MIF_E31222691/system/crypt.php

121 lines
3.0 KiB
PHP

<?php namespace System;
class Crypt {
/**
* The encryption cipher.
*
* @var string
*/
public static $cipher = 'rijndael-256';
/**
* The encryption mode.
*
* @var string
*/
public static $mode = 'cbc';
/**
* Encrypt a value using the MCrypt library.
*
* @param string $value
* @return string
*/
public static function encrypt($value)
{
// -----------------------------------------------------
// Determine the input vector source. Different servers
// and operating systems will have varying options.
// -----------------------------------------------------
if (defined('MCRYPT_DEV_URANDOM'))
{
$random = MCRYPT_DEV_URANDOM;
}
elseif (defined('MCRYPT_DEV_RANDOM'))
{
$random = MCRYPT_DEV_RANDOM;
}
else
{
$random = MCRYPT_RAND;
}
// -----------------------------------------------------
// The system random number generator must be seeded
// to produce adequately random results.
// -----------------------------------------------------
if ($random === MCRYPT_RAND)
{
mt_srand();
}
$iv = mcrypt_create_iv(static::iv_size(), $random);
$value = mcrypt_encrypt(static::$cipher, static::key(), $value, static::$mode, $iv);
// -----------------------------------------------------
// We use base64 encoding to get a nice string value.
// -----------------------------------------------------
return base64_encode($iv.$value);
}
/**
* Decrypt a value using the MCrypt library.
*
* @param string $value
* @return string
*/
public static function decrypt($value)
{
// -----------------------------------------------------
// Since all of our encrypted values are base64 encoded,
// we will decode the value here and verify it.
// -----------------------------------------------------
$value = base64_decode($value, true);
if ( ! $value)
{
throw new \Exception('Decryption error. Input value is not valid base64 data.');
}
// -----------------------------------------------------
// Extract the input vector from the value.
// -----------------------------------------------------
$iv = substr($value, 0, static::iv_size());
// -----------------------------------------------------
// Remove the input vector from the encrypted value.
// -----------------------------------------------------
$value = substr($value, static::iv_size());
return rtrim(mcrypt_decrypt(static::$cipher, static::key(), $value, static::$mode, $iv), "\0");
}
/**
* Get the application key.
*
* @return string
*/
private static function key()
{
if (is_null($key = Config::get('application.key')) or $key == '')
{
throw new \Exception("The encryption class can not be used without an encryption key.");
}
return $key;
}
/**
* Get the input vector size for the cipher and mode.
*
* Different ciphers and modes use varying lengths of input vectors.
*
* @return int
*/
private static function iv_size()
{
return mcrypt_get_iv_size(static::$cipher, static::$mode);
}
}