493 lines
15 KiB
PHP
493 lines
15 KiB
PHP
|
<?php
|
||
|
|
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Pure-PHP implementation of RC4.
|
||
|
|
*
|
||
|
|
* Uses mcrypt, if available, and an internal implementation, otherwise.
|
||
|
|
*
|
||
|
|
* PHP versions 4 and 5
|
||
|
|
*
|
||
|
|
* Useful resources are as follows:
|
||
|
|
*
|
||
|
|
* - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}
|
||
|
|
* - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}
|
||
|
|
*
|
||
|
|
* RC4 is also known as ARCFOUR or ARC4. The reason is elaborated upon at Wikipedia. This class is named RC4 and not
|
||
|
|
* ARCFOUR or ARC4 because RC4 is how it is referred to in the SSH1 specification.
|
||
|
|
*
|
||
|
|
* Here's a short example of how to use this library:
|
||
|
|
* <code>
|
||
|
|
* <?php
|
||
|
|
* include('Crypt/RC4.php');
|
||
|
|
*
|
||
|
|
* $rc4 = new Crypt_RC4();
|
||
|
|
*
|
||
|
|
* $rc4->setKey('abcdefgh');
|
||
|
|
*
|
||
|
|
* $size = 10 * 1024;
|
||
|
|
* $plaintext = '';
|
||
|
|
* for ($i = 0; $i < $size; $i++) {
|
||
|
|
* $plaintext.= 'a';
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* echo $rc4->decrypt($rc4->encrypt($plaintext));
|
||
|
|
* ?>
|
||
|
|
* </code>
|
||
|
|
*
|
||
|
|
* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
|
||
|
|
* of this software and associated documentation files (the "Software"), to deal
|
||
|
|
* in the Software without restriction, including without limitation the rights
|
||
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
||
|
|
* copies of the Software, and to permit persons to whom the Software is
|
||
|
|
* furnished to do so, subject to the following conditions:
|
||
|
|
*
|
||
|
|
* The above copyright notice and this permission notice shall be included in
|
||
|
|
* all copies or substantial portions of the Software.
|
||
|
|
*
|
||
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
||
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
||
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
||
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
||
|
|
* THE SOFTWARE.
|
||
|
|
*
|
||
|
|
* @category Crypt
|
||
|
|
* @package Crypt_RC4
|
||
|
|
* @author Jim Wigginton <terrafrost@php.net>
|
||
|
|
* @copyright MMVII Jim Wigginton
|
||
|
|
* @license http://www.opensource.org/licenses/mit-license.html MIT License
|
||
|
|
* @link http://phpseclib.sourceforge.net
|
||
|
|
*/
|
||
|
|
|
||
|
|
/**#@+
|
||
|
|
* @access private
|
||
|
|
* @see Crypt_RC4::Crypt_RC4()
|
||
|
|
*/
|
||
|
|
/**
|
||
|
|
* Toggles the internal implementation
|
||
|
|
*/
|
||
|
|
define('CRYPT_RC4_MODE_INTERNAL', 1);
|
||
|
|
/**
|
||
|
|
* Toggles the mcrypt implementation
|
||
|
|
*/
|
||
|
|
define('CRYPT_RC4_MODE_MCRYPT', 2);
|
||
|
|
/**#@-*/
|
||
|
|
|
||
|
|
/**#@+
|
||
|
|
* @access private
|
||
|
|
* @see Crypt_RC4::_crypt()
|
||
|
|
*/
|
||
|
|
define('CRYPT_RC4_ENCRYPT', 0);
|
||
|
|
define('CRYPT_RC4_DECRYPT', 1);
|
||
|
|
/**#@-*/
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Pure-PHP implementation of RC4.
