1 files changed, 1428 insertions, 0 deletions
diff --git a/phpBB/includes/sftp/des.php b/phpBB/includes/sftp/des.php
new file mode 100644
index 0000000000..278de64a01
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+++ b/phpBB/includes/sftp/des.php
@@ -0,0 +1,1428 @@
+<?php
+/**
+*
+* @package sftp
+* @version $Id$
+* @copyright (c) 2006 phpBB Group
+* @license http://opensource.org/licenses/gpl-license.php GNU Public License
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* Code from http://phpseclib.sourceforge.net/
+*
+* Modified by phpBB Group to meet our coding standards
+* and being able to integrate into phpBB
+*
+* Pure-PHP implementation of DES.
+*
+* Copyright 2007-2009 TerraFrost <terrafrost@php.net>
+* Copyright 2009+ phpBB
+*
+* @package sftp
+* @author  TerraFrost <terrafrost@php.net>
+*/
+
+/**#@+
+ * @access private
+ * @see des::_prepare_key()
+ * @see des::_process_block()
+ */
+/**
+ * Contains array_reverse($keys[CRYPT_DES_DECRYPT])
+ */
+define('CRYPT_DES_ENCRYPT', 0);
+/**
+ * Contains array_reverse($keys[CRYPT_DES_ENCRYPT])
+ */
+define('CRYPT_DES_DECRYPT', 1);
+/**#@-*/
+
+/**#@+
+ * @access public
+ * @see des::encrypt()
+ * @see des::decrypt()
+ */
+/**
+ * Encrypt / decrypt using the Electronic Code Book mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
+ */
+define('CRYPT_DES_MODE_ECB', 1);
+/**
+ * Encrypt / decrypt using the Code Book Chaining mode.
+ *
+ * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
+ */
+define('CRYPT_DES_MODE_CBC', 2);
+/**#@-*/
+
+/**
+ * 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', 3);
+
+/**
+ * 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);
+
+/**#@+
+ * @access private
+ * @see des::__construct()
+ */
+/**
+ * Toggles the internal implementation
+ */
+define('CRYPT_DES_MODE_INTERNAL', 1);
+/**
+ * Toggles the mcrypt implementation
+ */
+define('CRYPT_DES_MODE_MCRYPT', 2);
+/**#@-*/
+
+/**
+ * Pure-PHP implementation of DES.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package des
+ */
+class des
+{
+	/**
+	 * The Key Schedule
+	 *
+	 * @see des::setKey()
+	 * @var Array
+	 * @access private
+	 */
+	var $keys = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * The Encryption Mode
+	 *
+	 * @see des::des()
+	 * @var Integer
+	 * @access private
+	 */
+	var $mode;
+
+	/**
+	 * Continuous Buffer status
+	 *
+	 * @see des::enableContinuousBuffer()
+	 * @var Boolean
+	 * @access private
+	 */
+	var $continuousBuffer = false;
+
+	/**
+	 * Padding status
+	 *
+	 * @see des::enablePadding()
+	 * @var Boolean
+	 * @access private
+	 */
+	var $padding = true;
+
+	/**
+	 * The Initialization Vector
+	 *
+	 * @see des::setIV()
+	 * @var String
+	 * @access private
+	 */
+	var $iv = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * A "sliding" Initialization Vector
+	 *
+	 * @see des::enableContinuousBuffer()
+	 * @var String
+	 * @access private
+	 */
+	var $encryptIV = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * A "sliding" Initialization Vector
+	 *
+	 * @see des::enableContinuousBuffer()
+	 * @var String
+	 * @access private
+	 */
+	var $decryptIV = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * MCrypt parameters
+	 *
+	 * @see des::setMCrypt()
+	 * @var Array
+	 * @access private
+	 */
+	var $mcrypt = array('', '');
+
+	/**
+	 * 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 $mode
+	 * @return des
+	 * @access public
+	 */
+	function __construct($mode = CRYPT_MODE_DES_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);
+			}
+		}
+
+		switch ( CRYPT_DES_MODE )
+		{
+			case CRYPT_DES_MODE_MCRYPT:
+				switch ($mode)
+				{
+					case CRYPT_DES_MODE_ECB:
+						$this->mode = MCRYPT_MODE_ECB;
+						break;
+					case CRYPT_DES_MODE_CBC:
+					default:
+						$this->mode = MCRYPT_MODE_CBC;
+				}
+
+				break;
+			default:
+				switch ($mode)
+				{
+					case CRYPT_DES_MODE_ECB:
+					case CRYPT_DES_MODE_CBC:
+						$this->mode = $mode;
+						break;
+					default:
+						$this->mode = CRYPT_DES_MODE_CBC;
+				}
+		}
+	}
+
+	/**
+	 * Sets the key.
+	 *
+	 * Keys can be of any length.  DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we
+	 * only use the first eight, if $key has more then eight characters in it, and pad $key with the
+	 * null byte if it is less then eight characters long.
+	 *
+	 * 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 $key
+	 */
+	function set_key($key)
+	{
+		$this->keys = ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) ? substr($key, 0, 8) : $this->_prepare_key($key);
+	}
+
+	/**
+	 * 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 $iv
+	 */
+	function set_iv($iv)
+	{
+		$this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));;
+	}
+
+	/**
+	 * 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 $mode_directory
+	 */
+	function set_mcrypt($algorithm_directory = '', $mode_directory = '')
+	{
+		$this->mcrypt = array($algorithm_directory, $mode_directory);
+	}
+
+	/**
+	 * Encrypts a message.
