<?php
namespace Kant\Secure\Crypt;

/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**
 * Pure-PHP implementation of Rijndael.
 *
 * Does not use mcrypt, even when available, for reasons that are explained below.
 *
 * PHP versions 4 and 5
 *
 * If {@link Crypt_Rijndael::setBlockLength() setBlockLength()} isn't called, it'll be assumed to be 128 bits. If
 * {@link Crypt_Rijndael::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
 * {@link Crypt_Rijndael::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's
 * 136-bits it'll be null-padded to 160-bits and 160 bits will be the key length until
 * {@link Crypt_Rijndael::setKey() setKey()} is called, again, at which point, it'll be recalculated.
 *
 * Not all Rijndael implementations may support 160-bits or 224-bits as the block length / key length. mcrypt, for example,
 * does not. AES, itself, only supports block lengths of 128 and key lengths of 128, 192, and 256.
 * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=10 Rijndael-ammended.pdf#page=10} defines the
 * algorithm for block lengths of 192 and 256 but not for block lengths / key lengths of 160 and 224. Indeed, 160 and 224
 * are first defined as valid key / block lengths in
 * {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=44 Rijndael-ammended.pdf#page=44}:
 * Extensions: Other block and Cipher Key lengths.
 *
 * {@internal The variable names are the same as those in
 * {@link http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf#page=10 fips-197.pdf#page=10}.}}
 *
 * Here's a short example of how to use this library:
 * <code>
 * <?php
 * include('Crypt/Rijndael.php');
 *
 * $rijndael = new Crypt_Rijndael();
 *
 * $rijndael->setKey('abcdefghijklmnop');
 *
 * $size = 10 * 1024;
 * $plaintext = '';
 * for ($i = 0; $i < $size; $i++) {
 * $plaintext.= 'a';
 * }
 *
 * echo $rijndael->decrypt($rijndael->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_Rijndael
 * @author Jim Wigginton <terrafrost@php.net>
 * @copyright MMVIII Jim Wigginton
 * @license http://www.opensource.org/licenses/mit-license.html MIT License
 * @version $Id: Rijndael.php,v 1.12 2010/02/09 06:10:26 terrafrost Exp $
 * @link http://phpseclib.sourceforge.net
 */
/*
 * #@+
 * @access public
 * @see Crypt_Rijndael::encrypt()
 * @see Crypt_Rijndael::decrypt()
 */
/**
 * Encrypt / decrypt using the Counter mode.
 *
 * Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
 *
 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
 */
define('CRYPT_RIJNDAEL_MODE_CTR', - 1);
/**
 * 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_RIJNDAEL_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_RIJNDAEL_MODE_CBC', 2);
/**
 * Encrypt / decrypt using the Cipher Feedback mode.
 *
 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
 */
define('CRYPT_RIJNDAEL_MODE_CFB', 3);
/**
 * Encrypt / decrypt using the Cipher Feedback mode.
 *
 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
 */
define('CRYPT_RIJNDAEL_MODE_OFB', 4);
/* * #@- */

/*
 * #@+
 * @access private
 * @see Crypt_Rijndael::Crypt_Rijndael()
 */
/**
 * Toggles the internal implementation
 */
define('CRYPT_RIJNDAEL_MODE_INTERNAL', 1);
/**
 * Toggles the mcrypt implementation
 */
define('CRYPT_RIJNDAEL_MODE_MCRYPT', 2);

/* * #@- */

/**
 * Pure-PHP implementation of Rijndael.
 *
 * @author Jim Wigginton <terrafrost@php.net>
 * @version 0.1.0
 * @access public
 * @package Crypt_Rijndael
 */
class Crypt_Rijndael
{

    /**
     * The Encryption Mode
     *
     * @see Crypt_Rijndael::Crypt_Rijndael()
     * @var Integer
     * @access private
     */
    var $mode;

    /**
     * The Key
     *
     * @see Crypt_Rijndael::setKey()
     * @var String
     * @access private
     */
    var $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";

    /**
     * The Initialization Vector
     *
     * @see Crypt_Rijndael::setIV()
     * @var String
     * @access private
     */
    var $iv = '';

    /**
     * A "sliding" Initialization Vector
     *
     * @see Crypt_Rijndael::enableContinuousBuffer()
     * @var String
     * @access private
     */
    var $encryptIV = '';

    /**
     * A "sliding" Initialization Vector
     *
     * @see Crypt_Rijndael::enableContinuousBuffer()
     * @var String
     * @access private
     */
    var $decryptIV = '';

    /**
     * Continuous Buffer status
     *
     * @see Crypt_Rijndael::enableContinuousBuffer()
     * @var Boolean
     * @access private
     */
    var $continuousBuffer = false;

    /**
     * Padding status
     *
     * @see Crypt_Rijndael::enablePadding()
     * @var Boolean
     * @access private
     */
    var $padding = true;

    /**
     * Does the key schedule need to be (re)calculated?
     *
     * @see setKey()
     * @see setBlockLength()
     * @see setKeyLength()
     * @var Boolean
     * @access private
     */
    var $changed = true;

    /**
     * Has the key length explicitly been set or should it be derived from the key, itself?
     *
     * @see setKeyLength()
     * @var Boolean
     * @access private
     */
    var $explicit_key_length = false;

    /**
     * The Key Schedule
     *
     * @see _setup()
     * @var Array
     * @access private
     */
    var $w;

    /**
     * The Inverse Key Schedule
     *
     * @see _setup()
     * @var Array
     * @access private
     */
    var $dw;

    /**
     * The Block Length
     *
     * @see setBlockLength()
     * @var Integer
     * @access private
     * @internal The max value is 32, the min value is 16. All valid values are multiples of 4. Exists in conjunction with
     *           $Nb because we need this value and not $Nb to pad strings appropriately.
     */
    var $block_size = 16;

    /**
     * The Block Length divided by 32
     *
     * @see setBlockLength()
     * @var Integer
     * @access private
     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4. Exists in conjunction with $block_size
     *           because the encryption / decryption / key schedule creation requires this number and not $block_size. We could
     *           derive this from $block_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu
     *           of that, we'll just precompute it once.
     *          
     */
    var $Nb = 4;

    /**
     * The Key Length
     *
     * @see setKeyLength()
     * @var Integer
     * @access private
     * @internal The max value is 256 / 8 = 32, the min value is 128 / 8 = 16. Exists in conjunction with $key_size
     *           because the encryption / decryption / key schedule creation requires this number and not $key_size. We could
     *           derive this from $key_size or vice versa, but that'd mean we'd have to do multiple shift operations, so in lieu
     *           of that, we'll just precompute it once.
     */
    var $key_size = 16;

    /**
     * The Key Length divided by 32
     *
     * @see setKeyLength()
     * @var Integer
     * @access private
     * @internal The max value is 256 / 32 = 8, the min value is 128 / 32 = 4
     */
    var $Nk = 4;

    /**
     * The Number of Rounds
     *
     * @var Integer
     * @access private
     * @internal The max value is 14, the min value is 10.
     */
    var $Nr;

    /**
     * Shift offsets
     *
     * @var Array
     * @access private
     */
    var $c;

    /**
     * Precomputed mixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $t0;

    /**
     * Precomputed mixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $t1;

    /**
     * Precomputed mixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $t2;

    /**
     * Precomputed mixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $t3;

    /**
     * Precomputed invMixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $dt0;

    /**
     * Precomputed invMixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $dt1;

    /**
     * Precomputed invMixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $dt2;

    /**
     * Precomputed invMixColumns table
     *
     * @see Crypt_Rijndael()
     * @var Array
     * @access private
     */
    var $dt3;

    /**
     * The SubByte S-Box
     *
     * @see Crypt_Rijndael::_encryptBlock()
     * @var Array
     * @access private
     */
    var $sbox;

    /**
     * The inverse SubByte S-Box
     *
     * @see Crypt_Rijndael::_decryptBlock()
     * @var Array
     * @access private
     */
    var $isbox;

    /**
     * Performance-optimized callback function for en/decrypt()
     *
     * @see Crypt_Rijndael::encrypt()
     * @see Crypt_Rijndael::decrypt()
     * @see Crypt_Rijndael::inline_crypt_setup()
     * @see Crypt_Rijndael::$use_inline_crypt
     * @var Callback
     * @access private
     */
    var $inline_crypt;

    /**
     * Holds whether performance-optimized $inline_crypt should be used or not.
     *
     * @see Crypt_Rijndael::Crypt_Rijndael()
     * @see Crypt_Rijndael::inline_crypt_setup()
     * @see Crypt_Rijndael::$inline_crypt
     * @var Boolean
     * @access private
     */
    var $use_inline_crypt = true;

    /**
     * Is the mode one that is paddable?
     *
     * @see Crypt_Rijndael::Crypt_Rijndael()
     * @var Boolean
     * @access private
     */
    var $paddable = false;

    /**
     * Encryption buffer for CTR, OFB and CFB modes
     *
     * @see Crypt_Rijndael::encrypt()
     * @var String
     * @access private
     */
    var $enbuffer = array(
        'encrypted' => '',
        'xor' => '',
        'pos' => 0
    );

    /**
     * Decryption buffer for CTR, OFB and CFB modes
     *
     * @see Crypt_Rijndael::decrypt()
     * @var String
     * @access private
     */
    var $debuffer = array(
        'ciphertext' => '',
        'xor' => '',
        'pos' => 0
    );

    /**
     * Default Constructor.
     *
     * Determines whether or not the mcrypt extension should be used. $mode should only, at present, be
     * CRYPT_RIJNDAEL_MODE_ECB or CRYPT_RIJNDAEL_MODE_CBC. If not explictly set, CRYPT_RIJNDAEL_MODE_CBC will be used.
     *
     * @param
     *            optional Integer $mode
     * @return Crypt_Rijndael
     * @access public
     */
    function __construct($mode = CRYPT_RIJNDAEL_MODE_CBC)
    {
        switch ($mode) {
            case CRYPT_RIJNDAEL_MODE_ECB:
            case CRYPT_RIJNDAEL_MODE_CBC:
                $this->paddable = true;
                $this->mode = $mode;
                break;
            case CRYPT_RIJNDAEL_MODE_CTR:
            case CRYPT_RIJNDAEL_MODE_CFB:
            case CRYPT_RIJNDAEL_MODE_OFB:
                $this->mode = $mode;
                break;
            default:
                $this->paddable = true;
                $this->mode = CRYPT_RIJNDAEL_MODE_CBC;
        }
        