|
||
|
|
*
|
||
|
|
* @author Jim Wigginton <terrafrost@php.net>
|
||
|
|
* @version 0.1.0
|
||
|
|
* @access public
|
||
|
|
* @package Crypt_RC4
|
||
|
|
*/
|
||
|
|
class Crypt_RC4 {
|
||
|
|
/**
|
||
|
|
* The Key
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::setKey()
|
||
|
|
* @var String
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $key = "\0";
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The Key Stream for encryption
|
||
|
|
*
|
||
|
|
* If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::setKey()
|
||
|
|
* @var Array
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $encryptStream = false;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The Key Stream for decryption
|
||
|
|
*
|
||
|
|
* If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::setKey()
|
||
|
|
* @var Array
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $decryptStream = false;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The $i and $j indexes for encryption
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::_crypt()
|
||
|
|
* @var Integer
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $encryptIndex = 0;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The $i and $j indexes for decryption
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::_crypt()
|
||
|
|
* @var Integer
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $decryptIndex = 0;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* The Encryption Algorithm
|
||
|
|
*
|
||
|
|
* Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT. Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::Crypt_RC4()
|
||
|
|
* @var Integer
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $mode;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Continuous Buffer status
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::enableContinuousBuffer()
|
||
|
|
* @var Boolean
|
||
|
|
* @access private
|
||
|
|
*/
|
||
|
|
var $continuousBuffer = false;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Default Constructor.
|
||
|
|
*
|
||
|
|
* Determines whether or not the mcrypt extension should be used.
|
||
|
|
*
|
||
|
|
* @return Crypt_RC4
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function Crypt_RC4()
|
||
|
|
{
|
||
|
|
if ( !defined('CRYPT_RC4_MODE') ) {
|
||
|
|
switch (true) {
|
||
|
|
case extension_loaded('mcrypt') && (defined('MCRYPT_ARCFOUR') || defined('MCRYPT_RC4')) && in_array('arcfour', mcrypt_list_algorithms()):
|
||
|
|
define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_MCRYPT);
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
switch ( CRYPT_RC4_MODE ) {
|
||
|
|
case CRYPT_RC4_MODE_MCRYPT:
|
||
|
|
switch (true) {
|
||
|
|
case defined('MCRYPT_ARCFOUR'):
|
||
|
|
$this->mode = MCRYPT_ARCFOUR;
|
||
|
|
break;
|
||
|
|
case defined('MCRYPT_RC4');
|
||
|
|
$this->mode = MCRYPT_RC4;
|
||
|
|
}
|
||
|
|
$this->encryptStream = mcrypt_module_open($this->mode, '', MCRYPT_MODE_STREAM, '');
|
||
|
|
$this->decryptStream = mcrypt_module_open($this->mode, '', MCRYPT_MODE_STREAM, '');
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Sets the key.
|
||
|
|
*
|
||
|
|
* Keys can be between 1 and 256 bytes long. If they are longer then 256 bytes, the first 256 bytes will
|
||
|
|
* be used. If no key is explicitly set, it'll be assumed to be a single null byte.
|
||
|
|
*
|
||
|
|
* @access public
|
||
|
|
* @param String $key
|
||
|
|
*/
|
||
|
|
function setKey($key)
|
||
|
|
{
|
||
|
|
$this->key = $key;
|
||
|
|
|
||
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
|
||
|
|
mcrypt_generic_init($this->encryptStream, $this->key, '');
|
||
|
|
mcrypt_generic_init($this->decryptStream, $this->key, '');
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
$keyLength = strlen($key);
|
||
|
|
$keyStream = array();
|
||
|
|
for ($i = 0; $i < 256; $i++) {
|
||
|
|
$keyStream[$i] = $i;
|
||
|
|
}
|
||
|
|
$j = 0;
|
||
|
|
for ($i = 0; $i < 256; $i++) {
|
||
|
|
$j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;
|
||
|
|
$temp = $keyStream[$i];
|
||
|
|
$keyStream[$i] = $keyStream[$j];
|
||
|
|
$keyStream[$j] = $temp;
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->encryptIndex = $this->decryptIndex = array(0, 0);
|
||
|
|
$this->encryptStream = $this->decryptStream = $keyStream;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Sets the password.
|
||
|
|
*
|
||
|
|
* Depending on what $method is set to, setPassword()'s (optional) parameters are as follows:
|
||
|
|
* {@link http://en.wikipedia.org/wiki/PBKDF2 pbkdf2}:
|
||
|
|
* $hash, $salt, $count, $dkLen
|
||
|
|
*
|
||
|
|
* @param String $password
|
||
|
|
* @param optional String $method
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function setPassword($password, $method = 'pbkdf2')
|
||
|
|
{
|
||
|
|
$key = '';
|
||
|
|
|
||
|
|
switch ($method) {
|
||
|
|
default: // 'pbkdf2'
|
||
|
|
list(, , $hash, $salt, $count) = func_get_args();
|
||
|
|
if (!isset($hash)) {
|
||
|
|
$hash = 'sha1';
|
||
|
|
}
|
||
|
|
// WPA and WPA2 use the SSID as the salt
|
||
|
|
if (!isset($salt)) {
|
||
|
|
$salt = 'phpseclib/salt';
|
||
|
|
}
|
||
|
|
// RFC2898#section-4.2 uses 1,000 iterations by default
|
||
|
|
// WPA and WPA2 use 4,096.
