Added: vcl/trunk/web/.ht-inc/phpseclib/Crypt/Base.php
URL: 
http://svn.apache.org/viewvc/vcl/trunk/web/.ht-inc/phpseclib/Crypt/Base.php?rev=1796097&view=auto
==============================================================================
--- vcl/trunk/web/.ht-inc/phpseclib/Crypt/Base.php (added)
+++ vcl/trunk/web/.ht-inc/phpseclib/Crypt/Base.php Wed May 24 20:28:10 2017
@@ -0,0 +1,2611 @@
+<?php
+
+/**
+ * Base Class for all Crypt_* cipher classes
+ *
+ * PHP versions 4 and 5
+ *
+ * Internally for phpseclib developers:
+ *  If you plan to add a new cipher class, please note following rules:
+ *
+ *  - The new Crypt_* cipher class should extend Crypt_Base
+ *
+ *  - Following methods are then required to be overridden/overloaded:
+ *
+ *    - _encryptBlock()
+ *
+ *    - _decryptBlock()
+ *
+ *    - _setupKey()
+ *
+ *  - All other methods are optional to be overridden/overloaded
+ *
+ *  - Look at the source code of the current ciphers how they extend Crypt_Base
+ *    and take one of them as a start up for the new cipher class.
+ *
+ *  - Please read all the other comments/notes/hints here also for each class 
var/method
+ *
+ * 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_Base
+ * @author    Jim Wigginton <[email protected]>
+ * @author    Hans-Juergen Petrich <[email protected]>
+ * @copyright 2007 Jim Wigginton
+ * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
+ * @link      http://phpseclib.sourceforge.net
+ */
+
+/**#@+
+ * @access public
+ * @see self::encrypt()
+ * @see self::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_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_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_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_MODE_CFB', 3);
+/**
+ * Encrypt / decrypt using the Output Feedback mode.
+ *
+ * @link 
http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
+ */
+define('CRYPT_MODE_OFB', 4);
+/**
+ * Encrypt / decrypt using streaming mode.
+ */
+define('CRYPT_MODE_STREAM', 5);
+/**#@-*/
+
+/**#@+
+ * @access private
+ * @see self::Crypt_Base()
+ * @internal These constants are for internal use only
+ */
+/**
+ * Base value for the internal implementation $engine switch
+ */
+define('CRYPT_ENGINE_INTERNAL', 1);
+/**
+ * Base value for the mcrypt implementation $engine switch
+ */
+define('CRYPT_ENGINE_MCRYPT', 2);
+/**
+ * Base value for the OpenSSL implementation $engine switch
+ */
+define('CRYPT_ENGINE_OPENSSL', 3);
+/**#@-*/
+
+/**
+ * Base Class for all Crypt_* cipher classes
+ *
+ * @package Crypt_Base
+ * @author  Jim Wigginton <[email protected]>
+ * @author  Hans-Juergen Petrich <[email protected]>
+ * @access  public
+ */
+class Crypt_Base
+{
+    /**
+     * The Encryption Mode
+     *
+     * @see self::Crypt_Base()
+     * @var int
+     * @access private
+     */
+    var $mode;
+
+    /**
+     * The Block Length of the block cipher
+     *
+     * @var int
+     * @access private
+     */
+    var $block_size = 16;
+
+    /**
+     * The Key
+     *
+     * @see self::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 self::setIV()
+     * @var string
+     * @access private
+     */
+    var $iv;
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see self::enableContinuousBuffer()
+     * @see self::_clearBuffers()
+     * @var string
+     * @access private
+     */
+    var $encryptIV;
+
+    /**
+     * A "sliding" Initialization Vector
+     *
+     * @see self::enableContinuousBuffer()
+     * @see self::_clearBuffers()
+     * @var string
+     * @access private
+     */
+    var $decryptIV;
+
+    /**
+     * Continuous Buffer status
+     *
+     * @see self::enableContinuousBuffer()
+     * @var bool
+     * @access private
+     */
+    var $continuousBuffer = false;
+
+    /**
+     * Encryption buffer for CTR, OFB and CFB modes
+     *
+     * @see self::encrypt()
+     * @see self::_clearBuffers()
+     * @var array
+     * @access private
+     */
+    var $enbuffer;
+
+    /**
+     * Decryption buffer for CTR, OFB and CFB modes
+     *
+     * @see self::decrypt()
+     * @see self::_clearBuffers()
+     * @var array
+     * @access private
+     */
+    var $debuffer;
+
+    /**
+     * mcrypt resource for encryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be 
created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be 
recreated when in non-continuous mode.
+     *
+     * @see self::encrypt()
+     * @var resource
+     * @access private
+     */
+    var $enmcrypt;
+
+    /**
+     * mcrypt resource for decryption
+     *
+     * The mcrypt resource can be recreated every time something needs to be 
created or it can be created just once.
+     * Since mcrypt operates in continuous mode, by default, it'll need to be 
recreated when in non-continuous mode.
+     *
+     * @see self::decrypt()
+     * @var resource
+     * @access private
+     */
+    var $demcrypt;
+
+    /**
+     * Does the enmcrypt resource need to be (re)initialized?
+     *
+     * @see Crypt_Twofish::setKey()
+     * @see Crypt_Twofish::setIV()
+     * @var bool
+     * @access private
+     */
+    var $enchanged = true;
+
+    /**
+     * Does the demcrypt resource need to be (re)initialized?
+     *
+     * @see Crypt_Twofish::setKey()
+     * @see Crypt_Twofish::setIV()
+     * @var bool
+     * @access private
+     */
+    var $dechanged = true;
+
+    /**
+     * mcrypt resource for CFB mode
+     *
+     * mcrypt's CFB mode, in (and only in) buffered context,
+     * is broken, so phpseclib implements the CFB mode by it self,
+     * even when the mcrypt php extension is available.
+     *
+     * In order to do the CFB-mode work (fast) phpseclib
+     * use a separate ECB-mode mcrypt resource.