        $t3 = &$this->t3;
        $t2 = &$this->t2;
        $t1 = &$this->t1;
        $t0 = &$this->t0;
        
        $dt3 = &$this->dt3;
        $dt2 = &$this->dt2;
        $dt1 = &$this->dt1;
        $dt0 = &$this->dt0;
        
        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=19> (section 5.2.1),
        // precomputed tables can be used in the mixColumns phase. in that example, they're assigned t0...t3, so
        // those are the names we'll use.
        $t3 = array(
            0x6363A5C6,
            0x7C7C84F8,
            0x777799EE,
            0x7B7B8DF6,
            0xF2F20DFF,
            0x6B6BBDD6,
            0x6F6FB1DE,
            0xC5C55491,
            0x30305060,
            0x01010302,
            0x6767A9CE,
            0x2B2B7D56,
            0xFEFE19E7,
            0xD7D762B5,
            0xABABE64D,
            0x76769AEC,
            0xCACA458F,
            0x82829D1F,
            0xC9C94089,
            0x7D7D87FA,
            0xFAFA15EF,
            0x5959EBB2,
            0x4747C98E,
            0xF0F00BFB,
            0xADADEC41,
            0xD4D467B3,
            0xA2A2FD5F,
            0xAFAFEA45,
            0x9C9CBF23,
            0xA4A4F753,
            0x727296E4,
            0xC0C05B9B,
            0xB7B7C275,
            0xFDFD1CE1,
            0x9393AE3D,
            0x26266A4C,
            0x36365A6C,
            0x3F3F417E,
            0xF7F702F5,
            0xCCCC4F83,
            0x34345C68,
            0xA5A5F451,
            0xE5E534D1,
            0xF1F108F9,
            0x717193E2,
            0xD8D873AB,
            0x31315362,
            0x15153F2A,
            0x04040C08,
            0xC7C75295,
            0x23236546,
            0xC3C35E9D,
            0x18182830,
            0x9696A137,
            0x05050F0A,
            0x9A9AB52F,
            0x0707090E,
            0x12123624,
            0x80809B1B,
            0xE2E23DDF,
            0xEBEB26CD,
            0x2727694E,
            0xB2B2CD7F,
            0x75759FEA,
            0x09091B12,
            0x83839E1D,
            0x2C2C7458,
            0x1A1A2E34,
            0x1B1B2D36,
            0x6E6EB2DC,
            0x5A5AEEB4,
            0xA0A0FB5B,
            0x5252F6A4,
            0x3B3B4D76,
            0xD6D661B7,
            0xB3B3CE7D,
            0x29297B52,
            0xE3E33EDD,
            0x2F2F715E,
            0x84849713,
            0x5353F5A6,
            0xD1D168B9,
            0x00000000,
            0xEDED2CC1,
            0x20206040,
            0xFCFC1FE3,
            0xB1B1C879,
            0x5B5BEDB6,
            0x6A6ABED4,
            0xCBCB468D,
            0xBEBED967,
            0x39394B72,
            0x4A4ADE94,
            0x4C4CD498,
            0x5858E8B0,
            0xCFCF4A85,
            0xD0D06BBB,
            0xEFEF2AC5,
            0xAAAAE54F,
            0xFBFB16ED,
            0x4343C586,
            0x4D4DD79A,
            0x33335566,
            0x85859411,
            0x4545CF8A,
            0xF9F910E9,
            0x02020604,
            0x7F7F81FE,
            0x5050F0A0,
            0x3C3C4478,
            0x9F9FBA25,
            0xA8A8E34B,
            0x5151F3A2,
            0xA3A3FE5D,
            0x4040C080,
            0x8F8F8A05,
            0x9292AD3F,
            0x9D9DBC21,
            0x38384870,
            0xF5F504F1,
            0xBCBCDF63,
            0xB6B6C177,
            0xDADA75AF,
            0x21216342,
            0x10103020,
            0xFFFF1AE5,
            0xF3F30EFD,
            0xD2D26DBF,
            0xCDCD4C81,
            0x0C0C1418,
            0x13133526,
            0xECEC2FC3,
            0x5F5FE1BE,
            0x9797A235,
            0x4444CC88,
            0x1717392E,
            0xC4C45793,
            0xA7A7F255,
            0x7E7E82FC,
            0x3D3D477A,
            0x6464ACC8,
            0x5D5DE7BA,
            0x19192B32,
            0x737395E6,
            0x6060A0C0,
            0x81819819,
            0x4F4FD19E,
            0xDCDC7FA3,
            0x22226644,
            0x2A2A7E54,
            0x9090AB3B,
            0x8888830B,
            0x4646CA8C,
            0xEEEE29C7,
            0xB8B8D36B,
            0x14143C28,
            0xDEDE79A7,
            0x5E5EE2BC,
            0x0B0B1D16,
            0xDBDB76AD,
            0xE0E03BDB,
            0x32325664,
            0x3A3A4E74,
            0x0A0A1E14,
            0x4949DB92,
            0x06060A0C,
            0x24246C48,
            0x5C5CE4B8,
            0xC2C25D9F,
            0xD3D36EBD,
            0xACACEF43,
            0x6262A6C4,
            0x9191A839,
            0x9595A431,
            0xE4E437D3,
            0x79798BF2,
            0xE7E732D5,
            0xC8C8438B,
            0x3737596E,
            0x6D6DB7DA,
            0x8D8D8C01,
            0xD5D564B1,
            0x4E4ED29C,
            0xA9A9E049,
            0x6C6CB4D8,
            0x5656FAAC,
            0xF4F407F3,
            0xEAEA25CF,
            0x6565AFCA,
            0x7A7A8EF4,
            0xAEAEE947,
            0x08081810,
            0xBABAD56F,
            0x787888F0,
            0x25256F4A,
            0x2E2E725C,
            0x1C1C2438,
            0xA6A6F157,
            0xB4B4C773,
            0xC6C65197,
            0xE8E823CB,
            0xDDDD7CA1,
            0x74749CE8,
            0x1F1F213E,
            0x4B4BDD96,
            0xBDBDDC61,
            0x8B8B860D,
            0x8A8A850F,
            0x707090E0,
            0x3E3E427C,
            0xB5B5C471,
            0x6666AACC,
            0x4848D890,
            0x03030506,
            0xF6F601F7,
            0x0E0E121C,
            0x6161A3C2,
            0x35355F6A,
            0x5757F9AE,
            0xB9B9D069,
            0x86869117,
            0xC1C15899,
            0x1D1D273A,
            0x9E9EB927,
            0xE1E138D9,
            0xF8F813EB,
            0x9898B32B,
            0x11113322,
            0x6969BBD2,
            0xD9D970A9,
            0x8E8E8907,
            0x9494A733,
            0x9B9BB62D,
            0x1E1E223C,
            0x87879215,
            0xE9E920C9,
            0xCECE4987,
            0x5555FFAA,
            0x28287850,
            0xDFDF7AA5,
            0x8C8C8F03,
            0xA1A1F859,
            0x89898009,
            0x0D0D171A,
            0xBFBFDA65,
            0xE6E631D7,
            0x4242C684,
            0x6868B8D0,
            0x4141C382,
            0x9999B029,
            0x2D2D775A,
            0x0F0F111E,
            0xB0B0CB7B,
            0x5454FCA8,
            0xBBBBD66D,
            0x16163A2C
        );
        