|
||
|
|
if (!isset($count)) {
|
||
|
|
$count = 1000;
|
||
|
|
}
|
||
|
|
if (!isset($dkLen)) {
|
||
|
|
$dkLen = 128;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!class_exists('Crypt_Hash')) {
|
||
|
|
require_once('Crypt/Hash.php');
|
||
|
|
}
|
||
|
|
|
||
|
|
$i = 1;
|
||
|
|
while (strlen($key) < $dkLen) {
|
||
|
|
//$dk.= $this->_pbkdf($password, $salt, $count, $i++);
|
||
|
|
$hmac = new Crypt_Hash();
|
||
|
|
$hmac->setHash($hash);
|
||
|
|
$hmac->setKey($password);
|
||
|
|
$f = $u = $hmac->hash($salt . pack('N', $i++));
|
||
|
|
for ($j = 2; $j <= $count; $j++) {
|
||
|
|
$u = $hmac->hash($u);
|
||
|
|
$f^= $u;
|
||
|
|
}
|
||
|
|
$key.= $f;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->setKey(substr($key, 0, $dkLen));
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Dummy function.
|
||
|
|
*
|
||
|
|
* Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].
|
||
|
|
* If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before
|
||
|
|
* calling setKey().
|
||
|
|
*
|
||
|
|
* [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way. Since, in that protocol,
|
||
|
|
* the IV's are relatively easy to predict, an attack described by
|
||
|
|
* {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}
|
||
|
|
* can be used to quickly guess at the rest of the key. The following links elaborate:
|
||
|
|
*
|
||
|
|
* {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}
|
||
|
|
* {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}
|
||
|
|
*
|
||
|
|
* @param String $iv
|
||
|
|
* @see Crypt_RC4::setKey()
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function setIV($iv)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Encrypts a message.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::_crypt()
|
||
|
|
* @access public
|
||
|
|
* @param String $plaintext
|
||
|
|
*/
|
||
|
|
function encrypt($plaintext)
|
||
|
|
{
|
||
|
|
return $this->_crypt($plaintext, CRYPT_RC4_ENCRYPT);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Decrypts a message.
|
||
|
|
*
|
||
|
|
* $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
|
||
|
|
* Atleast if the continuous buffer is disabled.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::_crypt()
|
||
|
|
* @access public
|
||
|
|
* @param String $ciphertext
|
||
|
|
*/
|
||
|
|
function decrypt($ciphertext)
|
||
|
|
{
|
||
|
|
return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Encrypts or decrypts a message.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::encrypt()
|
||
|
|
* @see Crypt_RC4::decrypt()
|
||
|
|
* @access private
|
||
|
|
* @param String $text
|
||
|
|
* @param Integer $mode
|
||
|
|
*/
|
||
|
|
function _crypt($text, $mode)
|
||
|
|
{
|
||
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
|
||
|
|
$keyStream = $mode == CRYPT_RC4_ENCRYPT ? 'encryptStream' : 'decryptStream';
|
||
|
|
|
||
|
|
if (!$this->continuousBuffer) {
|
||
|
|
mcrypt_generic_init($this->$keyStream, $this->key, '');
|
||
|
|
}
|
||
|
|
|
||
|
|
return mcrypt_generic($this->$keyStream, $text);
|
||
|
|
}
|
||
|
|
|
||
|
|
if ($this->encryptStream === false) {
|
||
|
|
$this->setKey($this->key);
|
||
|
|
}
|
||
|
|
|
||
|
|
switch ($mode) {
|
||
|
|
case CRYPT_RC4_ENCRYPT:
|
||
|
|
$keyStream = $this->encryptStream;
|
||
|
|
list($i, $j) = $this->encryptIndex;
|
||
|
|
break;
|
||
|
|
case CRYPT_RC4_DECRYPT:
|
||
|
|
$keyStream = $this->decryptStream;
|
||
|
|
list($i, $j) = $this->decryptIndex;
|
||
|
|
}
|
||
|
|
|
||
|
|
$newText = '';
|
||
|
|
for ($k = 0; $k < strlen($text); $k++) {
|
||
|
|
$i = ($i + 1) & 255;
|
||
|
|
$j = ($j + $keyStream[$i]) & 255;
|
||
|
|
$temp = $keyStream[$i];
|
||
|
|
$keyStream[$i] = $keyStream[$j];
|
||
|
|
$keyStream[$j] = $temp;
|
||
|
|
$temp = $keyStream[($keyStream[$i] + $keyStream[$j]) & 255];