+	 *
+	 * $plaintext will be padded with up to 8 additional bytes.  Other DES implementations may or may not pad in the
+	 * same manner.  Other common approaches to padding and the reasons why it's necessary are discussed in the following
+	 * URL:
+	 *
+	 * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
+	 *
+	 * An alternative to padding is to, separately, send the length of the file.  This is what SSH, in fact, does.
+	 * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that
+	 * length.
+	 *
+	 * @see des::decrypt()
+	 * @access public
+	 * @param String $plaintext
+	 */
+	function encrypt($plaintext)
+	{
+		$plaintext = $this->_pad($plaintext);
+
+		if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT )
+		{
+			$td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);
+			mcrypt_generic_init($td, $this->keys, $this->encryptIV);
+
+			$ciphertext = mcrypt_generic($td, $plaintext);
+
+			mcrypt_generic_deinit($td);
+			mcrypt_module_close($td);
+
+			if ($this->continuousBuffer)
+			{
+				$this->encryptIV = substr($ciphertext, -8);
+			}
+
+			return $ciphertext;
+		}
+
+		if (!is_array($this->keys))
+		{
+			$this->keys = $this->_prepare_key("\0\0\0\0\0\0\0\0");
+		}
+
+		$ciphertext = '';
+		switch ($this->mode)
+		{
+			case CRYPT_DES_MODE_ECB:
+				for ($i = 0; $i < strlen($plaintext); $i+=8)
+				{
+					$ciphertext.= $this->_process_block(substr($plaintext, $i, 8), CRYPT_DES_ENCRYPT);
+				}
+				break;
+			case CRYPT_DES_MODE_CBC:
+				$xor = $this->encryptIV;
+				for ($i = 0; $i < strlen($plaintext); $i+=8)
+				{
+					$block = substr($plaintext, $i, 8);
+					$block = $this->_process_block($block ^ $xor, CRYPT_DES_ENCRYPT);
+					$xor = $block;
+					$ciphertext.= $block;
+				}
+				if ($this->continuousBuffer)
+				{
+					$this->encryptIV = $xor;
+				}
+		}
+
+		return $ciphertext;
+	}
+
+	/**
+	 * Decrypts a message.
+	 *
+	 * If strlen($ciphertext) is not a multiple of 8, null bytes will be added to the end of the string until it is.
+	 *
+	 * @see des::encrypt()
+	 * @access public
+	 * @param String $ciphertext
+	 */
+	function decrypt($ciphertext)
+	{
+		// 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 )
+		{
+			$td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);
+			mcrypt_generic_init($td, $this->keys, $this->decryptIV);
+
+			$plaintext = mdecrypt_generic($td, $ciphertext);
+
+			mcrypt_generic_deinit($td);
+			mcrypt_module_close($td);
+
+			if ($this->continuousBuffer)
+			{
+				$this->decryptIV = substr($ciphertext, -8);
+			}
+
+			return $this->_unpad($plaintext);
+		}
+
+	 	if (!is_array($this->keys))
+		{
+			$this->keys = $this->_prepare_key("\0\0\0\0\0\0\0\0");
+		}
+
+		$plaintext = '';
+		switch ($this->mode)
+		{
+			case CRYPT_DES_MODE_ECB:
+				for ($i = 0; $i < strlen($ciphertext); $i+=8)
+				{
+					$plaintext.= $this->_process_block(substr($ciphertext, $i, 8), CRYPT_DES_DECRYPT);
+				}
+				break;
+			case CRYPT_DES_MODE_CBC:
+				$xor = $this->decryptIV;
+				for ($i = 0; $i < strlen($ciphertext); $i+=8)
+				{
+					$block = substr($ciphertext, $i, 8);
+					$plaintext.= $this->_process_block($block, CRYPT_DES_DECRYPT) ^ $xor;
+					$xor = $block;
+				}
+				if ($this->continuousBuffer)
+				{
+					$this->decryptIV = $xor;
+				}
+		}
+
+		return $this->_unpad($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 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 des::disableContinuousBuffer()
+	 * @access public
+	 */
+	function enable_continuous_buffer()
+	{
+		$this->continuousBuffer = true;
+	}
+
+	/**
+	 * Treat consecutive packets as if they are a discontinuous buffer.
+	 *
+	 * The default behavior.
+	 *
+	 * @see des::enableContinuousBuffer()
+	 * @access public
+	 */
+	function disable_continuous_buffer()
+	{
+		$this->continuousBuffer = false;
+		$this->encryptIV = $this->iv;
+		$this->decryptIV = $this->iv;
+	}
+
+	/**
+	 * 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 des::disablePadding()
+	 * @access public
+	 */
+	function enable_padding()
+	{
+		$this->padding = true;
+	}
+
+	/**
+	 * Do not pad packets.
+	 *
+	 * @see des::enablePadding()
+	 * @access public
+	 */
+	function disable_padding()
+	{
+		$this->padding = false;
+	}
+
+	/**
+	 * Pads a string
+	 *
+	 * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).
+	 * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)
+	 *
+	 * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
+	 * and padding will, hence forth, be enabled.
+	 *
+	 * @see des::_unpad()
+	 * @access private
+	 */
+	function _pad($text)
+	{
+		$length = strlen($text);
+
+		if (!$this->padding)
+		{
+			if (($length & 7) == 0)
+			{
+				return $text;
+			}
+			else
+			{
+				$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 exceeds the block size, padding will be, hence forth, disabled.
