comment update

src/app/services/cryptoService.js

@@ -431,7 +431,7 @@ angular
             return b64Output ? forge.util.encode64(mac.getBytes()) : mac.getBytes();
         }
 
-        // Safely compare two MACs in a way that protects against timing attacks.
+        // Safely compare two MACs in a way that protects against timing attacks (Double HMAC Verification).
         // ref: https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2011/february/double-hmac-verification/
         function macsEqual(macKey, mac1, mac2) {
             var hmac = forge.hmac.create();