        $dt3 = array(
            0xF4A75051,
            0x4165537E,
            0x17A4C31A,
            0x275E963A,
            0xAB6BCB3B,
            0x9D45F11F,
            0xFA58ABAC,
            0xE303934B,
            0x30FA5520,
            0x766DF6AD,
            0xCC769188,
            0x024C25F5,
            0xE5D7FC4F,
            0x2ACBD7C5,
            0x35448026,
            0x62A38FB5,
            0xB15A49DE,
            0xBA1B6725,
            0xEA0E9845,
            0xFEC0E15D,
            0x2F7502C3,
            0x4CF01281,
            0x4697A38D,
            0xD3F9C66B,
            0x8F5FE703,
            0x929C9515,
            0x6D7AEBBF,
            0x5259DA95,
            0xBE832DD4,
            0x7421D358,
            0xE0692949,
            0xC9C8448E,
            0xC2896A75,
            0x8E7978F4,
            0x583E6B99,
            0xB971DD27,
            0xE14FB6BE,
            0x88AD17F0,
            0x20AC66C9,
            0xCE3AB47D,
            0xDF4A1863,
            0x1A3182E5,
            0x51336097,
            0x537F4562,
            0x6477E0B1,
            0x6BAE84BB,
            0x81A01CFE,
            0x082B94F9,
            0x48685870,
            0x45FD198F,
            0xDE6C8794,
            0x7BF8B752,
            0x73D323AB,
            0x4B02E272,
            0x1F8F57E3,
            0x55AB2A66,
            0xEB2807B2,
            0xB5C2032F,
            0xC57B9A86,
            0x3708A5D3,
            0x2887F230,
            0xBFA5B223,
            0x036ABA02,
            0x16825CED,
            0xCF1C2B8A,
            0x79B492A7,
            0x07F2F0F3,
            0x69E2A14E,
            0xDAF4CD65,
            0x05BED506,
            0x34621FD1,
            0xA6FE8AC4,
            0x2E539D34,
            0xF355A0A2,
            0x8AE13205,
            0xF6EB75A4,
            0x83EC390B,
            0x60EFAA40,
            0x719F065E,
            0x6E1051BD,
            0x218AF93E,
            0xDD063D96,
            0x3E05AEDD,
            0xE6BD464D,
            0x548DB591,
            0xC45D0571,
            0x06D46F04,
            0x5015FF60,
            0x98FB2419,
            0xBDE997D6,
            0x4043CC89,
            0xD99E7767,
            0xE842BDB0,
            0x898B8807,
            0x195B38E7,
            0xC8EEDB79,
            0x7C0A47A1,
            0x420FE97C,
            0x841EC9F8,
            0x00000000,
            0x80868309,
            0x2BED4832,
            0x1170AC1E,
            0x5A724E6C,
            0x0EFFFBFD,
            0x8538560F,
            0xAED51E3D,
            0x2D392736,
            0x0FD9640A,
            0x5CA62168,
            0x5B54D19B,
            0x362E3A24,
            0x0A67B10C,
            0x57E70F93,
            0xEE96D2B4,
            0x9B919E1B,
            0xC0C54F80,
            0xDC20A261,
            0x774B695A,
            0x121A161C,
            0x93BA0AE2,
            0xA02AE5C0,
            0x22E0433C,
            0x1B171D12,
            0x090D0B0E,
            0x8BC7ADF2,
            0xB6A8B92D,
            0x1EA9C814,
            0xF1198557,
            0x75074CAF,
            0x99DDBBEE,
            0x7F60FDA3,
            0x01269FF7,
            0x72F5BC5C,
            0x663BC544,
            0xFB7E345B,
            0x4329768B,
            0x23C6DCCB,
            0xEDFC68B6,
            0xE4F163B8,
            0x31DCCAD7,
            0x63851042,
            0x97224013,
            0xC6112084,
            0x4A247D85,
            0xBB3DF8D2,
            0xF93211AE,
            0x29A16DC7,
            0x9E2F4B1D,
            0xB230F3DC,
            0x8652EC0D,
            0xC1E3D077,
            0xB3166C2B,
            0x70B999A9,
            0x9448FA11,
            0xE9642247,
            0xFC8CC4A8,
            0xF03F1AA0,
            0x7D2CD856,
            0x3390EF22,
            0x494EC787,
            0x38D1C1D9,
            0xCAA2FE8C,
            0xD40B3698,
            0xF581CFA6,
            0x7ADE28A5,
            0xB78E26DA,
            0xADBFA43F,
            0x3A9DE42C,
            0x78920D50,
            0x5FCC9B6A,
            0x7E466254,
            0x8D13C2F6,
            0xD8B8E890,
            0x39F75E2E,
            0xC3AFF582,
            0x5D80BE9F,
            0xD0937C69,
            0xD52DA96F,
            0x2512B3CF,
            0xAC993BC8,
            0x187DA710,
            0x9C636EE8,
            0x3BBB7BDB,
            0x267809CD,
            0x5918F46E,
            0x9AB701EC,
            0x4F9AA883,
            0x956E65E6,
            0xFFE67EAA,
            0xBCCF0821,
            0x15E8E6EF,
            0xE79BD9BA,
            0x6F36CE4A,
            0x9F09D4EA,
            0xB07CD629,
            0xA4B2AF31,
            0x3F23312A,
            0xA59430C6,
            0xA266C035,
            0x4EBC3774,
            0x82CAA6FC,
            0x90D0B0E0,
            0xA7D81533,
            0x04984AF1,
            0xECDAF741,
            0xCD500E7F,
            0x91F62F17,
            0x4DD68D76,
            0xEFB04D43,
            0xAA4D54CC,
            0x9604DFE4,
            0xD1B5E39E,
            0x6A881B4C,
            0x2C1FB8C1,
            0x65517F46,
            0x5EEA049D,
            0x8C355D01,
            0x877473FA,
            0x0B412EFB,
            0x671D5AB3,
            0xDBD25292,
            0x105633E9,
            0xD647136D,
            0xD7618C9A,
            0xA10C7A37,
            0xF8148E59,
            0x133C89EB,
            0xA927EECE,
            0x61C935B7,
            0x1CE5EDE1,
            0x47B13C7A,
            0xD2DF599C,
            0xF2733F55,
            0x14CE7918,
            0xC737BF73,
            0xF7CDEA53,
            0xFDAA5B5F,
            0x3D6F14DF,
            0x44DB8678,
            0xAFF381CA,
            0x68C43EB9,
            0x24342C38,
            0xA3405FC2,
            0x1DC37216,
            0xE2250CBC,
            0x3C498B28,
            0x0D9541FF,
            0xA8017139,
            0x0CB3DE08,
            0xB4E49CD8,
            0x56C19064,
            0xCB84617B,
            0x32B670D5,
            0x6C5C7448,
            0xB85742D0
        );
        
        for ($i = 0; $i < 256; $i ++) {
            $t2[] = (($t3[$i] << 8) & 0xFFFFFF00) | (($t3[$i] >> 24) & 0x000000FF);
            $t1[] = (($t3[$i] << 16) & 0xFFFF0000) | (($t3[$i] >> 16) & 0x0000FFFF);
            $t0[] = (($t3[$i] << 24) & 0xFF000000) | (($t3[$i] >> 8) & 0x00FFFFFF);
            
            $dt2[] = (($dt3[$i] << 8) & 0xFFFFFF00) | (($dt3[$i] >> 24) & 0x000000FF);
            $dt1[] = (($dt3[$i] << 16) & 0xFFFF0000) | (($dt3[$i] >> 16) & 0x0000FFFF);
            $dt0[] = (($dt3[$i] << 24) & 0xFF000000) | (($dt3[$i] >> 8) & 0x00FFFFFF);
        }
        
        // sbox for the S-Box substitution
        $this->sbox = array(
            0x63,
            0x7C,
            0x77,
            0x7B,
            0xF2,
            0x6B,
            0x6F,
            0xC5,
            0x30,
            0x01,
            0x67,
            0x2B,
            0xFE,
            0xD7,
            0xAB,
            0x76,
            0xCA,
            0x82,
            0xC9,
            0x7D,
            0xFA,
            0x59,
            0x47,
            0xF0,
            0xAD,
            0xD4,
            0xA2,
            0xAF,
            0x9C,
            0xA4,
            0x72,
            0xC0,
            0xB7,
            0xFD,
            0x93,
            0x26,
            0x36,
            0x3F,
            0xF7,
            0xCC,
            0x34,
            0xA5,
            0xE5,
            0xF1,
            0x71,
            0xD8,
            0x31,
            0x15,
            0x04,
            0xC7,
            0x23,
            0xC3,
            0x18,
            0x96,
            0x05,
            0x9A,
            0x07,
            0x12,
            0x80,
            0xE2,
            0xEB,
            0x27,
            0xB2,
            0x75,
            0x09,
            0x83,
            0x2C,
            0x1A,
            0x1B,
            0x6E,
            0x5A,
            0xA0,
            0x52,
            0x3B,
            0xD6,
            0xB3,
            0x29,
            0xE3,
            0x2F,
            0x84,
            0x53,
            0xD1,
            0x00,
            0xED,
            0x20,
            0xFC,
            0xB1,
            0x5B,
            0x6A,
            0xCB,
            0xBE,
            0x39,
            0x4A,
            0x4C,
            0x58,
            0xCF,
            0xD0,
            0xEF,
            0xAA,
            0xFB,
            0x43,
            0x4D,
            0x33,
            0x85,
            0x45,
            0xF9,
            0x02,
            0x7F,
            0x50,
            0x3C,
            0x9F,
            0xA8,
            0x51,
            0xA3,
            0x40,
            0x8F,
            0x92,
            0x9D,
            0x38,
            0xF5,
            0xBC,
            0xB6,
            0xDA,
            0x21,
            0x10,
            0xFF,
            0xF3,
            0xD2,
            0xCD,
            0x0C,
            0x13,
            0xEC,
            0x5F,
            0x97,
            0x44,
            0x17,
            0xC4,
            0xA7,
            0x7E,
            0x3D,
            0x64,
            0x5D,
            0x19,
            0x73,
            0x60,
            0x81,
            0x4F,
            0xDC,
            0x22,
            0x2A,
            0x90,
            0x88,
            0x46,
            0xEE,
            0xB8,
            0x14,
            0xDE,
            0x5E,
            0x0B,
            0xDB,
            0xE0,
            0x32,
            0x3A,
            0x0A,
            0x49,
            0x06,
            0x24,
            0x5C,
            0xC2,
            0xD3,
            0xAC,
            0x62,
            0x91,
            0x95,
            0xE4,
            0x79,
            0xE7,
            0xC8,
            0x37,
            0x6D,
            0x8D,
            0xD5,
            0x4E,
            0xA9,
            0x6C,
            0x56,
            0xF4,
            0xEA,
            0x65,
            0x7A,
            0xAE,
            0x08,
            0xBA,
            0x78,
            0x25,
            0x2E,
            0x1C,
            0xA6,
            0xB4,
            0xC6,
            0xE8,
            0xDD,
            0x74,
            0x1F,
            0x4B,
            0xBD,
            0x8B,
            0x8A,
            0x70,
            0x3E,
            0xB5,
            0x66,
            0x48,
            0x03,
            0xF6,
            0x0E,
            0x61,
            0x35,
            0x57,
            0xB9,
            0x86,
            0xC1,
            0x1D,
            0x9E,
            0xE1,
            0xF8,
            0x98,
            0x11,
            0x69,
            0xD9,
            0x8E,
            0x94,
            0x9B,
            0x1E,
            0x87,
            0xE9,
            0xCE,
            0x55,
            0x28,
            0xDF,
            0x8C,
            0xA1,
            0x89,
            0x0D,
            0xBF,
            0xE6,
            0x42,
            0x68,
            0x41,
            0x99,
            0x2D,
            0x0F,
            0xB0,
            0x54,
            0xBB,
            0x16
        );
        
