diff --git a/lib/aes.js b/lib/aes.js
index 3c1ddb29b..cf3d2e8a0 100644
--- a/lib/aes.js
+++ b/lib/aes.js
@@ -200,7 +200,7 @@ forge.aes.Algorithm.prototype.initialize = function(options) {
     key = [];
 
     // key lengths of 16, 24, 32 bytes allowed
-    var len = tmp.length();
+    var len = tmp.length;
     if(len === 16 || len === 24 || len === 32) {
       len = len >>> 2;
       for(var i = 0; i < len; ++i) {