diff --git a/library/pkcs5.c b/library/pkcs5.c
index b9b51e5..182d632 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -201,7 +201,7 @@
     if( ( ret = cipher_init_ctx( &cipher_ctx, cipher_info ) ) != 0 )
         goto exit;
 
-    if( ( ret = cipher_setkey( &cipher_ctx, key, 8 * keylen, mode ) ) != 0 )
+    if( ( ret = cipher_setkey( &cipher_ctx, key, 8 * keylen, (operation_t) mode ) ) != 0 )
         goto exit;
 
     if( ( ret = cipher_crypt( &cipher_ctx, iv, enc_scheme_params.len,