Question

So basically I have these snippets of code and would like them to produce the same output:

require 'openssl'
aes = OpenSSL::Cipher::Cipher.new("AES-128-CBC")
aes.key = "aaaaaaaaaaaaaaaa"
aes.iv = "aaaaaaaaaaaaaaaa"
aes.encrypt
encrypted = aes.update("1234567890123456") << aes.final
puts encrypted.unpack('H*').join

This prints:

8d3bbffade308f8e4e80cb77ecb8df19ee933f75438cec1315c4a491bd1b83f4

And this Java code:

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
String key = "aaaaaaaaaaaaaaaa";
String textToEncryptpt = "1234567890123456";

SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
IvParameterSpec ivspec = new IvParameterSpec(key.getBytes());
cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
byte[] encrypted = cipher.doFinal(textToEncryptpt.getBytes());
System.out.println(Crypto.bytesToHex(encrypted));

Prints:

2d3760f53b8b3dee722aed83224f418f9dd70e089ecfe9dc689147cfe0927ddb

Annoying thing is that it was working a couple of days ago… so I am not sure what happened. What’s wrong with this code? Do you see anything unusual?

Answer 1

Ruby script is wrong. You have to first call the encrypt method, and then set the key and iv:

require 'openssl'
aes = OpenSSL::Cipher::Cipher.new("AES-128-CBC")
aes.encrypt
aes.key = "aaaaaaaaaaaaaaaa"
aes.iv = "aaaaaaaaaaaaaaaa"
encrypted = aes.update("1234567890123456") << aes.final
puts encrypted.unpack('H*').join

I figured out because when trying to decode an encrypted string I got:

aescrypt.rb:13:in `final': bad decrypt (OpenSSL::Cipher::CipherError)
    from aescrypt.rb:13:in `<main>'