOLFSSL_MAX_16BIT) {
        return BAD_LENGTH_E;
    }

    ssl-&gt;options.haveSessionId = 1;

    SetupSession(ssl);
    /* Only add to cache when support built in and when the ticket contains
     * an ID. Otherwise we have no way to actually retrieve the ticket from the
     * cache. */
#if !defined(NO_SESSION_CACHE) &amp;&amp; defined(WOLFSSL_TICKET_HAVE_ID)
    AddSession(ssl);
#endif

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        return Dtls13HandshakeSend(ssl, output, (word16)sendSz,
                                   (word16)idx, session_ticket, 0);
#endif /* WOLFSSL_DTLS13 */

    /* This message is always encrypted. */
    sendSz = BuildTls13Message(ssl, output, sendSz,
                               output + RECORD_HEADER_SZ,
                               (word16)idx - RECORD_HEADER_SZ,
                               handshake, 0, 0, 0);
    if (sendSz &lt; 0)
        return sendSz;

    ssl-&gt;buffers.outputBuffer.length += sendSz;

    /* Always send as this is either directly after server&#039;s Finished or only
     * message after client&#039;s Finished.
     */
    ret = SendBuffered(ssl);

    WOLFSSL_LEAVE(&quot;SendTls13NewSessionTicket&quot;, 0);
    WOLFSSL_END(WC_FUNC_NEW_SESSION_TICKET_SEND);

    return ret;
}
    #endif /* HAVE_SESSION_TICKET */
#endif /* NO_WOLFSSL_SERVER */

/* Make sure no duplicates, no fast forward, or other problems
 *
 * ssl   The SSL/TLS object.
 * type  Type of handshake message received.
 * returns 0 on success, otherwise failure.
 */
static int SanityCheckTls13MsgReceived(WOLFSSL* ssl, byte type)
{
    /* verify not a duplicate, mark received, check state */
    switch (type) {

#ifndef NO_WOLFSSL_SERVER
        case client_hello:
        #ifndef NO_WOLFSSL_CLIENT
            /* Only valid when received on SERVER side. */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
                WOLFSSL_MSG(&quot;ClientHello received by client&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
            if (ssl-&gt;options.clientState &gt;= CLIENT_HELLO_COMPLETE) {
                WOLFSSL_MSG(&quot;ClientHello received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            /* Check previously seen. */
            /* Initial and after HelloRetryRequest - no more than 2. */
            if (ssl-&gt;msgsReceived.got_client_hello == 2) {
                WOLFSSL_MSG(&quot;Too many ClientHello received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            /* Second only after HelloRetryRequest seen. */
            if (ssl-&gt;msgsReceived.got_client_hello == 1 &amp;&amp;
                ssl-&gt;options.serverState !=
                                          SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
                WOLFSSL_MSG(&quot;Duplicate ClientHello received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_client_hello++;

            break;
#endif

#ifndef NO_WOLFSSL_CLIENT
        case server_hello:
        #ifndef NO_WOLFSSL_SERVER
            /* Only valid when received on CLIENT side. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                WOLFSSL_MSG(&quot;ServerHello received by server&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
            if (ssl-&gt;options.serverState &gt;= SERVER_HELLO_COMPLETE) {
                WOLFSSL_MSG(&quot;ServerHello received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            /* Check previously seen. */
            /* Only once after ClientHello.
             * HelloRetryRequest has ServerHello type but count fixed up later
             * - see DoTls13ServerHello().
             */
            if (ssl-&gt;msgsReceived.got_server_hello) {
                WOLFSSL_MSG(&quot;Duplicate ServerHello received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_server_hello = 1;

            break;
#endif

#ifndef NO_WOLFSSL_CLIENT
        case session_ticket:
        #ifndef NO_WOLFSSL_SERVER
            /* Only valid when received on CLIENT side. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                WOLFSSL_MSG(&quot;NewSessionTicket received by server&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
        #ifdef WOLFSSL_TLS13_TICKET_BEFORE_FINISHED
            /* Only allowed after server&#039;s Finished message. */
            if (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;NewSessionTicket received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
        #else
            /* Only allowed after client&#039;s Finished message. */
            if (ssl-&gt;options.clientState &lt; CLIENT_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;NewSessionTicket received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
        #endif
            /* Many SessionTickets can be sent. */
            ssl-&gt;msgsReceived.got_session_ticket = 1;

            break;
#endif

#ifndef NO_WOLFSSL_SERVER
    #ifdef WOLFSSL_EARLY_DATA
        case end_of_early_data:
        #ifndef NO_WOLFSSL_CLIENT
            /* Only valid when received on SERVER side. */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
                WOLFSSL_MSG(&quot;EndOfEarlyData received by client&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
            /* Only after server&#039;s Finished and before client&#039;s Finished. */
            if (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;EndOfEarlyData received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            if (ssl-&gt;options.clientState &gt;= CLIENT_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;EndOfEarlyData received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            /* Check previously seen. */
            if (ssl-&gt;msgsReceived.got_end_of_early_data) {
                WOLFSSL_MSG(&quot;Too many EndOfEarlyData received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_end_of_early_data = 1;

            break;
    #endif
#endif

#ifndef NO_WOLFSSL_CLIENT
        case encrypted_extensions:
        #ifndef NO_WOLFSSL_SERVER
            /* Only valid when received on CLIENT side. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                WOLFSSL_MSG(&quot;EncryptedExtensions received by server&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
            /* Must be received directly after ServerHello.
             * DoTls13EncryptedExtensions() changes state to:
             *   SERVER_ENCRYPTED_EXTENSIONS_COMPLETE.
             */
            if (ssl-&gt;options.serverState != SERVER_HELLO_COMPLETE) {
                WOLFSSL_MSG(&quot;EncryptedExtensions received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            /* Check previously seen. */
            if (ssl-&gt;msgsReceived.got_encrypted_extensions) {
                WOLFSSL_MSG(&quot;Duplicate EncryptedExtensions received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_encrypted_extensions = 1;

            break;
#endif

        case certificate:
            /* Valid on both sides. */
    #ifndef NO_WOLFSSL_CLIENT
            /* Check state. */
            /* On client, seen after EncryptedExtension and CertificateRequest
             * (if sent) and before CertificateVerify and Finished.
             * DoTls13Certificate() sets serverState to SERVER_CERT_COMPLETE.
             */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp;
                ssl-&gt;options.serverState !=
                                         SERVER_ENCRYPTED_EXTENSIONS_COMPLETE) {
                WOLFSSL_MSG(&quot;Certificate received out of order - Client&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
        #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
            /* Server&#039;s authenticating with PSK must not send this. */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp;
                             ssl-&gt;options.serverState == SERVER_CERT_COMPLETE &amp;&amp;
                             ssl-&gt;options.pskNegotiated) {
                WOLFSSL_MSG(&quot;Certificate received while using PSK&quot;);
                WOLFSSL_ERROR_VERBOSE(SANITY_MSG_E);
                return SANITY_MSG_E;
            }
        #endif
    #endif
    #ifndef NO_WOLFSSL_SERVER
            /* Check state. */
            /* On Server, valid after ClientHello received and ServerFinished
             * sent. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp;
                ssl-&gt;options.clientState != CLIENT_HELLO_COMPLETE &amp;&amp;
                ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;Certificate received out of order - Server&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
    #endif
            /* Check previously seen. */
            if (ssl-&gt;msgsReceived.got_certificate) {
                WOLFSSL_MSG(&quot;Duplicate Certificate received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_certificate = 1;

            break;

#ifndef NO_WOLFSSL_CLIENT
        case certificate_request:
        #ifndef NO_WOLFSSL_SERVER
            /* Only valid when received on CLIENT side. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                WOLFSSL_MSG(&quot;CertificateRequest received by server&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
        #endif
            /* Check state. */
        #ifndef WOLFSSL_POST_HANDSHAKE_AUTH
            /* Only valid when sent after EncryptedExtensions and before
             * Certificate. */
            if (ssl-&gt;options.serverState !=
                                         SERVER_ENCRYPTED_EXTENSIONS_COMPLETE) {
                WOLFSSL_MSG(&quot;CertificateRequest received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
        #else
            /* Valid when sent after EncryptedExtensions and before Certificate
             * and after both client and server have sent Finished (Post
             * Handshake Authentication). */
            if (ssl-&gt;options.serverState !=
                                         SERVER_ENCRYPTED_EXTENSIONS_COMPLETE &amp;&amp;
                       (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE ||
                        ssl-&gt;options.clientState != CLIENT_FINISHED_COMPLETE)) {
                WOLFSSL_MSG(&quot;CertificateRequest received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
        #endif
        #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
            /* Server&#039;s authenticating with PSK must not send this. */
            if (ssl-&gt;options.pskNegotiated) {
                WOLFSSL_MSG(&quot;CertificateRequest received while using PSK&quot;);
                WOLFSSL_ERROR_VERBOSE(SANITY_MSG_E);
                return SANITY_MSG_E;
            }
        #endif
            /* Check previously seen. */
        #ifndef WOLFSSL_POST_HANDSHAKE_AUTH
            /* Only once during handshake. */
            if (ssl-&gt;msgsReceived.got_certificate_request) {
                WOLFSSL_MSG(&quot;Duplicate CertificateRequest received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
        #else
            /* Only once during handshake. */
            if (ssl-&gt;msgsReceived.got_certificate_request &amp;&amp;
                ssl-&gt;options.clientState != CLIENT_FINISHED_COMPLETE) {
                WOLFSSL_MSG(&quot;Duplicate CertificateRequest received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
        #endif
            ssl-&gt;msgsReceived.got_certificate_request = 1;

            break;
#endif

        case certificate_verify:
            /* Valid on both sides. */
    #ifndef NO_WOLFSSL_CLIENT
            /* Check state on client.
             * Valid only directly after a Certificate message. */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
                if (ssl-&gt;options.serverState != SERVER_CERT_COMPLETE) {
                    WOLFSSL_MSG(&quot;No Cert before CertVerify&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
                /* Server&#039;s authenticating with PSK must not send this. */
                if (ssl-&gt;options.pskNegotiated) {
                    WOLFSSL_MSG(&quot;CertificateVerify received while using PSK&quot;);
                    WOLFSSL_ERROR_VERBOSE(SANITY_MSG_E);
                    return SANITY_MSG_E;
                }
            #endif
            }
    #endif
    #ifndef NO_WOLFSSL_SERVER
            /* Check state on server. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                /* Server must have sent Finished message. */
                if (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
                    WOLFSSL_MSG(&quot;CertificateVerify received out of order&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                /* Valid only directly after a Certificate message. */
                if (ssl-&gt;options.clientState &lt; CLIENT_HELLO_COMPLETE) {
                    WOLFSSL_MSG(&quot;CertificateVerify before ClientHello done&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                if (!ssl-&gt;msgsReceived.got_certificate) {
                    WOLFSSL_MSG(&quot;No Cert before CertificateVerify&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            }
    #endif
            /* Check previously seen. */
            if (ssl-&gt;msgsReceived.got_certificate_verify) {
                WOLFSSL_MSG(&quot;Duplicate CertificateVerify received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_certificate_verify = 1;

            break;

        case finished:
            /* Valid on both sides. */
        #ifndef NO_WOLFSSL_CLIENT
            /* Check state on client. */
            if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
                /* After sending ClientHello */
                if (ssl-&gt;options.clientState &lt; CLIENT_HELLO_COMPLETE) {
                    WOLFSSL_MSG(&quot;Finished received out of order - clientState&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                /* Must have seen certificate and verify from server except when
                 * using PSK. */
            #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
                if (ssl-&gt;options.pskNegotiated) {
                    if (ssl-&gt;options.serverState !=
                                         SERVER_ENCRYPTED_EXTENSIONS_COMPLETE) {
                        WOLFSSL_MSG(&quot;Finished received out of order - PSK&quot;);
                        WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                        return OUT_OF_ORDER_E;
                    }
                }
                else
            #endif
                if (ssl-&gt;options.serverState != SERVER_CERT_VERIFY_COMPLETE) {
                    WOLFSSL_MSG(&quot;Finished received out of order - serverState&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            }
        #endif
        #ifndef NO_WOLFSSL_SERVER
            /* Check state on server. */
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                if (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
                    WOLFSSL_MSG(&quot;Finished received out of order - serverState&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                if (ssl-&gt;options.clientState &lt; CLIENT_HELLO_COMPLETE) {
                    WOLFSSL_MSG(&quot;Finished received out of order - clientState&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            #ifdef WOLFSSL_EARLY_DATA
                if (ssl-&gt;earlyData == process_early_data &amp;&amp;
                    /* early data may be lost when using DTLS */
                    !ssl-&gt;options.dtls
                    /* QUIC does not use EndOfEarlyData records */
                    &amp;&amp; !WOLFSSL_IS_QUIC(ssl)) {
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            #endif
            }
        #endif
        #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
            if (!ssl-&gt;options.pskNegotiated)
        #endif
            {
                /* Must have received a Certificate message from client if
                 * verifying the peer. Empty certificate message indicates
                 * no certificate available.
                 */
                if (ssl-&gt;options.verifyPeer &amp;&amp;
                #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
                    !ssl-&gt;options.verifyPostHandshake &amp;&amp;
                #endif
                                           !ssl-&gt;msgsReceived.got_certificate) {
                    WOLFSSL_MSG(&quot;Finished received out of order - &quot;
                                &quot;missing Certificate message&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                /* Mutual authentication on server requires a certificate from
                 * peer. Verify peer set on client side requires a certificate
                 * from peer as not doing PSK.
                 */
                if ((ssl-&gt;options.mutualAuth ||
                    (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp;
                     ssl-&gt;options.verifyPeer)) &amp;&amp; !ssl-&gt;options.havePeerCert) {
                    WOLFSSL_MSG(&quot;Finished received out of order - &quot;
                                &quot;no valid certificate&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
                /* Must have received a valid CertificateVerify if verifying
                 * peer and got a peer certificate.
                 */
                if ((ssl-&gt;options.mutualAuth || ssl-&gt;options.verifyPeer) &amp;&amp;
                    ssl-&gt;options.havePeerCert &amp;&amp; !ssl-&gt;options.havePeerVerify) {
                    WOLFSSL_MSG(&quot;Finished received out of order - &quot;
                                &quot;Certificate message but no CertificateVerify&quot;);
                    WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                    return OUT_OF_ORDER_E;
                }
            }
            /* Check previously seen. */
            if (ssl-&gt;msgsReceived.got_finished) {
                WOLFSSL_MSG(&quot;Duplicate Finished received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_finished = 1;

