diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index bdf882d87..597494ead 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -850,20 +850,21 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
          * Encrypt and authenticate
          */
 
-        if( ( ret = mbedtls_cipher_auth_encrypt( &transform->cipher_ctx_enc,
+        if( ( ret = mbedtls_cipher_auth_encrypt_ext( &transform->cipher_ctx_enc,
                    iv, transform->ivlen,
-                   add_data, add_data_len,       /* add data     */
-                   data, rec->data_len,          /* source       */
-                   data, &rec->data_len,         /* destination  */
-                   data + rec->data_len, transform->taglen ) ) != 0 )
+                   add_data, add_data_len,
+                   data, rec->data_len,                     /* src */
+                   data, rec->buf_len - (data - rec->buf),  /* dst */
+                   &rec->data_len,
+                   transform->taglen ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_encrypt", ret );
             return( ret );
         }
         MBEDTLS_SSL_DEBUG_BUF( 4, "after encrypt: tag",
-                               data + rec->data_len, transform->taglen );
+                               data + rec->data_len - transform->taglen,
+                               transform->taglen );
         /* Account for authentication tag. */
-        rec->data_len += transform->taglen;
         post_avail -= transform->taglen;
 
         /*
@@ -1420,12 +1421,11 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
         /*
          * Decrypt and authenticate
          */
-        if( ( ret = mbedtls_cipher_auth_decrypt( &transform->cipher_ctx_dec,
+        if( ( ret = mbedtls_cipher_auth_decrypt_ext( &transform->cipher_ctx_dec,
                   iv, transform->ivlen,
                   add_data, add_data_len,
-                  data, rec->data_len,
-                  data, &olen,
-                  data + rec->data_len,
+                  data, rec->data_len + transform->taglen,          /* src */
+                  data, rec->buf_len - (data - rec->buf), &olen,    /* dst */
                   transform->taglen ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_decrypt", ret );
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index e3e802315..626d137cc 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -209,7 +209,6 @@ int mbedtls_ssl_ticket_write( void *p_ticket,
     unsigned char *iv = start + TICKET_KEY_NAME_BYTES;
     unsigned char *state_len_bytes = iv + TICKET_IV_BYTES;
     unsigned char *state = state_len_bytes + TICKET_CRYPT_LEN_BYTES;
-    unsigned char *tag;
     size_t clear_len, ciph_len;
 
     *tlen = 0;
@@ -250,23 +249,23 @@ int mbedtls_ssl_ticket_write( void *p_ticket,
     state_len_bytes[1] = ( clear_len      ) & 0xff;
 
     /* Encrypt and authenticate */
-    tag = state + clear_len;
-    if( ( ret = mbedtls_cipher_auth_encrypt( &key->ctx,
+    if( ( ret = mbedtls_cipher_auth_encrypt_ext( &key->ctx,
                     iv, TICKET_IV_BYTES,
                     /* Additional data: key name, IV and length */
                     key_name, TICKET_ADD_DATA_LEN,
-                    state, clear_len, state, &ciph_len,
-                    tag, TICKET_AUTH_TAG_BYTES ) ) != 0 )
+                    state, clear_len,
+                    state, end - state, &ciph_len,
+                    TICKET_AUTH_TAG_BYTES ) ) != 0 )
     {
         goto cleanup;
     }
-    if( ciph_len != clear_len )
+    if( ciph_len != clear_len + TICKET_AUTH_TAG_BYTES )
     {
         ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
         goto cleanup;
     }
 
-    *tlen = TICKET_MIN_LEN + ciph_len;
+    *tlen = TICKET_MIN_LEN + ciph_len - TICKET_AUTH_TAG_BYTES;
 
 cleanup:
 #if defined(MBEDTLS_THREADING_C)
@@ -308,7 +307,6 @@ int mbedtls_ssl_ticket_parse( void *p_ticket,
     unsigned char *iv = buf + TICKET_KEY_NAME_BYTES;
     unsigned char *enc_len_p = iv + TICKET_IV_BYTES;
     unsigned char *ticket = enc_len_p + TICKET_CRYPT_LEN_BYTES;
-    unsigned char *tag;
     size_t enc_len, clear_len;
 
     if( ctx == NULL || ctx->f_rng == NULL )
@@ -326,7 +324,6 @@ int mbedtls_ssl_ticket_parse( void *p_ticket,
         goto cleanup;
 
     enc_len = ( enc_len_p[0] << 8 ) | enc_len_p[1];
-    tag = ticket + enc_len;
 
     if( len != TICKET_MIN_LEN + enc_len )
     {
@@ -344,13 +341,13 @@ int mbedtls_ssl_ticket_parse( void *p_ticket,
     }
 
     /* Decrypt and authenticate */
-    if( ( ret = mbedtls_cipher_auth_decrypt( &key->ctx,
+    if( ( ret = mbedtls_cipher_auth_decrypt_ext( &key->ctx,
                     iv, TICKET_IV_BYTES,
                     /* Additional data: key name, IV and length */
                     key_name, TICKET_ADD_DATA_LEN,
-                    ticket, enc_len,
-                    ticket, &clear_len,
-                    tag, TICKET_AUTH_TAG_BYTES ) ) != 0 )
+                    ticket, enc_len + TICKET_AUTH_TAG_BYTES,
+                    ticket, enc_len, &clear_len,
+                    TICKET_AUTH_TAG_BYTES ) ) != 0 )
     {
         if( ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED )
             ret = MBEDTLS_ERR_SSL_INVALID_MAC;