+	 *
+	 * @see des::_pad()
+	 * @access private
+	 */
+	function _unpad($text)
+	{
+		if (!$this->padding)
+		{
+			return $text;
+		}
+
+		$length = ord($text[strlen($text) - 1]);
+
+		if ($length > 8)
+		{
+			$this->padding = false;
+			return $text;
+		}
+
+		return substr($text, 0, -$length);
+	}
+
+	/**
+	 * Encrypts or decrypts a 64-bit block
+	 *
+	 * $mode should be either CRYPT_DES_ENCRYPT or CRYPT_DES_DECRYPT.  See
+	 * {@link http://en.wikipedia.org/wiki/Image:Feistel.png Feistel.png} to get a general
+	 * idea of what this function does.
+	 *
+	 * @access private
+	 * @param String $block
+	 * @param Integer $mode
+	 * @return String
+	 */
+	function _process_block($block, $mode)
+	{
+		// s-boxes.  in the official DES docs, they're described as being matrices that
+		// one accesses by using the first and last bits to determine the row and the
+		// middle four bits to determine the column.  in this implementation, they've
+		// been converted to vectors
+		static $sbox = array(
+			array(
+				14,  0,  4, 15, 13,  7,  1,  4,  2, 14, 15,  2, 11, 13,  8,  1,
+				 3, 10 ,10,  6,  6, 12, 12, 11,  5,  9,  9,  5,  0,  3,  7,  8,
+				 4, 15,  1, 12, 14,  8,  8,  2, 13,  4,  6,  9,  2,  1, 11,  7,
+				15,  5, 12, 11,  9,  3,  7, 14,  3, 10, 10,  0,  5,  6,  0, 13
+			),
+			array(
+				15,  3,  1, 13,  8,  4, 14,  7,  6, 15, 11,  2,  3,  8,  4, 14,
+				 9, 12,  7,  0,  2,  1, 13, 10, 12,  6,  0,  9,  5, 11, 10,  5,
+				 0, 13, 14,  8,  7, 10, 11,  1, 10,  3,  4, 15, 13,  4,  1,  2,
+				 5, 11,  8,  6, 12,  7,  6, 12,  9,  0,  3,  5,  2, 14, 15,  9
+			),
+			array(
+				10, 13,  0,  7,  9,  0, 14,  9,  6,  3,  3,  4, 15,  6,  5, 10,
+				 1,  2, 13,  8, 12,  5,  7, 14, 11, 12,  4, 11,  2, 15,  8,  1,
+				13,  1,  6, 10,  4, 13,  9,  0,  8,  6, 15,  9,  3,  8,  0,  7,
+				11,  4,  1, 15,  2, 14, 12,  3,  5, 11, 10,  5, 14,  2,  7, 12
+			),
+			array(
+				 7, 13, 13,  8, 14, 11,  3,  5,  0,  6,  6, 15,  9,  0, 10,  3,
+				 1,  4,  2,  7,  8,  2,  5, 12, 11,  1, 12, 10,  4, 14, 15,  9,
+				10,  3,  6, 15,  9,  0,  0,  6, 12, 10, 11,  1,  7, 13, 13,  8,
+				15,  9,  1,  4,  3,  5, 14, 11,  5, 12,  2,  7,  8,  2,  4, 14
+			),
+			array(
+				 2, 14, 12, 11,  4,  2,  1, 12,  7,  4, 10,  7, 11, 13,  6,  1,
+				 8,  5,  5,  0,  3, 15, 15, 10, 13,  3,  0,  9, 14,  8,  9,  6,
+				 4, 11,  2,  8,  1, 12, 11,  7, 10,  1, 13, 14,  7,  2,  8, 13,
+				15,  6,  9, 15, 12,  0,  5,  9,  6, 10,  3,  4,  0,  5, 14,  3
+			),
+			array(
+				12, 10,  1, 15, 10,  4, 15,  2,  9,  7,  2, 12,  6,  9,  8,  5,
+				 0,  6, 13,  1,  3, 13,  4, 14, 14,  0,  7, 11,  5,  3, 11,  8,
+				 9,  4, 14,  3, 15,  2,  5, 12,  2,  9,  8,  5, 12, 15,  3, 10,
+				 7, 11,  0, 14,  4,  1, 10,  7,  1,  6, 13,  0, 11,  8,  6, 13
+			),
+			array(
+				 4, 13, 11,  0,  2, 11, 14,  7, 15,  4,  0,  9,  8,  1, 13, 10,
+				 3, 14, 12,  3,  9,  5,  7, 12,  5,  2, 10, 15,  6,  8,  1,  6,
+				 1,  6,  4, 11, 11, 13, 13,  8, 12,  1,  3,  4,  7, 10, 14,  7,
+				10,  9, 15,  5,  6,  0,  8, 15,  0, 14,  5,  2,  9,  3,  2, 12
+			),
+			array(
+				13,  1,  2, 15,  8, 13,  4,  8,  6, 10, 15,  3, 11,  7,  1,  4,
+				10, 12,  9,  5,  3,  6, 14, 11,  5,  0,  0, 14, 12,  9,  7,  2,
+				 7,  2, 11,  1,  4, 14,  1,  7,  9,  4, 12, 10, 14,  8,  2, 13,
+				 0, 15,  6, 12, 10,  9, 13,  0, 15,  3,  3,  5,  5,  6,  8, 11
+			)
+		);
+
+		$temp = unpack('Na/Nb', $block);
+		$block = array($temp['a'], $temp['b']);
+
+		// because php does arithmetic right shifts, if the most significant bits are set, right
+		// shifting those into the correct position will add 1's - not 0's.  this will intefere
+		// with the | operation unless a second & is done.  so we isolate these bits and left shift
+		// them into place.  we then & each block with 0x7FFFFFFF to prevennt 1's from being added
+		// for any other shifts.
