diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index d6c5443..5b590db 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -144,7 +144,7 @@
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
 
-    memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
+    mbedtls_platform_memcpy( *p, hmac_out, COOKIE_HMAC_LEN );
     *p += COOKIE_HMAC_LEN;
 
     return( 0 );