        // sbox for the inverse S-Box substitution
        $this->isbox = array(
            0x52,
            0x09,
            0x6A,
            0xD5,
            0x30,
            0x36,
            0xA5,
            0x38,
            0xBF,
            0x40,
            0xA3,
            0x9E,
            0x81,
            0xF3,
            0xD7,
            0xFB,
            0x7C,
            0xE3,
            0x39,
            0x82,
            0x9B,
            0x2F,
            0xFF,
            0x87,
            0x34,
            0x8E,
            0x43,
            0x44,
            0xC4,
            0xDE,
            0xE9,
            0xCB,
            0x54,
            0x7B,
            0x94,
            0x32,
            0xA6,
            0xC2,
            0x23,
            0x3D,
            0xEE,
            0x4C,
            0x95,
            0x0B,
            0x42,
            0xFA,
            0xC3,
            0x4E,
            0x08,
            0x2E,
            0xA1,
            0x66,
            0x28,
            0xD9,
            0x24,
            0xB2,
            0x76,
            0x5B,
            0xA2,
            0x49,
            0x6D,
            0x8B,
            0xD1,
            0x25,
            0x72,
            0xF8,
            0xF6,
            0x64,
            0x86,
            0x68,
            0x98,
            0x16,
            0xD4,
            0xA4,
            0x5C,
            0xCC,
            0x5D,
            0x65,
            0xB6,
            0x92,
            0x6C,
            0x70,
            0x48,
            0x50,
            0xFD,
            0xED,
            0xB9,
            0xDA,
            0x5E,
            0x15,
            0x46,
            0x57,
            0xA7,
            0x8D,
            0x9D,
            0x84,
            0x90,
            0xD8,
            0xAB,
            0x00,
            0x8C,
            0xBC,
            0xD3,
            0x0A,
            0xF7,
            0xE4,
            0x58,
            0x05,
            0xB8,
            0xB3,
            0x45,
            0x06,
            0xD0,
            0x2C,
            0x1E,
            0x8F,
            0xCA,
            0x3F,
            0x0F,
            0x02,
            0xC1,
            0xAF,
            0xBD,
            0x03,
            0x01,
            0x13,
            0x8A,
            0x6B,
            0x3A,
            0x91,
            0x11,
            0x41,
            0x4F,
            0x67,
            0xDC,
            0xEA,
            0x97,
            0xF2,
            0xCF,
            0xCE,
            0xF0,
            0xB4,
            0xE6,
            0x73,
            0x96,
            0xAC,
            0x74,
            0x22,
            0xE7,
            0xAD,
            0x35,
            0x85,
            0xE2,
            0xF9,
            0x37,
            0xE8,
            0x1C,
            0x75,
            0xDF,
            0x6E,
            0x47,
            0xF1,
            0x1A,
            0x71,
            0x1D,
            0x29,
            0xC5,
            0x89,
            0x6F,
            0xB7,
            0x62,
            0x0E,
            0xAA,
            0x18,
            0xBE,
            0x1B,
            0xFC,
            0x56,
            0x3E,
            0x4B,
            0xC6,
            0xD2,
            0x79,
            0x20,
            0x9A,
            0xDB,
            0xC0,
            0xFE,
            0x78,
            0xCD,
            0x5A,
            0xF4,
            0x1F,
            0xDD,
            0xA8,
            0x33,
            0x88,
            0x07,
            0xC7,
            0x31,
            0xB1,
            0x12,
            0x10,
            0x59,
            0x27,
            0x80,
            0xEC,
            0x5F,
            0x60,
            0x51,
            0x7F,
            0xA9,
            0x19,
            0xB5,
            0x4A,
            0x0D,
            0x2D,
            0xE5,
            0x7A,
            0x9F,
            0x93,
            0xC9,
            0x9C,
            0xEF,
            0xA0,
            0xE0,
            0x3B,
            0x4D,
            0xAE,
            0x2A,
            0xF5,
            0xB0,
            0xC8,
            0xEB,
            0xBB,
            0x3C,
            0x83,
            0x53,
            0x99,
            0x61,
            0x17,
            0x2B,
            0x04,
            0x7E,
            0xBA,
            0x77,
            0xD6,
            0x26,
            0xE1,
            0x69,
            0x14,
            0x63,
            0x55,
            0x21,
            0x0C,
            0x7D
        );
        
        if (!function_exists('create_function') || ! is_callable('create_function')) {
            $this->use_inline_crypt = false;
        }
    }

    /**
     * Sets the key.
     *
     * Keys can be of any length. Rijndael, itself, requires the use of a key that's between 128-bits and 256-bits long and
     * whose length is a multiple of 32. If the key is less than 256-bits and the key length isn't set, we round the length
     * up to the closest valid key length, padding $key with null bytes. If the key is more than 256-bits, we trim the
     * excess bits.
     *
     * If the key is not explicitly set, it'll be assumed to be all null bytes.
     *
     * @access public
     * @param String $key            
     */
    function setKey($key)
    {
        $this->key = $key;
        $this->changed = true;
    }

    /**
     * Sets the initialization vector.
     * (optional)
     *
     * SetIV is not required when CRYPT_RIJNDAEL_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, $this->block_size), $this->block_size, chr(0));
    }

    /**
     * Sets the key length
     *
     * Valid key lengths are 128, 160, 192, 224, and 256. If the length is less than 128, it will be rounded up to
     * 128. If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
     *
     * @access public
     * @param Integer $length            
     */
    function setKeyLength($length)
    {
        $length >>= 5;
        if ($length > 8) {
            $length = 8;
        } else 
            if ($length < 4) {
                $length = 4;
            }
        $this->Nk = $length;
        $this->key_size = $length << 2;
        
        $this->explicit_key_length = true;
        $this->changed = true;
    }

    /**
     * Sets the password.
     *
     * Depending on what $method is set to, setPassword()'s (optional) parameters are as follows:
     * {@link http://en.wikipedia.org/wiki/PBKDF2 pbkdf2}:
     * $hash, $salt, $method
     * Set $dkLen by calling setKeyLength()
     *
     * @param String $password            
     * @param
     *            optional String $method
     * @access public
     */
    function setPassword($password, $method = 'pbkdf2')
    {
        $key = '';
        
        switch ($method) {
            default: // 'pbkdf2'
                list (, , $hash, $salt, $count) = func_get_args();
                if (!isset($hash)) {
                    $hash = 'sha1';
                }
                // WPA and WPA2 use the SSID as the salt
                if (!isset($salt)) {
                    $salt = 'phpseclib';
                }
                // RFC2898#section-4.2 uses 1,000 iterations by default
                // WPA and WPA2 use 4,096.
                if (!isset($count)) {
                    $count = 1000;
                }
                
                if (!class_exists('Crypt_Hash')) {
                    require_once ('Crypt/Hash.php');
                }
                
                $i = 1;
                while (strlen($key) < $this->key_size) { // $dkLen == $this->key_size
                                                         // $dk.= $this->_pbkdf($password, $salt, $count, $i++);
                    $hmac = new Crypt_Hash();
                    $hmac->setHash($hash);
                    $hmac->setKey($password);
                    $f = $u = $hmac->hash($salt . pack('N', $i ++));
                    for ($j = 2; $j <= $count; $j ++) {
                        $u = $hmac->hash($u);
                        $f ^= $u;
                    }
                    $key .= $f;
                }
        }
        
        $this->setKey(substr($key, 0, $this->key_size));
    }

    /**
     * Sets the block length
     *
     * Valid block lengths are 128, 160, 192, 224, and 256. If the length is less than 128, it will be rounded up to
     * 128. If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
     *
     * @access public
     * @param Integer $length            
     */
    function setBlockLength($length)
    {
        $length >>= 5;
        if ($length > 8) {
            $length = 8;
        } else 
            if ($length < 4) {
                $length = 4;
            }
        $this->Nb = $length;
        $this->block_size = $length << 2;
        $this->changed = 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_Rijndael::decrypt()
     * @see Crypt_Rijndael::encrypt()
     * @access public
     * @param Integer $length            
     * @param String $iv            
     */
    function _generate_xor($length, &$iv)
    {
        $xor = '';
        $block_size = $this->block_size;
        $num_blocks = floor(($length + ($block_size - 1)) / $block_size);
        for ($i = 0; $i < $num_blocks; $i ++) {
            $xor .= $iv;
            for ($j = 4; $j <= $block_size; $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.
     *
     * $plaintext will be padded with additional bytes such that it's length is a multiple of the block size. Other Rjindael
     * implementations may or may not pad in the same manner. Other common approaches to padding and the reasons why it's
     * necessary are discussed in the following
     * URL:
     *
     * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html}
     *
     * An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does.
     * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that
     * length.
     *
     * @see Crypt_Rijndael::decrypt()
     * @access public
     * @param String $plaintext            
     */
    function encrypt($plaintext)
    {
        if ($this->changed) {
            $this->_setup();
        }
        if ($this->use_inline_crypt) {
            $inline = $this->inline_crypt;
            return $inline('encrypt', $this, $plaintext);
        }
        if ($this->paddable) {
            $plaintext = $this->_pad($plaintext);
        }
        