            break;

        case key_update:
            /* Valid on both sides. */
            /* Check state.
             * Client and server must have received finished message from other
             * side.
             */
            if (!ssl-&gt;msgsReceived.got_finished) {
                WOLFSSL_MSG(&quot;No KeyUpdate before Finished&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            /* Multiple KeyUpdates can be sent. */
            break;
#if defined(WOLFSSL_DTLS13) &amp;&amp; !defined(WOLFSSL_NO_TLS12)
        case hello_verify_request:
            if (!ssl-&gt;options.dtls) {
                WOLFSSL_MSG(&quot;HelloVerifyRequest when not in DTLS&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            if (ssl-&gt;msgsReceived.got_hello_verify_request) {
                WOLFSSL_MSG(&quot;Duplicate HelloVerifyRequest received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            ssl-&gt;msgsReceived.got_hello_verify_request = 1;
            if (ssl-&gt;msgsReceived.got_hello_retry_request) {
                WOLFSSL_MSG(
                    &quot;Both HelloVerifyRequest and HelloRetryRequest received&quot;);
                WOLFSSL_ERROR_VERBOSE(DUPLICATE_MSG_E);
                return DUPLICATE_MSG_E;
            }
            if (ssl-&gt;options.serverState &gt;=
                    SERVER_HELLO_RETRY_REQUEST_COMPLETE ||
                ssl-&gt;options.connectState != CLIENT_HELLO_SENT) {
                WOLFSSL_MSG(&quot;HelloVerifyRequest received out of order&quot;);
                WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
                return OUT_OF_ORDER_E;
            }
            if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
                WOLFSSL_MSG(&quot;HelloVerifyRequest received on the server&quot;);
                WOLFSSL_ERROR_VERBOSE(SIDE_ERROR);
                return SIDE_ERROR;
            }
            if (!ssl-&gt;options.downgrade ||
                ssl-&gt;options.minDowngrade &lt; DTLSv1_2_MINOR) {
                WOLFSSL_MSG(
                    &quot;HelloVerifyRequest received but not DTLSv1.2 allowed&quot;);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }
            break;
#endif /* WOLFSSL_DTLS13 &amp;&amp; !WOLFSSL_NO_TLS12*/

        default:
            WOLFSSL_MSG(&quot;Unknown message type&quot;);
            WOLFSSL_ERROR_VERBOSE(SANITY_MSG_E);
            return SANITY_MSG_E;
    }

    return 0;
}

/* Handle a type of handshake message that has been received.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the buffer of the current message.
 *           On exit, the index into the buffer of the next message.
 * size      The length of the current handshake message.
 * totalSz   Length of remaining data in the message buffer.
 * returns 0 on success and otherwise failure.
 */
int DoTls13HandShakeMsgType(WOLFSSL* ssl, byte* input, word32* inOutIdx,
                            byte type, word32 size, word32 totalSz)
{
    int ret = 0, tmp;
    word32 inIdx = *inOutIdx;
    int alertType;
#if defined(HAVE_ECH)
    TLSX* echX = NULL;
    word32 echInOutIdx;
#endif

    (void)totalSz;

    WOLFSSL_ENTER(&quot;DoTls13HandShakeMsgType&quot;);

    /* make sure we can read the message */
    if (*inOutIdx + size &gt; totalSz)
        return INCOMPLETE_DATA;

    /* sanity check msg received */
    if ((ret = SanityCheckTls13MsgReceived(ssl, type)) != 0) {
        WOLFSSL_MSG(&quot;Sanity Check on handshake message type received failed&quot;);
        if (ret == WC_NO_ERR_TRACE(VERSION_ERROR))
            SendAlert(ssl, alert_fatal, wolfssl_alert_protocol_version);
        else
            SendAlert(ssl, alert_fatal, unexpected_message);
        return ret;
    }

#if defined(WOLFSSL_CALLBACKS)
    /* add name later, add on record and handshake header part back on */
    if (ssl-&gt;toInfoOn) {
        ret = AddPacketInfo(ssl, 0, handshake, input + *inOutIdx -
            HANDSHAKE_HEADER_SZ, size + HANDSHAKE_HEADER_SZ, READ_PROTO,
            RECORD_HEADER_SZ, ssl-&gt;heap);
        if (ret != 0)
            return ret;
        AddLateRecordHeader(&amp;ssl-&gt;curRL, &amp;ssl-&gt;timeoutInfo);
    }
#endif

    if (ssl-&gt;options.handShakeState == HANDSHAKE_DONE &amp;&amp;
            type != session_ticket &amp;&amp; type != certificate_request &amp;&amp;
            type != certificate &amp;&amp; type != key_update &amp;&amp; type != finished) {
        WOLFSSL_MSG(&quot;HandShake message after handshake complete&quot;);
        SendAlert(ssl, alert_fatal, unexpected_message);
        WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
        return OUT_OF_ORDER_E;
    }

    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END &amp;&amp;
               ssl-&gt;options.serverState == NULL_STATE &amp;&amp;
               type != server_hello &amp;&amp; type != hello_retry_request
#if defined(WOLFSSL_DTLS13) &amp;&amp; !defined(WOLFSSL_NO_TLS12)
        &amp;&amp; (!ssl-&gt;options.dtls || type != hello_verify_request)
#endif /* defined(WOLFSSL_DTLS13) &amp;&amp; !defined(WOLFSSL_NO_TLS12) */
        ) {
        WOLFSSL_MSG(&quot;First server message not server hello&quot;);
        SendAlert(ssl, alert_fatal, unexpected_message);
        WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
        return OUT_OF_ORDER_E;
    }

    if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp;
               ssl-&gt;options.clientState == NULL_STATE &amp;&amp; type != client_hello) {
        WOLFSSL_MSG(&quot;First client message not client hello&quot;);
        SendAlert(ssl, alert_fatal, unexpected_message);
        WOLFSSL_ERROR_VERBOSE(OUT_OF_ORDER_E);
        return OUT_OF_ORDER_E;
    }

    /* above checks handshake state */
    switch (type) {
#ifndef NO_WOLFSSL_CLIENT
    /* Messages only received by client. */
    case server_hello:
        WOLFSSL_MSG(&quot;processing server hello&quot;);
        ret = DoTls13ServerHello(ssl, input, inOutIdx, size, &amp;type);
    #if !defined(WOLFSSL_NO_CLIENT_AUTH) &amp;&amp; \
               ((defined(HAVE_ED25519) &amp;&amp; !defined(NO_ED25519_CLIENT_AUTH)) || \
                (defined(HAVE_ED448) &amp;&amp; !defined(NO_ED448_CLIENT_AUTH)))
        if (ssl-&gt;options.resuming || !IsAtLeastTLSv1_2(ssl) ||
                                               IsAtLeastTLSv1_3(ssl-&gt;version)) {
            ssl-&gt;options.cacheMessages = 0;
            if ((ssl-&gt;hsHashes != NULL) &amp;&amp; (ssl-&gt;hsHashes-&gt;messages != NULL)) {
                ForceZero(ssl-&gt;hsHashes-&gt;messages, ssl-&gt;hsHashes-&gt;length);
                XFREE(ssl-&gt;hsHashes-&gt;messages, ssl-&gt;heap, DYNAMIC_TYPE_HASHES);
                ssl-&gt;hsHashes-&gt;messages = NULL;
            }
        }
    #endif
        break;

    case encrypted_extensions:
        WOLFSSL_MSG(&quot;processing encrypted extensions&quot;);
        ret = DoTls13EncryptedExtensions(ssl, input, inOutIdx, size);
        break;

    #ifndef NO_CERTS
    case certificate_request:
        WOLFSSL_MSG(&quot;processing certificate request&quot;);
        ret = DoTls13CertificateRequest(ssl, input, inOutIdx, size);
        break;
    #endif

    case session_ticket:
        WOLFSSL_MSG(&quot;processing new session ticket&quot;);
        ret = DoTls13NewSessionTicket(ssl, input, inOutIdx, size);
        break;
#endif /* !NO_WOLFSSL_CLIENT */

#ifndef NO_WOLFSSL_SERVER
    /* Messages only received by server. */
    case client_hello:
        WOLFSSL_MSG(&quot;processing client hello&quot;);
#if defined(HAVE_ECH)
        /* keep the start idx so we can restore it for the inner call */
        echInOutIdx = *inOutIdx;
#endif
        ret = DoTls13ClientHello(ssl, input, inOutIdx, size);
    #if !defined(WOLFSSL_NO_CLIENT_AUTH) &amp;&amp; \
               ((defined(HAVE_ED25519) &amp;&amp; !defined(NO_ED25519_CLIENT_AUTH)) || \
                (defined(HAVE_ED448) &amp;&amp; !defined(NO_ED448_CLIENT_AUTH)))
        if ((ssl-&gt;options.resuming || !ssl-&gt;options.verifyPeer ||
               !IsAtLeastTLSv1_2(ssl) || IsAtLeastTLSv1_3(ssl-&gt;version))
        #ifdef WOLFSSL_DTLS13
               &amp;&amp; (!ssl-&gt;options.dtls)
        #endif
               ) {
        #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLFSSL_NONBLOCK_OCSP)
            if (ret != WC_NO_ERR_TRACE(WC_PENDING_E) &amp;&amp;
                ret != WC_NO_ERR_TRACE(OCSP_WANT_READ))
        #endif
            {
                ssl-&gt;options.cacheMessages = 0;
                if ((ssl-&gt;hsHashes != NULL) &amp;&amp;
                        (ssl-&gt;hsHashes-&gt;messages != NULL)) {
                    ForceZero(ssl-&gt;hsHashes-&gt;messages, ssl-&gt;hsHashes-&gt;length);
                    XFREE(ssl-&gt;hsHashes-&gt;messages, ssl-&gt;heap,
                        DYNAMIC_TYPE_HASHES);
                    ssl-&gt;hsHashes-&gt;messages = NULL;
                }
            }
        }
    #endif
#if defined(HAVE_ECH)
        if (ret == 0) {
            echX = TLSX_Find(ssl-&gt;extensions, TLSX_ECH);

            if (echX != NULL &amp;&amp;
                ((WOLFSSL_ECH*)echX-&gt;data)-&gt;state == ECH_WRITE_NONE) {

                /* reset the inOutIdx to the outer start */
                *inOutIdx = echInOutIdx;

                /* call again with the inner hello */
                ret = DoTls13ClientHello(ssl,
                    ((WOLFSSL_ECH*)echX-&gt;data)-&gt;innerClientHello,
                    &amp;echInOutIdx,
                    ((WOLFSSL_ECH*)echX-&gt;data)-&gt;innerClientHelloLen);

                /* if the inner ech parsed successfully we have successfully
                 * handled the hello and can skip the whole message */
                if (ret == 0)
                    *inOutIdx += size;
            }
        }
#endif /* HAVE_ECH */
        break;

    #ifdef WOLFSSL_EARLY_DATA
    case end_of_early_data:
        WOLFSSL_MSG(&quot;processing end of early data&quot;);
        ret = DoTls13EndOfEarlyData(ssl, input, inOutIdx, size);
        break;
    #endif
#endif /* !NO_WOLFSSL_SERVER */

    /* Messages received by both client and server. */
#if !defined(NO_CERTS) &amp;&amp; (!defined(NO_WOLFSSL_CLIENT) || \
                           !defined(WOLFSSL_NO_CLIENT_AUTH))
    case certificate:
        WOLFSSL_MSG(&quot;processing certificate&quot;);
        ret = DoTls13Certificate(ssl, input, inOutIdx, size);
        break;
#endif

#if !defined(NO_RSA) || defined(HAVE_ECC) || defined(HAVE_ED25519) || \
    defined(HAVE_ED448) || defined(HAVE_FALCON) || defined(HAVE_DILITHIUM)
    case certificate_verify:
        WOLFSSL_MSG(&quot;processing certificate verify&quot;);
        ret = DoTls13CertificateVerify(ssl, input, inOutIdx, size);
        break;
#endif
    case finished:
        WOLFSSL_MSG(&quot;processing finished&quot;);
        ret = DoTls13Finished(ssl, input, inOutIdx, size, totalSz, NO_SNIFF);
        break;

    case key_update:
        WOLFSSL_MSG(&quot;processing key update&quot;);
        ret = DoTls13KeyUpdate(ssl, input, inOutIdx, size);
        break;

#if defined(WOLFSSL_DTLS13) &amp;&amp; !defined(WOLFSSL_NO_TLS12) &amp;&amp; \
    !defined(NO_WOLFSSL_CLIENT)
    case hello_verify_request:
        WOLFSSL_MSG(&quot;processing hello verify request&quot;);
        ret = DoHelloVerifyRequest(ssl, input, inOutIdx, size);
        break;
#endif
    default:
        WOLFSSL_MSG(&quot;Unknown handshake message type&quot;);
        ret = UNKNOWN_HANDSHAKE_TYPE;
        break;
    }

#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLFSSL_ASYNC_IO)
    /* if async, offset index so this msg will be processed again */
    /* NOTE: check this now before other calls can overwrite ret */
    if ((ret == WC_NO_ERR_TRACE(WC_PENDING_E) ||
         ret == WC_NO_ERR_TRACE(OCSP_WANT_READ)) &amp;&amp; *inOutIdx &gt; 0) {
        /* DTLS always stores a message in a buffer when async is enable, so we
         * don&#039;t need to adjust for the extra bytes here (*inOutIdx is always
         * == 0) */
        *inOutIdx -= HANDSHAKE_HEADER_SZ;
    }

