diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index dbef29b..06194bd 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -1124,7 +1124,9 @@
                              mbedtls_ssl_transform *transform,
                              mbedtls_record *rec )
 {
+#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) || defined(MBEDTLS_CIPHER_MODE_AEAD)
     size_t olen;
+#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC || MBEDTLS_CIPHER_MODE_AEAD */
     mbedtls_ssl_mode_t ssl_mode;
     int ret;