        $block_size = $this->block_size;
        $buffer = &$this->enbuffer;
        $ciphertext = '';
        switch ($this->mode) {
            case CRYPT_RIJNDAEL_MODE_ECB:
                for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                    $ciphertext .= $this->_encryptBlock(substr($plaintext, $i, $block_size));
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CBC:
                $xor = $this->encryptIV;
                for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                    $block = substr($plaintext, $i, $block_size);
                    $block = $this->_encryptBlock($block ^ $xor);
                    $xor = $block;
                    $ciphertext .= $block;
                }
                if ($this->continuousBuffer) {
                    $this->encryptIV = $xor;
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CTR:
                $xor = $this->encryptIV;
                if (strlen($buffer['encrypted'])) {
                    for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                        $block = substr($plaintext, $i, $block_size);
                        if (strlen($block) > strlen($buffer['encrypted'])) {
                            $buffer['encrypted'] .= $this->_encryptBlock($this->_generate_xor($block_size, $xor));
                        }
                        $key = $this->_string_shift($buffer['encrypted'], $block_size);
                        $ciphertext .= $block ^ $key;
                    }
                } else {
                    for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                        $block = substr($plaintext, $i, $block_size);
                        $key = $this->_encryptBlock($this->_generate_xor($block_size, $xor));
                        $ciphertext .= $block ^ $key;
                    }
                }
                if ($this->continuousBuffer) {
                    $this->encryptIV = $xor;
                    if ($start = strlen($plaintext) % $block_size) {
                        $buffer['encrypted'] = substr($key, $start) . $buffer['encrypted'];
                    }
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CFB:
                // cfb loosely routines inspired by openssl's:
                // http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1
                if ($this->continuousBuffer) {
                    $iv = &$this->encryptIV;
                    $pos = &$buffer['pos'];
                } else {
                    $iv = $this->encryptIV;
                    $pos = 0;
                }
                $len = strlen($plaintext);
                $i = 0;
                if ($pos) {
                    $orig_pos = $pos;
                    $max = $block_size - $pos;
                    if ($len >= $max) {
                        $i = $max;
                        $len -= $max;
                        $pos = 0;
                    } else {
                        $i = $len;
                        $pos += $len;
                        $len = 0;
                    }
                    // ie. $i = min($max, $len), $len-= $i, $pos+= $i, $pos%= $blocksize
                    $ciphertext = substr($iv, $orig_pos) ^ $plaintext;
                    $iv = substr_replace($iv, $ciphertext, $orig_pos, $i);
                }
                while ($len >= $block_size) {
                    $iv = $this->_encryptBlock($iv) ^ substr($plaintext, $i, $block_size);
                    $ciphertext .= $iv;
                    $len -= $block_size;
                    $i += $block_size;
                }
                if ($len) {
                    $iv = $this->_encryptBlock($iv);
                    $block = $iv ^ substr($plaintext, $i);
                    $iv = substr_replace($iv, $block, 0, $len);
                    $ciphertext .= $block;
                    $pos = $len;
                }
                break;
            case CRYPT_RIJNDAEL_MODE_OFB:
                $xor = $this->encryptIV;
                if (strlen($buffer['xor'])) {
                    for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                        $block = substr($plaintext, $i, $block_size);
                        if (strlen($block) > strlen($buffer['xor'])) {
                            $xor = $this->_encryptBlock($xor);
                            $buffer['xor'] .= $xor;
                        }
                        $key = $this->_string_shift($buffer['xor'], $block_size);
                        $ciphertext .= $block ^ $key;
                    }
                } else {
                    for ($i = 0; $i < strlen($plaintext); $i += $block_size) {
                        $xor = $this->_encryptBlock($xor);
                        $ciphertext .= substr($plaintext, $i, $block_size) ^ $xor;
                    }
                    $key = $xor;
                }
                if ($this->continuousBuffer) {
                    $this->encryptIV = $xor;
                    if ($start = strlen($plaintext) % $block_size) {
                        $buffer['xor'] = substr($key, $start) . $buffer['xor'];
                    }
                }
        }
        
        return $ciphertext;
    }

    /**
     * Decrypts a message.
     *
     * If strlen($ciphertext) is not a multiple of the block size, null bytes will be added to the end of the string until
     * it is.
     *
     * @see Crypt_Rijndael::encrypt()
     * @access public
     * @param String $ciphertext            
     */
    function decrypt($ciphertext)
    {
        if ($this->changed) {
            $this->_setup();
        }
        if ($this->use_inline_crypt) {
            $inline = $this->inline_crypt;
            return $inline('decrypt', $this, $ciphertext);
        }
        if ($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($ciphertext) + ($this->block_size - strlen($ciphertext) % $this->block_size) % $this->block_size, chr(0));
        }
        
        $block_size = $this->block_size;
        $buffer = &$this->debuffer;
        $plaintext = '';
        switch ($this->mode) {
            case CRYPT_RIJNDAEL_MODE_ECB:
                for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                    $plaintext .= $this->_decryptBlock(substr($ciphertext, $i, $block_size));
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CBC:
                $xor = $this->decryptIV;
                for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                    $block = substr($ciphertext, $i, $block_size);
                    $plaintext .= $this->_decryptBlock($block) ^ $xor;
                    $xor = $block;
                }
                if ($this->continuousBuffer) {
                    $this->decryptIV = $xor;
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CTR:
                $xor = $this->decryptIV;
                if (strlen($buffer['ciphertext'])) {
                    for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                        $block = substr($ciphertext, $i, $block_size);
                        if (strlen($block) > strlen($buffer['ciphertext'])) {
                            $buffer['ciphertext'] .= $this->_encryptBlock($this->_generate_xor($block_size, $xor));
                        }
                        $key = $this->_string_shift($buffer['ciphertext'], $block_size);
                        $plaintext .= $block ^ $key;
                    }
                } else {
                    for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                        $block = substr($ciphertext, $i, $block_size);
                        $key = $this->_encryptBlock($this->_generate_xor($block_size, $xor));
                        $plaintext .= $block ^ $key;
                    }
                }
                if ($this->continuousBuffer) {
                    $this->decryptIV = $xor;
                    if ($start = strlen($ciphertext) % $block_size) {
                        $buffer['ciphertext'] = substr($key, $start) . $buffer['ciphertext'];
                    }
                }
                break;
            case CRYPT_RIJNDAEL_MODE_CFB:
                if ($this->continuousBuffer) {
                    $iv = &$this->decryptIV;
                    $pos = &$buffer['pos'];
                } else {
                    $iv = $this->decryptIV;
                    $pos = 0;
                }
                $len = strlen($ciphertext);
                $i = 0;
                if ($pos) {
                    $orig_pos = $pos;
                    $max = $block_size - $pos;
                    if ($len >= $max) {
                        $i = $max;
                        $len -= $max;
                        $pos = 0;
                    } else {
                        $i = $len;
                        $pos += $len;
                        $len = 0;
                    }
                    // ie. $i = min($max, $len), $len-= $i, $pos+= $i, $pos%= $blocksize
                    $plaintext = substr($iv, $orig_pos) ^ $ciphertext;
                    $iv = substr_replace($iv, substr($ciphertext, 0, $i), $orig_pos, $i);
                }
                while ($len >= $block_size) {
                    $iv = $this->_encryptBlock($iv);
                    $cb = substr($ciphertext, $i, $block_size);
                    $plaintext .= $iv ^ $cb;
                    $iv = $cb;
                    $len -= $block_size;
                    $i += $block_size;
                }
                if ($len) {
                    $iv = $this->_encryptBlock($iv);
                    $plaintext .= $iv ^ substr($ciphertext, $i);
                    $iv = substr_replace($iv, substr($ciphertext, $i), 0, $len);
                    $pos = $len;
                }
                break;
            case CRYPT_RIJNDAEL_MODE_OFB:
                $xor = $this->decryptIV;
                if (strlen($buffer['xor'])) {
                    for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                        $block = substr($ciphertext, $i, $block_size);
                        if (strlen($block) > strlen($buffer['xor'])) {
                            $xor = $this->_encryptBlock($xor);
                            $buffer['xor'] .= $xor;
                        }
                        $key = $this->_string_shift($buffer['xor'], $block_size);
                        $plaintext .= $block ^ $key;
                    }
                } else {
                    for ($i = 0; $i < strlen($ciphertext); $i += $block_size) {
                        $xor = $this->_encryptBlock($xor);
                        $plaintext .= substr($ciphertext, $i, $block_size) ^ $xor;
                    }
                    $key = $xor;
                }
                if ($this->continuousBuffer) {
                    $this->decryptIV = $xor;
                    if ($start = strlen($ciphertext) % $block_size) {
                        $buffer['xor'] = substr($key, $start) . $buffer['xor'];
                    }
                }
        }
        
        return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
    }

    /**
     * Encrypts a block
     *
     * @access private
     * @param String $in            
     * @return String
     */
    function _encryptBlock($in)
    {
        $state = array();
        $words = unpack('N*word', $in);
        
        $w = $this->w;
        $t0 = $this->t0;
        $t1 = $this->t1;
        $t2 = $this->t2;
        $t3 = $this->t3;
        $Nb = $this->Nb;
        $Nr = $this->Nr;
        $c = $this->c;
        
        // addRoundKey
        $i = - 1;
        foreach ($words as $word) {
            $state[] = $word ^ $w[0][++ $i];
        }
        
        // fips-197.pdf#page=19, "Figure 5. Pseudo Code for the Cipher", states that this loop has four components -
        // subBytes, shiftRows, mixColumns, and addRoundKey. fips-197.pdf#page=30, "Implementation Suggestions Regarding
        // Various Platforms" suggests that performs enhanced implementations are described in Rijndael-ammended.pdf.
        // Rijndael-ammended.pdf#page=20, "Implementation aspects / 32-bit processor", discusses such an optimization.
        // Unfortunately, the description given there is not quite correct. Per aes.spec.v316.pdf#page=19 [1],
        // equation (7.4.7) is supposed to use addition instead of subtraction, so we'll do that here, as well.
        // [1] http://fp.gladman.plus.com/cryptography_technology/rijndael/aes.spec.v316.pdf
        $temp = array();
        for ($round = 1; $round < $Nr; ++ $round) {
            $i = 0; // $c[0] == 0
            $j = $c[1];
            $k = $c[2];
            $l = $c[3];
            
            while ($i < $Nb) {
                $temp[$i] = $t0[$state[$i] >> 24 & 0x000000FF] ^ $t1[$state[$j] >> 16 & 0x000000FF] ^ $t2[$state[$k] >> 8 & 0x000000FF] ^ $t3[$state[$l] & 0x000000FF] ^ $w[$round][$i];
                ++ $i;
                $j = ($j + 1) % $Nb;
                $k = ($k + 1) % $Nb;
                $l = ($l + 1) % $Nb;
            }
            $state = $temp;
        }
        
        // subWord
        for ($i = 0; $i < $Nb; ++ $i) {
            $state[$i] = $this->_subWord($state[$i]);
        }
        
        // shiftRows + addRoundKey
        $i = 0; // $c[0] == 0
        $j = $c[1];
        $k = $c[2];
        $l = $c[3];
        while ($i < $Nb) {
            $temp[$i] = ($state[$i] & 0xFF000000) ^ ($state[$j] & 0x00FF0000) ^ ($state[$k] & 0x0000FF00) ^ ($state[$l] & 0x000000FF) ^ $w[$Nr][$i];
            ++ $i;
            $j = ($j + 1) % $Nb;
            $k = ($k + 1) % $Nb;
            $l = ($l + 1) % $Nb;
        }
        
