Crypto.js decrypt with key and iv (vector) in byte arrays

Question

I have to decrypt some strings which are AES encrypted.

Example encrypted string: 129212143036071008133136215105140171136216244116

I have a key, and a vector (iv) supplied to me in a byte-array format:

Key: [ 123, 217, 20, 11, 24, 26, 85, 45, 114, 184, 27, 162, 37, 115, 222, 209, 241, 24, 175, 144, 175, 53, 196, 29, 24, 23, 17, 218, 131, 226, 53, 209 ]

Vector (iv): [ 146, 66, 191, 151, 23, 3, 113, 119, 231, 131, 133, 112, 79, 32, 114, 136 ]

I should be able to decrypt the string and get:

Correct output: testtest

I'm trying to use Crypto.js but I can't find a way to use the supplied key and vector. I can't find a way to convert the byte-arrays to hex.

var encrypted = '129212143036071008133136215105140171136216244116';
var key = CryptoJS.enc.Hex.parse([ 123, 217, 20, 11, 24, 26, 85, 45, 114, 184, 27, 162, 37, 115, 222, 209, 241, 24, 175, 144, 175, 53, 196, 29, 24, 23, 17, 218, 131, 226, 53, 209 ]);
var iv  = CryptoJS.enc.Hex.parse([ 146, 66, 191, 151, 23, 3, 113, 119, 231, 131, 133, 112, 79, 32, 114, 136 ]);

var decrypted = CryptoJS.AES.decrypt(encrypted, key, { iv: iv });

console.log('Output: '+decrypted.toString(CryptoJS.enc.Utf8)); //Should be "testtest"

I would be so grateful if anyone could show me how to decrypt the example string using the key and vector with Crypto.js OR any other js method.

Thanks so much for any help, Kind regards

Answer 1

I can't manage to decrypt your original string, but I can successful use it to encrypt and decrypt a new string. In your initial implementation, an error occurs in aes.js because it expects key and iv to be strings rather than arrays. I have corrected this code example below:

//var encrypted = '129212143036071008133136215105140171136216244116';

var key = CryptoJS.enc.Hex.parse(CryptoJS.lib.ByteArray([123, 217, 20, 11, 24, 26, 85, 45, 114, 184, 27, 162, 37, 115, 222, 209, 241, 24, 175, 144, 175, 53, 196, 29, 24, 23, 17, 218, 131, 226, 53, 209]));
var iv = CryptoJS.enc.Hex.parse(CryptoJS.lib.ByteArray([146, 66, 191, 151, 23, 3, 113, 119, 231, 131, 133, 112, 79, 32, 114, 136]));

var  message = 'testest'
var encrypted =  CryptoJS.AES.encrypt(message, key, {
  'iv': iv
});


var decrypted = CryptoJS.AES.decrypt(encrypted, key, {
  'iv': iv
});
document.write('Output: ' + decrypted.toString(CryptoJS.enc.Utf8)); //Should be "testtest"

<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/aes.js"></script>
<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/components/pad-nopadding-min.js"></script>
<script src="https://greasyfork.org/scripts/6696-cryptojs-lib-bytearray/code/CryptoJSlibByteArray.js"></script>