Added: incubator/vcl/trunk/web/.ht-inc/phpseclib/Crypt/TripleDES.php
URL: 
http://svn.apache.org/viewvc/incubator/vcl/trunk/web/.ht-inc/phpseclib/Crypt/TripleDES.php?rev=1136647&view=auto
==============================================================================
--- incubator/vcl/trunk/web/.ht-inc/phpseclib/Crypt/TripleDES.php (added)
+++ incubator/vcl/trunk/web/.ht-inc/phpseclib/Crypt/TripleDES.php Thu Jun 16 
20:18:36 2011
@@ -0,0 +1,1009 @@
+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Pure-PHP implementation of Triple DES.
+ *
+ * Uses mcrypt, if available, and an internal implementation, otherwise.  
Operates in the EDE3 mode (encrypt-decrypt-encrypt).
+ *
+ * PHP versions 4 and 5
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ *    include('Crypt/TripleDES.php');
+ *
+ *    $des = new Crypt_TripleDES();
+ *
+ *    $des->setKey('abcdefghijklmnopqrstuvwx');
+ *
+ *    $size = 10 * 1024;
+ *    $plaintext = '';
+ *    for ($i = 0; $i < $size; $i++) {
+ *        $plaintext.= 'a';
+ *    }
+ *
+ *    echo $des->decrypt($des->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_TripleDES
+ * @author     Jim Wigginton <terrafr...@php.net>
+ * @copyright  MMVII Jim Wigginton
+ * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
+ * @version    $Id: TripleDES.php,v 1.13 2010/02/26 03:40:25 terrafrost Exp $
+ * @link       http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Include Crypt_DES
+ */
+require_once('DES.php');
+
+/**
+ * Encrypt / decrypt using inner chaining
+ *
+ * Inner chaining is used by SSH-1 and is generally considered to be less 
secure then outer chaining (CRYPT_DES_MODE_CBC3).
+ */
+define('CRYPT_DES_MODE_3CBC', -2);
+
+/**
+ * Encrypt / decrypt using outer chaining
+ *
+ * Outer chaining is used by SSH-2 and when the mode is set to 
CRYPT_DES_MODE_CBC.
+ */
+define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC);
+
+/**
+ * Pure-PHP implementation of Triple DES.
+ *
+ * @author  Jim Wigginton <terrafr...@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_TerraDES
+ */
+class Crypt_TripleDES {
+    /**
+     * The Three Keys
+     *
+     * @see Crypt_TripleDES::setKey()
+     * @var String
+     * @access private
+     */
+    var $key = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Encryption Mode
+     *
+     * @see Crypt_TripleDES::Crypt_TripleDES()
+     * @var Integer
+     * @access private
+     */
+    var $mode = CRYPT_DES_MODE_CBC;
+
+    /**
+     * Continuous Buffer status
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var Boolean
+     * @access private
+     */
+    var $continuousBuffer = false;
+
+    /**
+     * Padding status
+     *
+     * @see Crypt_TripleDES::enablePadding()
+     * @var Boolean
+     * @access private
+     */
+    var $padding = true;
+
+    /**
+     * The Initialization Vector
+     *
+     * @see Crypt_TripleDES::setIV()
+     * @var String
+     * @access private
+     */
+    var $iv = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $encryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @var String
+     * @access private
+     */
+    var $decryptIV = "\0\0\0\0\0\0\0\0";
+
+    /**
+     * The Crypt_DES objects
+     *
+     * @var Array
+     * @access private
+     */
+    var $des;
+
+    /**
+     * mcrypt resource for encryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be 
created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be 
recreated when in non-continuous mode.
+     *
+     * @see Crypt_TripleDES::encrypt()
+     * @var String
+     * @access private
+     */
+    var $enmcrypt;
+
+    /**
+     * mcrypt resource for decryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be 
created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be 
recreated when in non-continuous mode.
+     *
+     * @see Crypt_TripleDES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $demcrypt;
+
+    /**
+     * Does the enmcrypt resource need to be (re)initialized?
+     *
+     * @see Crypt_TripleDES::setKey()
+     * @see Crypt_TripleDES::setIV()
+     * @var Boolean
+     * @access private
+     */
+    var $enchanged = true;
+
+    /**
+     * Does the demcrypt resource need to be (re)initialized?