        // 100% ugly switch/case code... but ~5% faster ("smart code" below commented out)
        switch ($Nb) {
            case 8:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5], $temp[6], $temp[7]);
            case 7:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5], $temp[6]);
            case 6:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5]);
            case 5:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4]);
            default:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3]);
        }
        /*
         * $state = $temp;
         *
         * array_unshift($state, 'N*');
         *
         * return call_user_func_array('pack', $state);
         */
    }

    /**
     * Decrypts a block
     *
     * @access private
     * @param String $in            
     * @return String
     */
    function _decryptBlock($in)
    {
        $state = array();
        $words = unpack('N*word', $in);
        
        $dw = $this->dw;
        $dt0 = $this->dt0;
        $dt1 = $this->dt1;
        $dt2 = $this->dt2;
        $dt3 = $this->dt3;
        $Nb = $this->Nb;
        $Nr = $this->Nr;
        $c = $this->c;
        
        // addRoundKey
        $i = - 1;
        foreach ($words as $word) {
            $state[] = $word ^ $dw[$Nr][++ $i];
        }
        
        $temp = array();
        for ($round = $Nr - 1; $round > 0; -- $round) {
            $i = 0; // $c[0] == 0
            $j = $Nb - $c[1];
            $k = $Nb - $c[2];
            $l = $Nb - $c[3];
            
            while ($i < $Nb) {
                $temp[$i] = $dt0[$state[$i] >> 24 & 0x000000FF] ^ $dt1[$state[$j] >> 16 & 0x000000FF] ^ $dt2[$state[$k] >> 8 & 0x000000FF] ^ $dt3[$state[$l] & 0x000000FF] ^ $dw[$round][$i];
                ++ $i;
                $j = ($j + 1) % $Nb;
                $k = ($k + 1) % $Nb;
                $l = ($l + 1) % $Nb;
            }
            $state = $temp;
        }
        
        // invShiftRows + invSubWord + addRoundKey
        $i = 0; // $c[0] == 0
        $j = $Nb - $c[1];
        $k = $Nb - $c[2];
        $l = $Nb - $c[3];
        
        while ($i < $Nb) {
            $temp[$i] = $dw[0][$i] ^ $this->_invSubWord(($state[$i] & 0xFF000000) | ($state[$j] & 0x00FF0000) | ($state[$k] & 0x0000FF00) | ($state[$l] & 0x000000FF));
            ++ $i;
            $j = ($j + 1) % $Nb;
            $k = ($k + 1) % $Nb;
            $l = ($l + 1) % $Nb;
        }
        
        switch ($Nb) {
            case 8:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5], $temp[6], $temp[7]);
            case 7:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5], $temp[6]);
            case 6:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4], $temp[5]);
            case 5:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3], $temp[4]);
            default:
                return pack('N*', $temp[0], $temp[1], $temp[2], $temp[3]);
        }
        /*
         * $state = $temp;
         *
         * array_unshift($state, 'N*');
         *
         * return call_user_func_array('pack', $state);
         */
    }

    /**
     * Setup Rijndael
     *
     * Validates all the variables and calculates $Nr - the number of rounds that need to be performed - and $w - the key
     * key schedule.
     *
     * @access private
     */
    function _setup()
    {
        // Each number in $rcon is equal to the previous number multiplied by two in Rijndael's finite field.
        // See http://en.wikipedia.org/wiki/Finite_field_arithmetic#Multiplicative_inverse
        static $rcon = array(
            0,
            0x01000000,
            0x02000000,
            0x04000000,
            0x08000000,
            0x10000000,
            0x20000000,
            0x40000000,
            0x80000000,
            0x1B000000,
            0x36000000,
            0x6C000000,
            0xD8000000,
            0xAB000000,
            0x4D000000,
            0x9A000000,
            0x2F000000,
            0x5E000000,
            0xBC000000,
            0x63000000,
            0xC6000000,
            0x97000000,
            0x35000000,
            0x6A000000,
            0xD4000000,
            0xB3000000,
            0x7D000000,
            0xFA000000,
            0xEF000000,
            0xC5000000,
            0x91000000
        );
        
        if (!$this->explicit_key_length) {
            // we do >> 2, here, and not >> 5, as we do above, since strlen($this->key) tells us the number of bytes - not bits
            $length = strlen($this->key) >> 2;
            if ($length > 8) {
                $length = 8;
            } else 
                if ($length < 4) {
                    $length = 4;
                }
            $this->Nk = $length;
            $this->key_size = $length << 2;
        }
        
        $this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, chr(0));
        $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($this->iv, 0, $this->block_size), $this->block_size, chr(0));
        
        // see Rijndael-ammended.pdf#page=44
        $this->Nr = max($this->Nk, $this->Nb) + 6;
        
        // shift offsets for Nb = 5, 7 are defined in Rijndael-ammended.pdf#page=44,
        // "Table 8: Shift offsets in Shiftrow for the alternative block lengths"
        // shift offsets for Nb = 4, 6, 8 are defined in Rijndael-ammended.pdf#page=14,
        // "Table 2: Shift offsets for different block lengths"
        switch ($this->Nb) {
            case 4:
            case 5:
            case 6:
                $this->c = array(
                    0,
                    1,
                    2,
                    3
                );
                break;
            case 7:
                $this->c = array(
                    0,
                    1,
                    2,
                    4
                );
                break;
            case 8:
                $this->c = array(
                    0,
                    1,
                    3,
                    4
                );
        }
        
        $key = $this->key;
        
        $w = array_values(unpack('N*words', $key));
        
        $length = $this->Nb * ($this->Nr + 1);
        for ($i = $this->Nk; $i < $length; $i ++) {
            $temp = $w[$i - 1];
            if ($i % $this->Nk == 0) {
                // according to <http://php.net/language.types.integer>, "the size of an integer is platform-dependent".
                // on a 32-bit machine, it's 32-bits, and on a 64-bit machine, it's 64-bits. on a 32-bit machine,
                // 0xFFFFFFFF << 8 == 0xFFFFFF00, but on a 64-bit machine, it equals 0xFFFFFFFF00. as such, doing 'and'
                // with 0xFFFFFFFF (or 0xFFFFFF00) on a 32-bit machine is unnecessary, but on a 64-bit machine, it is.
                $temp = (($temp << 8) & 0xFFFFFF00) | (($temp >> 24) & 0x000000FF); // rotWord
                $temp = $this->_subWord($temp) ^ $rcon[$i / $this->Nk];
            } else 
                if ($this->Nk > 6 && $i % $this->Nk == 4) {
                    $temp = $this->_subWord($temp);
                }
            $w[$i] = $w[$i - $this->Nk] ^ $temp;
        }
        
        // convert the key schedule from a vector of $Nb * ($Nr + 1) length to a matrix with $Nr + 1 rows and $Nb columns
        // and generate the inverse key schedule. more specifically,
        // according to <http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=23> (section 5.3.3),
        // "The key expansion for the Inverse Cipher is defined as follows:
        // 1. Apply the Key Expansion.
        // 2. Apply InvMixColumn to all Round Keys except the first and the last one."
        // also, see fips-197.pdf#page=27, "5.3.5 Equivalent Inverse Cipher"
        $temp = $this->w = $this->dw = array();
        for ($i = $row = $col = 0; $i < $length; $i ++, $col ++) {
            if ($col == $this->Nb) {
                if ($row == 0) {
                    $this->dw[0] = $this->w[0];
                } else {
                    // subWord + invMixColumn + invSubWord = invMixColumn
                    $j = 0;
                    while ($j < $this->Nb) {
                        $dw = $this->_subWord($this->w[$row][$j]);
                        $temp[$j] = $this->dt0[$dw >> 24 & 0x000000FF] ^ $this->dt1[$dw >> 16 & 0x000000FF] ^ $this->dt2[$dw >> 8 & 0x000000FF] ^ $this->dt3[$dw & 0x000000FF];
                        $j ++;
                    }
                    $this->dw[$row] = $temp;
                }
                
                $col = 0;
                $row ++;
            }
            $this->w[$row][$col] = $w[$i];
        }
        
        $this->dw[$row] = $this->w[$row];
        
        // In case of $this->use_inline_crypt === true we have to use 1-dim key arrays (both ascending)
        if ($this->use_inline_crypt) {
            $this->dw = array_reverse($this->dw);
            $w = array_pop($this->w);
            $dw = array_pop($this->dw);
            foreach ($this->w as $r => $wr) {
                foreach ($wr as $c => $wc) {
                    $w[] = $wc;
                    $dw[] = $this->dw[$r][$c];
                }
            }
            $this->w = $w;
            $this->dw = $dw;
            
            $this->inline_crypt_setup();
        }
        
        $this->changed = false;
    }

    /**
     * Performs S-Box substitutions
     *
     * @access private
     */
    function _subWord($word)
    {
        $sbox = $this->sbox;
        
        return $sbox[$word & 0x000000FF] | ($sbox[$word >> 8 & 0x000000FF] << 8) | ($sbox[$word >> 16 & 0x000000FF] << 16) | ($sbox[$word >> 24 & 0x000000FF] << 24);
    }

    /**
     * Performs inverse S-Box substitutions
     *
     * @access private
     */
    function _invSubWord($word)
    {
        $isbox = $this->isbox;
        
        return $isbox[$word & 0x000000FF] | ($isbox[$word >> 8 & 0x000000FF] << 8) | ($isbox[$word >> 16 & 0x000000FF] << 16) | ($isbox[$word >> 24 & 0x000000FF] << 24);
    }

    /**
     * Pad "packets".
     *
     * Rijndael works by encrypting between sixteen and thirty-two bytes at a time, provided that number is also a multiple
     * of four. If you ever need to encrypt or decrypt something that isn't of the proper length, it becomes necessary to
     * pad the input so that it is of the proper length.
     *
     * Padding is enabled by default. Sometimes, however, it is undesirable to pad strings. Such is the case in SSH,
     * 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_Rijndael::disablePadding()
     * @access public
     */
    function enablePadding()
    {
        $this->padding = true;
    }