+     *
+     * @link http://phpseclib.sourceforge.net/cfb-demo.phps
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @see self::_setupMcrypt()
+     * @var resource
+     * @access private
+     */
+    var $ecb;
+
+    /**
+     * Optimizing value while CFB-encrypting
+     *
+     * Only relevant if $continuousBuffer enabled
+     * and $engine == CRYPT_ENGINE_MCRYPT
+     *
+     * It's faster to re-init $enmcrypt if
+     * $buffer bytes > $cfb_init_len than
+     * using the $ecb resource furthermore.
+     *
+     * This value depends of the chosen cipher
+     * and the time it would be needed for it's
+     * initialization [by mcrypt_generic_init()]
+     * which, typically, depends on the complexity
+     * on its internaly Key-expanding algorithm.
+     *
+     * @see self::encrypt()
+     * @var int
+     * @access private
+     */
+    var $cfb_init_len = 600;
+
+    /**
+     * Does internal cipher state need to be (re)initialized?
+     *
+     * @see self::setKey()
+     * @see self::setIV()
+     * @see self::disableContinuousBuffer()
+     * @var bool
+     * @access private
+     */
+    var $changed = true;
+
+    /**
+     * Padding status
+     *
+     * @see self::enablePadding()
+     * @var bool
+     * @access private
+     */
+    var $padding = true;
+
+    /**
+     * Is the mode one that is paddable?
+     *
+     * @see self::Crypt_Base()
+     * @var bool
+     * @access private
+     */
+    var $paddable = false;
+
+    /**
+     * Holds which crypt engine internaly should be use,
+     * which will be determined automatically on __construct()
+     *
+     * Currently available $engines are:
+     * - CRYPT_ENGINE_OPENSSL  (very fast, php-extension: openssl, 
extension_loaded('openssl') required)
+     * - CRYPT_ENGINE_MCRYPT   (fast, php-extension: mcrypt, 
extension_loaded('mcrypt') required)
+     * - CRYPT_ENGINE_INTERNAL (slower, pure php-engine, no php-extension 
required)
+     *
+     * @see self::_setEngine()
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @var int
+     * @access private
+     */
+    var $engine;
+
+    /**
+     * Holds the preferred crypt engine
+     *
+     * @see self::_setEngine()
+     * @see self::setPreferredEngine()
+     * @var int
+     * @access private
+     */
+    var $preferredEngine;
+
+    /**
+     * The mcrypt specific name of the cipher
+     *
+     * Only used if $engine == CRYPT_ENGINE_MCRYPT
+     *
+     * @link http://www.php.net/mcrypt_module_open
+     * @link http://www.php.net/mcrypt_list_algorithms
+     * @see self::_setupMcrypt()
+     * @var string
+     * @access private
+     */
+    var $cipher_name_mcrypt;
+
+    /**
+     * The openssl specific name of the cipher
+     *
+     * Only used if $engine == CRYPT_ENGINE_OPENSSL
+     *
+     * @link http://www.php.net/openssl-get-cipher-methods
+     * @var string
+     * @access private
+     */
+    var $cipher_name_openssl;
+
+    /**
+     * The openssl specific name of the cipher in ECB mode
+     *
+     * If OpenSSL does not support the mode we're trying to use (CTR)
+     * it can still be emulated with ECB mode.
+     *
+     * @link http://www.php.net/openssl-get-cipher-methods
+     * @var string
+     * @access private
+     */
+    var $cipher_name_openssl_ecb;
+
+    /**
+     * The default salt used by setPassword()
+     *
+     * @see self::setPassword()
+     * @var string
+     * @access private
+     */
+    var $password_default_salt = 'phpseclib/salt';
+
+    /**
+     * The namespace used by the cipher for its constants.
+     *
+     * ie: AES.php is using CRYPT_AES_MODE_* for its constants
+     *     so $const_namespace is AES
+     *
+     *     DES.php is using CRYPT_DES_MODE_* for its constants
+     *     so $const_namespace is DES... and so on
+     *
+     * All CRYPT_<$const_namespace>_MODE_* are aliases of
+     * the generic CRYPT_MODE_* constants, so both could be used
+     * for each cipher.
+     *
+     * Example:
+     * $aes = new Crypt_AES(CRYPT_AES_MODE_CFB); // $aes will operate in cfb 
mode
+     * $aes = new Crypt_AES(CRYPT_MODE_CFB);     // identical
+     *
+     * @see self::Crypt_Base()
+     * @var string
+     * @access private
+     */
+    var $const_namespace;
+
+    /**
+     * The name of the performance-optimized callback function
+     *
+     * Used by encrypt() / decrypt()
+     * only if $engine == CRYPT_ENGINE_INTERNAL
+     *
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @see self::_setupInlineCrypt()
+     * @see self::$use_inline_crypt
+     * @var Callback
+     * @access private
+     */
+    var $inline_crypt;
+
+    /**
+     * Holds whether performance-optimized $inline_crypt() can/should be used.
+     *
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @see self::inline_crypt
+     * @var mixed
+     * @access private
+     */
+    var $use_inline_crypt;
+
+    /**
+     * If OpenSSL can be used in ECB but not in CTR we can emulate CTR
+     *
+     * @see self::_openssl_ctr_process()
+     * @var bool
+     * @access private
+     */
+    var $openssl_emulate_ctr = false;
+
+    /**
+     * Determines what options are passed to openssl_encrypt/decrypt
+     *
+     * @see self::isValidEngine()
+     * @var mixed
+     * @access private
+     */
+    var $openssl_options;
+
+    /**
+     * Has the key length explicitly been set or should it be derived from the 
key, itself?
+     *
+     * @see self::setKeyLength()
+     * @var bool
+     * @access private
+     */
+    var $explicit_key_length = false;
+
+    /**
+     * Don't truncate / null pad key
+     *
+     * @see self::_clearBuffers()
+     * @var bool
+     * @access private
+     */
+    var $skip_key_adjustment = false;
+
+    /**
+     * Default Constructor.
+     *
+     * Determines whether or not the mcrypt extension should be used.