    /* make sure async error is cleared */
    if (ret == 0 &amp;&amp;
        (ssl-&gt;error == WC_NO_ERR_TRACE(WC_PENDING_E) ||
         ssl-&gt;error == WC_NO_ERR_TRACE(OCSP_WANT_READ))) {
        ssl-&gt;error = 0;
    }
#endif
    if (ret == 0 &amp;&amp; type != client_hello &amp;&amp; type != session_ticket &amp;&amp;
                                                           type != key_update) {
        ret = HashInput(ssl, input + inIdx, (int)size);
    }

    alertType = TranslateErrorToAlert(ret);

    if (alertType != invalid_alert) {
#ifdef WOLFSSL_DTLS13
        if (type == client_hello &amp;&amp; ssl-&gt;options.dtls)
            DtlsSetSeqNumForReply(ssl);
#endif
        tmp = SendAlert(ssl, alert_fatal, alertType);
        /* propagate socket error instead of tls error to be sure the error is
         * not ignored by DTLS code */
        if (tmp == WC_NO_ERR_TRACE(SOCKET_ERROR_E))
            ret = SOCKET_ERROR_E;
    }

    if (ret == 0 &amp;&amp; ssl-&gt;options.tls1_3) {
        /* Need to hash input message before deriving secrets. */
    #ifndef NO_WOLFSSL_CLIENT
        if (ssl-&gt;options.side == WOLFSSL_CLIENT_END) {
            if (type == server_hello) {
                if ((ret = DeriveEarlySecret(ssl)) != 0)
                    return ret;
                if ((ret = DeriveHandshakeSecret(ssl)) != 0)
                    return ret;

                if ((ret = DeriveTls13Keys(ssl, handshake_key,
                                        ENCRYPT_AND_DECRYPT_SIDE, 1)) != 0) {
                    return ret;
                }
        #ifdef WOLFSSL_EARLY_DATA
                if (ssl-&gt;earlyData != no_early_data) {
                    if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
                        return ret;
                }
                else
        #endif
                if ((ret = SetKeysSide(ssl, ENCRYPT_AND_DECRYPT_SIDE)) != 0)
                    return ret;

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    w64wrapper epochHandshake;
                    epochHandshake = w64From32(0, DTLS13_EPOCH_HANDSHAKE);
                    ssl-&gt;dtls13Epoch = epochHandshake;
                    ssl-&gt;dtls13PeerEpoch = epochHandshake;

                    ret = Dtls13NewEpoch(
                        ssl, epochHandshake, ENCRYPT_AND_DECRYPT_SIDE);
                    if (ret != 0)
                        return ret;

                    ret = Dtls13SetEpochKeys(
                        ssl, epochHandshake, ENCRYPT_AND_DECRYPT_SIDE);
                    if (ret != 0)
                        return ret;

                }
#endif /* WOLFSSL_DTLS13 */
            }

            if (type == finished) {
                if ((ret = DeriveMasterSecret(ssl)) != 0)
                    return ret;
                /* Last use of preMasterSecret - zeroize as soon as possible. */
                ForceZero(ssl-&gt;arrays-&gt;preMasterSecret,
                    ssl-&gt;arrays-&gt;preMasterSz);
        #ifdef WOLFSSL_EARLY_DATA
        #ifdef WOLFSSL_QUIC
                if (WOLFSSL_IS_QUIC(ssl) &amp;&amp; ssl-&gt;earlyData != no_early_data) {
                    /* QUIC never sends/receives EndOfEarlyData, but having
                     * early data means the last encryption keys had not been
                     * set yet. */
                    if ((ret = SetKeysSide(ssl, ENCRYPT_SIDE_ONLY)) != 0)
                        return ret;
                }
        #endif
                if ((ret = DeriveTls13Keys(ssl, traffic_key,
                                    ENCRYPT_AND_DECRYPT_SIDE,
                                    ssl-&gt;earlyData == no_early_data)) != 0) {
                    return ret;
                }
                if (ssl-&gt;earlyData != no_early_data) {
                    if ((ret = DeriveTls13Keys(ssl, no_key, DECRYPT_SIDE_ONLY,
                                                                  1)) != 0) {
                            return ret;
                    }
                }
        #else
                if ((ret = DeriveTls13Keys(ssl, traffic_key,
                                        ENCRYPT_AND_DECRYPT_SIDE, 1)) != 0) {
                    return ret;
                }
        #endif
                /* Setup keys for application data messages. */
                if ((ret = SetKeysSide(ssl, DECRYPT_SIDE_ONLY)) != 0)
                    return ret;
            }
        #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
            if (type == certificate_request &amp;&amp;
                                ssl-&gt;options.handShakeState == HANDSHAKE_DONE) {
                /* reset handshake states */
                ssl-&gt;options.clientState = CLIENT_HELLO_COMPLETE;
                ssl-&gt;options.connectState  = FIRST_REPLY_DONE;
                ssl-&gt;options.handShakeState = CLIENT_HELLO_COMPLETE;
                ssl-&gt;options.processReply = 0; /* doProcessInit */

                /*
                   DTLSv1.3 note: We can&#039;t reset serverState to
                   SERVER_FINISHED_COMPLETE with the goal that this connect
                   blocks until the cert/cert_verify/finished flight gets ACKed
                   by the server. The problem is that we will invoke
                   ProcessReplyEx() in that case, but we came here from
                   ProcessReplyEx() and it is not re-entrant safe (the input
                   buffer would still have the certificate_request message). */

                if (wolfSSL_connect_TLSv13(ssl) != WOLFSSL_SUCCESS) {
                    ret = ssl-&gt;error;
                    if (ret != WC_NO_ERR_TRACE(WC_PENDING_E))
                        ret = POST_HAND_AUTH_ERROR;
                }
            }
        #endif
        }
    #endif /* NO_WOLFSSL_CLIENT */

#ifndef NO_WOLFSSL_SERVER
    #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
        if (ssl-&gt;options.side == WOLFSSL_SERVER_END &amp;&amp; type == finished) {
            ret = DeriveResumptionSecret(ssl, ssl-&gt;session-&gt;masterSecret);
            if (ret != 0)
                return ret;
        }
    #endif
#endif /* NO_WOLFSSL_SERVER */
    }

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls &amp;&amp; !ssl-&gt;options.dtlsStateful) {
        DtlsResetState(ssl);
        if (DtlsIgnoreError(ret))
            ret = 0;
    }
#endif

    WOLFSSL_LEAVE(&quot;DoTls13HandShakeMsgType()&quot;, ret);
    return ret;
}


/* Handle a handshake message that has been received.
 *
 * ssl       The SSL/TLS object.
 * input     The message buffer.
 * inOutIdx  On entry, the index into the buffer of the current message.
 *           On exit, the index into the buffer of the next message.
 * totalSz   Length of remaining data in the message buffer.
 * returns 0 on success and otherwise failure.
 */
int DoTls13HandShakeMsg(WOLFSSL* ssl, byte* input, word32* inOutIdx,
                        word32 totalSz)
{
    int    ret = 0;
    word32 inputLength;
    byte   type;
    word32 size = 0;

    WOLFSSL_ENTER(&quot;DoTls13HandShakeMsg&quot;);

    if (ssl-&gt;arrays == NULL) {
        if (GetHandshakeHeader(ssl, input, inOutIdx, &amp;type, &amp;size,
                                                                totalSz) != 0) {
            SendAlert(ssl, alert_fatal, unexpected_message);
            WOLFSSL_ERROR_VERBOSE(PARSE_ERROR);
            return PARSE_ERROR;
        }

        ret = EarlySanityCheckMsgReceived(ssl, type, size);
        if (ret != 0) {
            WOLFSSL_ERROR(ret);
            return ret;
        }

        return DoTls13HandShakeMsgType(ssl, input, inOutIdx, type, size,
                                       totalSz);
    }

    inputLength = ssl-&gt;buffers.inputBuffer.length - *inOutIdx - ssl-&gt;keys.padSz;

    /* If there is a pending fragmented handshake message,
     * pending message size will be non-zero. */
    if (ssl-&gt;arrays-&gt;pendingMsgSz == 0) {

        if (GetHandshakeHeader(ssl, input, inOutIdx, &amp;type, &amp;size,
                               totalSz) != 0) {
            WOLFSSL_ERROR_VERBOSE(PARSE_ERROR);
            return PARSE_ERROR;
        }

        ret = EarlySanityCheckMsgReceived(ssl, type,
                min(inputLength - HANDSHAKE_HEADER_SZ, size));
        if (ret != 0) {
            WOLFSSL_ERROR(ret);
            return ret;
        }

        /* Cap the maximum size of a handshake message to something reasonable.
         * By default is the maximum size of a certificate message assuming
         * nine 2048-bit RSA certificates in the chain. */
        if (size &gt; MAX_HANDSHAKE_SZ) {
            WOLFSSL_MSG(&quot;Handshake message too large&quot;);
            WOLFSSL_ERROR_VERBOSE(HANDSHAKE_SIZE_ERROR);
            return HANDSHAKE_SIZE_ERROR;
        }

        /* size is the size of the certificate message payload */
        if (inputLength - HANDSHAKE_HEADER_SZ &lt; size) {
            ssl-&gt;arrays-&gt;pendingMsgType = type;
            ssl-&gt;arrays-&gt;pendingMsgSz = size + HANDSHAKE_HEADER_SZ;
            ssl-&gt;arrays-&gt;pendingMsg = (byte*)XMALLOC(size + HANDSHAKE_HEADER_SZ,
                                                     ssl-&gt;heap,
                                                     DYNAMIC_TYPE_ARRAYS);
            if (ssl-&gt;arrays-&gt;pendingMsg == NULL)
                return MEMORY_E;
            XMEMCPY(ssl-&gt;arrays-&gt;pendingMsg,
                    input + *inOutIdx - HANDSHAKE_HEADER_SZ,
                    inputLength);
            ssl-&gt;arrays-&gt;pendingMsgOffset = inputLength;
            *inOutIdx += inputLength + ssl-&gt;keys.padSz - HANDSHAKE_HEADER_SZ;
            return 0;
        }

        ret = DoTls13HandShakeMsgType(ssl, input, inOutIdx, type, size,
                                      totalSz);
    }
    else {
        if (inputLength + ssl-&gt;arrays-&gt;pendingMsgOffset &gt;
                                                    ssl-&gt;arrays-&gt;pendingMsgSz) {
            inputLength = ssl-&gt;arrays-&gt;pendingMsgSz -
                                                  ssl-&gt;arrays-&gt;pendingMsgOffset;
        }

        ret = EarlySanityCheckMsgReceived(ssl, ssl-&gt;arrays-&gt;pendingMsgType,
                inputLength);
        if (ret != 0) {
            WOLFSSL_ERROR(ret);
            return ret;
        }

        XMEMCPY(ssl-&gt;arrays-&gt;pendingMsg + ssl-&gt;arrays-&gt;pendingMsgOffset,
                input + *inOutIdx, inputLength);
        ssl-&gt;arrays-&gt;pendingMsgOffset += inputLength;
        *inOutIdx += inputLength + ssl-&gt;keys.padSz;

        if (ssl-&gt;arrays-&gt;pendingMsgOffset == ssl-&gt;arrays-&gt;pendingMsgSz)
        {
            word32 idx = 0;
            ret = DoTls13HandShakeMsgType(ssl,
                                ssl-&gt;arrays-&gt;pendingMsg + HANDSHAKE_HEADER_SZ,
                                &amp;idx, ssl-&gt;arrays-&gt;pendingMsgType,
                                ssl-&gt;arrays-&gt;pendingMsgSz - HANDSHAKE_HEADER_SZ,
                                ssl-&gt;arrays-&gt;pendingMsgSz);
        #ifdef WOLFSSL_ASYNC_CRYPT
            if (ret == WC_NO_ERR_TRACE(WC_PENDING_E)) {
                /* setup to process fragment again */
                ssl-&gt;arrays-&gt;pendingMsgOffset -= inputLength;
                *inOutIdx -= inputLength + ssl-&gt;keys.padSz;
            }
            else
        #endif
            {
                XFREE(ssl-&gt;arrays-&gt;pendingMsg, ssl-&gt;heap, DYNAMIC_TYPE_ARRAYS);
                ssl-&gt;arrays-&gt;pendingMsg = NULL;
                ssl-&gt;arrays-&gt;pendingMsgSz = 0;
            }
        }
    }

    WOLFSSL_LEAVE(&quot;DoTls13HandShakeMsg&quot;, ret);
    return ret;
}

#ifndef NO_WOLFSSL_CLIENT

/* The client connecting to the server.
 * The protocol version is expecting to be TLS v1.3.
 * If the server downgrades, and older versions of the protocol are compiled
 * in, the client will fallback to wolfSSL_connect().
 * Please see note at top of README if you get an error from connect.
 *
 * ssl  The SSL/TLS object.
 * returns WOLFSSL_SUCCESS on successful handshake, WOLFSSL_FATAL_ERROR when
 * unrecoverable error occurs and 0 otherwise.
 * For more error information use wolfSSL_get_error().
 */
int wolfSSL_connect_TLSv13(WOLFSSL* ssl)
{
    int advanceState;
    int ret = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_connect_TLSv13&quot;);

#ifdef HAVE_ERRNO_H
    errno = 0;
#endif

    if (ssl == NULL)
        return BAD_FUNC_ARG;

    if (ssl-&gt;options.side != WOLFSSL_CLIENT_END) {
        ssl-&gt;error = SIDE_ERROR;
        WOLFSSL_ERROR(ssl-&gt;error);
        return WOLFSSL_FATAL_ERROR;
    }

    /* make sure this wolfSSL object has arrays and rng setup. Protects
     * case where the WOLFSSL object is reused via wolfSSL_clear() */
    if ((ret = ReinitSSL(ssl, ssl-&gt;ctx, 0)) != 0) {
        return ret;
    }

