How to decrypt message with CryptoJS AES. I have a working Ruby example

Priit picture Priit · Feb 19, 2013 · Viewed 78.9k times · Source

I'm able to decrypt AES encrypted message with Ruby like this:

require 'openssl'
require 'base64'

data = "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"
key = "2e35f242a46d67eeb74aabc37d5e5d05"

aes = OpenSSL::Cipher::Cipher.new('aes-128-cbc')
aes.decrypt
aes.key = key.scan(/../).collect{ |x| x.hex }.pack('c*')
aes.iv = Base64.decode64(data)[0...16]
puts aes.update(Base64.decode64(data)[16..-1]) + aes.final
# => JSON data...

Being new to CryptoJS I fail to put together working alternative. Here's what i've done so far:

data = "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";
key = "2e35f242a46d67eeb74aabc37d5e5d05";

CryptoJS.AES.decrypt(atob(data).substring(16), key, {
    iv: atob(cipher).substring(0, 16),
    mode: CryptoJS.mode.CBC,
    padding: CryptoJS.pad.Pkcs7
});

Does CryptoJS expect data, key and initialization vector in some different way? As far as i understand, the IV are the first 16 bytes in data.

Answer

rkj picture rkj · Mar 24, 2014

This works for decryption using javascript.

<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.9-1/aes.js"></script>
var key = "2e35f242a46d67eeb74aabc37d5e5d05";
var data = CryptoJS.AES.encrypt("Message", key); // Encryption Part
var decrypted = CryptoJS.AES.decrypt(data, key).toString(CryptoJS.enc.Utf8); // Message

Guess I am a little late to the party.