+		$msb = array(
+			($block[0] >> 31) & 1,
+			($block[1] >> 31) & 1
+		);
+		$block[0] &= 0x7FFFFFFF;
+		$block[1] &= 0x7FFFFFFF;
+
+		// we isolate the appropriate bit in the appropriate integer and shift as appropriate.  in
+		// some cases, there are going to be multiple bits in the same integer that need to be shifted
+		// in the same way.  we combine those into one shift operation.
+		$block = array(
+			(($block[1] & 0x00000040) << 25) | (($block[1] & 0x00004000) << 16) |
+			(($block[1] & 0x00400001) <<  7) | (($block[1] & 0x40000100) >>  2) |
+			(($block[0] & 0x00000040) << 21) | (($block[0] & 0x00004000) << 12) |
+			(($block[0] & 0x00400001) <<  3) | (($block[0] & 0x40000100) >>  6) |
+			(($block[1] & 0x00000010) << 19) | (($block[1] & 0x00001000) << 10) |
+			(($block[1] & 0x00100000) <<  1) | (($block[1] & 0x10000000) >>  8) |
+			(($block[0] & 0x00000010) << 15) | (($block[0] & 0x00001000) <<  6) |
+			(($block[0] & 0x00100000) >>  3) | (($block[0] & 0x10000000) >> 12) |
+			(($block[1] & 0x00000004) << 13) | (($block[1] & 0x00000400) <<  4) |
+			(($block[1] & 0x00040000) >>  5) | (($block[1] & 0x04000000) >> 14) |
+			(($block[0] & 0x00000004) <<  9) | ( $block[0] & 0x00000400	   ) |
+			(($block[0] & 0x00040000) >>  9) | (($block[0] & 0x04000000) >> 18) |
+			(($block[1] & 0x00010000) >> 11) | (($block[1] & 0x01000000) >> 20) |
+			(($block[0] & 0x00010000) >> 15) | (($block[0] & 0x01000000) >> 24)
+		,
+			(($block[1] & 0x00000080) << 24) | (($block[1] & 0x00008000) << 15) |
+			(($block[1] & 0x00800002) <<  6) | (($block[0] & 0x00000080) << 20) |
+			(($block[0] & 0x00008000) << 11) | (($block[0] & 0x00800002) <<  2) |
+			(($block[1] & 0x00000020) << 18) | (($block[1] & 0x00002000) <<  9) |
+			( $block[1] & 0x00200000	   ) | (($block[1] & 0x20000000) >>  9) |
+			(($block[0] & 0x00000020) << 14) | (($block[0] & 0x00002000) <<  5) |
+			(($block[0] & 0x00200000) >>  4) | (($block[0] & 0x20000000) >> 13) |
+			(($block[1] & 0x00000008) << 12) | (($block[1] & 0x00000800) <<  3) |
+			(($block[1] & 0x00080000) >>  6) | (($block[1] & 0x08000000) >> 15) |
+			(($block[0] & 0x00000008) <<  8) | (($block[0] & 0x00000800) >>  1) |
+			(($block[0] & 0x00080000) >> 10) | (($block[0] & 0x08000000) >> 19) |
+			(($block[1] & 0x00000200) >>  3) | (($block[0] & 0x00000200) >>  7) |
+			(($block[1] & 0x00020000) >> 12) | (($block[1] & 0x02000000) >> 21) |
+			(($block[0] & 0x00020000) >> 16) | (($block[0] & 0x02000000) >> 25) |
+			($msb[1] << 28) | ($msb[0] << 24)
+		);
+
+		for ($i = 0; $i < 16; $i++)
+		{
+			// start of "the Feistel (F) function" - see the following URL:
+			// http://en.wikipedia.org/wiki/Image:Data_Encryption_Standard_InfoBox_Diagram.png
+			$temp = (($sbox[0][((($block[1] >> 27) & 0x1F) | (($block[1] & 1) << 5)) ^ $this->keys[$mode][$i][0]]) << 28)
+				  | (($sbox[1][(($block[1] & 0x1F800000) >> 23) ^ $this->keys[$mode][$i][1]]) << 24)
+				  | (($sbox[2][(($block[1] & 0x01F80000) >> 19) ^ $this->keys[$mode][$i][2]]) << 20)
+				  | (($sbox[3][(($block[1] & 0x001F8000) >> 15) ^ $this->keys[$mode][$i][3]]) << 16)
+				  | (($sbox[4][(($block[1] & 0x0001F800) >> 11) ^ $this->keys[$mode][$i][4]]) << 12)
+				  | (($sbox[5][(($block[1] & 0x00001F80) >>  7) ^ $this->keys[$mode][$i][5]]) <<  8)
+				  | (($sbox[6][(($block[1] & 0x000001F8) >>  3) ^ $this->keys[$mode][$i][6]]) <<  4)
+				  | ( $sbox[7][((($block[1] & 0x1F) << 1) | (($block[1] >> 31) & 1)) ^ $this->keys[$mode][$i][7]]);
+
+			$msb = ($temp >> 31) & 1;
+			$temp &= 0x7FFFFFFF;