+     *
+     * @see Crypt_TripleDES::setKey()
+     * @see Crypt_TripleDES::setIV()
+     * @var Boolean
+     * @access private
+     */
+    var $dechanged = true;
+
+    /**
+     * Is the mode one that is paddable?
+     *
+     * @see Crypt_TripleDES::Crypt_TripleDES()
+     * @var Boolean
+     * @access private
+     */
+    var $paddable = false;
+
+    /**
+     * Encryption buffer for CTR, OFB and CFB modes
+     *
+     * @see Crypt_TripleDES::encrypt()
+     * @var String
+     * @access private
+     */
+    var $enbuffer = '';
+
+    /**
+     * Decryption buffer for CTR, OFB and CFB modes
+     *
+     * @see Crypt_TripleDES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $debuffer = '';
+
+    /**
+     * mcrypt resource for CFB mode
+     *
+     * @see Crypt_TripleDES::encrypt()
+     * @see Crypt_TripleDES::decrypt()
+     * @var String
+     * @access private
+     */
+    var $ecb;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.  $mode 
should only, at present, be
+     * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC.  If not explictly set, 
CRYPT_DES_MODE_CBC will be used.
+     *
+     * @param optional Integer $mode
+     * @return Crypt_TripleDES
+     * @access public
+     */
+    function Crypt_TripleDES($mode = CRYPT_DES_MODE_CBC)
+    {
+        if ( !defined('CRYPT_DES_MODE') ) {
+            switch (true) {
+                case extension_loaded('mcrypt'):
+                    // i'd check to see if des was supported, by doing 
in_array('des', 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_DES_MODE', CRYPT_DES_MODE_MCRYPT);
+                    break;
+                default:
+                    define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL);
+            }
+        }
+
+        if ( $mode == CRYPT_DES_MODE_3CBC ) {
+            $this->mode = CRYPT_DES_MODE_3CBC;
+            $this->des = array(
+                new Crypt_DES(CRYPT_DES_MODE_CBC),
+                new Crypt_DES(CRYPT_DES_MODE_CBC),
+                new Crypt_DES(CRYPT_DES_MODE_CBC)
+            );
+
+            // we're going to be doing the padding, ourselves, so disable it 
in the Crypt_DES objects
+            $this->des[0]->disablePadding();
+            $this->des[1]->disablePadding();
+            $this->des[2]->disablePadding();
+
+            return;
+        }
+
+        switch ( CRYPT_DES_MODE ) {
+            case CRYPT_DES_MODE_MCRYPT:
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                        $this->paddable = true;
+                        $this->mode = MCRYPT_MODE_ECB;
+                        break;
+                    case CRYPT_DES_MODE_CTR:
+                        $this->mode = 'ctr';
+                        break;
+                    case CRYPT_DES_MODE_CFB:
+                        $this->mode = 'ncfb';
+                        break;
+                    case CRYPT_DES_MODE_OFB:
+                        $this->mode = MCRYPT_MODE_NOFB;
+                        break;
+                    case CRYPT_DES_MODE_CBC:
+                    default:
+                        $this->paddable = true;
+                        $this->mode = MCRYPT_MODE_CBC;
+                }
+
+                break;
+            default:
+                $this->des = array(
+                    new Crypt_DES(CRYPT_DES_MODE_ECB),
+                    new Crypt_DES(CRYPT_DES_MODE_ECB),
+                    new Crypt_DES(CRYPT_DES_MODE_ECB)
+                );
+ 
+                // we're going to be doing the padding, ourselves, so disable 
it in the Crypt_DES objects
+                $this->des[0]->disablePadding();
+                $this->des[1]->disablePadding();
+                $this->des[2]->disablePadding();
+
+                switch ($mode) {
+                    case CRYPT_DES_MODE_ECB:
+                    case CRYPT_DES_MODE_CBC:
+                        $this->paddable = true;
+                        $this->mode = $mode;
+                        break;
+                    case CRYPT_DES_MODE_CTR:
+                    case CRYPT_DES_MODE_CFB:
+                    case CRYPT_DES_MODE_OFB:
+                        $this->mode = $mode;
+                        break;
+                    default:
+                        $this->paddable = true;
+                        $this->mode = CRYPT_DES_MODE_CBC;
+                }
+        }
+    }
+
+    /**
+     * Sets the key.
