diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 90e2a81..468273d 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -93,7 +93,7 @@
             continue;
         }
 
-        if( memcmp( session->id, entry->session.id,
+        if( mbedtls_platform_memcmp( session->id, entry->session.id,
                     entry->session.id_len ) != 0 )
             continue;
 
@@ -179,7 +179,7 @@
         }
 #endif
 
-        if( memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 )
+        if( mbedtls_platform_memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 )
             break; /* client reconnected, keep timestamp for session id */
 
 #if defined(MBEDTLS_HAVE_TIME)