supporting disabled password option in the JS part, fixes #55

js/zerobin.js

@@ -443,7 +443,7 @@ $(function() {
          */
         cipher: function(key, password, message)
         {
-            password = password.trim();
+            password = (password || '').trim();
             if (password.length == 0)
             {
                 return sjcl.encrypt(key, this.compress(message));