diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 9e6c52a..88e7de9 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -1128,6 +1128,111 @@
 
 #endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
 
+static int ssl_hash_transcript_core( mbedtls_ssl_context *ssl,
+                                     mbedtls_md_type_t md,
+                                     unsigned char *transcript,
+                                     size_t len,
+                                     size_t *olen )
+{
+    int ret;
+    size_t hash_size;
+
+    if( len < 4 )
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+
+    ret = mbedtls_ssl_get_handshake_transcript( ssl, md,
+                                                transcript + 4,
+                                                len - 4,
+                                                &hash_size );
+    if( ret != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 4, "mbedtls_ssl_get_handshake_transcript", ret );
+        return( ret );
+    }
+
+    transcript[0] = MBEDTLS_SSL_HS_MESSAGE_HASH;
+    transcript[1] = 0;
+    transcript[2] = 0;
+    transcript[3] = (unsigned char) hash_size;
+
+    *olen = 4 + hash_size;
+    return( 0 );
+}
+
+/* Reset SSL context and update hash for handling HRR.
+ *
+ * Replace Transcript-Hash(X) by
+ * Transcript-Hash( message_hash     ||
+ *                 00 00 Hash.length ||
+ *                 X )
+ * A few states of the handshake are preserved, including:
+ *   - session ID
+ *   - session ticket
+ *   - negotiated ciphersuite
+ */
+int mbedtls_ssl_reset_transcript_for_hrr( mbedtls_ssl_context *ssl )
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char hash_transcript[ MBEDTLS_MD_MAX_SIZE + 4 ];
+    size_t hash_olen;
+    const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
+    uint16_t cipher_suite = ssl->session_negotiate->ciphersuite;
+    ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( cipher_suite );
+
+    MBEDTLS_SSL_DEBUG_MSG( 3, ( "Reset SSL session for HRR" ) );
+
+    if( ciphersuite_info->mac == MBEDTLS_MD_SHA256 )
+    {
+#if defined(MBEDTLS_SHA256_C)
+        ret = ssl_hash_transcript_core( ssl, MBEDTLS_MD_SHA256,
+                                        hash_transcript,
+                                        sizeof( hash_transcript ),
+                                        &hash_olen );
+        if( ret != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 4, "ssl_hash_transcript_core", ret );
+            return( ret );
+        }
+        MBEDTLS_SSL_DEBUG_BUF( 4, "Truncated SHA-256 handshake transcript",
+                               hash_transcript, hash_olen );
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+        psa_hash_abort( &ssl->handshake->fin_sha256_psa );
+        psa_hash_setup( &ssl->handshake->fin_sha256_psa, PSA_ALG_SHA_256 );
+#else
+        mbedtls_sha256_starts( &ssl->handshake->fin_sha256, 0 );
+#endif
+    ssl->handshake->update_checksum( ssl, hash_transcript, hash_olen );
+#endif /* MBEDTLS_SHA256_C */
+    }
+    else if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
+    {
+#if defined(MBEDTLS_SHA384_C)
+        ret = ssl_hash_transcript_core( ssl, MBEDTLS_MD_SHA384,
+                                        hash_transcript,
+                                        sizeof( hash_transcript ),
+                                        &hash_olen );
+        if( ret != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 4, "ssl_hash_transcript_core", ret );
+            return( ret );
+        }
+        MBEDTLS_SSL_DEBUG_BUF( 4, "Truncated SHA-384 handshake transcript",
+                               hash_transcript, hash_olen );
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+        psa_hash_abort( &ssl->handshake->fin_sha384_psa );
+        psa_hash_setup( &ssl->handshake->fin_sha384_psa, PSA_ALG_SHA_384 );
+#else
+        mbedtls_sha512_starts( &ssl->handshake->fin_sha512, 1 );
+#endif
+    ssl->handshake->update_checksum( ssl, hash_transcript, hash_olen );
+#endif /* MBEDTLS_SHA384_C */
+    }
+
+    return( ret );
+}
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
 
 #endif /* MBEDTLS_SSL_TLS_C */