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<?php
/**
* Joomla! Content Management System
*
* @copyright (C) 2013 Open Source Matters, Inc. <https://www.joomla.org>
* @license GNU General Public License version 2 or later; see LICENSE.txt
* @note This file has been modified by the Joomla! Project and no longer reflects the original work of its author.
*/
namespace Joomla\CMS\Encrypt;
use Joomla\CMS\Encrypt\AES\AesInterface;
use Joomla\CMS\Encrypt\AES\Mcrypt;
use Joomla\CMS\Encrypt\AES\OpenSSL;
\defined('JPATH_PLATFORM') or die;
/**
* A simple implementation of AES-128, AES-192 and AES-256 encryption using the
* high performance mcrypt library.
*
* @since 1.0
*/
class Aes
{
/**
* The cipher key.
*
* @var string
*/
protected $key = '';
/**
* The AES encryption adapter in use.
*
* @var AesInterface
*/
protected $adapter;
/**
* Initialise the AES encryption object.
*
* Note: If the key is not 16 bytes this class will do a stupid key expansion for legacy reasons (produce the
* SHA-256 of the key string and throw away half of it).
*
* @param string $key The encryption key (password). It can be a raw key (16 bytes) or a passphrase.
* @param int $strength Bit strength (128, 192 or 256) – ALWAYS USE 128 BITS. THIS PARAMETER IS DEPRECATED.
* @param string $mode Encryption mode. Can be ebc or cbc. We recommend using cbc.
* @param string $priority Priority which adapter we should try first
*/
public function __construct($key, $strength = 128, $mode = 'cbc', $priority = 'openssl')
{
if ($priority === 'openssl')
{
$this->adapter = new OpenSSL;
if (!$this->adapter->isSupported())
{
$this->adapter = new Mcrypt;
}
}
else
{
$this->adapter = new Mcrypt;
if (!$this->adapter->isSupported())
{
$this->adapter = new OpenSSL;
}
}
$this->adapter->setEncryptionMode($mode, $strength);
$this->setPassword($key, true);
}
/**
* Sets the password for this instance.
*
* WARNING: Do not use the legacy mode, it's insecure
*
* @param string $password The password (either user-provided password or binary encryption key) to use
* @param bool $legacyMode True to use the legacy key expansion. We recommend against using it.
*
* @since 4.0.0
* @return void
*/
public function setPassword($password, $legacyMode = false)
{
$this->key = $password;
$passLength = \strlen($password);
if (\function_exists('mb_strlen'))
{
$passLength = mb_strlen($password, 'ASCII');
}
// Legacy mode was doing something stupid, requiring a key of 32 bytes. DO NOT USE LEGACY MODE!
if ($legacyMode && ($passLength != 32))
{
// Legacy mode: use the sha256 of the password
$this->key = hash('sha256', $password, true);
// We have to trim or zero pad the password (we end up throwing half of it away in Rijndael-128 / AES...)
$this->key = $this->adapter->resizeKey($this->key, $this->adapter->getBlockSize());
}
}
/**
* Encrypts a string using AES
*
* @param string $stringToEncrypt The plaintext to encrypt
* @param bool $base64encoded Should I Base64-encode the result?
*
* @return string The cryptotext. Please note that the first 16 bytes of
* the raw string is the IV (initialisation vector) which
* is necessary for decoding the string.
*/
public function encryptString($stringToEncrypt, $base64encoded = true)
{
$blockSize = $this->adapter->getBlockSize();
$randVal = new Randval;
$iv = $randVal->generate($blockSize);
$key = $this->getExpandedKey($blockSize, $iv);
$cipherText = $this->adapter->encrypt($stringToEncrypt, $key, $iv);
// Optionally pass the result through Base64 encoding
if ($base64encoded)
{
$cipherText = base64_encode($cipherText);
}
// Return the result
return $cipherText;
}
/**
* Decrypts a ciphertext into a plaintext string using AES
*
* @param string $stringToDecrypt The ciphertext to decrypt. The first 16 bytes of the raw string must contain
* the IV (initialisation vector).