+     *
+     * $mode could be:
+     *
+     * - CRYPT_MODE_ECB
+     *
+     * - CRYPT_MODE_CBC
+     *
+     * - CRYPT_MODE_CTR
+     *
+     * - CRYPT_MODE_CFB
+     *
+     * - CRYPT_MODE_OFB
+     *
+     * (or the alias constants of the chosen cipher, for example for AES: 
CRYPT_AES_MODE_ECB or CRYPT_AES_MODE_CBC ...)
+     *
+     * If not explicitly set, CRYPT_MODE_CBC will be used.
+     *
+     * @param int $mode
+     * @access public
+     */
+    function __construct($mode = CRYPT_MODE_CBC)
+    {
+        // $mode dependent settings
+        switch ($mode) {
+            case CRYPT_MODE_ECB:
+                $this->paddable = true;
+                $this->mode = CRYPT_MODE_ECB;
+                break;
+            case CRYPT_MODE_CTR:
+            case CRYPT_MODE_CFB:
+            case CRYPT_MODE_OFB:
+            case CRYPT_MODE_STREAM:
+                $this->mode = $mode;
+                break;
+            case CRYPT_MODE_CBC:
+            default:
+                $this->paddable = true;
+                $this->mode = CRYPT_MODE_CBC;
+        }
+
+        $this->_setEngine();
+
+        // Determining whether inline crypting can be used by the cipher
+        if ($this->use_inline_crypt !== false && 
function_exists('create_function')) {
+            $this->use_inline_crypt = true;
+        }
+    }
+
+    /**
+     * PHP4 compatible Default Constructor.
+     *
+     * @see self::__construct()
+     * @param int $mode
+     * @access public
+     */
+    function Crypt_Base($mode = CRYPT_MODE_CBC)
+    {
+        $this->__construct($mode);
+    }
+
+    /**
+     * Sets the initialization vector. (optional)
+     *
+     * SetIV is not required when CRYPT_MODE_ECB (or ie for AES: 
CRYPT_AES_MODE_ECB) is being used.  If not explicitly set, it'll be assumed
+     * to be all zero's.
+     *
+     * @access public
+     * @param string $iv
+     * @internal Can be overwritten by a sub class, but does not have to be
+     */
+    function setIV($iv)
+    {
+        if ($this->mode == CRYPT_MODE_ECB) {
+            return;
+        }
+
+        $this->iv = $iv;
+        $this->changed = true;
+    }
+
+    /**
+     * Sets the key length.
+     *
+     * Keys with explicitly set lengths need to be treated accordingly
+     *
+     * @access public
+     * @param int $length
+     */
+    function setKeyLength($length)
+    {
+        $this->explicit_key_length = true;
+        $this->changed = true;
+        $this->_setEngine();
+    }
+
+    /**
+     * Returns the current key length in bits
+     *
+     * @access public
+     * @return int
+     */
+    function getKeyLength()
+    {
+        return $this->key_length << 3;
+    }
+
+    /**
+     * Returns the current block length in bits
+     *
+     * @access public
+     * @return int
+     */
+    function getBlockLength()
+    {
+        return $this->block_size << 3;
+    }
+
+    /**
+     * Sets the key.
+     *
+     * The min/max length(s) of the key depends on the cipher which is used.
+     * If the key not fits the length(s) of the cipher it will paded with null 
bytes
+     * up to the closest valid key length.  If the key is more than max length,
+     * 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 $key
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function setKey($key)
+    {
+        if (!$this->explicit_key_length) {
+            $this->setKeyLength(strlen($key) << 3);
+            $this->explicit_key_length = false;
+        }
+
+        $this->key = $key;
+        $this->changed = true;
+        $this->_setEngine();
+    }
+
+    /**
+     * 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} or pbkdf1:
+     *         $hash, $salt, $count, $dkLen
+     *
+     *         Where $hash (default = sha1) currently supports the following 
hashes: see: Crypt/Hash.php
+     *
+     * @see Crypt/Hash.php
+     * @param string $password
+     * @param string $method
+     * @return bool
+     * @access public
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function setPassword($password, $method = 'pbkdf2')
+    {
+        $key = '';
+
+        switch ($method) {
+            default: // 'pbkdf2' or 'pbkdf1'
+                $func_args = func_get_args();
+
+                // Hash function
+                $hash = isset($func_args[2]) ? $func_args[2] : 'sha1';
+
+                // WPA and WPA2 use the SSID as the salt
+                $salt = isset($func_args[3]) ? $func_args[3] : 
$this->password_default_salt;
+
+                // RFC2898#section-4.2 uses 1,000 iterations by default
+                // WPA and WPA2 use 4,096.
+                $count = isset($func_args[4]) ? $func_args[4] : 1000;
+
+                // Keylength
+                if (isset($func_args[5])) {
+                    $dkLen = $func_args[5];
+                } else {
+                    $dkLen = $method == 'pbkdf1' ? 2 * $this->key_length : 
$this->key_length;
+                }
+
+                switch (true) {
+                    case $method == 'pbkdf1':
+                        if (!class_exists('Crypt_Hash')) {
+                            include_once 'Crypt/Hash.php';
+                        }
+                        $hashObj = new Crypt_Hash();
+                        $hashObj->setHash($hash);
+                        if ($dkLen > $hashObj->getLength()) {
+                            user_error('Derived key too long');
+                            return false;
+                        }
+                        $t = $password . $salt;
+                        for ($i = 0; $i < $count; ++$i) {
+                            $t = $hashObj->hash($t);
+                        }
+                        $key = substr($t, 0, $dkLen);
+
+                        $this->setKey(substr($key, 0, $dkLen >> 1));
+                        $this->setIV(substr($key, $dkLen >> 1));
+
+                        return true;
+                    // Determining if php[>=5.5.0]'s hash_pbkdf2() function 
avail- and useable
+                    case !function_exists('hash_pbkdf2'):
+                    case !function_exists('hash_algos'):
+                    case !in_array($hash, hash_algos()):
+                        if (!class_exists('Crypt_Hash')) {
+                            include_once 'Crypt/Hash.php';
+                        }
+                        $i = 1;
+                        while (strlen($key) < $dkLen) {
+                            $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;
+                        }
+                        $key = substr($key, 0, $dkLen);
+                        break;
+                    default:
+                        $key = hash_pbkdf2($hash, $password, $salt, $count, 
$dkLen, true);
+                }
+        }
+
+        $this->setKey($key);
+
+        return true;
+    }
+
+    /**
+     * Encrypts a message.
