slowAES decrypt to another key - php

Question

There was a problem with the old slowAES library.
When trying to decrypt, in js it produces one, and in php it produces another.
There are a lot of errors in the console that I can’t figure out.
Tell me what's wrong? How to get the same keys?
<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
$a = "cd36b76f96b103402924bd5f76d3c204";
$b = "680eb6a492f48ea1b342aea7b79e18eb";
$c = "f746749b113236227058bd471f5c91dc";
function toHex($args){
if(func_num_args() != 1 || !is_array($args)){
$args = func_get_args();
}
$ret = '';
for($i = 0; $i < count($args) ;$i++)
$ret .= sprintf('%02x', $args[$i]);
return $ret;
}
function toNumbers($s){
$ret = array();
for($i=0; $i<strlen($s); $i+=2){
$ret[] = hexdec(substr($s, $i, 2));
}
return $ret;
}
function getRandom($min,$max){
if($min === null)
$min = 0;
if($max === null)
$max = 1;
return mt_rand($min, $max);
}
function generateSharedKey($len){
if($len === null)
$len = 16;
$key = array();
for($i = 0; $i < $len; $i++)
$key[] = getRandom(0,255);
return $key;
}
function generatePrivateKey($s,$size){
if(function_exists('mhash') && defined('MHASH_SHA256')){
return convertStringToByteArray(substr(mhash(MHASH_SHA256, $s), 0, $size));
}else{
throw new Exception('cryptoHelpers::generatePrivateKey currently requires mhash');
}
}
function convertStringToByteArray($s){
$byteArray = array();
for($i = 0; $i < strlen($s); $i++){
$byteArray[] = ord($s[$i]);
}
return $byteArray;
}
function convertByteArrayToString($byteArray){
$s = '';
for($i = 0; $i < count($byteArray); $i++){
$s .= chr($byteArray[$i]);
}
return $s;
}
include 'cryptovh/aes.php';
$aes = new AES();
$token = $aes->decrypt(toNumbers($c), 16, 2, toNumbers($a), 16, toNumbers($b));
echo toHex($token); // WHAT I HAVE
echo "<br>";
echo "016e9be78dd5130beb5febcd328ff588"; // WHAT I NEED
?>
cryptovh/aes.php
that is copy of: https://github.com/aleaxit/slowaes/blob/master/php/aes_fast.php
use this library:
https://github.com/aleaxit/slowaes
At the output, I get this token:
dd2f6d60b939b390dc19688babc3873d
And console errors:
Notice: Undefined offset: 16 in
/var/www/myuser/data/www/example.com/cryptovh/aes.php on line 386
Notice: Undefined index: in
/var/www/myuser/data/www/example.com/cryptovh/aes.php on line 386
Notice: Undefined offset: 20 in
/var/www/myuser/data/www/example.com/cryptovh/aes.php on line 386
Notice: Undefined index: in
/var/www/myuser/data/www/example.com/cryptovh/aes.php on line 386
Notice: Undefined offset: 24 in
/var/www/myuser/data/www/example.com/cryptovh/aes.php on line 386
Notice: Undefined index: in
/var/www/myuser/data/www/example.com/panel/cryptovh/aes.php on line
386

Answer 1

In slowaes/php/aes_fast.php, the inversion of the MixColumns operation in the mixColumns method is implemented incorrectly, the else-block must be:
...
} else {
for ($c = 0; $c < 4; $c++) {
$t[ $c] = self::$GEX[$state[$c]] ^ self::$GBX[$state[4+$c]] ^ self::$GDX[$state[8+$c]] ^ self::$G9X[$state[12+$c]];
$t[ 4+$c] = self::$G9X[$state[$c]] ^ self::$GEX[$state[4+$c]] ^ self::$GBX[$state[8+$c]] ^ self::$GDX[$state[12+$c]];
$t[ 8+$c] = self::$GDX[$state[$c]] ^ self::$G9X[$state[4+$c]] ^ self::$GEX[$state[8+$c]] ^ self::$GBX[$state[12+$c]];
$t[12+$c] = self::$GBX[$state[$c]] ^ self::$GDX[$state[4+$c]] ^ self::$G9X[$state[8+$c]] ^ self::$GEX[$state[12+$c]];
}
}
...
The inverse of the MixColumns operation is required for decryption.
There is also a typo in the method invMain, line 3, where i must be replaced by $i.
With these changes, the expected result is obtained, which can be verified e.g. here. The warnings are also no longer displayed.
I've filed an issue here. Note the ReadMe: The code is intended more for didactic purposes. In practice, openssl_encrypt / openssl_decrypt or similar should be used.