+			$newBlock = (($temp & 0x00010000) << 15) | (($temp & 0x02020120) <<  5)
+					  | (($temp & 0x00001800) << 17) | (($temp & 0x01000000) >> 10)
+					  | (($temp & 0x00000008) << 24) | (($temp & 0x00100000) <<  6)
+					  | (($temp & 0x00000010) << 21) | (($temp & 0x00008000) <<  9)
+					  | (($temp & 0x00000200) << 12) | (($temp & 0x10000000) >> 27)
+					  | (($temp & 0x00000040) << 14) | (($temp & 0x08000000) >>  8)
+					  | (($temp & 0x00004000) <<  4) | (($temp & 0x00000002) << 16)
+					  | (($temp & 0x00442000) >>  6) | (($temp & 0x40800000) >> 15)
+					  | (($temp & 0x00000001) << 11) | (($temp & 0x20000000) >> 20)
+					  | (($temp & 0x00080000) >> 13) | (($temp & 0x00000004) <<  3)
+					  | (($temp & 0x04000000) >> 22) | (($temp & 0x00000480) >>  7)
+					  | (($temp & 0x00200000) >> 19) | ($msb << 23);
+			// end of "the Feistel (F) function" - $newBlock is F's output
+
+			$temp = $block[1];
+			$block[1] = $block[0] ^ $newBlock;
+			$block[0] = $temp;
+		}
+
+		$msb = array(
+			($block[0] >> 31) & 1,
+			($block[1] >> 31) & 1
+		);
+		$block[0] &= 0x7FFFFFFF;
+		$block[1] &= 0x7FFFFFFF;
+
+		$block = array(
+			(($block[0] & 0x01000004) <<  7) | (($block[1] & 0x01000004) <<  6) |
+			(($block[0] & 0x00010000) << 13) | (($block[1] & 0x00010000) << 12) |
+			(($block[0] & 0x00000100) << 19) | (($block[1] & 0x00000100) << 18) |
+			(($block[0] & 0x00000001) << 25) | (($block[1] & 0x00000001) << 24) |
+			(($block[0] & 0x02000008) >>  2) | (($block[1] & 0x02000008) >>  3) |
+			(($block[0] & 0x00020000) <<  4) | (($block[1] & 0x00020000) <<  3) |
+			(($block[0] & 0x00000200) << 10) | (($block[1] & 0x00000200) <<  9) |
+			(($block[0] & 0x00000002) << 16) | (($block[1] & 0x00000002) << 15) |
+			(($block[0] & 0x04000000) >> 11) | (($block[1] & 0x04000000) >> 12) |
+			(($block[0] & 0x00040000) >>  5) | (($block[1] & 0x00040000) >>  6) |
+			(($block[0] & 0x00000400) <<  1) | ( $block[1] & 0x00000400	   ) |
+			(($block[0] & 0x08000000) >> 20) | (($block[1] & 0x08000000) >> 21) |
+			(($block[0] & 0x00080000) >> 14) | (($block[1] & 0x00080000) >> 15) |
+			(($block[0] & 0x00000800) >>  8) | (($block[1] & 0x00000800) >>  9)
+		,
+			(($block[0] & 0x10000040) <<  3) | (($block[1] & 0x10000040) <<  2) |
+			(($block[0] & 0x00100000) <<  9) | (($block[1] & 0x00100000) <<  8) |
+			(($block[0] & 0x00001000) << 15) | (($block[1] & 0x00001000) << 14) |
+			(($block[0] & 0x00000010) << 21) | (($block[1] & 0x00000010) << 20) |
+			(($block[0] & 0x20000080) >>  6) | (($block[1] & 0x20000080) >>  7) |
+			( $block[0] & 0x00200000	   ) | (($block[1] & 0x00200000) >>  1) |
+			(($block[0] & 0x00002000) <<  6) | (($block[1] & 0x00002000) <<  5) |
+			(($block[0] & 0x00000020) << 12) | (($block[1] & 0x00000020) << 11) |
+			(($block[0] & 0x40000000) >> 15) | (($block[1] & 0x40000000) >> 16) |
+			(($block[0] & 0x00400000) >>  9) | (($block[1] & 0x00400000) >> 10) |
+			(($block[0] & 0x00004000) >>  3) | (($block[1] & 0x00004000) >>  4) |
+			(($block[0] & 0x00800000) >> 18) | (($block[1] & 0x00800000) >> 19) |
+			(($block[0] & 0x00008000) >> 12) | (($block[1] & 0x00008000) >> 13) |
+			($msb[0] <<  7) | ($msb[1] <<  6)
+		);
+
+		return pack('NN', $block[0], $block[1]);
+	}
+
+	/**
+	 * Creates the key schedule.
+	 *
+	 * @access private
+	 * @param String $key
+	 * @return Array
+	 */
+	function _prepare_key($key)
+	{
+		static $shifts = array( // number of key bits shifted per round
+			1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
+		);
+
+		// pad the key and remove extra characters as appropriate.