    /**
     * Do not pad packets.
     *
     * @see Crypt_Rijndael::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.
     * $block_size - (strlen($text) % $block_size) bytes are added, each of which is equal to
     * chr($block_size - (strlen($text) % $block_size)
     *
     * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless
     * and padding will, hence forth, be enabled.
     *
     * @see Crypt_Rijndael::_unpad()
     * @access private
     */
    function _pad($text)
    {
        $length = strlen($text);
        
        if (!$this->padding) {
            if ($length % $this->block_size == 0) {
                return $text;
            } else {
                user_error("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size})");
                $this->padding = true;
            }
        }
        
        $pad = $this->block_size - ($length % $this->block_size);
        
        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_Rijndael::_pad()
     * @access private
     */
    function _unpad($text)
    {
        if (!$this->padding) {
            return $text;
        }
        
        $length = ord($text[strlen($text) - 1]);
        
        if (!$length || $length > $this->block_size) {
            return false;
        }
        
        return substr($text, 0, - $length);
    }

    /**
     * Treat consecutive "packets" as if they are a continuous buffer.
     *
     * Say you have a 32-byte plaintext $plaintext. Using the default behavior, the two following code snippets
     * will yield different outputs:
     *
     * <code>
     * echo $rijndael->encrypt(substr($plaintext, 0, 16));
     * echo $rijndael->encrypt(substr($plaintext, 16, 16));
     * </code>
     * <code>
     * echo $rijndael->encrypt($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>
     * $rijndael->encrypt(substr($plaintext, 0, 16));
     * echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));
     * </code>
     * <code>
     * echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16)));
     * </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_Rijndael() 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_Rijndael::disableContinuousBuffer()
     * @access public
     */
    function enableContinuousBuffer()
    {
        $this->continuousBuffer = true;
    }

    /**
     * Treat consecutive packets as if they are a discontinuous buffer.
     *
     * The default behavior.
     *
     * @see Crypt_Rijndael::enableContinuousBuffer()
     * @access public
     */
    function disableContinuousBuffer()
    {
        $this->continuousBuffer = false;
        $this->encryptIV = $this->iv;
        $this->decryptIV = $this->iv;
        $this->enbuffer = array(
            'encrypted' => '',
            'xor' => '',
            'pos' => 0
        );
        $this->debuffer = array(
            'ciphertext' => '',
            'xor' => '',
            'pos' => 0
        );
    }

    /**
     * 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;
    }

    /**
     * Creates performance-optimized function for de/encrypt(), storing it in $this->inline_crypt
     *
     * @see Crypt_Rijndael::encrypt()
     * @see Crypt_Rijndael::decrypt()
     * @access private
     */
    function inline_crypt_setup()
    {
        // Note: inline_crypt_setup() will be called only if $this->changed === true
        // So here we are'nt under the same heavy timing-stress as we are in _de/encryptBlock() or de/encrypt().
        // However...the here generated function- $code, stored as php callback in $this->inline_crypt, must work as fast as even possible.
        $lambda_functions = & Crypt_Rijndael::get_lambda_functions();
        $block_size = $this->block_size;
        $mode = $this->mode;
        
        // The first 5 generated $lambda_functions will use the key-words hardcoded for better performance.
        // For memory reason we limit those ultra-optimized function code to 5.
        // After that, we use pure (extracted) integer vars for the key-words which is faster than accessing them via array.
        if (count($lambda_functions) < 5) {
            $w = $this->w;
            $dw = $this->dw;
            $init_encryptBlock = '';
            $init_decryptBlock = '';
        } else {
            for ($i = 0, $cw = count($this->w); $i < $cw; ++ $i) {
                $w[] = '$w_' . $i;
                $dw[] = '$dw_' . $i;
            }
            $init_encryptBlock = 'extract($self->w,  EXTR_PREFIX_ALL, "w");';
            $init_decryptBlock = 'extract($self->dw, EXTR_PREFIX_ALL, "dw");';
        }
        
        $code_hash = md5("$mode, $block_size, " . implode(',', $w));
        
        if (!isset($lambda_functions[$code_hash])) {
            $Nr = $this->Nr;
            $Nb = $this->Nb;
            $c = $this->c;
            
            // Generating encrypt code:
            $init_encryptBlock .= '
                $t0 = $self->t0;
                $t1 = $self->t1;
                $t2 = $self->t2;
                $t3 = $self->t3;
                $sbox = $self->sbox;';
            
            $s = 'e';
            $e = 's';
            $wc = $Nb - 1;
            
            // Preround: addRoundKey
            $_encryptBlock = '$in = unpack("N*", $in);' . "\n";
            for ($i = 0; $i < $Nb; ++ $i) {
                $_encryptBlock .= '$s' . $i . ' = $in[' . ($i + 1) . '] ^ ' . $w[++ $wc] . ";\n";
            }
            
            // Mainrounds: shiftRows + subWord + mixColumns + addRoundKey
            for ($round = 1; $round < $Nr; ++ $round) {
                list ($s, $e) = array(
                    $e,
                    $s
                );
                for ($i = 0; $i < $Nb; ++ $i) {
                    $_encryptBlock .= '$' . $e . $i . ' =
                        $t0[($' . $s . $i . ' >> 24) & 0xff] ^
                        $t1[($' . $s . (($i + $c[1]) % $Nb) . ' >> 16) & 0xff] ^
                        $t2[($' . $s . (($i + $c[2]) % $Nb) . ' >>  8) & 0xff] ^
                        $t3[ $' . $s . (($i + $c[3]) % $Nb) . '        & 0xff] ^
                        ' . $w[++ $wc] . ";\n";
                }
            }
            
            // Finalround: subWord + shiftRows + addRoundKey
            for ($i = 0; $i < $Nb; ++ $i) {
                $_encryptBlock .= '$' . $e . $i . ' =
                     $sbox[ $' . $e . $i . '        & 0xff]        |
                    ($sbox[($' . $e . $i . ' >>  8) & 0xff] <<  8) |
                    ($sbox[($' . $e . $i . ' >> 16) & 0xff] << 16) |
                    ($sbox[($' . $e . $i . ' >> 24) & 0xff] << 24);' . "\n";
            }
            $_encryptBlock .= '$in = pack("N*"' . "\n";
            for ($i = 0; $i < $Nb; ++ $i) {
                $_encryptBlock .= ',
                    ($' . $e . $i . ' & 0xFF000000) ^
                    ($' . $e . (($i + $c[1]) % $Nb) . ' & 0x00FF0000) ^
                    ($' . $e . (($i + $c[2]) % $Nb) . ' & 0x0000FF00) ^
                    ($' . $e . (($i + $c[3]) % $Nb) . ' & 0x000000FF) ^
                    ' . $w[$i] . "\n";
            }
            $_encryptBlock .= ');';
            
            // Generating decrypt code:
            $init_decryptBlock .= '
                $dt0 = $self->dt0;
                $dt1 = $self->dt1;
                $dt2 = $self->dt2;
                $dt3 = $self->dt3;
                $isbox = $self->isbox;';
            
            $s = 'e';
            $e = 's';
            $wc = $Nb - 1;
            
            // Preround: addRoundKey
            $_decryptBlock = '$in = unpack("N*", $in);' . "\n";
            for ($i = 0; $i < $Nb; ++ $i) {
                $_decryptBlock .= '$s' . $i . ' = $in[' . ($i + 1) . '] ^ ' . $dw[++ $wc] . ';' . "\n";
            }
            
            // Mainrounds: shiftRows + subWord + mixColumns + addRoundKey
            for ($round = 1; $round < $Nr; ++ $round) {
                list ($s, $e) = array(
                    $e,
                    $s
                );
                for ($i = 0; $i < $Nb; ++ $i) {
                    $_decryptBlock .= '$' . $e . $i . ' =
                        $dt0[($' . $s . $i . ' >> 24) & 0xff] ^
                        $dt1[($' . $s . (($Nb + $i - $c[1]) % $Nb) . ' >> 16) & 0xff] ^
                        $dt2[($' . $s . (($Nb + $i - $c[2]) % $Nb) . ' >>  8) & 0xff] ^
                        $dt3[ $' . $s . (($Nb + $i - $c[3]) % $Nb) . '        & 0xff] ^
                        ' . $dw[++ $wc] . ";\n";
                }
            }
            
            // Finalround: subWord + shiftRows + addRoundKey
            for ($i = 0; $i < $Nb; ++ $i) {
                $_decryptBlock .= '$' . $e . $i . ' =
                     $isbox[ $' . $e . $i . '        & 0xff]        |
                    ($isbox[($' . $e . $i . ' >>  8) & 0xff] <<  8) |
                    ($isbox[($' . $e . $i . ' >> 16) & 0xff] << 16) |
                    ($isbox[($' . $e . $i . ' >> 24) & 0xff] << 24);' . "\n";
            }
            $_decryptBlock .= '$in = pack("N*"' . "\n";
            for ($i = 0; $i < $Nb; ++ $i) {
                $_decryptBlock .= ',
                    ($' . $e . $i . ' & 0xFF000000) ^
                    ($' . $e . (($Nb + $i - $c[1]) % $Nb) . ' & 0x00FF0000) ^
                    ($' . $e . (($Nb + $i - $c[2]) % $Nb) . ' & 0x0000FF00) ^
                    ($' . $e . (($Nb + $i - $c[3]) % $Nb) . ' & 0x000000FF) ^
                    ' . $dw[$i] . "\n";
            }
            $_decryptBlock .= ');';
            
            // Generating mode of operation code:
            switch ($mode) {
                case CRYPT_RIJNDAEL_MODE_ECB:
                    $encrypt = $init_encryptBlock . '
                        $ciphertext = "";
                        $text = $self->_pad($text);
                        $plaintext_len = strlen($text);

                        for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                            $in = substr($text, $i, ' . $block_size . ');
                            ' . $_encryptBlock . '
                            $ciphertext.= $in;
                        }
                       
                        return $ciphertext;
                        ';
                    
                    $decrypt = $init_decryptBlock . '
                        $plaintext = "";
                        $text = str_pad($text, strlen($text) + (' . $block_size . ' - strlen($text) % ' . $block_size . ') % ' . $block_size . ', chr(0));
                        $ciphertext_len = strlen($text);

                        for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                            $in = substr($text, $i, ' . $block_size . ');
                            ' . $_decryptBlock . '
                            $plaintext.= $in;
                        }