#ifdef WOLFSSL_DTLS
    if (ssl-&gt;version.major == DTLS_MAJOR) {
        ssl-&gt;options.dtls   = 1;
        ssl-&gt;options.dtlsStateful = 1;
    }
#endif

#ifdef WOLFSSL_WOLFSENTRY_HOOKS
    if ((ssl-&gt;ConnectFilter != NULL) &amp;&amp;
        (ssl-&gt;options.connectState == CONNECT_BEGIN))
    {
        wolfSSL_netfilter_decision_t res;
        if ((ssl-&gt;ConnectFilter(ssl, ssl-&gt;ConnectFilter_arg, &amp;res) ==
             WOLFSSL_SUCCESS) &amp;&amp;
            (res == WOLFSSL_NETFILTER_REJECT)) {
            ssl-&gt;error = SOCKET_FILTERED_E;
            WOLFSSL_ERROR(ssl-&gt;error);
            return WOLFSSL_FATAL_ERROR;
        }
    }
#endif /* WOLFSSL_WOLFSENTRY_HOOKS */

    /* fragOffset is non-zero when sending fragments. On the last
     * fragment, fragOffset is zero again, and the state can be
     * advanced. Also, only advance from states in which we send data */
    advanceState = (ssl-&gt;options.connectState == CONNECT_BEGIN ||
            ssl-&gt;options.connectState == HELLO_AGAIN ||
            (ssl-&gt;options.connectState &gt;= FIRST_REPLY_DONE &amp;&amp;
             ssl-&gt;options.connectState &lt;= FIRST_REPLY_FOURTH));

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls)
        advanceState = advanceState &amp;&amp; !ssl-&gt;dtls13SendingFragments
            &amp;&amp; !ssl-&gt;dtls13SendingAckOrRtx;
#endif /* WOLFSSL_DTLS13 */

    if (ssl-&gt;buffers.outputBuffer.length &gt; 0
    #ifdef WOLFSSL_ASYNC_CRYPT
        /* do not send buffered or advance state if last error was an
            async pending operation */
        &amp;&amp; ssl-&gt;error != WC_NO_ERR_TRACE(WC_PENDING_E)
    #endif
    ) {
        if ((ret = SendBuffered(ssl)) == 0) {
            if (ssl-&gt;fragOffset == 0 &amp;&amp; !ssl-&gt;options.buildingMsg) {
                if (advanceState) {
#ifdef WOLFSSL_DTLS13
                    if (ssl-&gt;options.dtls &amp;&amp; IsAtLeastTLSv1_3(ssl-&gt;version) &amp;&amp;
                        ssl-&gt;options.connectState == FIRST_REPLY_FOURTH) {
                    /* WAIT_FINISHED_ACK is a state added afterwards, but it
                       can&#039;t follow FIRST_REPLY_FOURTH in the enum order. Indeed
                       the value of the enum ConnectState is stored in
                       serialized session. This would make importing serialized
                       session from other wolfSSL version incompatible */
                        ssl-&gt;options.connectState = WAIT_FINISHED_ACK;
                    }
                    else
#endif /* WOLFSSL_DTLS13 */
                    {
                        ssl-&gt;options.connectState++;
                    }
                    WOLFSSL_MSG(&quot;connect state: &quot;
                                &quot;Advanced from last buffered fragment send&quot;);
#ifdef WOLFSSL_ASYNC_IO
                    FreeAsyncCtx(ssl, 0);
#endif

                }
            }
            else {
                WOLFSSL_MSG(&quot;connect state: &quot;
                            &quot;Not advanced, more fragments to send&quot;);
            }
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls)
                ssl-&gt;dtls13SendingAckOrRtx = 0;
#endif /* WOLFSSL_DTLS13 */

        }
        else {
            ssl-&gt;error = ret;
            WOLFSSL_ERROR(ssl-&gt;error);
            return WOLFSSL_FATAL_ERROR;
        }
    }

    ret = RetrySendAlert(ssl);
    if (ret != 0) {
        ssl-&gt;error = ret;
        WOLFSSL_ERROR(ssl-&gt;error);
        return WOLFSSL_FATAL_ERROR;
    }

#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;dtls13SendingFragments) {
        if ((ssl-&gt;error = Dtls13FragmentsContinue(ssl)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
        }

        /* we sent all the fragments. Advance state. */
        ssl-&gt;options.connectState++;
    }
#endif /* WOLFSSL_DTLS13 */

    switch (ssl-&gt;options.connectState) {

        case CONNECT_BEGIN:
            /* Always send client hello first. */
            if ((ssl-&gt;error = SendTls13ClientHello(ssl)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }

            ssl-&gt;options.connectState = CLIENT_HELLO_SENT;
            WOLFSSL_MSG(&quot;TLSv13 connect state: CLIENT_HELLO_SENT&quot;);
    #ifdef WOLFSSL_EARLY_DATA
            if (ssl-&gt;earlyData != no_early_data) {
        #if defined(WOLFSSL_TLS13_MIDDLEBOX_COMPAT)
                if (!ssl-&gt;options.dtls &amp;&amp; ssl-&gt;options.tls13MiddleBoxCompat) {
                    if ((ssl-&gt;error = SendChangeCipher(ssl)) != 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                    ssl-&gt;options.sentChangeCipher = 1;
                }
        #endif
            ssl-&gt;options.handShakeState = CLIENT_HELLO_COMPLETE;
            return WOLFSSL_SUCCESS;
            }
    #endif
            FALL_THROUGH;

        case CLIENT_HELLO_SENT:
            /* Get the response/s from the server. */
            while (ssl-&gt;options.serverState &lt;
                    SERVER_HELLOVERIFYREQUEST_COMPLETE) {
                if ((ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                }

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
#endif /* WOLFSSL_DTLS13 */
            }

            if (!ssl-&gt;options.tls1_3) {
    #ifndef WOLFSSL_NO_TLS12
                if (ssl-&gt;options.downgrade)
                    return wolfSSL_connect(ssl);
    #endif
                WOLFSSL_MSG(&quot;Client using higher version, fatal error&quot;);
                WOLFSSL_ERROR_VERBOSE(VERSION_ERROR);
                return VERSION_ERROR;
            }

            ssl-&gt;options.connectState = HELLO_AGAIN;
            WOLFSSL_MSG(&quot;connect state: HELLO_AGAIN&quot;);
            FALL_THROUGH;

        case HELLO_AGAIN:

            if (ssl-&gt;options.serverState ==
                                          SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
        #if defined(WOLFSSL_TLS13_MIDDLEBOX_COMPAT)
                if (!ssl-&gt;options.dtls &amp;&amp; !ssl-&gt;options.sentChangeCipher
                    &amp;&amp; ssl-&gt;options.tls13MiddleBoxCompat) {
                    if ((ssl-&gt;error = SendChangeCipher(ssl)) != 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                    ssl-&gt;options.sentChangeCipher = 1;
                }
        #endif
                /* Try again with different security parameters. */
                if ((ssl-&gt;error = SendTls13ClientHello(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }

            ssl-&gt;options.connectState = HELLO_AGAIN_REPLY;
            WOLFSSL_MSG(&quot;connect state: HELLO_AGAIN_REPLY&quot;);
            FALL_THROUGH;

        case HELLO_AGAIN_REPLY:
            /* Get the response/s from the server. */
            while (ssl-&gt;options.serverState &lt; SERVER_FINISHED_COMPLETE) {
#ifdef WOLFSSL_DTLS13
                if (!IsAtLeastTLSv1_3(ssl-&gt;version)) {
        #ifndef WOLFSSL_NO_TLS12
                    if (ssl-&gt;options.downgrade)
                        return wolfSSL_connect(ssl);
        #endif
                }
#endif /* WOLFSSL_DTLS13 */
                if ((ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                }

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
#endif /* WOLFSSL_DTLS13 */
            }

            ssl-&gt;options.connectState = FIRST_REPLY_DONE;
            WOLFSSL_MSG(&quot;connect state: FIRST_REPLY_DONE&quot;);
            FALL_THROUGH;

        case FIRST_REPLY_DONE:
            if (ssl-&gt;options.certOnly)
                return WOLFSSL_SUCCESS;
        #ifdef WOLFSSL_EARLY_DATA
            if (!ssl-&gt;options.dtls &amp;&amp; ssl-&gt;earlyData != no_early_data
                &amp;&amp; !WOLFSSL_IS_QUIC(ssl)) {
                if ((ssl-&gt;error = SendTls13EndOfEarlyData(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                WOLFSSL_MSG(&quot;sent: end_of_early_data&quot;);
            }
        #endif

            ssl-&gt;options.connectState = FIRST_REPLY_FIRST;
            WOLFSSL_MSG(&quot;connect state: FIRST_REPLY_FIRST&quot;);
            FALL_THROUGH;

        case FIRST_REPLY_FIRST:
        #if defined(WOLFSSL_TLS13_MIDDLEBOX_COMPAT)
            if (!ssl-&gt;options.sentChangeCipher &amp;&amp; !ssl-&gt;options.dtls
                &amp;&amp; ssl-&gt;options.tls13MiddleBoxCompat) {
                if ((ssl-&gt;error = SendChangeCipher(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                ssl-&gt;options.sentChangeCipher = 1;
            }
        #endif

            ssl-&gt;options.connectState = FIRST_REPLY_SECOND;
            WOLFSSL_MSG(&quot;connect state: FIRST_REPLY_SECOND&quot;);
            FALL_THROUGH;

        case FIRST_REPLY_SECOND:
            /* CLIENT: check peer authentication. */
            if (!ssl-&gt;options.peerAuthGood) {
                WOLFSSL_MSG(&quot;Server authentication did not happen&quot;);
                WOLFSSL_ERROR_VERBOSE(WOLFSSL_FATAL_ERROR);
                return WOLFSSL_FATAL_ERROR;
            }
        #ifndef NO_CERTS
            if (!ssl-&gt;options.resuming &amp;&amp; ssl-&gt;options.sendVerify) {
                ssl-&gt;error = SendTls13Certificate(ssl);
                if (ssl-&gt;error != 0) {
                #ifdef WOLFSSL_CHECK_ALERT_ON_ERR
                    ProcessReplyEx(ssl, 1); /* See if an alert was sent. */
                #endif
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                WOLFSSL_MSG(&quot;sent: certificate&quot;);
            }
        #endif

            ssl-&gt;options.connectState = FIRST_REPLY_THIRD;
            WOLFSSL_MSG(&quot;connect state: FIRST_REPLY_THIRD&quot;);
            FALL_THROUGH;

        case FIRST_REPLY_THIRD:
        #if (!defined(NO_CERTS) &amp;&amp; (!defined(NO_RSA) || defined(HAVE_ECC) || \
             defined(HAVE_ED25519) || defined(HAVE_ED448) || \
             defined(HAVE_FALCON) || defined(HAVE_DILITHIUM))) &amp;&amp; \
             (!defined(NO_WOLFSSL_SERVER) || !defined(WOLFSSL_NO_CLIENT_AUTH))
            if (!ssl-&gt;options.resuming &amp;&amp; ssl-&gt;options.sendVerify) {
                ssl-&gt;error = SendTls13CertificateVerify(ssl);
                if (ssl-&gt;error != 0) {
                #ifdef WOLFSSL_CHECK_ALERT_ON_ERR
                    ProcessReplyEx(ssl, 1); /* See if an alert was sent. */
                #endif
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                WOLFSSL_MSG(&quot;sent: certificate verify&quot;);
            }
        #endif

            ssl-&gt;options.connectState = FIRST_REPLY_FOURTH;
            WOLFSSL_MSG(&quot;connect state: FIRST_REPLY_FOURTH&quot;);
            FALL_THROUGH;

        case FIRST_REPLY_FOURTH:
            if ((ssl-&gt;error = SendTls13Finished(ssl)) != 0) {
            #ifdef WOLFSSL_CHECK_ALERT_ON_ERR
                ProcessReplyEx(ssl, 1); /* See if an alert was sent. */
            #endif
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }
            WOLFSSL_MSG(&quot;sent: finished&quot;);

#ifdef WOLFSSL_DTLS13
            ssl-&gt;options.connectState = WAIT_FINISHED_ACK;
            WOLFSSL_MSG(&quot;connect state: WAIT_FINISHED_ACK&quot;);
            FALL_THROUGH;

        case WAIT_FINISHED_ACK:
            if (ssl-&gt;options.dtls) {
                while (ssl-&gt;options.serverState != SERVER_FINISHED_ACKED) {
                    if ((ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }

                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
            }
#endif /* WOLFSSL_DTLS13 */
            ssl-&gt;options.connectState = FINISHED_DONE;
            WOLFSSL_MSG(&quot;connect state: FINISHED_DONE&quot;);
            FALL_THROUGH;

        case FINISHED_DONE:
        #ifndef NO_HANDSHAKE_DONE_CB
            if (ssl-&gt;hsDoneCb != NULL) {
                int cbret = ssl-&gt;hsDoneCb(ssl, ssl-&gt;hsDoneCtx);
                if (cbret &lt; 0) {
                    ssl-&gt;error = cbret;
                    WOLFSSL_ERROR_VERBOSE(ssl-&gt;error);
                    WOLFSSL_MSG(&quot;HandShake Done Cb don&#039;t continue error&quot;);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
        #endif /* NO_HANDSHAKE_DONE_CB */

            if (!ssl-&gt;options.keepResources) {
                FreeHandshakeResources(ssl);
            }
        #if defined(WOLFSSL_ASYNC_IO) &amp;&amp; !defined(WOLFSSL_ASYNC_CRYPT)
            /* Free the remaining async context if not using it for crypto */
            FreeAsyncCtx(ssl, 1);
        #endif

            ssl-&gt;error = 0; /* clear the error */

            WOLFSSL_LEAVE(&quot;wolfSSL_connect_TLSv13&quot;, WOLFSSL_SUCCESS);
            return WOLFSSL_SUCCESS;

        default:
            WOLFSSL_MSG(&quot;Unknown connect state ERROR&quot;);
            return WOLFSSL_FATAL_ERROR; /* unknown connect state */
    }
}
#endif