+		$key = str_pad(substr($key, 0, 8), 8, chr(0));
+
+		$temp = unpack('Na/Nb', $key);
+		$key = array($temp['a'], $temp['b']);
+		$msb = array(
+			($key[0] >> 31) & 1,
+			($key[1] >> 31) & 1
+		);
+		$key[0] &= 0x7FFFFFFF;
+		$key[1] &= 0x7FFFFFFF;
+
+		$key = array(
+			(($key[1] & 0x00000002) << 26) | (($key[1] & 0x00000204) << 17) |
+			(($key[1] & 0x00020408) <<  8) | (($key[1] & 0x02040800) >>  1) |
+			(($key[0] & 0x00000002) << 22) | (($key[0] & 0x00000204) << 13) |
+			(($key[0] & 0x00020408) <<  4) | (($key[0] & 0x02040800) >>  5) |
+			(($key[1] & 0x04080000) >> 10) | (($key[0] & 0x04080000) >> 14) |
+			(($key[1] & 0x08000000) >> 19) | (($key[0] & 0x08000000) >> 23) |
+			(($key[0] & 0x00000010) >>  1) | (($key[0] & 0x00001000) >> 10) |
+			(($key[0] & 0x00100000) >> 19) | (($key[0] & 0x10000000) >> 28)
+		,
+			(($key[1] & 0x00000080) << 20) | (($key[1] & 0x00008000) << 11) |
+			(($key[1] & 0x00800000) <<  2) | (($key[0] & 0x00000080) << 16) |
+			(($key[0] & 0x00008000) <<  7) | (($key[0] & 0x00800000) >>  2) |
+			(($key[1] & 0x00000040) << 13) | (($key[1] & 0x00004000) <<  4) |
+			(($key[1] & 0x00400000) >>  5) | (($key[1] & 0x40000000) >> 14) |
+			(($key[0] & 0x00000040) <<  9) | ( $key[0] & 0x00004000	   ) |
+			(($key[0] & 0x00400000) >>  9) | (($key[0] & 0x40000000) >> 18) |
+			(($key[1] & 0x00000020) <<  6) | (($key[1] & 0x00002000) >>  3) |
+			(($key[1] & 0x00200000) >> 12) | (($key[1] & 0x20000000) >> 21) |
+			(($key[0] & 0x00000020) <<  2) | (($key[0] & 0x00002000) >>  7) |
+			(($key[0] & 0x00200000) >> 16) | (($key[0] & 0x20000000) >> 25) |
+			(($key[1] & 0x00000010) >>  1) | (($key[1] & 0x00001000) >> 10) |
+			(($key[1] & 0x00100000) >> 19) | (($key[1] & 0x10000000) >> 28) |
+			($msb[1] << 24) | ($msb[0] << 20)
+		); 
+
+		$keys = array();
+		for ($i = 0; $i < 16; $i++)
+		{
+			$key[0] <<= $shifts[$i];
+			$temp = ($key[0] & 0xF0000000) >> 28;
+			$key[0] = ($key[0] | $temp) & 0x0FFFFFFF;
+
+			$key[1] <<= $shifts[$i];
+			$temp = ($key[1] & 0xF0000000) >> 28;
+			$key[1] = ($key[1] | $temp) & 0x0FFFFFFF;
+
+			$temp = array(
+				(($key[1] & 0x00004000) >>  9) | (($key[1] & 0x00000800) >>  7) |
+				(($key[1] & 0x00020000) >> 14) | (($key[1] & 0x00000010) >>  2) |
+				(($key[1] & 0x08000000) >> 26) | (($key[1] & 0x00800000) >> 23)
+			,
+				(($key[1] & 0x02400000) >> 20) | (($key[1] & 0x00000001) <<  4) |
+				(($key[1] & 0x00002000) >> 10) | (($key[1] & 0x00040000) >> 18) |
+				(($key[1] & 0x00000080) >>  6)
+			,
+				( $key[1] & 0x00000020	   ) | (($key[1] & 0x00000200) >>  5) |
+				(($key[1] & 0x00010000) >> 13) | (($key[1] & 0x01000000) >> 22) |
+				(($key[1] & 0x00000004) >>  1) | (($key[1] & 0x00100000) >> 20)
+			,
+				(($key[1] & 0x00001000) >>  7) | (($key[1] & 0x00200000) >> 17) |
+				(($key[1] & 0x00000002) <<  2) | (($key[1] & 0x00000100) >>  6) |
+				(($key[1] & 0x00008000) >> 14) | (($key[1] & 0x04000000) >> 26)
+			,
+				(($key[0] & 0x00008000) >> 10) | ( $key[0] & 0x00000010	   ) |
+				(($key[0] & 0x02000000) >> 22) | (($key[0] & 0x00080000) >> 17) |
+				(($key[0] & 0x00000200) >>  8) | (($key[0] & 0x00000002) >>  1)
+			,
+				(($key[0] & 0x04000000) >> 21) | (($key[0] & 0x00010000) >> 12) |
+				(($key[0] & 0x00000020) >>  2) | (($key[0] & 0x00000800) >>  9) |
+				(($key[0] & 0x00800000) >> 22) | (($key[0] & 0x00000100) >>  8)
+			,
+				(($key[0] & 0x00001000) >>  7) | (($key[0] & 0x00000088) >>  3) |
+				(($key[0] & 0x00020000) >> 14) | (($key[0] & 0x00000001) <<  2) |
+				(($key[0] & 0x00400000) >> 21)
+			,
+				(($key[0] & 0x00000400) >>  5) | (($key[0] & 0x00004000) >> 10) |
+				(($key[0] & 0x00000040) >>  3) | (($key[0] & 0x00100000) >> 18) |
+				(($key[0] & 0x08000000) >> 26) | (($key[0] & 0x01000000) >> 24)
+			);
+
+			$keys[] = $temp;
+		}
+
+		$temp = array(
+			CRYPT_DES_ENCRYPT => $keys,
+			CRYPT_DES_DECRYPT => array_reverse($keys)
+		);
+
+		return $temp;
+	}
+}
+
+
+
+/**
+ * Pure-PHP implementation of Triple DES.