+     *
+     * Keys can be of any length.  Triple DES, itself, can use 128-bit (eg. 
strlen($key) == 16) or
+     * 192-bit (eg. strlen($key) == 24) keys.  This function pads and 
truncates $key as appropriate.
+     *
+     * DES also requires that every eighth bit be a parity bit, however, we'll 
ignore that.
+     *
+     * If the key is not explicitly set, it'll be assumed to be all zero's.
+     *
+     * @access public
+     * @param String $key
+     */
+    function setKey($key)
+    {
+        $length = strlen($key);
+        if ($length > 8) {
+            $key = str_pad($key, 24, chr(0));
+            // if $key is between 64 and 128-bits, use the first 64-bits as 
the last, per this:
+            // http://php.net/function.mcrypt-encrypt#47973
+            //$key = $length <= 16 ? substr_replace($key, substr($key, 0, 8), 
16) : substr($key, 0, 24);
+        } else {
+            $key = str_pad($key, 8, chr(0));
+        }
+        $this->key = $key;
+        switch (true) {
+            case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL:
+            case $this->mode == CRYPT_DES_MODE_3CBC:
+                $this->des[0]->setKey(substr($key,  0, 8));
+                $this->des[1]->setKey(substr($key,  8, 8));
+                $this->des[2]->setKey(substr($key, 16, 8));
+        }
+        $this->enchanged = $this->dechanged = true;
+    }
+
+    /**
+     * Sets the initialization vector. (optional)
+     *
+     * SetIV is not required when CRYPT_DES_MODE_ECB is being used.  If not 
explictly set, it'll be assumed
+     * to be all zero's.
+     *
+     * @access public
+     * @param String $iv
+     */
+    function setIV($iv)
+    {
+        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 
0, 8), 8, chr(0));
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->setIV($iv);
+            $this->des[1]->setIV($iv);
+            $this->des[2]->setIV($iv);
+        }
+        $this->enchanged = $this->dechanged = true;
+    }
+
+    /**
+     * Generate CTR XOR encryption key
+     *
+     * Encrypt the output of this and XOR it against the ciphertext / 
plaintext to get the
+     * plaintext / ciphertext in CTR mode.
+     *
+     * @see Crypt_TripleDES::decrypt()
+     * @see Crypt_TripleDES::encrypt()
+     * @access private
+     * @param Integer $length
+     * @param String $iv
+     */
+    function _generate_xor($length, &$iv)
+    {
+        $xor = '';
+        $num_blocks = ($length + 7) >> 3;
+        for ($i = 0; $i < $num_blocks; $i++) {
+            $xor.= $iv;
+            for ($j = 4; $j <= 8; $j+=4) {
+                $temp = substr($iv, -$j, 4);
+                switch ($temp) {
+                    case "\xFF\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x00\x00\x00\x00", -$j, 4);
+                        break;
+                    case "\x7F\xFF\xFF\xFF":
+                        $iv = substr_replace($iv, "\x80\x00\x00\x00", -$j, 4);
+                        break 2;
+                    default:
+                        extract(unpack('Ncount', $temp));
+                        $iv = substr_replace($iv, pack('N', $count + 1), -$j, 
4);
+                        break 2;
+                }
+            }
+        }
+
+        return $xor;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * @access public
+     * @param String $plaintext
+     */
+    function encrypt($plaintext)
+    {
+        if ($this->paddable) {
+            $plaintext = $this->_pad($plaintext);
+        }
+
+        // if the key is smaller then 8, do what we'd normally do
+        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {
+            $ciphertext = 
$this->des[2]->encrypt($this->des[1]->decrypt($this->des[0]->encrypt($plaintext)));
+
+            return $ciphertext;
+        }
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->enchanged) {
+                if (!isset($this->enmcrypt)) {
+                    $this->enmcrypt = mcrypt_module_open(MCRYPT_3DES, '', 
$this->mode, '');
+                }
+                mcrypt_generic_init($this->enmcrypt, $this->key, 
$this->encryptIV);
+                if ($this->mode != 'ncfb') {
+                    $this->enchanged = false;
+                }
+            }
+
+            if ($this->mode != 'ncfb') {
+                $ciphertext = mcrypt_generic($this->enmcrypt, $plaintext);
+            } else {
+                if ($this->enchanged) {
+                    $this->ecb = mcrypt_module_open(MCRYPT_3DES, '', 
MCRYPT_MODE_ECB, '');
+                    mcrypt_generic_init($this->ecb, $this->key, 
"\0\0\0\0\0\0\0\0");
+                    $this->enchanged = false;
+                }
+
+                if (strlen($this->enbuffer)) {
+                    $ciphertext = $plaintext ^ substr($this->encryptIV, 
strlen($this->enbuffer));
+                    $this->enbuffer.= $ciphertext;