#if defined(WOLFSSL_SEND_HRR_COOKIE)
/* Send a cookie with the HelloRetryRequest to avoid storing state.
 *
 * ssl       SSL/TLS object.
 * secret    Secret to use when generating integrity check for cookie.
 *           A value of NULL indicates to generate a new random secret.
 * secretSz  Size of secret data in bytes.
 *           Use a value of 0 to indicate use of default size.
 * returns BAD_FUNC_ARG when ssl is NULL or not using TLS v1.3, SIDE_ERROR when
 * called on a client; WOLFSSL_SUCCESS on success and otherwise failure.
 */
int wolfSSL_send_hrr_cookie(WOLFSSL* ssl, const unsigned char* secret,
                            unsigned int secretSz)
{
    int ret;

    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
 #ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

    if (secretSz == 0) {
    #if !defined(NO_SHA) &amp;&amp; defined(NO_SHA256)
        secretSz = WC_SHA_DIGEST_SIZE;
    #endif /* NO_SHA */
    #ifndef NO_SHA256
        secretSz = WC_SHA256_DIGEST_SIZE;
    #endif /* NO_SHA256 */
    }

    if (secretSz != ssl-&gt;buffers.tls13CookieSecret.length) {
        byte* newSecret;

        if (ssl-&gt;buffers.tls13CookieSecret.buffer != NULL) {
            ForceZero(ssl-&gt;buffers.tls13CookieSecret.buffer,
                      ssl-&gt;buffers.tls13CookieSecret.length);
            XFREE(ssl-&gt;buffers.tls13CookieSecret.buffer,
                  ssl-&gt;heap, DYNAMIC_TYPE_COOKIE_PWD);
        }

        newSecret = (byte*)XMALLOC(secretSz, ssl-&gt;heap,
                                   DYNAMIC_TYPE_COOKIE_PWD);
        if (newSecret == NULL) {
            ssl-&gt;buffers.tls13CookieSecret.buffer = NULL;
            ssl-&gt;buffers.tls13CookieSecret.length = 0;
            WOLFSSL_MSG(&quot;couldn&#039;t allocate new cookie secret&quot;);
            return MEMORY_ERROR;
        }
        ssl-&gt;buffers.tls13CookieSecret.buffer = newSecret;
        ssl-&gt;buffers.tls13CookieSecret.length = secretSz;
    #ifdef WOLFSSL_CHECK_MEM_ZERO
        wc_MemZero_Add(&quot;wolfSSL_send_hrr_cookie secret&quot;,
            ssl-&gt;buffers.tls13CookieSecret.buffer,
            ssl-&gt;buffers.tls13CookieSecret.length);
    #endif
    }

    /* If the supplied secret is NULL, randomly generate a new secret. */
    if (secret == NULL) {
        ret = wc_RNG_GenerateBlock(ssl-&gt;rng,
                               ssl-&gt;buffers.tls13CookieSecret.buffer, secretSz);
        if (ret &lt; 0)
            return ret;
    }
    else
        XMEMCPY(ssl-&gt;buffers.tls13CookieSecret.buffer, secret, secretSz);

    ssl-&gt;options.sendCookie = 1;

    ret = WOLFSSL_SUCCESS;
#else
    (void)secret;
    (void)secretSz;

    ret = SIDE_ERROR;
#endif

    return ret;
}

int wolfSSL_disable_hrr_cookie(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

#ifdef NO_WOLFSSL_SERVER
    return SIDE_ERROR;
#else
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

    if (ssl-&gt;buffers.tls13CookieSecret.buffer != NULL) {
        ForceZero(ssl-&gt;buffers.tls13CookieSecret.buffer,
            ssl-&gt;buffers.tls13CookieSecret.length);
        XFREE(ssl-&gt;buffers.tls13CookieSecret.buffer, ssl-&gt;heap,
            DYNAMIC_TYPE_COOKIE_PWD);
        ssl-&gt;buffers.tls13CookieSecret.buffer = NULL;
        ssl-&gt;buffers.tls13CookieSecret.length = 0;
    }

    ssl-&gt;options.sendCookie = 0;
    return WOLFSSL_SUCCESS;
#endif /* NO_WOLFSSL_SERVER */
}

#endif /* defined(WOLFSSL_SEND_HRR_COOKIE) */

#ifdef HAVE_SUPPORTED_CURVES
/* Create a key share entry from group.
 * Generates a key pair.
 *
 * ssl    The SSL/TLS object.
 * group  The named group.
 * returns 0 on success, otherwise failure.
 *   for async can return WC_PENDING_E and should be called again
 */
int wolfSSL_UseKeyShare(WOLFSSL* ssl, word16 group)
{
    int ret;

    if (ssl == NULL)
        return BAD_FUNC_ARG;

#ifdef WOLFSSL_ASYNC_CRYPT
    ret = wolfSSL_AsyncPop(ssl, NULL);
    if (ret != WC_NO_ERR_TRACE(WC_NO_PENDING_E)) {
        /* Check for error */
        if (ret &lt; 0)
            return ret;
    }
#endif

#if defined(WOLFSSL_HAVE_KYBER)
    if (WOLFSSL_NAMED_GROUP_IS_PQC(group)) {

        if (ssl-&gt;ctx != NULL &amp;&amp; ssl-&gt;ctx-&gt;method != NULL &amp;&amp;
            !IsAtLeastTLSv1_3(ssl-&gt;version)) {
            return BAD_FUNC_ARG;
        }

        if (ssl-&gt;options.side == WOLFSSL_SERVER_END) {
            /* If I am the server of a KEM connection, do not do keygen because
             * I&#039;m going to encapsulate with the client&#039;s public key. Note that
             * I might be the client and ssl-&gt;option.side has not been properly
             * set yet. In that case the KeyGen operation will be deferred to
             * connection time. */
            return WOLFSSL_SUCCESS;
        }
    }
#endif
#if defined(NO_TLS)
    (void)ret;
    (void)group;
#else
    ret = TLSX_KeyShare_Use(ssl, group, 0, NULL, NULL, &amp;ssl-&gt;extensions);
    if (ret != 0)
        return ret;
#endif /* NO_TLS */
    return WOLFSSL_SUCCESS;
}

/* Send no key share entries - use HelloRetryRequest to negotiate shared group.
 *
 * ssl    The SSL/TLS object.
 * returns 0 on success, otherwise failure.
 */
int wolfSSL_NoKeyShares(WOLFSSL* ssl)
{
    int ret;

    if (ssl == NULL)
        return BAD_FUNC_ARG;
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END)
        return SIDE_ERROR;
#if defined(NO_TLS)
    (void)ret;
#else
    ret = TLSX_KeyShare_Empty(ssl);
    if (ret != 0)
        return ret;
#endif /* NO_TLS */
    return WOLFSSL_SUCCESS;
}
#endif

#ifdef WOLFSSL_DUAL_ALG_CERTS
int wolfSSL_UseCKS(WOLFSSL* ssl, byte *sigSpec, word16 sigSpecSz)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;ctx-&gt;method-&gt;version) ||
        sigSpec == NULL || sigSpecSz == 0)
        return BAD_FUNC_ARG;

    ssl-&gt;sigSpec = sigSpec;
    ssl-&gt;sigSpecSz = sigSpecSz;
    return WOLFSSL_SUCCESS;
}

int wolfSSL_CTX_UseCKS(WOLFSSL_CTX* ctx, byte *sigSpec, word16 sigSpecSz)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version) ||
        sigSpec == NULL || sigSpecSz == 0)
        return BAD_FUNC_ARG;

    ctx-&gt;sigSpec = sigSpec;
    ctx-&gt;sigSpecSz = sigSpecSz;
    return WOLFSSL_SUCCESS;
}
#endif /* WOLFSSL_DUAL_ALG_CERTS */

/* Do not send a ticket after TLS v1.3 handshake for resumption.
 *
 * ctx  The SSL/TLS CTX object.
 * returns BAD_FUNC_ARG when ctx is NULL and 0 on success.
 */
int wolfSSL_CTX_no_ticket_TLSv13(WOLFSSL_CTX* ctx)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;
    if (ctx-&gt;method-&gt;side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

#ifdef HAVE_SESSION_TICKET
    ctx-&gt;noTicketTls13 = 1;
#endif

    return 0;
}

/* Do not send a ticket after TLS v1.3 handshake for resumption.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, not using TLS v1.3, or called on
 * a client and 0 on success.
 */
int wolfSSL_no_ticket_TLSv13(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

#ifdef HAVE_SESSION_TICKET
    ssl-&gt;options.noTicketTls13 = 1;
#endif

    return 0;
}

/* Disallow (EC)DHE key exchange when using pre-shared keys.
 *
 * ctx  The SSL/TLS CTX object.
 * returns BAD_FUNC_ARG when ctx is NULL and 0 on success.
 */
int wolfSSL_CTX_no_dhe_psk(WOLFSSL_CTX* ctx)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ctx-&gt;noPskDheKe = 1;
#endif

    return 0;
}

/* Disallow (EC)DHE key exchange when using pre-shared keys.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3 and 0 on
 * success.
 */
int wolfSSL_no_dhe_psk(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ssl-&gt;options.noPskDheKe = 1;
#endif

    return 0;
}

#ifdef HAVE_SUPPORTED_CURVES
/* Only allow (EC)DHE key exchange when using pre-shared keys.
 *
 * ctx  The SSL/TLS CTX object.
 * returns BAD_FUNC_ARG when ctx is NULL and 0 on success.
 */
int wolfSSL_CTX_only_dhe_psk(WOLFSSL_CTX* ctx)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ctx-&gt;onlyPskDheKe = 1;
#endif

    return 0;
}

/* Only allow (EC)DHE key exchange when using pre-shared keys.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3 and 0 on
 * success.
 */
int wolfSSL_only_dhe_psk(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    ssl-&gt;options.onlyPskDheKe = 1;
#endif

    return 0;
}
#endif /* HAVE_SUPPORTED_CURVES */

int Tls13UpdateKeys(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

#ifdef WOLFSSL_DTLS13
    /* we are already waiting for the ack of a sent key update message. We can&#039;t
       send another one before receiving its ack. Either wolfSSL_update_keys()
       was invoked multiple times over a short period of time or we replied to a
       KeyUpdate with update request. We&#039;ll just ignore sending this
       KeyUpdate. */
    /* TODO: add WOLFSSL_ERROR_ALREADY_IN_PROGRESS type of error here */
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;dtls13WaitKeyUpdateAck)
        return 0;
#endif /* WOLFSSL_DTLS13 */

    return SendTls13KeyUpdate(ssl);
}

/* Update the keys for encryption and decryption.
 * If using non-blocking I/O and WOLFSSL_ERROR_WANT_WRITE is returned then
 * calling wolfSSL_write() will have the message sent when ready.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3,
 * WOLFSSL_ERROR_WANT_WRITE when non-blocking I/O is not ready to write,
 * WOLFSSL_SUCCESS on success and otherwise failure.
 */
int wolfSSL_update_keys(WOLFSSL* ssl)
{
    int ret;
    ret = Tls13UpdateKeys(ssl);
    if (ret == WC_NO_ERR_TRACE(WANT_WRITE))
        ret = WOLFSSL_ERROR_WANT_WRITE;
    else if (ret == 0)
        ret = WOLFSSL_SUCCESS;
    return ret;
}

/* Whether a response is waiting for key update request.
 *
 * ssl        The SSL/TLS object.
 * required   0 when no key update response required.
 *            1 when no key update response required.
 * return  0 on success.
 * return  BAD_FUNC_ARG when ssl is NULL or not using TLS v1.3
 */
int wolfSSL_key_update_response(WOLFSSL* ssl, int* required)
{
    if (required == NULL || ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

    *required = ssl-&gt;keys.updateResponseReq;

    return 0;
}

#if !defined(NO_CERTS) &amp;&amp; defined(WOLFSSL_POST_HANDSHAKE_AUTH)
/* Allow post-handshake authentication in TLS v1.3 connections.
 *
 * ctx  The SSL/TLS CTX object.
 * returns BAD_FUNC_ARG when ctx is NULL, SIDE_ERROR when not a client and
 * 0 on success.
 */
int wolfSSL_CTX_allow_post_handshake_auth(WOLFSSL_CTX* ctx)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;
    if (ctx-&gt;method-&gt;side == WOLFSSL_SERVER_END)
        return SIDE_ERROR;

    ctx-&gt;postHandshakeAuth = 1;

    return 0;
}

/* Allow post-handshake authentication in TLS v1.3 connection.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3,
 * SIDE_ERROR when not a client and 0 on success.
 */
int wolfSSL_allow_post_handshake_auth(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END)
        return SIDE_ERROR;

    ssl-&gt;options.postHandshakeAuth = 1;

    return 0;
}

/* Request a certificate of the client.
 * Can be called any time after handshake completion.
 * A maximum of 256 requests can be sent on a connection.
 *
 * ssl  SSL/TLS object.
 */
int wolfSSL_request_certificate(WOLFSSL* ssl)
{
    int         ret;
#ifndef NO_WOLFSSL_SERVER
    CertReqCtx* certReqCtx;
#endif

