<?php

// +----------------------------------------------------------------------+

// | Perfect Scripts class.pcrypt.php |

// | Brazilian Organization |

// +----------------------------------------------------------------------+

// | Viva ao Linux! |

// | Porque nós amamos a liberdade! |

// +----------------------------------------------------------------------+

// | Class Perfect Crypt |

// | Created By Igor Ribeiro de Assis |

// | <igor21@terra.com.br> UIN: 71064682 |

// +----------------------------------------------------------------------+

// | http://ps.wmforce.com |

// +----------------------------------------------------------------------+

// | Under GPL |

// +----------------------------------------------------------------------+

// | This program is free software; you can redistribute it and/or modify |

// | it under the terms of the GNU General Public License as published |

// | by the Free Software Foundation; either version 2 of the License, |

// | or (at your option) any later version. |

// | |

// | This program 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 General Public License for more details. |

// | |

// | You should have received a copy of the GNU General Public License |

// | along with this program; if not, write to the Free Software |

// | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |

// | 02111-1307 USA |

// +----------------------------------------------------------------------+

/**

* Encryption Block Mode constants

*

* @const MODE_ECB ecb mode

* @const MODE_CBC cbc mode

*/

define("MODE_ECB",0);

define("MODE_CBC",1);

/**

* An abstract layer class to encrypt data.

*

* This class is class is used to encrypt and decrypt data using different algorithms

* and modes.

*

* @author Igor Ribeiro de Assis <igor21@terra.com.br>

* @version 1.0-beta

* @access public

* @package Perfect Crypt

*/

class pcrypt

{

/** Encryption Block Mode: ECB, CBC actually.

*

* @var int the mode used

* @access private

*/

var $blockmode = MODE_ECB;

/** Key for Encryption

*

* @var string the key used in encryption and decryption

* @access public

*/

var $key = null;

/** IV - Initialization Vector String

*

* @var string initialization vector for some modes (CBC)

* @access public

*/

var $iv = "z4c8e7gh";

/** Methods */

/** Constructor of the class.

*

* The constructor initialize some important vars and include the algorithm

* file.

*

* @access public

* @param int $blockmode the blockmode to use

* @param string $cipher the algorithm used to crypt

* @param string $key the ley used to crypt

*

* @return void

*/

function pcrypt($blockmode = MODE_ECB, $cipher = 'BLOWFISH', $key = null)

{

// Include cipher_class file

$cipher = strtolower($cipher);

if (!file_exists($cipher.".php"))

{

//$this->error();

}

include_once $cipher.".php";

// Load cipher_class

if (!class_exists("pcrypt_".$cipher))

{

$this->error("Class pcrypt_".$cipher." doesn't exists");

}

$class = "pcrypt_".$cipher;

$this->cipher = new $class($key);

// Initialize Vars

$this->blockmode = $blockmode;

$this->key = $key;

}

/** Crypt data using the selected algorithm

*

* This method encrypt data using the selected algorithm and mode:

* Algorithms: Blowfish

* Modes: ECB, CBC

* For a description about algorithms and modes see:

* Applied Cryptography by Bruce Schneier

*

* @access public

* @param string $plain the plain text to be encrypted

* @return string $cipher the plain text encrypted

*/

function encrypt($plain)

{

if (empty($plain))

{

$this->error("Empty Plain Text");

}

// Encrypt using the correct mode

switch($this->blockmode) {

case MODE_ECB:

$cipher = $this->_ecb_encrypt($plain);

break;

case MODE_CBC:

$cipher = $this->_cbc_encrypt($plain);

break;

default:

$this->error("Invalid mode ".$this->blockmode);

}

return $cipher;

}

/** Decrypt using the selected algorithm

*

* This method decrypt data using the selected algorithm and mode.

* TODO: Discover the algorithm and mode auto

*

* @access public

* @param string $cipher the crypted data to be decrypted

* @return string $plain the cipher text decrypted

*/

function decrypt($cipher)

{

if (empty($cipher))

{

$this->error("Invalid Cipher Text");

}

// Decrypt with the correct mode

switch($this->blockmode) {

case MODE_ECB:

$plain = $this->_ecb_decrypt($cipher);

break;

case MODE_CBC:

$plain = $this->_cbc_decrypt($cipher);

break;

default:

$this->error("Invalid mode ".$this->blockmode);

}

return $plain;

}

/** Method to encrypt using ECB mode.

*

* In ECB mode the blocks are encrypted independently

*

* @access private

* @param string $plain the plain text to be encrypted

* @return string $cipher the plain text encrypted

*/

function _ecb_encrypt($plain)

{

$blocksize = $this->cipher->blocksize;

$plainsize = strlen($plain);

$cipher = '';

for($i = 0;$i < $plainsize;$i = $i + $blocksize)

{

$block = substr($plain,$i,$blocksize);

if(strlen($block) < $blocksize)

{

// pad block with '\0'

$block = str_pad($block,$blocksize,"\0",STR_PAD_LEFT);

}

$cipher .= $this->cipher->_encrypt($block);

}

return $cipher;

}

/** Method to decrypt using ECB mode.

*

* @access private

* @param string $cipher the cipher text

* @return string $plain the cipher text decrypted

*/

function _ecb_decrypt($cipher)

{

$blocksize = $this->cipher->blocksize;

$ciphersize = strlen($cipher);

$plain = '';

for($i = 0;$i < $ciphersize;$i = $i + $blocksize)

{

$block = substr($cipher,$i,$blocksize);

$block = $this->cipher->_decrypt($block);

// Remove padded chars

while(substr($block,0,1) == "\0")

{

$block = substr($block,1);

}

$plain .= $block;

}

return $plain;

}

/** This method encrypt using CBC mode.

*

* In CBC mode each block is xored with the last. This function use $iv as

* first block.

*

* @access private

* @param string $plain the plain text to be decrypted

* @return string $cipher the plain text encrypted

*/

function _cbc_encrypt($plain)

{

$blocksize = $this->cipher->blocksize;

$plainsize = strlen($plain);

$cipher = '';

$lcipher = $this->iv;

// encrypt each block

for($i = 0;$i < $plainsize;$i = $i + $blocksize)

{

$block = substr($plain,$i,$blocksize);

if(strlen($block) < $blocksize)

{

// pad block with '\0'

$block = str_pad($block,$blocksize,"\0",STR_PAD_LEFT);

}

// crypt the block xored with the last cipher block

$lcipher = $this->cipher->_encrypt($block ^ $lcipher);

$cipher .= $lcipher;

}

return $cipher;

}

/** This method decrypt using CBC.

*

* @access private

* @param string $cipher the cipher text

* @return string $plain the cipher text decrypted

*/

function _cbc_decrypt($cipher)

{

// get the block size of the cipher

$blocksize = $this->cipher->blocksize;

$ciphersize = strlen($cipher);

$plain = '';

$lcipher = $this->iv;

for($i = 0;$i < $ciphersize;$i = $i + $blocksize)

{

$block = substr($cipher,$i,$blocksize);

// xor the block with the last cipher block

$dblock = $lcipher ^ $this->cipher->_decrypt($block);

$lcipher = $block;

// Remove padded chars

while(substr($dblock,0,1) == "\0")

{

$dblock = substr($dblock,1);

}

$plain .= $dblock;

}

return $plain;

}

/**

* A simple function for error handling.

*

* TODO: Improve the error handling of the class

*

* @access private

* @param string $message erro message

* @return boolean true

*/

function error($message)

{

//echo "Error: ".$message."<br>";

return 1;

}

}

?>