+                    if (strlen($this->enbuffer) == 8) {
+                        $this->encryptIV = $this->enbuffer;
+                        $this->enbuffer = '';
+                        mcrypt_generic_init($this->enmcrypt, $this->key, 
$this->encryptIV);
+                    }
+                    $plaintext = substr($plaintext, strlen($ciphertext));
+                } else {
+                    $ciphertext = '';
+                }
+
+                $last_pos = strlen($plaintext) & 0xFFFFFFF8;
+                $ciphertext.= $last_pos ? mcrypt_generic($this->enmcrypt, 
substr($plaintext, 0, $last_pos)) : '';
+
+                if (strlen($plaintext) & 0x7) {
+                    if (strlen($ciphertext)) {
+                        $this->encryptIV = substr($ciphertext, -8);
+                    }
+                    $this->encryptIV = mcrypt_generic($this->ecb, 
$this->encryptIV);
+                    $this->enbuffer = substr($plaintext, $last_pos) ^ 
$this->encryptIV;
+                    $ciphertext.= $this->enbuffer;
+                }
+            }
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->enmcrypt, $this->key, 
$this->encryptIV);
+            }
+
+            return $ciphertext;
+        }
+
+        if (strlen($this->key) <= 8) {
+            $this->des[0]->mode = $this->mode;
+
+            return $this->des[0]->encrypt($plaintext);
+        }
+
+        $des = $this->des;
+
+        $buffer = &$this->enbuffer;
+        $continuousBuffer = $this->continuousBuffer;
+        $ciphertext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8);
+                    // all of these _processBlock calls could, in theory, be 
put in a function - say Crypt_TripleDES::_ede_encrypt() or something.
+                    // only problem with that: it would slow encryption and 
decryption down.  $this->des would have to be called every time that
+                    // function is called, instead of once for the whole 
string of text that's being encrypted, which would, in turn, make 
+                    // encryption and decryption take more time, per this:
+                    //
+                    // 
http://blog.libssh2.org/index.php?/archives/21-Compiled-Variables.html
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $ciphertext.= $block;
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->encryptIV;
+                for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8) ^ $xor;
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $xor = $block;
+                    $ciphertext.= $block;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->encryptIV;
+                if (strlen($buffer)) {
+                    for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                        $block = substr($plaintext, $i, 8);
+                        $key = $this->_generate_xor(8, $xor);
+                        $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                        $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $buffer.= $key;
+                        $key = $this->_string_shift($buffer, 8);
+                        $ciphertext.= $block ^ $key;
+                    }
+                } else {
+                    for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                        $block = substr($plaintext, $i, 8);
+                        $key = $this->_generate_xor(8, $xor);
+                        $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                        $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $ciphertext.= $block ^ $key;
+                    }
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                    if ($start = strlen($plaintext) & 7) {
+                        $buffer = substr($key, $start) . $buffer;
+                    }
+                }
+                break;
+            case CRYPT_DES_MODE_CFB:
+                if (!empty($buffer['xor'])) {
+                    $ciphertext = $plaintext ^ $buffer['xor'];
+                    $iv = $buffer['encrypted'] . $ciphertext;
+                    $start = strlen($ciphertext);
+                    $buffer['encrypted'].= $ciphertext;
+                    $buffer['xor'] = substr($buffer['xor'], 
strlen($ciphertext));
+                } else {
+                    $ciphertext = '';
+                    $iv = $this->encryptIV;
+                    $start = 0;
+                }
+
+                for ($i = $start; $i < strlen($plaintext); $i+=8) {
+                    $block = substr($plaintext, $i, 8);
+                    $iv = $des[0]->_processBlock($iv, CRYPT_DES_ENCRYPT);
+                    $iv = $des[1]->_processBlock($iv, CRYPT_DES_DECRYPT);
+                    $xor= $des[2]->_processBlock($iv, CRYPT_DES_ENCRYPT);
+
+                    $iv = $block ^ $xor;
+                    if ($continuousBuffer && strlen($iv) != 8) {