+     *
+     * $plaintext will be padded with additional bytes such that it's length 
is a multiple of the block size. Other cipher
+     * implementations may or may not pad in the same manner.  Other common 
approaches to padding and the reasons why it's
+     * necessary are discussed in the following
+     * URL:
+     *
+     * {@link http://www.di-mgt.com.au/cryptopad.html 
http://www.di-mgt.com.au/cryptopad.html}
+     *
+     * An alternative to padding is to, separately, send the length of the 
file.  This is what SSH, in fact, does.
+     * strlen($plaintext) will still need to be a multiple of the block size, 
however, arbitrary values can be added to make it that
+     * length.
+     *
+     * @see self::decrypt()
+     * @access public
+     * @param string $plaintext
+     * @return string $ciphertext
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function encrypt($plaintext)
+    {
+        if ($this->paddable) {
+            $plaintext = $this->_pad($plaintext);
+        }
+
+        if ($this->engine === CRYPT_ENGINE_OPENSSL) {
+            if ($this->changed) {
+                $this->_clearBuffers();
+                $this->changed = false;
+            }
+            switch ($this->mode) {
+                case CRYPT_MODE_STREAM:
+                    return openssl_encrypt($plaintext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options);
+                case CRYPT_MODE_ECB:
+                    $result = openssl_encrypt($plaintext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options);
+                    return !defined('OPENSSL_RAW_DATA') ? substr($result, 0, 
-$this->block_size) : $result;
+                case CRYPT_MODE_CBC:
+                    $result = openssl_encrypt($plaintext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options, 
$this->encryptIV);
+                    if (!defined('OPENSSL_RAW_DATA')) {
+                        $result = substr($result, 0, -$this->block_size);
+                    }
+                    if ($this->continuousBuffer) {
+                        $this->encryptIV = substr($result, -$this->block_size);
+                    }
+                    return $result;
+                case CRYPT_MODE_CTR:
+                    return $this->_openssl_ctr_process($plaintext, 
$this->encryptIV, $this->enbuffer);
+                case CRYPT_MODE_CFB:
+                    // cfb loosely routines inspired by openssl's:
+                    // {@link 
http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1}
+                    $ciphertext = '';
+                    if ($this->continuousBuffer) {
+                        $iv = &$this->encryptIV;
+                        $pos = &$this->enbuffer['pos'];
+                    } else {
+                        $iv = $this->encryptIV;
+                        $pos = 0;
+                    }
+                    $len = strlen($plaintext);
+                    $i = 0;
+                    if ($pos) {
+                        $orig_pos = $pos;
+                        $max = $this->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);
+                        $plaintext = substr($plaintext, $i);
+                    }
+
+                    $overflow = $len % $this->block_size;
+
+                    if ($overflow) {
+                        $ciphertext.= openssl_encrypt(substr($plaintext, 0, 
-$overflow) . str_repeat("\0", $this->block_size), $this->cipher_name_openssl, 
$this->key, $this->openssl_options, $iv);
+                        $iv = $this->_string_pop($ciphertext, 
$this->block_size);
+
+                        $size = $len - $overflow;
+                        $block = $iv ^ substr($plaintext, -$overflow);
+                        $iv = substr_replace($iv, $block, 0, $overflow);
+                        $ciphertext.= $block;
+                        $pos = $overflow;
+                    } elseif ($len) {
+                        $ciphertext = openssl_encrypt($plaintext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options, $iv);
+                        $iv = substr($ciphertext, -$this->block_size);
+                    }
+
+                    return $ciphertext;
+                case CRYPT_MODE_OFB:
+                    return $this->_openssl_ofb_process($plaintext, 
$this->encryptIV, $this->enbuffer);
+            }
+        }
+
+        if ($this->engine === CRYPT_ENGINE_MCRYPT) {
+            if ($this->changed) {
+                $this->_setupMcrypt();
+                $this->changed = false;
+            }
+            if ($this->enchanged) {
+                @mcrypt_generic_init($this->enmcrypt, $this->key, 
$this->encryptIV);
+                $this->enchanged = false;
+            }
+
+            // re: {@link http://phpseclib.sourceforge.net/cfb-demo.phps}
+            // using mcrypt's default handing of CFB the above would output 
two different things.  using phpseclib's
+            // rewritten CFB implementation the above outputs the same thing 
twice.