+ *
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @version 0.1.0
+ * @access  public
+ * @package Crypt_TerraDES
+ */
+class tripledes
+{
+	/**
+	 * The Three Keys
+	 *
+	 * @see tripledes::setKey()
+	 * @var String
+	 * @access private
+	 */
+	var $key = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * The Encryption Mode
+	 *
+	 * @see tripledes::tripledes()
+	 * @var Integer
+	 * @access private
+	 */
+	var $mode = CRYPT_DES_MODE_CBC;
+
+	/**
+	 * Continuous Buffer status
+	 *
+	 * @see tripledes::enableContinuousBuffer()
+	 * @var Boolean
+	 * @access private
+	 */
+	var $continuousBuffer = false;
+
+	/**
+	 * Padding status
+	 *
+	 * @see tripledes::enablePadding()
+	 * @var Boolean
+	 * @access private
+	 */
+	var $padding = true;
+
+	/**
+	 * The Initialization Vector
+	 *
+	 * @see tripledes::setIV()
+	 * @var String
+	 * @access private
+	 */
+	var $iv = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * A "sliding" Initialization Vector
+	 *
+	 * @see tripledes::enableContinuousBuffer()
+	 * @var String
+	 * @access private
+	 */
+	var $encryptIV = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * A "sliding" Initialization Vector
+	 *
+	 * @see tripledes::enableContinuousBuffer()
+	 * @var String
+	 * @access private
+	 */
+	var $decryptIV = "\0\0\0\0\0\0\0\0";
+
+	/**
+	 * MCrypt parameters
+	 *
+	 * @see tripledes::setMCrypt()
+	 * @var Array
+	 * @access private
+	 */
+	var $mcrypt = array('', '');
+
+	/**
+	 * The des objects
+	 *
+	 * @var Array
+	 * @access private
+	 */
+	var $des;
+
+	/**
+	 * 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 $mode
+	 * @return tripledes
+	 * @access public
+	 */
+	function __construct($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 des(CRYPT_DES_MODE_CBC),
+				new des(CRYPT_DES_MODE_CBC),
+				new des(CRYPT_DES_MODE_CBC)
+			);
+
+			// we're going to be doing the padding, ourselves, so disable it in the des objects
+			$this->des[0]->disable_padding();
+			$this->des[1]->disable_padding();
+			$this->des[2]->disable_padding();
+
+			return;
+		}
+
+		switch ( CRYPT_DES_MODE )
+		{
+			case CRYPT_DES_MODE_MCRYPT:
+				switch ($mode)
+				{
+					case CRYPT_DES_MODE_ECB:
+						$this->mode = MCRYPT_MODE_ECB;	break;
+					case CRYPT_DES_MODE_CBC:
+					default:
+						$this->mode = MCRYPT_MODE_CBC;
+				}
+
+				break;
+			default:
+				$this->des = array(
+					new des(CRYPT_DES_MODE_ECB),
+					new des(CRYPT_DES_MODE_ECB),
+					new des(CRYPT_DES_MODE_ECB)
+				);
+ 
+				// we're going to be doing the padding, ourselves, so disable it in the des objects
+				$this->des[0]->disable_padding();
+				$this->des[1]->disable_padding();
+				$this->des[2]->disable_padding();
+
+				switch ($mode)
+				{
+					case CRYPT_DES_MODE_ECB:
+					case CRYPT_DES_MODE_CBC:
+						$this->mode = $mode;
+						break;
+					default:
+						$this->mode = CRYPT_DES_MODE_CBC;
+				}
+		}
+	}
+
+	/**
+	 * Sets the key.
+	 *
+	 * Keys can be of any length.  Triple DES, itself, can use 128-bit (eg. strlen($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 $key
+	 */
+	function set_key($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);
+		}
+		$this->key = $key;
+		switch (true)
+		{
+			case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL:
+			case $this->mode == CRYPT_DES_MODE_3CBC:
+				$this->des[0]->set_key(substr($key,  0, 8));
+				$this->des[1]->set_key(substr($key,  8, 8));
+				$this->des[2]->set_key(substr($key, 16, 8));
+		}
+	}
+
+	/**
+	 * 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 $iv
+	 */
+	function set_iv($iv)
+	{
+		$this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));
+		if ($this->mode == CRYPT_DES_MODE_3CBC)
+		{
+			$this->des[0]->set_iv($iv);
+			$this->des[1]->set_iv($iv);
+			$this->des[2]->set_iv($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 $mode_directory
+	 */
+	function set_mcrypt($algorithm_directory = '', $mode_directory = '')
+	{
+		$this->mcrypt = array($algorithm_directory, $mode_directory);
+		if ( $this->mode == CRYPT_DES_MODE_3CBC )
+		{
+			$this->des[0]->set_mcrypt($algorithm_directory, $mode_directory);
+			$this->des[1]->set_mcrypt($algorithm_directory, $mode_directory);
+			$this->des[2]->set_mcrypt($algorithm_directory, $mode_directory);
+		}
+	}
+
+	/**
+	 * Encrypts a message.
+	 *
+	 * @access public
+	 * @param String $plaintext
+	 */
+	function encrypt($plaintext)
+	{
+		$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 )
+		{
+			$td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);
+			mcrypt_generic_init($td, $this->key, $this->encryptIV);
+
+			$ciphertext = mcrypt_generic($td, $plaintext);
+
+			mcrypt_generic_deinit($td);
+			mcrypt_module_close($td);
+
+			if ($this->continuousBuffer)
+			{
+				$this->encryptIV = substr($ciphertext, -8);
+			}
+
+			return $ciphertext;
+		}
+
+		if (strlen($this->key) <= 8)
+		{
+			$this->des[0]->mode = $this->mode;
+
+			return $this->des[0]->encrypt($plaintext);
+		}
+
+		// 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."