+                        $buffer = array(
+                            'encrypted' => $iv,
+                            'xor' => substr($xor, strlen($iv))
+                        );
+                    }
+                    $ciphertext.= $iv;
+                }
+
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $iv;
+                }
+                break;
+            case CRYPT_DES_MODE_OFB:
+                $xor = $this->encryptIV;
+                if (strlen($buffer)) {
+                    for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                        $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $buffer.= $xor;
+                        $key = $this->_string_shift($buffer, 8);
+                        $ciphertext.= substr($plaintext, $i, 8) ^ $key;
+                    }
+                } else {
+                    for ($i = 0; $i < strlen($plaintext); $i+=8) {
+                        $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $ciphertext.= substr($plaintext, $i, 8) ^ $xor;
+                    }
+                    $key = $xor;
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                    if ($start = strlen($plaintext) & 7) {
+                         $buffer = substr($key, $start) . $buffer;
+                    }
+                }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * Decrypts a message.
+     *
+     * @access public
+     * @param String $ciphertext
+     */
+    function decrypt($ciphertext)
+    {
+        if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) {
+            $plaintext = 
$this->des[0]->decrypt($this->des[1]->encrypt($this->des[2]->decrypt($ciphertext)));
+
+            return $this->_unpad($plaintext);
+        }
+
+        if ($this->paddable) {
+            // we pad with chr(0) since that's what mcrypt_generic does.  to 
quote from http://php.net/function.mcrypt-generic :
+            // "The data is padded with "\0" to make sure the length of the 
data is n * blocksize."
+            $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 
0xFFFFFFF8, chr(0));
+        }
+
+        if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) {
+            if ($this->dechanged) {
+                if (!isset($this->demcrypt)) {
+                    $this->demcrypt = mcrypt_module_open(MCRYPT_3DES, '', 
$this->mode, '');
+                }
+                mcrypt_generic_init($this->demcrypt, $this->key, 
$this->decryptIV);
+                if ($this->mode != 'ncfb') {
+                    $this->dechanged = false;
+                }
+            }
+
+            if ($this->mode != 'ncfb') {
+                $plaintext = mdecrypt_generic($this->demcrypt, $ciphertext);
+            } else {
+                if ($this->dechanged) {
+                    $this->ecb = mcrypt_module_open(MCRYPT_3DES, '', 
MCRYPT_MODE_ECB, '');
+                    mcrypt_generic_init($this->ecb, $this->key, 
"\0\0\0\0\0\0\0\0");
+                    $this->dechanged = false;
+                }
+
+                if (strlen($this->debuffer)) {
+                    $plaintext = $ciphertext ^ substr($this->decryptIV, 
strlen($this->debuffer));
+
+                    $this->debuffer.= substr($ciphertext, 0, 
strlen($plaintext));
+                    if (strlen($this->debuffer) == 8) {
+                        $this->decryptIV = $this->debuffer;
+                        $this->debuffer = '';
+                        mcrypt_generic_init($this->demcrypt, $this->key, 
$this->decryptIV);
+                    }
+                    $ciphertext = substr($ciphertext, strlen($plaintext));
+                } else {
+                    $plaintext = '';
+                }
+
+                $last_pos = strlen($ciphertext) & 0xFFFFFFF8;
+                $plaintext.= $last_pos ? mdecrypt_generic($this->demcrypt, 
substr($ciphertext, 0, $last_pos)) : '';
+
+                if (strlen($ciphertext) & 0x7) {
+                    if (strlen($plaintext)) {
+                        $this->decryptIV = substr($ciphertext, $last_pos - 8, 
8);
+                    }
+                    $this->decryptIV = mcrypt_generic($this->ecb, 
$this->decryptIV);
+                    $this->debuffer = substr($ciphertext, $last_pos);
+                    $plaintext.= $this->debuffer ^ $this->decryptIV;
+                }
+
+                return $plaintext;
+            }
+
+            if (!$this->continuousBuffer) {
+                mcrypt_generic_init($this->demcrypt, $this->key, 
$this->decryptIV);
+            }
+
+            return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        if (strlen($this->key) <= 8) {
+            $this->des[0]->mode = $this->mode;
+            $plaintext = $this->des[0]->decrypt($ciphertext);
+            return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        $des = $this->des;
