<?php
/**
* @version $Id: crypto.php 48641 2011-05-30 17:24:41Z kt $
* @category Divinity
* @package Framework
* @subpackage Crypt
*/

///////////////////////////////////////////////////////////////////////////////

/**
* Cryptographic-related functionality
*
* @package Framework
* @subpackage Crypt
*/
class crypto {

	/**
	 * Encrypt a string
	 *
	 * @param string $input plain original text for encryption
	 * @param string $cipher algorithm for encryption
	 * @param string $mode mode for encryprtion
	 * @return string
	 */
	public static function encrypt($input, $key = null, $cipher = 'blowfish', $mode = 'ecb') {

		if (!isset($key)) {
			$key = vars::get_var('crypt_key');
		}

		$td = mcrypt_module_open($cipher, '', $mode, '');

		$random_seed = strstr(PHP_OS, 'WIN')
			? MCRYPT_RAND
			: MCRYPT_DEV_URANDOM;

		$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), $random_seed);
	   	$ks = mcrypt_enc_get_key_size($td);
	   	$key = substr(sha1($key), 0, $ks); //  Create key

	   	mcrypt_generic_init($td, $key, $iv);
	   	$encrypted_data = base64_encode(mcrypt_generic($td, $input));
	   	mcrypt_generic_deinit($td);
	   	mcrypt_module_close($td);

	  	return $encrypted_data;
  	}


  	/**
	 * Decrypt a string
	 *
	 * @param string $input encrypted string for decryption
	 * @param string $cipher algorithm for decryption
	 * @param string $mode mode for decryption
	 * @return string
	 */
	public static function decrypt($input, $key = null, $cipher = 'blowfish', $mode = 'ecb') {

		if (!isset($key)) {
			$key = vars::get_var('crypt_key');
		}

		$td = mcrypt_module_open($cipher, '', $mode, '');

		$random_seed = strstr(PHP_OS, 'WIN')
			? MCRYPT_RAND
			: MCRYPT_DEV_URANDOM;

		$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), $random_seed);
		$ks = mcrypt_enc_get_key_size($td);
		$key = substr(sha1($key), 0, $ks); //  Create key

		mcrypt_generic_init($td, $key, $iv);
		$decrypted = @mdecrypt_generic($td, base64_decode($input));
		mcrypt_generic_deinit($td);
		mcrypt_module_close($td);

		return trim($decrypted);
	}

  	// -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

  	/**
	 * Returns all supported algorithms
	 * @return array
	 */
  	public static function algorithms() {
   		return mcrypt_list_algorithms();
  	}

  	/**
	 * Returns all supported modes
	 * @return array
	 */
  	public static function modes() {
   		return mcrypt_list_modes();
  	}

 	// -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

	/**
	* Returns a random unique (by default) id
	*
	* @param string	$prefix
	* @param boolean $pseudo return a pseudo random id
	* @return	string
	*/
	public static function id($prefix = '', $pseudo = false) {

		if ($prefix == '') {
			$prefix = site::hostnames_and_uris(null, 'hostname');
			}

		if ($pseudo) {
			return sha1(uniqid($prefix, true));
		}

		// todo ?? same as the pseudo option
		//
		return sha1(uniqid($prefix, true));
	}

	/**
	* Returns a pseudo random id
	*/
	public static function pseudo_id($prefix = '') {
		return self::id($prefix, true);
	}

	/**
	* Generates a HMAC using the default MAS key
	*/
	public static function hmac($data, $key = null) {
		return self::hmac_sha1($data, $key);
	}

	/**
	* Generates a SHA1 HMAC using the default MAS key
	* @uses Crypt_HMAC
	*/
	public static function hmac_sha1($data, $key = null) {

		require_once 'Crypt/HMAC.php';

		if (!isset($key)) {
			$key = vars::get_var('hmac_key');
		}

		$crypt = new Crypt_HMAC($key, 'sha1');
		return $crypt->hash($data);
	}

	/**
	* Checks HMACs used in URLs
	*
	* @param	string	$data	serialized hmac and data
	* @param	boolean	$error_redirect	the user should be redirected to a security error page
	* @return	string
	*/
	public static function get_from_hmac($data, $error_redirect = true) {

		list($hmac, $string) = unserialize($data);

		if (self::hmac($string) != $hmac) {
			info('Invalid HMAC.');

			if ($error_redirect) {
				http::redirect(http::html_url() . 'index.php?page=errors&id=security');
			}
			return '';
		}

		return $string;
	}

	/**
	* Adds a HMAC to a value
	*
	* @param	string	$data	serialized data
	* @return	string
	*/
	public static function add_hmac($data) {
		return serialize(array(self::hmac($data), $data));
	}

  	/**
  	* Generates a random password (do not use O/0, I/l/1)
  	*
  	* 35-126 alphanumeric + symbols
  	* 65-122 alphanumeric + less symbols
  	*
  	* @param integer $min_length
  	* @param integer $max_length
  	* @return	string
  	*/
  	public static function random_password($min_length = 6, $max_length = 8) {

		$password = '';
		$length = mt_rand($min_length, $max_length);
		$avoid = array(73, 76, 79, 105, 108, 111);

		while (strlen($password) < $length) {
			$rand = mt_rand(50, 122);

			if ($rand > 90 and $rand < 97) {
				continue;
			}

			if ($rand > 57 and $rand < 65) {
				continue;
			}

			if (in_array($rand, $avoid)) {
				continue;
			}

			$password .= chr($rand);
		}

		return $password;
  	}

  	/**
  	* Generates a random string of digits
  	*
  	* @param integer $min_length
  	* @param integer $max_length
  	* @return	string
  	*/
  	public static function random_digits($min_length = 4, $max_length = 8) {

		$password = '';
		$length = mt_rand($min_length, $max_length);

		for ($i = 0; $i < $length; $i++) {
			$password .= mt_rand(0, 9);
		}

		return $password;
  	}

	/**
	* Generate random user password
	*
	* @param string $type type of the password: "admin" for toolkit accounts and empty for regular
	* @return boolean
	*/
	public static function generate_user_password ($type = '') {

	$password = '';
	$avoid = array(48, 73, 76, 79, 105, 108, 111);
	$spec_chars = array(
		'`', '~', '!', '@', '#', '$', '%', '^', '&', '*', '(',
		')', '-', '_', '=', '+', '[', '{', ']', '}', '\\', '|',
		';', ':', '\'', '"', ',', '<', '.', '>', '/', '?'
	);

	while (!user::validate_password($password, $type)) {

		$char = chr(mt_rand(97, 122));

		if (!in_array($char, $avoid)) {
			$password .= $char;
		}

		$char = chr(mt_rand(65, 90));
		if (!in_array($char, $avoid)) {
			$password .= $char;
		}

		$char = chr(mt_rand(48, 57));
		if (!in_array($char, $avoid)) {
			$password .= $char;
		}

		if ($type == 'admin') {
			$password .= $spec_chars[array_rand($spec_chars)];
		}
	}

	return $password;
		}

  	/**
  	 * Reverse the bin2hex func
  	 *
  	 * @param string $h
  	 * @return string
  	 */
  	public static function hex2bin($h) {

  		if (!is_string($h)) {
			return null;
		}

		$r = '';

		for ($a=0; $a<strlen($h); $a+=2) {
			$r .= chr(hexdec($h{$a} . $h{($a+1)}));
		}

  		return $r;
  }

	////--end-of-file----
	}