                        return $self->_unpad($plaintext);
                        ';
                    break;
                case CRYPT_RIJNDAEL_MODE_CBC:
                    $encrypt = $init_encryptBlock . '
                        $ciphertext = "";
                        $text = $self->_pad($text);
                        $plaintext_len = strlen($text);

                        $in = $self->encryptIV;

                        for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                            $in = substr($text, $i, ' . $block_size . ') ^ $in;
                            ' . $_encryptBlock . '
                            $ciphertext.= $in;
                        }

                        if ($self->continuousBuffer) {
                            $self->encryptIV = $in;
                        }

                        return $ciphertext;
                        ';
                    
                    $decrypt = $init_decryptBlock . '
                        $plaintext = "";
                        $text = str_pad($text, strlen($text) + (' . $block_size . ' - strlen($text) % ' . $block_size . ') % ' . $block_size . ', chr(0));
                        $ciphertext_len = strlen($text);

                        $iv = $self->decryptIV;

                        for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                            $in = $block = substr($text, $i, ' . $block_size . ');
                            ' . $_decryptBlock . '
                            $plaintext.= $in ^ $iv;
                            $iv = $block;
                        }

                        if ($self->continuousBuffer) {
                            $self->decryptIV = $iv;
                        }

                        return $self->_unpad($plaintext);
                        ';
                    break;
                case CRYPT_RIJNDAEL_MODE_CTR:
                    $encrypt = $init_encryptBlock . '
                        $ciphertext = "";
                        $plaintext_len = strlen($text);
                        $xor = $self->encryptIV;
                        $buffer = &$self->enbuffer;

                        if (strlen($buffer["encrypted"])) {
                            for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                if (strlen($block) > strlen($buffer["encrypted"])) {
                                    $in = $self->_generate_xor(' . $block_size . ', $xor);
                                    ' . $_encryptBlock . '
                                    $buffer["encrypted"].= $in;
                                }
                                $key = $self->_string_shift($buffer["encrypted"], ' . $block_size . ');
                                $ciphertext.= $block ^ $key;
                            }
                        } else {
                            for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                $in = $self->_generate_xor(' . $block_size . ', $xor);
                                ' . $_encryptBlock . '
                                $key = $in;
                                $ciphertext.= $block ^ $key;
                            }
                        }
                        if ($self->continuousBuffer) {
                            $self->encryptIV = $xor;
                            if ($start = $plaintext_len % ' . $block_size . ') {
                                $buffer["encrypted"] = substr($key, $start) . $buffer["encrypted"];
                            }
                        }

                        return $ciphertext;
                    ';
                    
                    $decrypt = $init_encryptBlock . '
                        $plaintext = "";
                        $ciphertext_len = strlen($text);
                        $xor = $self->decryptIV;
                        $buffer = &$self->debuffer;

                        if (strlen($buffer["ciphertext"])) {
                            for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                if (strlen($block) > strlen($buffer["ciphertext"])) {
                                    $in = $self->_generate_xor(' . $block_size . ', $xor);
                                    ' . $_encryptBlock . '
                                    $buffer["ciphertext"].= $in;
                                }
                                $key = $self->_string_shift($buffer["ciphertext"], ' . $block_size . ');
                                $plaintext.= $block ^ $key;
                            }
                        } else {
                            for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                $in = $self->_generate_xor(' . $block_size . ', $xor);
                                ' . $_encryptBlock . '
                                $key = $in;
                                $plaintext.= $block ^ $key;
                            }
                        }
                        if ($self->continuousBuffer) {
                            $self->decryptIV = $xor;
                            if ($start = $ciphertext_len % ' . $block_size . ') {
                                $buffer["ciphertext"] = substr($key, $start) . $buffer["ciphertext"];
                            }
                        }
                       
                        return $plaintext;
                        ';
                    break;
                case CRYPT_RIJNDAEL_MODE_CFB:
                    $encrypt = $init_encryptBlock . '
                        $ciphertext = "";
                        $buffer = &$self->enbuffer;

                        if ($self->continuousBuffer) {
                            $iv = &$self->encryptIV;
                            $pos = &$buffer["pos"];
                        } else {
                            $iv = $self->encryptIV;
                            $pos = 0;
                        }
                        $len = strlen($text);
                        $i = 0;
                        if ($pos) {
                            $orig_pos = $pos;
                            $max = ' . $block_size . ' - $pos;
                            if ($len >= $max) {
                                $i = $max;
                                $len-= $max;
                                $pos = 0;
                            } else {
                                $i = $len;
                                $pos+= $len;
                                $len = 0;
                            }
                            $ciphertext = substr($iv, $orig_pos) ^ $text;
                            $iv = substr_replace($iv, $ciphertext, $orig_pos, $i);
                        }
                        while ($len >= ' . $block_size . ') {
                            $in = $iv;
                            ' . $_encryptBlock . ';
                            $iv = $in ^ substr($text, $i, ' . $block_size . ');
                            $ciphertext.= $iv;
                            $len-= ' . $block_size . ';
                            $i+= ' . $block_size . ';
                        }
                        if ($len) {
                            $in = $iv;
                            ' . $_encryptBlock . '
                            $iv = $in;
                            $block = $iv ^ substr($text, $i);
                            $iv = substr_replace($iv, $block, 0, $len);
                            $ciphertext.= $block;
                            $pos = $len;
                        }
                        return $ciphertext;
                    ';
                    
                    $decrypt = $init_encryptBlock . '
                        $plaintext = "";
                        $buffer = &$self->debuffer;

                        if ($self->continuousBuffer) {
                            $iv = &$self->decryptIV;
                            $pos = &$buffer["pos"];
                        } else {
                            $iv = $self->decryptIV;
                            $pos = 0;
                        }
                        $len = strlen($text);
                        $i = 0;
                        if ($pos) {
                            $orig_pos = $pos;
                            $max = ' . $block_size . ' - $pos;
                            if ($len >= $max) {
                                $i = $max;
                                $len-= $max;
                                $pos = 0;
                            } else {
                                $i = $len;
                                $pos+= $len;
                                $len = 0;
                            }
                            $plaintext = substr($iv, $orig_pos) ^ $text;
                            $iv = substr_replace($iv, substr($text, 0, $i), $orig_pos, $i);
                        }
                        while ($len >= ' . $block_size . ') {
                            $in = $iv;
                            ' . $_encryptBlock . '
                            $iv = $in;
                            $cb = substr($text, $i, ' . $block_size . ');
                            $plaintext.= $iv ^ $cb;
                            $iv = $cb;
                            $len-= ' . $block_size . ';
                            $i+= ' . $block_size . ';
                        }
                        if ($len) {
                            $in = $iv;
                            ' . $_encryptBlock . '
                            $iv = $in;
                            $plaintext.= $iv ^ substr($text, $i);
                            $iv = substr_replace($iv, substr($text, $i), 0, $len);
                            $pos = $len;
                        }

                        return $plaintext;
                        ';
                    break;
                case CRYPT_RIJNDAEL_MODE_OFB:
                    $encrypt = $init_encryptBlock . '
                        $ciphertext = "";
                        $plaintext_len = strlen($text);
                        $xor = $self->encryptIV;
                        $buffer = &$self->enbuffer;

                        if (strlen($buffer["xor"])) {
                            for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                if (strlen($block) > strlen($buffer["xor"])) {
                                    $in = $xor;
                                    ' . $_encryptBlock . '
                                    $xor = $in;
                                    $buffer["xor"].= $xor;
                                }
                                $key = $self->_string_shift($buffer["xor"], ' . $block_size . ');
                                $ciphertext.= $block ^ $key;
                            }
                        } else {
                            for ($i = 0; $i < $plaintext_len; $i+= ' . $block_size . ') {
                                $in = $xor;
                                ' . $_encryptBlock . '
                                $xor = $in;
                                $ciphertext.= substr($text, $i, ' . $block_size . ') ^ $xor;
                            }
                            $key = $xor;
                        }
                        if ($self->continuousBuffer) {
                            $self->encryptIV = $xor;
                            if ($start = $plaintext_len % ' . $block_size . ') {
                                 $buffer["xor"] = substr($key, $start) . $buffer["xor"];
                            }
                        }
                        return $ciphertext;
                        ';
                    
                    $decrypt = $init_encryptBlock . '
                        $plaintext = "";
                        $ciphertext_len = strlen($text);
                        $xor = $self->decryptIV;
                        $buffer = &$self->debuffer;

                        if (strlen($buffer["xor"])) {
                            for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                                $block = substr($text, $i, ' . $block_size . ');
                                if (strlen($block) > strlen($buffer["xor"])) {
                                    $in = $xor;
                                    ' . $_encryptBlock . '
                                    $xor = $in;
                                    $buffer["xor"].= $xor;
                                }
                                $key = $self->_string_shift($buffer["xor"], ' . $block_size . ');
                                $plaintext.= $block ^ $key;
                            }
                        } else {
                            for ($i = 0; $i < $ciphertext_len; $i+= ' . $block_size . ') {
                                $in = $xor;
                                ' . $_encryptBlock . '
                                $xor = $in;
                                $plaintext.= substr($text, $i, ' . $block_size . ') ^ $xor;
                            }
                            $key = $xor;
                        }
                        if ($self->continuousBuffer) {
                            $self->decryptIV = $xor;
                            if ($start = $ciphertext_len % ' . $block_size . ') {
                                 $buffer["xor"] = substr($key, $start) . $buffer["xor"];
                            }
                        }
                        return $plaintext;
                        ';
                    break;
            }
            $lambda_functions[$code_hash] = create_function('$action, &$self, $text', 'if ($action == "encrypt") { ' . $encrypt . ' } else { ' . $decrypt . ' }');
        }
        $this->inline_crypt = $lambda_functions[$code_hash];
    }

    /**
     * Holds the lambda_functions table (classwide)
     *
     * @see Crypt_Rijndael::inline_crypt_setup()
     * @return Array
     * @access private
     */
    function &get_lambda_functions()
    {
        static $functions = array();
        return $functions;
    }
}

// vim: ts=4:sw=4:et:
// vim6: fdl=1:
