Shows what cyrpto-js returns when random cyphers / keys are used when calling decrypt

crypto-js-decryption-test.js

var CryptoJS = require('crypto-js');

var total = 100000;
var counter = 0;
var empty = 0;
var other = 0;

function makeString(len)
{
    var text = "";
    var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 ;+=";
    for( var i=0; i < len; i++ ) {
      text += possible.charAt(Math.floor(Math.random() * possible.length));    
    }
    return text;
}

for ( var i = 0; i < total; i++) {
 var cypher = makeString(10);
 var key = makeString(15);
  var bytes  = CryptoJS.AES.decrypt(cypher,key);
  try {
      var plaintext = bytes.toString(CryptoJS.enc.Utf8);
      if ( plaintext === '' ) {
          empty++;
      } else {
          other++;
      }  
  } catch(e) {
      counter ++;
  }
}

console.log("total caught: " + counter + " " + ((counter / total)*100) + "%");
console.log("total empty: " + empty + " " + ((empty / total)*100)+ "%");
console.log("total other: " + other + " " + ((other / total)*100)+ "%");

Ian,

Thank you for writing that blog post describing your findings from this test. It directly addressed a frustratingly elusive bug that I'd been dealing with.

Cheers!