    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
#ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;
    if (ssl-&gt;options.handShakeState != HANDSHAKE_DONE)
        return NOT_READY_ERROR;
    if (!ssl-&gt;options.postHandshakeAuth)
        return POST_HAND_AUTH_ERROR;

    certReqCtx = (CertReqCtx*)XMALLOC(sizeof(CertReqCtx), ssl-&gt;heap,
                                                       DYNAMIC_TYPE_TMP_BUFFER);
    if (certReqCtx == NULL)
        return MEMORY_E;
    XMEMSET(certReqCtx, 0, sizeof(CertReqCtx));
    certReqCtx-&gt;next = ssl-&gt;certReqCtx;
    certReqCtx-&gt;len = 1;
    if (certReqCtx-&gt;next != NULL)
        certReqCtx-&gt;ctx = certReqCtx-&gt;next-&gt;ctx + 1;
    ssl-&gt;certReqCtx = certReqCtx;

    ssl-&gt;msgsReceived.got_certificate = 0;
    ssl-&gt;msgsReceived.got_certificate_verify = 0;
    ssl-&gt;msgsReceived.got_finished = 0;

    ret = SendTls13CertificateRequest(ssl, &amp;certReqCtx-&gt;ctx, certReqCtx-&gt;len);
    if (ret == WC_NO_ERR_TRACE(WANT_WRITE))
        ret = WOLFSSL_ERROR_WANT_WRITE;
    else if (ret == 0)
        ret = WOLFSSL_SUCCESS;
#else
    ret = SIDE_ERROR;
#endif

    return ret;
}
#endif /* !NO_CERTS &amp;&amp; WOLFSSL_POST_HANDSHAKE_AUTH */

#if !defined(WOLFSSL_NO_SERVER_GROUPS_EXT)
/* Get the preferred key exchange group.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL or not using TLS v1.3,
 * SIDE_ERROR when not a client, NOT_READY_ERROR when handshake not complete
 * and group number on success.
 */
int wolfSSL_preferred_group(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
#ifndef NO_WOLFSSL_CLIENT
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END)
        return SIDE_ERROR;
    if (ssl-&gt;options.handShakeState != HANDSHAKE_DONE)
        return NOT_READY_ERROR;

#ifdef HAVE_SUPPORTED_CURVES
    /* Return supported groups only. */
    return TLSX_SupportedCurve_Preferred(ssl, 1);
#else
    return 0;
#endif
#else
    return SIDE_ERROR;
#endif
}
#endif

#ifndef NO_PSK
/* Set the PSK callback, that is passed the cipher suite, for a client to use
 * against context object.
 *
 * @param [in, out] ctx  SSL/TLS context object.
 * @param [in]      cb   Client PSK callback passed a cipher suite.
 */
void wolfSSL_CTX_set_psk_client_cs_callback(WOLFSSL_CTX* ctx,
                                            wc_psk_client_cs_callback cb)
{
    WOLFSSL_ENTER(&quot;wolfSSL_CTX_set_psk_client_cs_callback&quot;);

    if (ctx == NULL)
        return;

    ctx-&gt;havePSK = 1;
    ctx-&gt;client_psk_cs_cb = cb;
}

/* Set the PSK callback, that is passed the cipher suite, for a client to use
 * against SSL object.
 *
 * @param [in, out] ssl  SSL/TLS object.
 * @param [in]      cb   Client PSK callback passed a cipher suite.
 */
void wolfSSL_set_psk_client_cs_callback(WOLFSSL* ssl,
                                        wc_psk_client_cs_callback cb)
{
    byte haveRSA = 1;
    int  keySz   = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_set_psk_client_cs_callback&quot;);

    if (ssl == NULL)
        return;

    ssl-&gt;options.havePSK = 1;
    ssl-&gt;options.client_psk_cs_cb = cb;

    #ifdef NO_RSA
        haveRSA = 0;
    #endif
    #ifndef NO_CERTS
        keySz = ssl-&gt;buffers.keySz;
    #endif
    if (AllocateSuites(ssl) != 0)
        return;
    InitSuites(ssl-&gt;suites, ssl-&gt;version, keySz, haveRSA, TRUE,
               ssl-&gt;options.haveDH, ssl-&gt;options.haveECDSAsig,
               ssl-&gt;options.haveECC, TRUE, ssl-&gt;options.haveStaticECC,
               ssl-&gt;options.useAnon, TRUE, TRUE, TRUE, TRUE, ssl-&gt;options.side);
}

/* Set the PSK callback that returns the cipher suite for a client to use
 * against context object.
 *
 * @param [in, out] ctx  SSL/TLS context object.
 * @param [in]      cb   Client PSK callback returning cipher suite.
 */
void wolfSSL_CTX_set_psk_client_tls13_callback(WOLFSSL_CTX* ctx,
                                               wc_psk_client_tls13_callback cb)
{
    WOLFSSL_ENTER(&quot;wolfSSL_CTX_set_psk_client_tls13_callback&quot;);

    if (ctx == NULL)
        return;

    ctx-&gt;havePSK = 1;
    ctx-&gt;client_psk_tls13_cb = cb;
}

/* Set the PSK callback that returns the cipher suite for a client to use
 * against SSL object.
 *
 * @param [in, out] ssl  SSL/TLS object.
 * @param [in]      cb   Client PSK callback returning cipher suite.
 */
void wolfSSL_set_psk_client_tls13_callback(WOLFSSL* ssl,
                                           wc_psk_client_tls13_callback cb)
{
    byte haveRSA = 1;
    int  keySz   = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_set_psk_client_tls13_callback&quot;);

    if (ssl == NULL)
        return;

    ssl-&gt;options.havePSK = 1;
    ssl-&gt;options.client_psk_tls13_cb = cb;

    #ifdef NO_RSA
        haveRSA = 0;
    #endif
    #ifndef NO_CERTS
        keySz = ssl-&gt;buffers.keySz;
    #endif
    if (AllocateSuites(ssl) != 0)
        return;
    InitSuites(ssl-&gt;suites, ssl-&gt;version, keySz, haveRSA, TRUE,
               ssl-&gt;options.haveDH, ssl-&gt;options.haveECDSAsig,
               ssl-&gt;options.haveECC, TRUE, ssl-&gt;options.haveStaticECC,
               ssl-&gt;options.useAnon, TRUE, TRUE, TRUE, TRUE, ssl-&gt;options.side);
}

/* Set the PSK callback that returns the cipher suite for a server to use
 * against context object.
 *
 * @param [in, out] ctx  SSL/TLS context object.
 * @param [in]      cb   Server PSK callback returning cipher suite.
 */
void wolfSSL_CTX_set_psk_server_tls13_callback(WOLFSSL_CTX* ctx,
                                               wc_psk_server_tls13_callback cb)
{
    WOLFSSL_ENTER(&quot;wolfSSL_CTX_set_psk_server_tls13_callback&quot;);
    if (ctx == NULL)
        return;
    ctx-&gt;havePSK = 1;
    ctx-&gt;server_psk_tls13_cb = cb;
}

/* Set the PSK callback that returns the cipher suite for a server to use
 * against SSL object.
 *
 * @param [in, out] ssl  SSL/TLS object.
 * @param [in]      cb   Server PSK callback returning cipher suite.
 */
void wolfSSL_set_psk_server_tls13_callback(WOLFSSL* ssl,
                                           wc_psk_server_tls13_callback cb)
{
    byte haveRSA = 1;
    int  keySz   = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_set_psk_server_tls13_callback&quot;);
    if (ssl == NULL)
        return;

    ssl-&gt;options.havePSK = 1;
    ssl-&gt;options.server_psk_tls13_cb = cb;

    #ifdef NO_RSA
        haveRSA = 0;
    #endif
    #ifndef NO_CERTS
        keySz = ssl-&gt;buffers.keySz;
    #endif
    if (AllocateSuites(ssl) != 0)
        return;
    InitSuites(ssl-&gt;suites, ssl-&gt;version, keySz, haveRSA, TRUE,
               ssl-&gt;options.haveDH, ssl-&gt;options.haveECDSAsig,
               ssl-&gt;options.haveECC, TRUE, ssl-&gt;options.haveStaticECC,
               ssl-&gt;options.useAnon, TRUE, TRUE, TRUE, TRUE, ssl-&gt;options.side);
}

/* Get name of first supported cipher suite that uses the hash indicated.
 *
 * @param [in] ssl   SSL/TLS object.
 * @param [in] hash  Name of hash algorithm. e.g. &quot;SHA256&quot;, &quot;SHA384&quot;
 * @return  Name of cipher suite.
 * @return  NULL on failure.
 */
const char* wolfSSL_get_cipher_name_by_hash(WOLFSSL* ssl, const char* hash)
{
    const char* name = NULL;
    byte mac = no_mac;
    int i;
    const Suites* suites = WOLFSSL_SUITES(ssl);

    if (XSTRCMP(hash, &quot;SHA256&quot;) == 0) {
        mac = sha256_mac;
    }
    else if (XSTRCMP(hash, &quot;SHA384&quot;) == 0) {
        mac = sha384_mac;
    }
    if (mac != no_mac) {
        for (i = 0; i &lt; suites-&gt;suiteSz; i += 2) {
            if (SuiteMac(suites-&gt;suites + i) == mac) {
                name = GetCipherNameInternal(suites-&gt;suites[i + 0],
                                             suites-&gt;suites[i + 1]);
                break;
            }
        }
    }
    return name;
}
#endif /* !NO_PSK */


#ifndef NO_WOLFSSL_SERVER

/* The server accepting a connection from a client.
 * The protocol version is expecting to be TLS v1.3.
 * If the client downgrades, and older versions of the protocol are compiled
 * in, the server will fallback to wolfSSL_accept().
 * Please see note at top of README if you get an error from accept.
 *
 * ssl  The SSL/TLS object.
 * returns WOLFSSL_SUCCESS on successful handshake, WOLFSSL_FATAL_ERROR when
 * unrecoverable error occurs and 0 otherwise.
 * For more error information use wolfSSL_get_error().
 */
int wolfSSL_accept_TLSv13(WOLFSSL* ssl)
{
#if !defined(NO_CERTS) &amp;&amp; (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK))
    word16 havePSK = 0;
#endif
    int ret = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_accept_TLSv13&quot;);

#ifdef HAVE_ERRNO_H
    errno = 0;
#endif

    if (ssl == NULL)
        return WOLFSSL_FATAL_ERROR;

#if !defined(NO_CERTS) &amp;&amp; (defined(HAVE_SESSION_TICKET) || !defined(NO_PSK))
    havePSK = ssl-&gt;options.havePSK;
#endif

    if (ssl-&gt;options.side != WOLFSSL_SERVER_END) {
        ssl-&gt;error = SIDE_ERROR;
        WOLFSSL_ERROR(ssl-&gt;error);
        return WOLFSSL_FATAL_ERROR;
    }

    /* make sure this wolfSSL object has arrays and rng setup. Protects
     * case where the WOLFSSL object is reused via wolfSSL_clear() */
    if ((ret = ReinitSSL(ssl, ssl-&gt;ctx, 0)) != 0) {
        return ret;
    }

#ifdef WOLFSSL_DTLS
    if (ssl-&gt;version.major == DTLS_MAJOR) {
        ssl-&gt;options.dtls   = 1;
        if (!IsDtlsNotSctpMode(ssl) || !ssl-&gt;options.sendCookie)
            ssl-&gt;options.dtlsStateful = 1;
    }
#endif

#ifdef WOLFSSL_WOLFSENTRY_HOOKS
    if ((ssl-&gt;AcceptFilter != NULL) &amp;&amp;
            ((ssl-&gt;options.acceptState == TLS13_ACCEPT_BEGIN)
#ifdef HAVE_SECURE_RENEGOTIATION
             || (ssl-&gt;options.acceptState == TLS13_ACCEPT_BEGIN_RENEG)
#endif
                ))
    {
        wolfSSL_netfilter_decision_t res;
        if ((ssl-&gt;AcceptFilter(ssl, ssl-&gt;AcceptFilter_arg, &amp;res) ==
             WOLFSSL_SUCCESS) &amp;&amp;
            (res == WOLFSSL_NETFILTER_REJECT)) {
            ssl-&gt;error = SOCKET_FILTERED_E;
            WOLFSSL_ERROR(ssl-&gt;error);
            return WOLFSSL_FATAL_ERROR;
        }
    }
#endif /* WOLFSSL_WOLFSENTRY_HOOKS */

#ifndef NO_CERTS
#if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
    if (!havePSK)
#endif
    {
    #if defined(OPENSSL_ALL) || defined(OPENSSL_EXTRA) || \
        defined(WOLFSSL_NGINX) || defined (WOLFSSL_HAPROXY)
        if (ssl-&gt;ctx-&gt;certSetupCb != NULL) {
            WOLFSSL_MSG(&quot;CertSetupCb set. server cert and &quot;
                        &quot;key not checked&quot;);
        }
        else
    #endif
        {
            if (!ssl-&gt;buffers.certificate ||
                !ssl-&gt;buffers.certificate-&gt;buffer) {

                WOLFSSL_MSG(&quot;accept error: server cert required&quot;);
                ssl-&gt;error = NO_PRIVATE_KEY;
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }

            if (!ssl-&gt;buffers.key || !ssl-&gt;buffers.key-&gt;buffer) {
                /* allow no private key if using existing key */
            #ifdef WOLF_PRIVATE_KEY_ID
                if (ssl-&gt;devId != INVALID_DEVID
                #ifdef HAVE_PK_CALLBACKS
                    || wolfSSL_CTX_IsPrivatePkSet(ssl-&gt;ctx)
                #endif
                ) {
                    WOLFSSL_MSG(&quot;Allowing no server private key (external)&quot;);
                }
                else
            #endif
                {
                    WOLFSSL_MSG(&quot;accept error: server key required&quot;);
                    ssl-&gt;error = NO_PRIVATE_KEY;
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
        }
    }
#endif /* NO_CERTS */

    if (ssl-&gt;buffers.outputBuffer.length &gt; 0
    #ifdef WOLFSSL_ASYNC_CRYPT
        /* do not send buffered or advance state if last error was an
            async pending operation */
        &amp;&amp; ssl-&gt;error != WC_NO_ERR_TRACE(WC_PENDING_E)
    #endif
    ) {

