diff --git a/library/rsa.c b/library/rsa.c
index 6b034c6..abc028d 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -604,7 +604,7 @@
             // Check if RNG failed to generate data
             //
             if( rng_dl == 0 || ret != 0)
-                return POLARSSL_ERR_RSA_RNG_FAILED + ret;
+                return( POLARSSL_ERR_RSA_RNG_FAILED + ret );
 
             p++;
         }