* @param bool $base64encoded Should I Base64-decode the data before decryption?
*
* @return string The plain text string
*/
public function decryptString($stringToDecrypt, $base64encoded = true)
{
if ($base64encoded)
{
$stringToDecrypt = base64_decode($stringToDecrypt);
}
// Extract IV
$iv_size = $this->adapter->getBlockSize();
$iv = substr($stringToDecrypt, 0, $iv_size);
$key = $this->getExpandedKey($iv_size, $iv);
// Decrypt the data
$plainText = $this->adapter->decrypt($stringToDecrypt, $key);
return $plainText;
}
/**
* Is AES encryption supported by this PHP installation?
*
* @return boolean
*/
public static function isSupported()
{
$adapter = new Mcrypt;
if (!$adapter->isSupported())
{
$adapter = new OpenSSL;
}
if (!$adapter->isSupported())
{
return false;
}
if (!\function_exists('base64_encode'))
{
return false;
}
if (!\function_exists('base64_decode'))
{
return false;
}
if (!\function_exists('hash_algos'))
{
return false;
}
$algorightms = hash_algos();
if (!\in_array('sha256', $algorightms))
{
return false;
}
return true;
}
/**
* Get the expanded key
*
* @param integer $blockSize Blocksize to process
* @param string $iv IV
*
* @return string
*/
public function getExpandedKey($blockSize, $iv)
{
$key = $this->key;
$passLength = \strlen($key);
if (\function_exists('mb_strlen'))
{
$passLength = mb_strlen($key, 'ASCII');
}
if ($passLength != $blockSize)
{
$iterations = 1000;
$salt = $this->adapter->resizeKey($iv, 16);
$key = hash_pbkdf2('sha256', $this->key, $salt, $iterations, $blockSize, true);
}
return $key;
}
}
if (!\function_exists('hash_pbkdf2'))
{
/**
* Shim for missing hash_pbkdf2
*
* @param string $algo Algorithm to use
* @param string $password Plaintext password
* @param string $salt Salt for the hash
* @param integer $count Number of iterations
* @param integer $length Length
* @param boolean $rawOutput Raw output
*
* @return string Hashed string
*/
function hash_pbkdf2($algo, $password, $salt, $count, $length = 0, $rawOutput = false)
{
if (!\in_array(strtolower($algo), hash_algos()))
{
trigger_error(__FUNCTION__ . '(): Unknown hashing algorithm: ' . $algo, E_USER_WARNING);
}
if (!is_numeric($count))
{
trigger_error(__FUNCTION__ . '(): expects parameter 4 to be long, ' . \gettype($count) . ' given', E_USER_WARNING);
}
if (!is_numeric($length))
{
trigger_error(__FUNCTION__ . '(): expects parameter 5 to be long, ' . \gettype($length) . ' given', E_USER_WARNING);
}
if ($count <= 0)
{
trigger_error(__FUNCTION__ . '(): Iterations must be a positive integer: ' . $count, E_USER_WARNING);
}
if ($length < 0)
{
trigger_error(__FUNCTION__ . '(): Length must be greater than or equal to 0: ' . $length, E_USER_WARNING);
}
$output = '';
$block_count = $length ? ceil($length / \strlen(hash($algo, '', $rawOutput))) : 1;
for ($i = 1; $i <= $block_count; $i++)
{
$last = $xorsum = hash_hmac($algo, $salt . pack('N', $i), $password, true);
for ($j = 1; $j < $count; $j++)
{
$xorsum ^= ($last = hash_hmac($algo, $last, $password, true));
}
$output .= $xorsum;
}
if (!$rawOutput)
{
$output = bin2hex($output);
}
return $length ? substr($output, 0, $length) : $output;
}
}