+            if ($this->mode == CRYPT_MODE_CFB && $this->continuousBuffer) {
+                $block_size = $this->block_size;
+                $iv = &$this->encryptIV;
+                $pos = &$this->enbuffer['pos'];
+                $len = strlen($plaintext);
+                $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;
+                    }
+                    $ciphertext = substr($iv, $orig_pos) ^ $plaintext;
+                    $iv = substr_replace($iv, $ciphertext, $orig_pos, $i);
+                    $this->enbuffer['enmcrypt_init'] = true;
+                }
+                if ($len >= $block_size) {
+                    if ($this->enbuffer['enmcrypt_init'] === false || $len > 
$this->cfb_init_len) {
+                        if ($this->enbuffer['enmcrypt_init'] === true) {
+                            @mcrypt_generic_init($this->enmcrypt, $this->key, 
$iv);
+                            $this->enbuffer['enmcrypt_init'] = false;
+                        }
+                        $ciphertext.= @mcrypt_generic($this->enmcrypt, 
substr($plaintext, $i, $len - $len % $block_size));
+                        $iv = substr($ciphertext, -$block_size);
+                        $len%= $block_size;
+                    } else {
+                        while ($len >= $block_size) {
+                            $iv = @mcrypt_generic($this->ecb, $iv) ^ 
substr($plaintext, $i, $block_size);
+                            $ciphertext.= $iv;
+                            $len-= $block_size;
+                            $i+= $block_size;
+                        }
+                    }
+                }
+
+                if ($len) {
+                    $iv = @mcrypt_generic($this->ecb, $iv);
+                    $block = $iv ^ substr($plaintext, -$len);
+                    $iv = substr_replace($iv, $block, 0, $len);
+                    $ciphertext.= $block;
+                    $pos = $len;
+                }
+
+                return $ciphertext;
+            }
+
+            $ciphertext = @mcrypt_generic($this->enmcrypt, $plaintext);
+
+            if (!$this->continuousBuffer) {
+                @mcrypt_generic_init($this->enmcrypt, $this->key, 
$this->encryptIV);
+            }
+
+            return $ciphertext;
+        }
+
+        if ($this->changed) {
+            $this->_setup();
+            $this->changed = false;
+        }
+        if ($this->use_inline_crypt) {
+            $inline = $this->inline_crypt;
+            return $inline('encrypt', $this, $plaintext);
+        }
+
+        $buffer = &$this->enbuffer;
+        $block_size = $this->block_size;
+        $ciphertext = '';
+        switch ($this->mode) {
+            case CRYPT_MODE_ECB:
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $ciphertext.= $this->_encryptBlock(substr($plaintext, $i, 
$block_size));
+                }
+                break;
+            case CRYPT_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_MODE_CTR:
+                $xor = $this->encryptIV;
+                if (strlen($buffer['ciphertext'])) {
+                    for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                        $block = substr($plaintext, $i, $block_size);
+                        if (strlen($block) > strlen($buffer['ciphertext'])) {
+                            $buffer['ciphertext'].= $this->_encryptBlock($xor);
+                        }
+                        $this->_increment_str($xor);
+                        $key = $this->_string_shift($buffer['ciphertext'], 
$block_size);
+                        $ciphertext.= $block ^ $key;
+                    }
+                } else {
+                    for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                        $block = substr($plaintext, $i, $block_size);
+                        $key = $this->_encryptBlock($xor);
+                        $this->_increment_str($xor);
+                        $ciphertext.= $block ^ $key;
+                    }
+                }
+                if ($this->continuousBuffer) {
+                    $this->encryptIV = $xor;
+                    if ($start = strlen($plaintext) % $block_size) {
+                        $buffer['ciphertext'] = substr($key, $start) . 
$buffer['ciphertext'];
+                    }
+                }
+                break;
+            case CRYPT_MODE_CFB:
+                // cfb loosely routines inspired by openssl's:
+                // {@link 
http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1}
+                if ($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_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'];
+                    }
+                }
+                break;
+            case CRYPT_MODE_STREAM:
+                $ciphertext = $this->_encryptBlock($plaintext);
+                break;
+        }
+
+        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 self::encrypt()
+     * @access public
+     * @param string $ciphertext
+     * @return string $plaintext
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function decrypt($ciphertext)
+    {
+        if ($this->paddable) {
+            // we pad with chr(0) since that's what mcrypt_generic does.  to 
quote from {@link http://www.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) % 
$this->block_size, chr(0));
+        }
+
+        if ($this->engine === CRYPT_ENGINE_OPENSSL) {
+            if ($this->changed) {
+                $this->_clearBuffers();
+                $this->changed = false;
+            }
+            switch ($this->mode) {
+                case CRYPT_MODE_STREAM:
+                    $plaintext = openssl_decrypt($ciphertext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options);
+                    break;
+                case CRYPT_MODE_ECB:
+                    if (!defined('OPENSSL_RAW_DATA')) {
+                        $ciphertext.= openssl_encrypt('', 
$this->cipher_name_openssl_ecb, $this->key, true);
+                    }
+                    $plaintext = openssl_decrypt($ciphertext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options);
+                    break;
+                case CRYPT_MODE_CBC:
+                    if (!defined('OPENSSL_RAW_DATA')) {
+                        $padding = str_repeat(chr($this->block_size), 
$this->block_size) ^ substr($ciphertext, -$this->block_size);
+                        $ciphertext.= substr(openssl_encrypt($padding, 
$this->cipher_name_openssl_ecb, $this->key, true), 0, $this->block_size);
+                        $offset = 2 * $this->block_size;
+                    } else {
+                        $offset = $this->block_size;
+                    }
+                    $plaintext = openssl_decrypt($ciphertext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options, 
$this->decryptIV);
+                    if ($this->continuousBuffer) {
+                        $this->decryptIV = substr($ciphertext, -$offset, 
$this->block_size);
+                    }
+                    break;
+                case CRYPT_MODE_CTR:
+                    $plaintext = $this->_openssl_ctr_process($ciphertext, 
$this->decryptIV, $this->debuffer);
+                    break;
+                case CRYPT_MODE_CFB:
+                    // cfb loosely routines inspired by openssl's:
+                    // {@link 
http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1}
+                    $plaintext = '';
+                    if ($this->continuousBuffer) {
+                        $iv = &$this->decryptIV;
+                        $pos = &$this->buffer['pos'];
+                    } else {
+                        $iv = $this->decryptIV;
+                        $pos = 0;
+                    }
+                    $len = strlen($ciphertext);
+                    $i = 0;
+                    if ($pos) {