        /* fragOffset is non-zero when sending fragments. On the last
         * fragment, fragOffset is zero again, and the state can be
         * advanced. */
        int advanceState =
            (ssl-&gt;options.acceptState == TLS13_ACCEPT_CLIENT_HELLO_DONE ||
                ssl-&gt;options.acceptState ==
                    TLS13_ACCEPT_HELLO_RETRY_REQUEST_DONE ||
                ssl-&gt;options.acceptState == TLS13_ACCEPT_SECOND_REPLY_DONE ||
                ssl-&gt;options.acceptState == TLS13_SERVER_HELLO_SENT ||
                ssl-&gt;options.acceptState == TLS13_ACCEPT_THIRD_REPLY_DONE ||
                ssl-&gt;options.acceptState == TLS13_SERVER_EXTENSIONS_SENT ||
                ssl-&gt;options.acceptState == TLS13_CERT_REQ_SENT ||
                ssl-&gt;options.acceptState == TLS13_CERT_SENT ||
                ssl-&gt;options.acceptState == TLS13_CERT_VERIFY_SENT ||
                ssl-&gt;options.acceptState == TLS13_ACCEPT_FINISHED_SENT ||
                ssl-&gt;options.acceptState == TLS13_ACCEPT_FINISHED_DONE);

#ifdef WOLFSSL_DTLS13
        if (ssl-&gt;options.dtls)
            advanceState = advanceState &amp;&amp; !ssl-&gt;dtls13SendingFragments
                &amp;&amp; !ssl-&gt;dtls13SendingAckOrRtx;
#endif /* WOLFSSL_DTLS13 */

        ret = SendBuffered(ssl);
        if (ret == 0) {
            if (ssl-&gt;fragOffset == 0 &amp;&amp; !ssl-&gt;options.buildingMsg) {
                if (advanceState) {
                    ssl-&gt;options.acceptState++;
                    WOLFSSL_MSG(&quot;accept state: &quot;
                                &quot;Advanced from last buffered fragment send&quot;);
#ifdef WOLFSSL_ASYNC_IO
                    FreeAsyncCtx(ssl, 0);
#endif
                }
            }
            else {
                WOLFSSL_MSG(&quot;accept state: &quot;
                            &quot;Not advanced, more fragments to send&quot;);
            }

#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls)
                ssl-&gt;dtls13SendingAckOrRtx = 0;
#endif /* WOLFSSL_DTLS13 */

        }
        else {
            ssl-&gt;error = ret;
            WOLFSSL_ERROR(ssl-&gt;error);
            return WOLFSSL_FATAL_ERROR;
        }
    }

    ret = RetrySendAlert(ssl);
    if (ret != 0) {
        ssl-&gt;error = ret;
        WOLFSSL_ERROR(ssl-&gt;error);
        return WOLFSSL_FATAL_ERROR;
    }
#ifdef WOLFSSL_DTLS13
    if (ssl-&gt;options.dtls &amp;&amp; ssl-&gt;dtls13SendingFragments) {
        if ((ssl-&gt;error = Dtls13FragmentsContinue(ssl)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
        }

        /* we sent all the fragments. Advance state. */
        ssl-&gt;options.acceptState++;
    }
#endif /* WOLFSSL_DTLS13 */

    switch (ssl-&gt;options.acceptState) {

#ifdef HAVE_SECURE_RENEGOTIATION
        case TLS13_ACCEPT_BEGIN_RENEG:
#endif
        case TLS13_ACCEPT_BEGIN :
            /* get client_hello */

            while (ssl-&gt;options.clientState &lt; CLIENT_HELLO_COMPLETE) {
                if ((ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
#endif /* WOLFSSL_DTLS13 */

            }

            ssl-&gt;options.acceptState = TLS13_ACCEPT_CLIENT_HELLO_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_CLIENT_HELLO_DONE&quot;);
            if (!IsAtLeastTLSv1_3(ssl-&gt;version))
                return wolfSSL_accept(ssl);
            FALL_THROUGH;

        case TLS13_ACCEPT_CLIENT_HELLO_DONE :
            if (ssl-&gt;options.serverState ==
                                          SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
                if ((ssl-&gt;error = SendTls13ServerHello(ssl,
                                                   hello_retry_request)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }

            ssl-&gt;options.acceptState = TLS13_ACCEPT_HELLO_RETRY_REQUEST_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_HELLO_RETRY_REQUEST_DONE&quot;);
            FALL_THROUGH;

        case TLS13_ACCEPT_HELLO_RETRY_REQUEST_DONE :
    #ifdef WOLFSSL_TLS13_MIDDLEBOX_COMPAT
            if (!ssl-&gt;options.dtls &amp;&amp; ssl-&gt;options.tls13MiddleBoxCompat
                &amp;&amp; ssl-&gt;options.serverState ==
                                          SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
                if ((ssl-&gt;error = SendChangeCipher(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                ssl-&gt;options.sentChangeCipher = 1;
                ssl-&gt;options.serverState = SERVER_HELLO_RETRY_REQUEST_COMPLETE;
            }
    #endif
            ssl-&gt;options.acceptState = TLS13_ACCEPT_FIRST_REPLY_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_FIRST_REPLY_DONE&quot;);
            FALL_THROUGH;

        case TLS13_ACCEPT_FIRST_REPLY_DONE :
            if (ssl-&gt;options.serverState ==
                                          SERVER_HELLO_RETRY_REQUEST_COMPLETE) {
                ssl-&gt;options.clientState = CLIENT_HELLO_RETRY;
                while (ssl-&gt;options.clientState &lt; CLIENT_HELLO_COMPLETE) {
                    if ((ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
#endif /* WOLFSSL_DTLS13 */

                }
            }

            ssl-&gt;options.acceptState = TLS13_ACCEPT_SECOND_REPLY_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_SECOND_REPLY_DONE&quot;);
            FALL_THROUGH;

        case TLS13_ACCEPT_SECOND_REPLY_DONE :

            if ((ssl-&gt;error = SendTls13ServerHello(ssl, server_hello)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }
            ssl-&gt;options.acceptState = TLS13_SERVER_HELLO_SENT;
            WOLFSSL_MSG(&quot;accept state SERVER_HELLO_SENT&quot;);
            FALL_THROUGH;

        case TLS13_SERVER_HELLO_SENT :
    #if defined(WOLFSSL_TLS13_MIDDLEBOX_COMPAT)
            if (!ssl-&gt;options.dtls &amp;&amp; ssl-&gt;options.tls13MiddleBoxCompat
                          &amp;&amp; !ssl-&gt;options.sentChangeCipher &amp;&amp; !ssl-&gt;options.dtls) {
                if ((ssl-&gt;error = SendChangeCipher(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                ssl-&gt;options.sentChangeCipher = 1;
            }
    #endif

            ssl-&gt;options.acceptState = TLS13_ACCEPT_THIRD_REPLY_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_THIRD_REPLY_DONE&quot;);
            FALL_THROUGH;

        case TLS13_ACCEPT_THIRD_REPLY_DONE :
    #ifdef HAVE_SUPPORTED_CURVES
        #if defined(HAVE_SESSION_TICKET) || !defined(NO_PSK)
            if (!ssl-&gt;options.noPskDheKe)
        #endif
            {
                ssl-&gt;error = TLSX_KeyShare_DeriveSecret(ssl);
                if (ssl-&gt;error != 0)
                    return WOLFSSL_FATAL_ERROR;
            }
    #endif

            if ((ssl-&gt;error = SendTls13EncryptedExtensions(ssl)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }
            ssl-&gt;options.acceptState = TLS13_SERVER_EXTENSIONS_SENT;
            WOLFSSL_MSG(&quot;accept state SERVER_EXTENSIONS_SENT&quot;);
            FALL_THROUGH;

        case TLS13_SERVER_EXTENSIONS_SENT :
#ifndef NO_CERTS
            if (!ssl-&gt;options.resuming) {
                if (ssl-&gt;options.verifyPeer
    #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
                    &amp;&amp; !ssl-&gt;options.verifyPostHandshake
    #endif
                   ) {
                    ssl-&gt;error = SendTls13CertificateRequest(ssl, NULL, 0);
                    if (ssl-&gt;error != 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
                else {
                    /* SERVER: Peer auth good if not verifying client. */
                    ssl-&gt;options.peerAuthGood = 1;
                }
            }
#endif
            ssl-&gt;options.acceptState = TLS13_CERT_REQ_SENT;
            WOLFSSL_MSG(&quot;accept state CERT_REQ_SENT&quot;);
            FALL_THROUGH;

        case TLS13_CERT_REQ_SENT :
#ifndef NO_CERTS
            if (!ssl-&gt;options.resuming &amp;&amp; ssl-&gt;options.sendVerify) {
                if ((ssl-&gt;error = SendTls13Certificate(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
#endif
            ssl-&gt;options.acceptState = TLS13_CERT_SENT;
            WOLFSSL_MSG(&quot;accept state CERT_SENT&quot;);
            FALL_THROUGH;

        case TLS13_CERT_SENT :
#if !defined(NO_CERTS) &amp;&amp; (!defined(NO_RSA) || defined(HAVE_ECC) || \
     defined(HAVE_ED25519) || defined(HAVE_ED448) || defined(HAVE_FALCON) || \
     defined(HAVE_DILITHIUM))
            if (!ssl-&gt;options.resuming &amp;&amp; ssl-&gt;options.sendVerify) {
                if ((ssl-&gt;error = SendTls13CertificateVerify(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
#endif
            ssl-&gt;options.acceptState = TLS13_CERT_VERIFY_SENT;
            WOLFSSL_MSG(&quot;accept state CERT_VERIFY_SENT&quot;);
            FALL_THROUGH;

        case TLS13_CERT_VERIFY_SENT :
            if ((ssl-&gt;error = SendTls13Finished(ssl)) != 0) {
                WOLFSSL_ERROR(ssl-&gt;error);
                return WOLFSSL_FATAL_ERROR;
            }

            ssl-&gt;options.acceptState = TLS13_ACCEPT_FINISHED_SENT;
            WOLFSSL_MSG(&quot;accept state ACCEPT_FINISHED_SENT&quot;);
#ifdef WOLFSSL_EARLY_DATA
            if (ssl-&gt;earlyData != no_early_data) {
                ssl-&gt;options.handShakeState = SERVER_FINISHED_COMPLETE;
                return WOLFSSL_SUCCESS;
            }
#endif
            FALL_THROUGH;

        case TLS13_ACCEPT_FINISHED_SENT :
#ifdef HAVE_SESSION_TICKET
    #ifdef WOLFSSL_TLS13_TICKET_BEFORE_FINISHED
            if (!ssl-&gt;options.verifyPeer &amp;&amp; !ssl-&gt;options.noTicketTls13 &amp;&amp;
                                                ssl-&gt;ctx-&gt;ticketEncCb != NULL) {
                if ((ssl-&gt;error = SendTls13NewSessionTicket(ssl)) != 0) {
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
                ssl-&gt;options.ticketsSent = 1;
            }
    #endif
#endif /* HAVE_SESSION_TICKET */
            ssl-&gt;options.acceptState = TLS13_PRE_TICKET_SENT;
            WOLFSSL_MSG(&quot;accept state  TICKET_SENT&quot;);
            FALL_THROUGH;

        case TLS13_PRE_TICKET_SENT :
            while (ssl-&gt;options.clientState &lt; CLIENT_FINISHED_COMPLETE) {
                if ( (ssl-&gt;error = ProcessReply(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }

#ifdef WOLFSSL_DTLS13
                if (ssl-&gt;options.dtls) {
                    if ((ssl-&gt;error = Dtls13DoScheduledWork(ssl)) &lt; 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
#endif /* WOLFSSL_DTLS13 */
            }

            ssl-&gt;options.acceptState = TLS13_ACCEPT_FINISHED_DONE;
            WOLFSSL_MSG(&quot;accept state ACCEPT_FINISHED_DONE&quot;);
            FALL_THROUGH;

        case TLS13_ACCEPT_FINISHED_DONE :
            /* SERVER: When not resuming and verifying peer but no certificate
             * received and not failing when not received then peer auth good.
             */
            if (!ssl-&gt;options.resuming &amp;&amp; ssl-&gt;options.verifyPeer &amp;&amp;
        #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
                !ssl-&gt;options.verifyPostHandshake &amp;&amp;
        #endif
                !ssl-&gt;options.havePeerCert &amp;&amp; !ssl-&gt;options.failNoCert) {
                ssl-&gt;options.peerAuthGood = 1;
            }
            /* SERVER: check peer authentication. */
            if (!ssl-&gt;options.peerAuthGood) {
                WOLFSSL_MSG(&quot;Client authentication did not happen&quot;);
                return WOLFSSL_FATAL_ERROR;
            }
#ifdef HAVE_SESSION_TICKET
            while (ssl-&gt;options.ticketsSent &lt; ssl-&gt;options.maxTicketTls13) {
                if (!ssl-&gt;options.noTicketTls13 &amp;&amp; ssl-&gt;ctx-&gt;ticketEncCb
                        != NULL) {
                    if ((ssl-&gt;error = SendTls13NewSessionTicket(ssl)) != 0) {
                        WOLFSSL_ERROR(ssl-&gt;error);
                        return WOLFSSL_FATAL_ERROR;
                    }
                }
                ssl-&gt;options.ticketsSent++;

                /* only one session ticket is sent on session resumption */
                if (ssl-&gt;options.resuming) {
                    break;
                }
            }
#endif /* HAVE_SESSION_TICKET */
            ssl-&gt;options.acceptState = TLS13_TICKET_SENT;
            WOLFSSL_MSG(&quot;accept state TICKET_SENT&quot;);
            FALL_THROUGH;

        case TLS13_TICKET_SENT :
#ifndef NO_HANDSHAKE_DONE_CB
            if (ssl-&gt;hsDoneCb) {
                int cbret = ssl-&gt;hsDoneCb(ssl, ssl-&gt;hsDoneCtx);
                if (cbret &lt; 0) {
                    ssl-&gt;error = cbret;
                    WOLFSSL_MSG(&quot;HandShake Done Cb don&#039;t continue error&quot;);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
#endif /* NO_HANDSHAKE_DONE_CB */

            if (!ssl-&gt;options.keepResources) {
                FreeHandshakeResources(ssl);
            }

