<?php
/* $Id$ */
namespace Mammut\Crypt;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

/**
 * A encapsulation class of the mcrypt extension functions
 * 
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\Security
 */
class MCrypt extends \Mammut\StrictObject {
	private $key = NULL;
	private $cipher;
	private $iv = NULL;
	const CIPHER_AES = MCRYPT_RIJNDAEL_128;
	const CIPHER_BLOWFISH = MCRYPT_BLOWFISH;
	const CIPHER_RIJNDAEL_128 = MCRYPT_RIJNDAEL_128;

	public function __construct($cipher) {
		if(!extension_loaded('mcrypt'))
			throw new \Mammut\Exception\ExtensionException('mcrypt');
		$this->cipher = $cipher;
		
		$this->iv = '';
		
		for($i = 0; $i < mcrypt_get_iv_size($cipher, MCRYPT_MODE_CBC); $i++) {
			$this->iv .= chr(65 + $i % 6);
		}
	}

	public function setKey($key) {
		$this->key = $key;
	}

	/**
	 * encodes a string with the parameters given
	 *
	 * @param string $data
	 *        	paintext
	 * @return string the encoded string
	 */
	public function encode($data, $key = false) {
		if(empty($key))
			$key = $this->key;
		return mcrypt_encrypt($this->cipher, $key, $data, MCRYPT_MODE_CBC, $this->iv);
	}

	/**
	 * decodes a string with the parameters given
	 *
	 * @param string $data
	 *        	crypttext
	 * @return string the decoded string
	 */
	public function decode($data, $key = false) {
		if(empty($key))
			$key = $this->key;
		return mcrypt_decrypt($this->cipher, $key, $data, MCRYPT_MODE_CBC, $this->iv);
	}
}