+                        $orig_pos = $pos;
+                        $max = $this->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%= $this->blocksize
+                        $plaintext = substr($iv, $orig_pos) ^ $ciphertext;
+                        $iv = substr_replace($iv, substr($ciphertext, 0, $i), 
$orig_pos, $i);
+                        $ciphertext = substr($ciphertext, $i);
+                    }
+                    $overflow = $len % $this->block_size;
+                    if ($overflow) {
+                        $plaintext.= openssl_decrypt(substr($ciphertext, 0, 
-$overflow), $this->cipher_name_openssl, $this->key, $this->openssl_options, 
$iv);
+                        if ($len - $overflow) {
+                            $iv = substr($ciphertext, -$overflow - 
$this->block_size, -$overflow);
+                        }
+                        $iv = openssl_encrypt(str_repeat("\0", 
$this->block_size), $this->cipher_name_openssl, $this->key, 
$this->openssl_options, $iv);
+                        $plaintext.= $iv ^ substr($ciphertext, -$overflow);
+                        $iv = substr_replace($iv, substr($ciphertext, 
-$overflow), 0, $overflow);
+                        $pos = $overflow;
+                    } elseif ($len) {
+                        $plaintext.= openssl_decrypt($ciphertext, 
$this->cipher_name_openssl, $this->key, $this->openssl_options, $iv);
+                        $iv = substr($ciphertext, -$this->block_size);
+                    }
+                    break;
+                case CRYPT_MODE_OFB:
+                    $plaintext = $this->_openssl_ofb_process($ciphertext, 
$this->decryptIV, $this->debuffer);
+            }
+
+            return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        if ($this->engine === CRYPT_ENGINE_MCRYPT) {
+            $block_size = $this->block_size;
+            if ($this->changed) {
+                $this->_setupMcrypt();
+                $this->changed = false;
+            }
+            if ($this->dechanged) {
+                @mcrypt_generic_init($this->demcrypt, $this->key, 
$this->decryptIV);
+                $this->dechanged = false;
+            }
+
+            if ($this->mode == CRYPT_MODE_CFB && $this->continuousBuffer) {
+                $iv = &$this->decryptIV;
+                $pos = &$this->debuffer['pos'];
+                $len = strlen($ciphertext);
+                $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
+                    $plaintext = substr($iv, $orig_pos) ^ $ciphertext;
+                    $iv = substr_replace($iv, substr($ciphertext, 0, $i), 
$orig_pos, $i);
+                }
+                if ($len >= $block_size) {
+                    $cb = substr($ciphertext, $i, $len - $len % $block_size);
+                    $plaintext.= @mcrypt_generic($this->ecb, $iv . $cb) ^ $cb;
+                    $iv = substr($cb, -$block_size);
+                    $len%= $block_size;
+                }
+                if ($len) {
+                    $iv = @mcrypt_generic($this->ecb, $iv);
+                    $plaintext.= $iv ^ substr($ciphertext, -$len);
+                    $iv = substr_replace($iv, substr($ciphertext, -$len), 0, 
$len);
+                    $pos = $len;
+                }
+
+                return $plaintext;
+            }
+
+            $plaintext = @mdecrypt_generic($this->demcrypt, $ciphertext);
+
+            if (!$this->continuousBuffer) {
+                @mcrypt_generic_init($this->demcrypt, $this->key, 
$this->decryptIV);
+            }
+
+            return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+        }
+
+        if ($this->changed) {
+            $this->_setup();
+            $this->changed = false;
+        }
+        if ($this->use_inline_crypt) {
+            $inline = $this->inline_crypt;
+            return $inline('decrypt', $this, $ciphertext);
+        }
+
+        $block_size = $this->block_size;
+
+        $buffer = &$this->debuffer;
+        $plaintext = '';
+        switch ($this->mode) {
+            case CRYPT_MODE_ECB:
+                for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
+                    $plaintext.= $this->_decryptBlock(substr($ciphertext, $i, 
$block_size));
+                }
+                break;
+            case CRYPT_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_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'].= $this->_encryptBlock($xor);
+                            $this->_increment_str($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 = $this->_encryptBlock($xor);
+                        $this->_increment_str($xor);
+                        $plaintext.= $block ^ $key;
+                    }
+                }
+                if ($this->continuousBuffer) {
+                    $this->decryptIV = $xor;
+                    if ($start = strlen($ciphertext) % $block_size) {
+                        $buffer['ciphertext'] = substr($key, $start) . 
$buffer['ciphertext'];
+                    }
+                }
+                break;
+            case CRYPT_MODE_CFB:
+                if ($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_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'];
+                    }
+                }
+                break;
+            case CRYPT_MODE_STREAM:
+                $plaintext = $this->_decryptBlock($ciphertext);
+                break;
+        }
+        return $this->paddable ? $this->_unpad($plaintext) : $plaintext;
+    }
+
+    /**
+     * OpenSSL CTR Processor
+     *
+     * PHP's OpenSSL bindings do not operate in continuous mode so we'll wrap 
around it. Since the keystream
+     * for CTR is the same for both encrypting and decrypting this function is 
re-used by both Crypt_Base::encrypt()
+     * and Crypt_Base::decrypt(). Also, OpenSSL doesn't implement CTR for all 
of it's symmetric ciphers so this
+     * function will emulate CTR with ECB when necessary.
+     *
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @param string $plaintext
+     * @param string $encryptIV
+     * @param array $buffer
+     * @return string
+     * @access private
+     */
+    function _openssl_ctr_process($plaintext, &$encryptIV, &$buffer)
+    {
+        $ciphertext = '';
+
+        $block_size = $this->block_size;
+        $key = $this->key;
+
+        if ($this->openssl_emulate_ctr) {
+            $xor = $encryptIV;
+            if (strlen($buffer['ciphertext'])) {
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $block = substr($plaintext, $i, $block_size);
+                    if (strlen($block) > strlen($buffer['ciphertext'])) {
+                        $result = openssl_encrypt($xor, 
$this->cipher_name_openssl_ecb, $key, $this->openssl_options);
+                        $result = !defined('OPENSSL_RAW_DATA') ? 
substr($result, 0, -$this->block_size) : $result;
+                        $buffer['ciphertext'].= $result;
+                    }
+                    $this->_increment_str($xor);
+                    $otp = $this->_string_shift($buffer['ciphertext'], 
$block_size);
+                    $ciphertext.= $block ^ $otp;
+                }
+            } else {
+                for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
+                    $block = substr($plaintext, $i, $block_size);
+                    $otp = openssl_encrypt($xor, 
$this->cipher_name_openssl_ecb, $key, $this->openssl_options);
+                    $otp = !defined('OPENSSL_RAW_DATA') ? substr($otp, 0, 
-$this->block_size) : $otp;
+                    $this->_increment_str($xor);
+                    $ciphertext.= $block ^ $otp;
+                }
+            }
+            if ($this->continuousBuffer) {
+                $encryptIV = $xor;
+                if ($start = strlen($plaintext) % $block_size) {
+                    $buffer['ciphertext'] = substr($key, $start) . 
