<?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;
    }
}