#if defined(WOLFSSL_ASYNC_IO) &amp;&amp; !defined(WOLFSSL_ASYNC_CRYPT)
            /* Free the remaining async context if not using it for crypto */
            FreeAsyncCtx(ssl, 1);
#endif

            ssl-&gt;error = 0; /* clear the error */

            WOLFSSL_LEAVE(&quot;wolfSSL_accept&quot;, WOLFSSL_SUCCESS);
            return WOLFSSL_SUCCESS;

        default:
            WOLFSSL_MSG(&quot;Unknown accept state ERROR&quot;);
            return WOLFSSL_FATAL_ERROR;
    }
}
#endif

#if !defined(NO_WOLFSSL_SERVER) &amp;&amp; defined(HAVE_SESSION_TICKET)
/* Server sends a session ticket to the peer.
 *
 * RFC 8446, section 4.6.1, para 1.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3,
 *         SIDE_ERROR when not a server,
 *         NOT_READY_ERROR when handshake not complete,
 *         WOLFSSL_FATAL_ERROR when creating or sending message fails, and
 *         WOLFSSL_SUCCESS on success.
 */
int wolfSSL_send_SessionTicket(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;
    if (ssl-&gt;options.handShakeState != HANDSHAKE_DONE)
        return NOT_READY_ERROR;

    if ((ssl-&gt;error = SendTls13NewSessionTicket(ssl)) != 0) {
        WOLFSSL_ERROR(ssl-&gt;error);
        return WOLFSSL_FATAL_ERROR;
    }
    ssl-&gt;options.ticketsSent++;

    return WOLFSSL_SUCCESS;
}
#endif

#ifdef WOLFSSL_EARLY_DATA
/* Sets the maximum amount of early data that can be seen by server when using
 * session tickets for resumption.
 * A value of zero indicates no early data is to be sent by client using session
 * tickets.
 *
 * ctx  The SSL/TLS CTX object.
 * sz   Maximum size of the early data.
 * returns BAD_FUNC_ARG when ctx is NULL, SIDE_ERROR when not a server and
 * 0 on success.
 */
int wolfSSL_CTX_set_max_early_data(WOLFSSL_CTX* ctx, unsigned int sz)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;
    if (ctx-&gt;method-&gt;side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

    ctx-&gt;maxEarlyDataSz = sz;

#if defined(OPENSSL_EXTRA) || defined(WOLFSSL_ERROR_CODE_OPENSSL)
    /* 1 on success in OpenSSL*/
    return WOLFSSL_SUCCESS;
#else
    return 0;
#endif
}

/* Sets the maximum amount of early data that a client or server would like
 * to exchange. Servers will advertise this value in session tickets sent
 * to a client.
 * A value of zero indicates no early data will be sent by a client, or
 * no early data is accepted by a server (and announced as such in send out
 * session tickets).
 *
 * ssl  The SSL/TLS object.
 * sz   Maximum size of the early data.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3,
 * and 0 on success.
 */
int wolfSSL_set_max_early_data(WOLFSSL* ssl, unsigned int sz)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

    ssl-&gt;options.maxEarlyDataSz = sz;
#if defined(OPENSSL_EXTRA) || defined(WOLFSSL_ERROR_CODE_OPENSSL)
    /* 1 on success in OpenSSL*/
    return WOLFSSL_SUCCESS;
#else
    return 0;
#endif
}

/* Gets the maximum amount of early data that can be seen by server when using
 * session tickets for resumption.
 * A value of zero indicates no early data is to be sent by client using session
 * tickets.
 *
 * ctx  The SSL/TLS CTX object.
 * returns BAD_FUNC_ARG when ctx is NULL, SIDE_ERROR when not a server and
 * returns the maximum amount of early data to be set
 */
int wolfSSL_CTX_get_max_early_data(WOLFSSL_CTX* ctx)
{
    if (ctx == NULL || !IsAtLeastTLSv1_3(ctx-&gt;method-&gt;version))
        return BAD_FUNC_ARG;
    if (ctx-&gt;method-&gt;side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

    return ctx-&gt;maxEarlyDataSz;
}

/* Gets the maximum amount of early data that can be seen by server when using
 * session tickets for resumption.
 * A value of zero indicates no early data is to be sent by client using session
 * tickets.
 *
 * ssl  The SSL/TLS object.
 * returns BAD_FUNC_ARG when ssl is NULL, or not using TLS v1.3,
 * SIDE_ERROR when not a server and
 * returns the maximum amount of early data to be set
 */
int wolfSSL_get_max_early_data(WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

    return ssl-&gt;options.maxEarlyDataSz;
}

/* Write early data to the server.
 *
 * ssl    The SSL/TLS object.
 * data   Early data to write
 * sz     The size of the early data in bytes.
 * outSz  The number of early data bytes written.
 * returns BAD_FUNC_ARG when: ssl, data or outSz is NULL; sz is negative;
 * or not using TLS v1.3. SIDE ERROR when not a server. Otherwise the number of
 * early data bytes written.
 */
int wolfSSL_write_early_data(WOLFSSL* ssl, const void* data, int sz, int* outSz)
{
    int ret = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_write_early_data&quot;);

    if (ssl == NULL || data == NULL || sz &lt; 0 || outSz == NULL)
        return BAD_FUNC_ARG;
    if (!IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

#ifndef NO_WOLFSSL_CLIENT
    if (ssl-&gt;options.side == WOLFSSL_SERVER_END)
        return SIDE_ERROR;

    if (ssl-&gt;options.handShakeState == NULL_STATE) {
        if (ssl-&gt;error != WC_NO_ERR_TRACE(WC_PENDING_E))
            ssl-&gt;earlyData = expecting_early_data;
        ret = wolfSSL_connect_TLSv13(ssl);
        if (ret != WOLFSSL_SUCCESS)
            return WOLFSSL_FATAL_ERROR;
        /* on client side, status is set to rejected        */
        /* until sever accepts the early data extension.    */
        ssl-&gt;earlyDataStatus = WOLFSSL_EARLY_DATA_REJECTED;
    }
    if (ssl-&gt;options.handShakeState == CLIENT_HELLO_COMPLETE) {
#ifdef OPENSSL_EXTRA
        /* when processed early data exceeds max size */
        if (ssl-&gt;session-&gt;maxEarlyDataSz &gt; 0 &amp;&amp;
            (ssl-&gt;earlyDataSz + sz &gt; ssl-&gt;session-&gt;maxEarlyDataSz)) {
            ssl-&gt;error = TOO_MUCH_EARLY_DATA;
            return WOLFSSL_FATAL_ERROR;
        }
#endif
        ret = SendData(ssl, data, sz);
        if (ret &gt; 0) {
            *outSz = ret;
            /* store amount of processed early data from client */
            ssl-&gt;earlyDataSz += ret;
        }
    }
#else
    return SIDE_ERROR;
#endif

    WOLFSSL_LEAVE(&quot;wolfSSL_write_early_data&quot;, ret);

    if (ret &lt; 0)
        ret = WOLFSSL_FATAL_ERROR;
    return ret;
}

/* Read the any early data from the client.
 *
 * ssl    The SSL/TLS object.
 * data   Buffer to put the early data into.
 * sz     The size of the buffer in bytes.
 * outSz  The number of early data bytes read.
 * returns BAD_FUNC_ARG when: ssl, data or outSz is NULL; sz is negative;
 * or not using TLS v1.3. SIDE ERROR when not a server. Otherwise the number of
 * early data bytes read.
 */
int wolfSSL_read_early_data(WOLFSSL* ssl, void* data, int sz, int* outSz)
{
    int ret = 0;

    WOLFSSL_ENTER(&quot;wolfSSL_read_early_data&quot;);


    if (ssl == NULL || data == NULL || sz &lt; 0 || outSz == NULL)
        return BAD_FUNC_ARG;
    if (!IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

    *outSz = 0;
#ifndef NO_WOLFSSL_SERVER
    if (ssl-&gt;options.side == WOLFSSL_CLIENT_END)
        return SIDE_ERROR;

    if (ssl-&gt;options.handShakeState == NULL_STATE) {
        if (ssl-&gt;error != WC_NO_ERR_TRACE(WC_PENDING_E))
            ssl-&gt;earlyData = expecting_early_data;
        /* this used to be: ret = wolfSSL_accept_TLSv13(ssl);
         * However, wolfSSL_accept_TLSv13() expects a certificate to
         * be installed already, which is not the case in servers
         * such as HAProxy. They do it after inspecting the ClientHello.
         * The common wolfssl_accept() allows that. */
        ret = wolfSSL_accept(ssl);
        if (ret &lt;= 0)
            return WOLFSSL_FATAL_ERROR;
    }
    if (ssl-&gt;options.handShakeState == SERVER_FINISHED_COMPLETE) {
        ret = ReceiveData(ssl, (byte*)data, sz, FALSE);
        if (ret &gt; 0)
            *outSz = ret;
        if (ssl-&gt;error == WC_NO_ERR_TRACE(ZERO_RETURN)) {
            ssl-&gt;error = WOLFSSL_ERROR_NONE;
#ifdef WOLFSSL_DTLS13
            if (ssl-&gt;options.dtls) {
                ret = Dtls13DoScheduledWork(ssl);
                if (ret  &lt; 0) {
                    ssl-&gt;error = ret;
                    WOLFSSL_ERROR(ssl-&gt;error);
                    return WOLFSSL_FATAL_ERROR;
                }
            }
#endif /* WOLFSSL_DTLS13 */
        }
    }
    else
        ret = 0;
#else
    return SIDE_ERROR;
#endif

    WOLFSSL_LEAVE(&quot;wolfSSL_read_early_data&quot;, ret);

    if (ret &lt; 0)
        ret = WOLFSSL_FATAL_ERROR;
    return ret;
}

/* Returns early data status
 *
 * ssl    The SSL/TLS object.
 * returns WOLFSSL_EARLY_DATA_ACCEPTED if the data was accepted
 *         WOLFSSL_EARLY_DATA_REJECTED if the data was rejected
 *         WOLFSSL_EARLY_DATA_NOT_SENT if no early data was sent
 */
int wolfSSL_get_early_data_status(const WOLFSSL* ssl)
{
    if (ssl == NULL || !IsAtLeastTLSv1_3(ssl-&gt;version))
        return BAD_FUNC_ARG;

    return ssl-&gt;earlyDataStatus;
}
#endif

#ifdef HAVE_SECRET_CALLBACK
int wolfSSL_set_tls13_secret_cb(WOLFSSL* ssl, Tls13SecretCb cb, void* ctx)
{
    WOLFSSL_ENTER(&quot;wolfSSL_set_tls13_secret_cb&quot;);
    if (ssl == NULL)
        return WOLFSSL_FATAL_ERROR;

    ssl-&gt;tls13SecretCb = cb;
    ssl-&gt;tls13SecretCtx = ctx;

    return WOLFSSL_SUCCESS;
}

#if defined(SHOW_SECRETS) &amp;&amp; defined(WOLFSSL_SSLKEYLOGFILE)
int tls13ShowSecrets(WOLFSSL* ssl, int id, const unsigned char* secret,
    int secretSz, void* ctx)
{
    int i;
    const char* str = NULL;
    byte clientRandom[RAN_LEN];
    int clientRandomSz;
    XFILE fp;

    (void) ctx;
#ifdef WOLFSSL_SSLKEYLOGFILE_OUTPUT
    fp = XFOPEN(WOLFSSL_SSLKEYLOGFILE_OUTPUT, &quot;ab&quot;);
    if (fp == XBADFILE) {
        return BAD_FUNC_ARG;
    }
#else
    fp = stderr;
#endif

    clientRandomSz = (int)wolfSSL_get_client_random(ssl, clientRandom,
        sizeof(clientRandom));

    if (clientRandomSz &lt;= 0) {
        printf(&quot;Error getting server random %d\n&quot;, clientRandomSz);
        return BAD_FUNC_ARG;
    }

#if 0
    printf(&quot;TLS Server Secret CB: Rand %d, Secret %d\n&quot;,
        serverRandomSz, secretSz);
#endif

    switch (id) {
        case CLIENT_EARLY_TRAFFIC_SECRET:
            str = &quot;CLIENT_EARLY_TRAFFIC_SECRET&quot;; break;
        case EARLY_EXPORTER_SECRET:
            str = &quot;EARLY_EXPORTER_SECRET&quot;; break;
        case CLIENT_HANDSHAKE_TRAFFIC_SECRET:
            str = &quot;CLIENT_HANDSHAKE_TRAFFIC_SECRET&quot;; break;
        case SERVER_HANDSHAKE_TRAFFIC_SECRET:
            str = &quot;SERVER_HANDSHAKE_TRAFFIC_SECRET&quot;; break;
        case CLIENT_TRAFFIC_SECRET:
            str = &quot;CLIENT_TRAFFIC_SECRET_0&quot;; break;
        case SERVER_TRAFFIC_SECRET:
            str = &quot;SERVER_TRAFFIC_SECRET_0&quot;; break;
        case EXPORTER_SECRET:
            str = &quot;EXPORTER_SECRET&quot;; break;
        default:
#ifdef WOLFSSL_SSLKEYLOGFILE_OUTPUT
            XFCLOSE(fp);
#endif
            return BAD_FUNC_ARG;
            break;
    }

    fprintf(fp, &quot;%s &quot;, str);
    for (i = 0; i &lt; (int)clientRandomSz; i++) {
        fprintf(fp, &quot;%02x&quot;, clientRandom[i]);
    }
    fprintf(fp, &quot; &quot;);
    for (i = 0; i &lt; secretSz; i++) {
        fprintf(fp, &quot;%02x&quot;, secret[i]);
    }
    fprintf(fp, &quot;\n&quot;);

#ifdef WOLFSSL_SSLKEYLOGFILE_OUTPUT
    XFCLOSE(fp);
#endif

    return 0;
}
#endif
#endif

#undef ERROR_OUT

#endif /* !WOLFCRYPT_ONLY */

#endif /* WOLFSSL_TLS13 */
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