|
||
|
|
$newText.= chr(ord($text[$k]) ^ $temp);
|
||
|
|
}
|
||
|
|
|
||
|
|
if ($this->continuousBuffer) {
|
||
|
|
switch ($mode) {
|
||
|
|
case CRYPT_RC4_ENCRYPT:
|
||
|
|
$this->encryptStream = $keyStream;
|
||
|
|
$this->encryptIndex = array($i, $j);
|
||
|
|
break;
|
||
|
|
case CRYPT_RC4_DECRYPT:
|
||
|
|
$this->decryptStream = $keyStream;
|
||
|
|
$this->decryptIndex = array($i, $j);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return $newText;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Treat consecutive "packets" as if they are a continuous buffer.
|
||
|
|
*
|
||
|
|
* Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets
|
||
|
|
* will yield different outputs:
|
||
|
|
*
|
||
|
|
* <code>
|
||
|
|
* echo $rc4->encrypt(substr($plaintext, 0, 8));
|
||
|
|
* echo $rc4->encrypt(substr($plaintext, 8, 8));
|
||
|
|
* </code>
|
||
|
|
* <code>
|
||
|
|
* echo $rc4->encrypt($plaintext);
|
||
|
|
* </code>
|
||
|
|
*
|
||
|
|
* The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates
|
||
|
|
* another, as demonstrated with the following:
|
||
|
|
*
|
||
|
|
* <code>
|
||
|
|
* $rc4->encrypt(substr($plaintext, 0, 8));
|
||
|
|
* echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
|
||
|
|
* </code>
|
||
|
|
* <code>
|
||
|
|
* echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
|
||
|
|
* </code>
|
||
|
|
*
|
||
|
|
* With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different
|
||
|
|
* outputs. The reason is due to the fact that the initialization vector's change after every encryption /
|
||
|
|
* decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.
|
||
|
|
*
|
||
|
|
* Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each
|
||
|
|
* encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that
|
||
|
|
* continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),
|
||
|
|
* however, they are also less intuitive and more likely to cause you problems.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::disableContinuousBuffer()
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function enableContinuousBuffer()
|
||
|
|
{
|
||
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
|
||
|
|
mcrypt_generic_init($this->encryptStream, $this->key, '');
|
||
|
|
mcrypt_generic_init($this->decryptStream, $this->key, '');
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->continuousBuffer = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Treat consecutive packets as if they are a discontinuous buffer.
|
||
|
|
*
|
||
|
|
* The default behavior.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::enableContinuousBuffer()
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function disableContinuousBuffer()
|
||
|
|
{
|
||
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_INTERNAL ) {
|
||
|
|
$this->encryptIndex = $this->decryptIndex = array(0, 0);
|
||
|
|
$this->encryptStream = $this->decryptStream = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
$this->continuousBuffer = false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Dummy function.
|
||
|
|
*
|
||
|
|
* Since RC4 is a stream cipher and not a block cipher, no padding is necessary. The only reason this function is
|
||
|
|
* included is so that you can switch between a block cipher and a stream cipher transparently.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::disablePadding()
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function enablePadding()
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Dummy function.
|
||
|
|
*
|
||
|
|
* @see Crypt_RC4::enablePadding()
|
||
|
|
* @access public
|
||
|
|
*/
|
||
|
|
function disablePadding()
|
||
|
|
{
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// vim: ts=4:sw=4:et:
|
||
|
|
// vim6: fdl=1:
|