diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index dc88af2..5c67bf7 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -9835,6 +9835,191 @@
 #endif /* MBEDTLS_SSL_CLI_C */
 
 /*
+ * Serialize a session in the following format:
+ *
+ * - If MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is enabled:
+ *    0       .   n-1   session structure, n = sizeof(mbedtls_ssl_session)
+ *    n       .   n+2   peer_cert length = m (0 if no certificate)
+ *    n+3     .   n+2+m peer cert ASN.1
+ *
+ * - If MBEDTLS_SSL_KEEP_PEER_CERTIFICATE is disabled:
+ *    0       .   n-1   session structure, n = sizeof(mbedtls_ssl_session)
+ *    n       .   n     length of peer certificate digest = k (0 if no digest)
+ *    n+1     .   n+k   peer certificate digest (digest type encoded in session)
+ */
+int mbedtls_ssl_session_save( const mbedtls_ssl_session *session,
+                              unsigned char *buf,
+                              size_t buf_len,
+                              size_t *olen )
+{
+    unsigned char *p = buf;
+    size_t left = buf_len;
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    size_t cert_len;
+#else
+    size_t cert_digest_len;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( left < sizeof( mbedtls_ssl_session ) )
+        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
+
+    /* This also copies the values of pointer fields in the
+     * session to be serialized, but they'll be ignored when
+     * loading the session through ssl_load_session(). */
+    memcpy( p, session, sizeof( mbedtls_ssl_session ) );
+    p += sizeof( mbedtls_ssl_session );
+    left -= sizeof( mbedtls_ssl_session );
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    if( session->peer_cert == NULL )
+        cert_len = 0;
+    else
+        cert_len = session->peer_cert->raw.len;
+
+    if( left < 3 + cert_len )
+        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
+
+    *p++ = (unsigned char)( ( cert_len >> 16 ) & 0xFF );
+    *p++ = (unsigned char)( ( cert_len >>  8 ) & 0xFF );
+    *p++ = (unsigned char)( ( cert_len       ) & 0xFF );
+    left -= 3;
+
+    if( session->peer_cert != NULL )
+        memcpy( p, session->peer_cert->raw.p, cert_len );
+
+    p += cert_len;
+    left -= cert_len;
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    if( session->peer_cert_digest != NULL )
+        cert_digest_len = 0;
+    else
+        cert_digest_len = session->peer_cert_digest_len;
+
+    if( left < 1 + cert_digest_len )
+        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
+
+    *p++ = (unsigned char) cert_digest_len;
+    left--;
+
+    if( session->peer_cert_digest != NULL )
+        memcpy( p, session->peer_cert_digest, cert_digest_len );
+
+    p    += cert_digest_len;
+    left -= cert_digest_len;
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    *olen = p - buf;
+
+    return( 0 );
+}
+
+/*
+ * Unserialise session, see ssl_save_session()
+ */
+int mbedtls_ssl_session_load( mbedtls_ssl_session *session,
+                              const unsigned char *buf,
+                              size_t len )
+{
+    const unsigned char *p = buf;
+    const unsigned char * const end = buf + len;
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    size_t cert_len;
+#else
+    size_t cert_digest_len;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( sizeof( mbedtls_ssl_session ) > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    memcpy( session, p, sizeof( mbedtls_ssl_session ) );
+    p += sizeof( mbedtls_ssl_session );
+
+    /* Non-NULL pointer fields of `session` are meaningless
+     * and potentially harmful. Zeroize them for safety. */
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    session->peer_cert = NULL;
+#else
+    session->peer_cert_digest = NULL;
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
+    session->ticket = NULL;
+#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    /* Deserialize CRT from the end of the ticket. */
+    if( 3 > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    cert_len = ( p[0] << 16 ) | ( p[1] << 8 ) | p[2];
+    p += 3;
+
+    if( cert_len != 0 )
+    {
+        int ret;
+
+        if( cert_len > (size_t)( end - p ) )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+        session->peer_cert = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
+
+        if( session->peer_cert == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        mbedtls_x509_crt_init( session->peer_cert );
+
+        if( ( ret = mbedtls_x509_crt_parse_der( session->peer_cert,
+                                                p, cert_len ) ) != 0 )
+        {
+            mbedtls_x509_crt_free( session->peer_cert );
+            mbedtls_free( session->peer_cert );
+            session->peer_cert = NULL;
+            return( ret );
+        }
+
+        p += cert_len;
+    }
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    /* Deserialize CRT digest from the end of the ticket. */
+    if( 1 > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    cert_digest_len = (size_t) p[0];
+    p++;
+
+    if( cert_digest_len != 0 )
+    {
+        if( cert_digest_len > (size_t)( end - p ) ||
+            cert_digest_len != session->peer_cert_digest_len )
+        {
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+        }
+
+        session->peer_cert_digest = mbedtls_calloc( 1, cert_digest_len );
+        if( session->peer_cert_digest == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        memcpy( session->peer_cert_digest, p, cert_digest_len );
+        p += cert_digest_len;
+    }
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( p != end )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    return( 0 );
+}
+
+/*
  * Perform a single step of the SSL handshake
  */
 int mbedtls_ssl_handshake_step( mbedtls_ssl_context *ssl )