MadelineProto/crypt.php
2016-07-15 13:03:36 +02:00

69 lines
2.5 KiB
PHP

<?php
set_include_path(get_include_path().PATH_SEPARATOR.dirname(__FILE__).DIRECTORY_SEPARATOR.'libpy2php');
require_once 'libpy2php.php';
require_once 'aes256.php';
class crypt
{
public function ige_encrypt($message, $key, $iv)
{
return _ige($message, $key, $iv, 'encrypt');
}
public function ige_decrypt($message, $key, $iv)
{
return _ige($message, $key, $iv, 'decrypt');
}
/**
* Given a key, given an iv, and message
* do whatever operation asked in the operation field.
* Operation will be checked for: "decrypt" and "encrypt" strings.
* Returns the message encrypted/decrypted.
* message must be a multiple by 16 bytes (for division in 16 byte blocks)
* key must be 32 byte
* iv must be 32 byte (it's not internally used in AES 256 ECB, but it's
* needed for IGE).
*/
public function _ige($message, $key, $iv, $operation = 'decrypt')
{
$message = str_split($message);
if ((len($key) != 32)) {
throw new Exception('key must be 32 bytes long (was '.len($key).' bytes)');
}
if ((len($iv) != 32)) {
throw new Exception('iv must be 32 bytes long (was '.len($iv).' bytes)');
}
$cipher = new AES($key);
$cipher = $cipher->encrypt($iv);
$blocksize = $cipher->block_size;
if ((len($message) % $blocksize) != 0) {
throw new Exception('message must be a multiple of 16 bytes (try adding '.(16 - (count($message) % 16)).' bytes of padding)');
}
$ivp = substr($iv, 0, $blocksize - 0);
$ivp2 = substr($iv, $blocksize, null);
$ciphered = null;
foreach (pyjslib_range(0, len($message), $blocksize) as $i) {
$indata = substr($message, $i, ($i + $blocksize) - $i);
if (($operation == 'decrypt')) {
$xored = strxor($indata, $ivp2);
$decrypt_xored = $cipher->decrypt($xored);
$outdata = strxor($decrypt_xored, $ivp);
$ivp = $indata;
$ivp2 = $outdata;
} elseif (($operation == 'encrypt')) {
$xored = strxor($indata, $ivp);
$encrypt_xored = $cipher->encrypt($xored);
$outdata = strxor($encrypt_xored, $ivp2);
$ivp = $outdata;
$ivp2 = $indata;
} else {
throw new Exception('operation must be either \'decrypt\' or \'encrypt\'');
}
$ciphered .= $outdata;
}
return $ciphered;
}
}