+
+        $buffer = &$this->enbuffer;
+        $continuousBuffer = $this->continuousBuffer;
+        $plaintext = '';
+        switch ($this->mode) {
+            case CRYPT_DES_MODE_ECB:
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $block = substr($ciphertext, $i, 8);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $plaintext.= $block;
+                }
+                break;
+            case CRYPT_DES_MODE_CBC:
+                $xor = $this->decryptIV;
+                for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                    $orig = $block = substr($ciphertext, $i, 8);
+                    $block = $des[2]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $block = $des[1]->_processBlock($block, CRYPT_DES_ENCRYPT);
+                    $block = $des[0]->_processBlock($block, CRYPT_DES_DECRYPT);
+                    $plaintext.= $block ^ $xor;
+                    $xor = $orig;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                }
+                break;
+            case CRYPT_DES_MODE_CTR:
+                $xor = $this->decryptIV;
+                if (strlen($buffer)) {
+                    for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                        $block = substr($ciphertext, $i, 8);
+                        $key = $this->_generate_xor(8, $xor);
+                        $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                        $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $buffer.= $key;
+                        $key = $this->_string_shift($buffer, 8);
+                        $plaintext.= $block ^ $key;
+                    }
+                } else {
+                    for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                        $block = substr($ciphertext, $i, 8);
+                        $key = $this->_generate_xor(8, $xor);
+                        $key = $des[0]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $key = $des[1]->_processBlock($key, CRYPT_DES_DECRYPT);
+                        $key = $des[2]->_processBlock($key, CRYPT_DES_ENCRYPT);
+                        $plaintext.= $block ^ $key;
+                    }
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                    if ($start = strlen($plaintext) & 7) {
+                        $buffer = substr($key, $start) . $buffer;
+                    }
+                }
+                break;
+            case CRYPT_DES_MODE_CFB:
+                if (!empty($buffer['ciphertext'])) {
+                    $plaintext = $ciphertext ^ substr($this->decryptIV, 
strlen($buffer['ciphertext']));
+                    $buffer['ciphertext'].= substr($ciphertext, 0, 
strlen($plaintext));
+                    if (strlen($buffer['ciphertext']) == 8) {
+                        $xor = $des[0]->_processBlock($buffer['ciphertext'], 
CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $buffer['ciphertext'] = '';
+                    }
+                    $start = strlen($plaintext);
+                    $block = $this->decryptIV;
+                } else {
+                    $plaintext = '';
+                    $xor = $des[0]->_processBlock($this->decryptIV, 
CRYPT_DES_ENCRYPT);
+                    $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                    $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                    $start = 0;
+                }
+
+                for ($i = $start; $i < strlen($ciphertext); $i+=8) {
+                    $block = substr($ciphertext, $i, 8);
+                    $plaintext.= $block ^ $xor;
+                    if ($continuousBuffer && strlen($block) != 8) {
+                        $buffer['ciphertext'].= $block;
+                        $block = $xor;
+                    } else if (strlen($block) == 8) {
+                        $xor = $des[0]->_processBlock($block, 
CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                    }
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $block;
+                }
+                break;
+            case CRYPT_DES_MODE_OFB:
+                $xor = $this->decryptIV;
+                if (strlen($buffer)) {
+                    for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                        $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $buffer.= $xor;
+                        $key = $this->_string_shift($buffer, 8);
+                        $plaintext.= substr($ciphertext, $i, 8) ^ $key;
+                    }
+                } else {
+                    for ($i = 0; $i < strlen($ciphertext); $i+=8) {
+                        $xor = $des[0]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $xor = $des[1]->_processBlock($xor, CRYPT_DES_DECRYPT);
+                        $xor = $des[2]->_processBlock($xor, CRYPT_DES_ENCRYPT);