$buffer['ciphertext'];
+                }
+            }
+
+            return $ciphertext;
+        }
+
+        if (strlen($buffer['ciphertext'])) {
+            $ciphertext = $plaintext ^ 
$this->_string_shift($buffer['ciphertext'], strlen($plaintext));
+            $plaintext = substr($plaintext, strlen($ciphertext));
+
+            if (!strlen($plaintext)) {
+                return $ciphertext;
+            }
+        }
+
+        $overflow = strlen($plaintext) % $block_size;
+        if ($overflow) {
+            $plaintext2 = $this->_string_pop($plaintext, $overflow); // ie. 
trim $plaintext to a multiple of $block_size and put rest of $plaintext in 
$plaintext2
+            $encrypted = openssl_encrypt($plaintext . str_repeat("\0", 
$block_size), $this->cipher_name_openssl, $key, $this->openssl_options, 
$encryptIV);
+            $temp = $this->_string_pop($encrypted, $block_size);
+            $ciphertext.= $encrypted . ($plaintext2 ^ $temp);
+            if ($this->continuousBuffer) {
+                $buffer['ciphertext'] = substr($temp, $overflow);
+                $encryptIV = $temp;
+            }
+        } elseif (!strlen($buffer['ciphertext'])) {
+            $ciphertext.= openssl_encrypt($plaintext . str_repeat("\0", 
$block_size), $this->cipher_name_openssl, $key, $this->openssl_options, 
$encryptIV);
+            $temp = $this->_string_pop($ciphertext, $block_size);
+            if ($this->continuousBuffer) {
+                $encryptIV = $temp;
+            }
+        }
+        if ($this->continuousBuffer) {
+            if (!defined('OPENSSL_RAW_DATA')) {
+                $encryptIV.= openssl_encrypt('', 
$this->cipher_name_openssl_ecb, $key, $this->openssl_options);
+            }
+            $encryptIV = openssl_decrypt($encryptIV, 
$this->cipher_name_openssl_ecb, $key, $this->openssl_options);
+            if ($overflow) {
+                $this->_increment_str($encryptIV);
+            }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * OpenSSL OFB Processor
+     *
+     * PHP's OpenSSL bindings do not operate in continuous mode so we'll wrap 
around it. Since the keystream
+     * for OFB is the same for both encrypting and decrypting this function is 
re-used by both Crypt_Base::encrypt()
+     * and Crypt_Base::decrypt().
+     *
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @param string $plaintext
+     * @param string $encryptIV
+     * @param array $buffer
+     * @return string
+     * @access private
+     */
+    function _openssl_ofb_process($plaintext, &$encryptIV, &$buffer)
+    {
+        if (strlen($buffer['xor'])) {
+            $ciphertext = $plaintext ^ $buffer['xor'];
+            $buffer['xor'] = substr($buffer['xor'], strlen($ciphertext));
+            $plaintext = substr($plaintext, strlen($ciphertext));
+        } else {
+            $ciphertext = '';
+        }
+
+        $block_size = $this->block_size;
+
+        $len = strlen($plaintext);
+        $key = $this->key;
+        $overflow = $len % $block_size;
+
+        if (strlen($plaintext)) {
+            if ($overflow) {
+                $ciphertext.= openssl_encrypt(substr($plaintext, 0, 
-$overflow) . str_repeat("\0", $block_size), $this->cipher_name_openssl, $key, 
$this->openssl_options, $encryptIV);
+                $xor = $this->_string_pop($ciphertext, $block_size);
+                if ($this->continuousBuffer) {
+                    $encryptIV = $xor;
+                }
+                $ciphertext.= $this->_string_shift($xor, $overflow) ^ 
substr($plaintext, -$overflow);
+                if ($this->continuousBuffer) {
+                    $buffer['xor'] = $xor;
+                }
+            } else {
+                $ciphertext = openssl_encrypt($plaintext, 
$this->cipher_name_openssl, $key, $this->openssl_options, $encryptIV);
+                if ($this->continuousBuffer) {
+                    $encryptIV = substr($ciphertext, -$block_size) ^ 
substr($plaintext, -$block_size);
+                }
+            }
+        }
+
+        return $ciphertext;
+    }
+
+    /**
+     * phpseclib <-> OpenSSL Mode Mapper
+     *
+     * May need to be overwritten by classes extending this one in some cases
+     *
+     * @return int
+     * @access private
+     */
+    function _openssl_translate_mode()
+    {
+        switch ($this->mode) {
+            case CRYPT_MODE_ECB:
+                return 'ecb';
+            case CRYPT_MODE_CBC:
+                return 'cbc';
+            case CRYPT_MODE_CTR:
+                return 'ctr';
+            case CRYPT_MODE_CFB:
+                return 'cfb';
+            case CRYPT_MODE_OFB:
+                return 'ofb';
+        }
+    }
+
+    /**
+     * Pad "packets".
+     *
+     * Block ciphers working by encrypting between their specified 
[$this->]block_size at a time
+     * 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 self::disablePadding()
+     * @access public
+     */
+    function enablePadding()
+    {
+        $this->padding = true;
+    }
+
+    /**
+     * Do not pad packets.
+     *
+     * @see self::enablePadding()
+     * @access public
+     */
+    function disablePadding()
+    {
+        $this->padding = false;
+    }
+
+    /**
+     * 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 $rijndael->decrypt($rijndael->encrypt(substr($plaintext, 16, 
16)));
+     * </code>
+     * <code>
+     *    echo $rijndael->decrypt($rijndael->encrypt(substr($plaintext, 16, 
16)));
+     * </code>
+     *
+     * With the continuous buffer disabled, these would yield the same output. 
 With it enabled, they yield different
+     * outputs.  The reason is due to the fact that the initialization 
vector's change after every encryption /
+     * decryption round when the continuous buffer is enabled.  When it's 
disabled, they remain constant.
