diff --git a/library/aes.c b/library/aes.c
index 766aa21..1f21587 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1013,7 +1013,7 @@
 
     do
     {
-        gf128mul_x_ble( t_buf, t_buf );
+        mbedtls_gf128mul_x_ble( t_buf, t_buf );
 
 first:
         /* PP <- T xor P */