+		$plaintext = str_pad($plaintext, ceil(strlen($plaintext) / 8) * 8, chr(0));
+
+		$ciphertext = '';
+		switch ($this->mode)
+		{
+			case CRYPT_DES_MODE_ECB:
+				for ($i = 0; $i < strlen($plaintext); $i+=8)
+				{
+					$block = substr($plaintext, $i, 8);
+					$block = $this->des[0]->_process_block($block, CRYPT_DES_ENCRYPT);
+					$block = $this->des[1]->_process_block($block, CRYPT_DES_DECRYPT);
+					$block = $this->des[2]->_process_block($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 = $this->des[0]->_process_block($block, CRYPT_DES_ENCRYPT);
+					$block = $this->des[1]->_process_block($block, CRYPT_DES_DECRYPT);
+					$block = $this->des[2]->_process_block($block, CRYPT_DES_ENCRYPT);
+					$xor = $block;
+					$ciphertext.= $block;
+				}
+				if ($this->continuousBuffer)
+				{
+					$this->encryptIV = $xor;
+				}
+		}
+
+		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);
+		}
+
+		// 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 )
+		{
+			$td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]);
+			mcrypt_generic_init($td, $this->key, $this->decryptIV);
+
+			$plaintext = mdecrypt_generic($td, $ciphertext);
+
+			mcrypt_generic_deinit($td);
+			mcrypt_module_close($td);
+
+			if ($this->continuousBuffer)
+			{
+				$this->decryptIV = substr($ciphertext, -8);
+			}
+
+			return $this->_unpad($plaintext);
+		}
+
+		if (strlen($this->key) <= 8)
+		{
+			$this->des[0]->mode = $this->mode;
+
+			return $this->_unpad($this->des[0]->decrypt($plaintext));
+		}
+
+		$plaintext = '';
+		switch ($this->mode)
+		{
+			case CRYPT_DES_MODE_ECB:
+				for ($i = 0; $i < strlen($ciphertext); $i+=8)
+				{
+					$block = substr($ciphertext, $i, 8);
+					$block = $this->des[2]->_process_block($block, CRYPT_DES_DECRYPT);
+					$block = $this->des[1]->_process_block($block, CRYPT_DES_ENCRYPT);
+					$block = $this->des[0]->_process_block($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 = $this->des[2]->_process_block($block, CRYPT_DES_DECRYPT);
+					$block = $this->des[1]->_process_block($block, CRYPT_DES_ENCRYPT);
+					$block = $this->des[0]->_process_block($block, CRYPT_DES_DECRYPT);
+					$plaintext.= $block ^ $xor;
+					$xor = $orig;
+				}
+				if ($this->continuousBuffer)
+				{
+					$this->decryptIV = $xor;
+				}
+		}
+
+		return $this->_unpad($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 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 tripledes::disableContinuousBuffer()
+	 * @access public
+	 */
+	function enable_continuous_buffer()
+	{
+		$this->continuousBuffer = true;
+		if ($this->mode == CRYPT_DES_MODE_3CBC)
+		{
+			$this->des[0]->enable_continuous_buffer();
+			$this->des[1]->enable_continuous_buffer();
+			$this->des[2]->enable_continuous_buffer();
+		}
+	}
+
+	/**
+	 * Treat consecutive packets as if they are a discontinuous buffer.
+	 *
+	 * The default behavior.
+	 *
+	 * @see tripledes::enableContinuousBuffer()
+	 * @access public
+	 */
+	function disable_continuous_buffer()
+	{
+		$this->continuousBuffer = false;
+		$this->encryptIV = $this->iv;
+		$this->decryptIV = $this->iv;
+
+		if ($this->mode == CRYPT_DES_MODE_3CBC)
+		{
+			$this->des[0]->disable_continuous_buffer();
+			$this->des[1]->disable_continuous_buffer();
+			$this->des[2]->disable_continuous_buffer();
+		}
+	}
+
+	/**
+	 * 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 tripledes::disable_padding()
+	 * @access public
+	 */
+	function enable_padding()
+	{
+		$this->padding = true;
+	}
+
+	/**
+	 * Do not pad packets.
+	 *
+	 * @see tripledes::enablePadding()
+	 * @access public
+	 */
+	function disable_padding()
+	{
+		$this->padding = false;
+	}
+
+	/**
+	 * Pads a string
+	 *
+	 * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8).
+	 * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7)
+	 *
+	 * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
+	 * and padding will, hence forth, be enabled.
+	 *
+	 * @see tripledes::_unpad()
+	 * @access private
+	 */
+	function _pad($text)
+	{
+		$length = strlen($text);
+
+		if (!$this->padding)
+		{
+			if (($length & 7) == 0)
+			{
+				return $text;
+			}
+			else
+			{
+				$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 exceeds the block size, padding will be, hence forth, disabled.
+	 *
+	 * @see tripledes::_pad()
+	 * @access private
+	 */
+	function _unpad($text)
+	{
+		if (!$this->padding)
+		{
+			return $text;
+		}
+
+		$length = ord($text[strlen($text) - 1]);
+
+		if ($length > 8)
+		{
+			$this->padding = false;
+			return $text;
+		}
+
+		return substr($text, 0, -$length);
+	}
+}
+
+?>
+\ No newline at end of file