kopia lustrzana https://github.com/friendica/friendica
493 wiersze
15 KiB
PHP
493 wiersze
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 refered 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: This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
* MA 02111-1307 USA
|
|
*
|
|
* @category Crypt
|
|
* @package Crypt_RC4
|
|
* @author Jim Wigginton <terrafrost@php.net>
|
|
* @copyright MMVII Jim Wigginton
|
|
* @license http://www.gnu.org/licenses/lgpl.txt
|
|
* @version $Id: RC4.php,v 1.8 2009/06/09 04:00:38 terrafrost Exp $
|
|
* @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;
|
|
|
|
/**
|
|
* MCrypt parameters
|
|
*
|
|
* @see Crypt_RC4::setMCrypt()
|
|
* @var Array
|
|
* @access private
|
|
*/
|
|
var $mcrypt = array('', '');
|
|
|
|
/**
|
|
* 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;
|
|
|
|
/**
|
|
* Default Constructor.
|
|
*
|
|
* Determines whether or not the mcrypt extension should be used.
|
|
*
|
|
* @param optional Integer $mode
|
|
* @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')):
|
|
// i'd check to see if rc4 was supported, by doing in_array('arcfour', mcrypt_list_algorithms('')),
|
|
// but since that can be changed after the object has been created, there doesn't seem to be
|
|
// a lot of point...
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 ) {
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
}
|
|
|
|
/**
|
|
* Sets MCrypt parameters. (optional)
|
|
*
|
|
* If MCrypt is being used, empty strings will be used, unless otherwise specified.
|
|
*
|
|
* @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open
|
|
* @access public
|
|
* @param optional Integer $algorithm_directory
|
|
* @param optional Integer $mode_directory
|
|
*/
|
|
function setMCrypt($algorithm_directory = '', $mode_directory = '')
|
|
{
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
|
|
$this->mcrypt = array($algorithm_directory, $mode_directory);
|
|
$this->_closeMCrypt();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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->$keyStream === false) {
|
|
$this->$keyStream = mcrypt_module_open($this->mode, $this->mcrypt[0], MCRYPT_MODE_STREAM, $this->mcrypt[1]);
|
|
mcrypt_generic_init($this->$keyStream, $this->key, '');
|
|
} else if (!$this->continuousBuffer) {
|
|
mcrypt_generic_init($this->$keyStream, $this->key, '');
|
|
}
|
|
$newText = mcrypt_generic($this->$keyStream, $text);
|
|
if (!$this->continuousBuffer) {
|
|
mcrypt_generic_deinit($this->$keyStream);
|
|
}
|
|
|
|
return $newText;
|
|
}
|
|
|
|
if ($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()
|
|
{
|
|
$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);
|
|
$this->setKey($this->key);
|
|
}
|
|
|
|
$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()
|
|
{
|
|
}
|
|
|
|
/**
|
|
* Class destructor.
|
|
*
|
|
* Will be called, automatically, if you're using PHP5. If you're using PHP4, call it yourself. Only really
|
|
* needs to be called if mcrypt is being used.
|
|
*
|
|
* @access public
|
|
*/
|
|
function __destruct()
|
|
{
|
|
if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
|
|
$this->_closeMCrypt();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Properly close the MCrypt objects.
|
|
*
|
|
* @access prviate
|
|
*/
|
|
function _closeMCrypt()
|
|
{
|
|
if ( $this->encryptStream !== false ) {
|
|
if ( $this->continuousBuffer ) {
|
|
mcrypt_generic_deinit($this->encryptStream);
|
|
}
|
|
|
|
mcrypt_module_close($this->encryptStream);
|
|
|
|
$this->encryptStream = false;
|
|
}
|
|
|
|
if ( $this->decryptStream !== false ) {
|
|
if ( $this->continuousBuffer ) {
|
|
mcrypt_generic_deinit($this->decryptStream);
|
|
}
|
|
|
|
mcrypt_module_close($this->decryptStream);
|
|
|
|
$this->decryptStream = false;
|
|
}
|
|
}
|
|
} |