+                        $plaintext.= substr($ciphertext, $i, 8) ^ $xor;
+                    }
+                    $key = $xor;
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                    if ($start = strlen($ciphertext) & 7) {
+                         $buffer = substr($key, $start) . $buffer;
+                    }
+                }
+        }
+
+        return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+    }
+
+    /**
+     * 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 $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->encrypt(substr($plaintext, 8, 8));
+     * </code>
+     * <code>
+     *    echo $des->encrypt($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>
+     *    $des->encrypt(substr($plaintext, 0, 8));
+     *    echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8)));
+     * </code>
+     * <code>
+     *    echo $des->decrypt($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_TripleDES::disableContinuousBuffer()
+     * @access public
+     */
+    function enableContinuousBuffer()
+    {
+        $this->continuousBuffer = true;
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->enableContinuousBuffer();
+            $this->des[1]->enableContinuousBuffer();
+            $this->des[2]->enableContinuousBuffer();
+        }
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see Crypt_TripleDES::enableContinuousBuffer()
+     * @access public
+     */
+    function disableContinuousBuffer()
+    {
+        $this->continuousBuffer = false;
+        $this->encryptIV = $this->iv;
+        $this->decryptIV = $this->iv;
+
+        if ($this->mode == CRYPT_DES_MODE_3CBC) {
+            $this->des[0]->disableContinuousBuffer();
+            $this->des[1]->disableContinuousBuffer();
+            $this->des[2]->disableContinuousBuffer();
+        }
+    }
+
+    /**
+     * Pad "packets".
+     *
+     * DES works by encrypting eight bytes at a time.  If you ever need to 
encrypt or decrypt something that's not
+     * a multiple of eight, it becomes necessary to pad the input so that it's 
length is a multiple of eight.
+     *
+     * Padding is enabled by default.  Sometimes, however, it is undesirable 
to pad strings.  Such is the case in SSH1,
+     * where "packets" are padded with random bytes before being encrypted.  
Unpad these packets and you risk stripping
+     * away characters that shouldn't be stripped away. (SSH knows how many 
bytes are added because the length is
+     * transmitted separately)
+     *
+     * @see Crypt_TripleDES::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+        $this->padding = true;
+    }
+
+    /**
+     * Do not pad packets.
+     *
+     * @see Crypt_TripleDES::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+        $this->padding = false;
+    }
+
+    /**
+     * Pads a string
+     *
+     * Pads a string using the RSA PKCS padding standards so that its length 
is a multiple of the blocksize (8).
+     * 8 - (strlen($text) & 7) bytes are added, each of which is equal to 
chr(8 - (strlen($text) & 7)
+     *
+     * If padding is disabled and $text is not a multiple of the blocksize, 
the string will be padded regardless
+     * and padding will, hence forth, be enabled.
+     *
+     * @see Crypt_TripleDES::_unpad()
+     * @access private
+     */
+    function _pad($text)
+    {
+        $length = strlen($text);
+
+        if (!$this->padding) {
+            if (($length & 7) == 0) {
+                return $text;
+            } else {
+                user_error("The plaintext's length ($length) is not a multiple 
of the block size (8)", E_USER_NOTICE);
+                $this->padding = true;
+            }
+        }
+
+        $pad = 8 - ($length & 7);
+        return str_pad($text, $length + $pad, chr($pad));
+    }
+
+    /**
+     * Unpads a string
+     *
+     * If padding is enabled and the reported padding length is invalid the 
encryption key will be assumed to be wrong
+     * and false will be returned.
+     *
+     * @see Crypt_TripleDES::_pad()
+     * @access private
+     */
+    function _unpad($text)
+    {
+        if (!$this->padding) {
+            return $text;
+        }
+
+        $length = ord($text[strlen($text) - 1]);
+
+        if (!$length || $length > 8) {
+            return false;
+        }
+
+        return substr($text, 0, -$length);
+    }
+
+    /**
+     * String Shift
+     *
+     * Inspired by array_shift
+     *
+     * @param String $string
+     * @param optional Integer $index
+     * @return String
+     * @access private
+     */
+    function _string_shift(&$string, $index = 1)
+    {
+        $substr = substr($string, 0, $index);
+        $string = substr($string, $index);
+        return $substr;
+    }
+}
+
+// vim: ts=4:sw=4:et:
+// vim6: fdl=1:
\ No newline at end of file


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