+     *
+     * Put another way, when the continuous buffer is enabled, the state of 
the Crypt_*() object changes after each
+     * encryption / decryption round, whereas otherwise, it'd remain constant. 
 For this reason, it's recommended that
+     * continuous buffers not be used.  They do offer better security and are, 
in fact, sometimes required (SSH uses them),
+     * however, they are also less intuitive and more likely to cause you 
problems.
+     *
+     * @see self::disableContinuousBuffer()
+     * @access public
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function enableContinuousBuffer()
+    {
+        if ($this->mode == CRYPT_MODE_ECB) {
+            return;
+        }
+
+        $this->continuousBuffer = true;
+
+        $this->_setEngine();
+    }
+
+    /**
+     * Treat consecutive packets as if they are a discontinuous buffer.
+     *
+     * The default behavior.
+     *
+     * @see self::enableContinuousBuffer()
+     * @access public
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function disableContinuousBuffer()
+    {
+        if ($this->mode == CRYPT_MODE_ECB) {
+            return;
+        }
+        if (!$this->continuousBuffer) {
+            return;
+        }
+
+        $this->continuousBuffer = false;
+        $this->changed = true;
+
+        $this->_setEngine();
+    }
+
+    /**
+     * Test for engine validity
+     *
+     * @see self::Crypt_Base()
+     * @param int $engine
+     * @access public
+     * @return bool
+     */
+    function isValidEngine($engine)
+    {
+        switch ($engine) {
+            case CRYPT_ENGINE_OPENSSL:
+                if ($this->mode == CRYPT_MODE_STREAM && 
$this->continuousBuffer) {
+                    return false;
+                }
+                $this->openssl_emulate_ctr = false;
+                $result = $this->cipher_name_openssl &&
+                          extension_loaded('openssl') &&
+                          // PHP 5.3.0 - 5.3.2 did not let you set IV's
+                          version_compare(PHP_VERSION, '5.3.3', '>=');
+                if (!$result) {
+                    return false;
+                }
+
+                // prior to PHP 5.4.0 OPENSSL_RAW_DATA and 
OPENSSL_ZERO_PADDING were not defined. instead of expecting an integer
+                // $options openssl_encrypt expected a boolean $raw_data.
+                if (!defined('OPENSSL_RAW_DATA')) {
+                    $this->openssl_options = true;
+                } else {
+                    $this->openssl_options = OPENSSL_RAW_DATA | 
OPENSSL_ZERO_PADDING;
+                }
+
+                $methods = openssl_get_cipher_methods();
+                if (in_array($this->cipher_name_openssl, $methods)) {
+                    return true;
+                }
+                // not all of openssl's symmetric cipher's support ctr. for 
those
+                // that don't we'll emulate it
+                switch ($this->mode) {
+                    case CRYPT_MODE_CTR:
+                        if (in_array($this->cipher_name_openssl_ecb, 
$methods)) {
+                            $this->openssl_emulate_ctr = true;
+                            return true;
+                        }
+                }
+                return false;
+            case CRYPT_ENGINE_MCRYPT:
+                return $this->cipher_name_mcrypt &&
+                       extension_loaded('mcrypt') &&
+                       in_array($this->cipher_name_mcrypt, 
@mcrypt_list_algorithms());
+            case CRYPT_ENGINE_INTERNAL:
+                return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Sets the preferred crypt engine
+     *
+     * Currently, $engine could be:
+     *
+     * - CRYPT_ENGINE_OPENSSL  [very fast]
+     *
+     * - CRYPT_ENGINE_MCRYPT   [fast]
+     *
+     * - CRYPT_ENGINE_INTERNAL [slow]
+     *
+     * If the preferred crypt engine is not available the fastest available 
one will be used
+     *
+     * @see self::Crypt_Base()
+     * @param int $engine
+     * @access public
+     */
+    function setPreferredEngine($engine)
+    {
+        switch ($engine) {
+            //case CRYPT_ENGINE_OPENSSL:
+            case CRYPT_ENGINE_MCRYPT:
+            case CRYPT_ENGINE_INTERNAL:
+                $this->preferredEngine = $engine;
+                break;
+            default:
+                $this->preferredEngine = CRYPT_ENGINE_OPENSSL;
+        }
+
+        $this->_setEngine();
+    }
+
+    /**
+     * Returns the engine currently being utilized
+     *
+     * @see self::_setEngine()
+     * @access public
+     */
+    function getEngine()
+    {
+        return $this->engine;
+    }
+
+    /**
+     * Sets the engine as appropriate
+     *
+     * @see self::Crypt_Base()
+     * @access private
+     */
+    function _setEngine()
+    {
+        $this->engine = null;
+
+        $candidateEngines = array(
+            $this->preferredEngine,
+            CRYPT_ENGINE_OPENSSL,
+            CRYPT_ENGINE_MCRYPT
+        );
+        foreach ($candidateEngines as $engine) {
+            if ($this->isValidEngine($engine)) {
+                $this->engine = $engine;
+                break;
+            }
+        }
+        if (!$this->engine) {
+            $this->engine = CRYPT_ENGINE_INTERNAL;
+        }
+
+        if ($this->engine != CRYPT_ENGINE_MCRYPT && $this->enmcrypt) {
+            // Closing the current mcrypt resource(s). _mcryptSetup() will, if 
needed,
+            // (re)open them with the module named in $this->cipher_name_mcrypt
+            @mcrypt_module_close($this->enmcrypt);
+            @mcrypt_module_close($this->demcrypt);
+            $this->enmcrypt = null;
+            $this->demcrypt = null;
+
+            if ($this->ecb) {
+                @mcrypt_module_close($this->ecb);
+                $this->ecb = null;
+            }
+        }
+
+        $this->changed = true;
+    }
+
+    /**
+     * Encrypts a block
+     *
+     * @access private
+     * @param string $in
+     * @return string
+     * @internal Must be extended by the child Crypt_* class
+     */
+    function _encryptBlock($in)
+    {
+        user_error((version_compare(PHP_VERSION, '5.0.0', '>=')  ? __METHOD__ 
: __FUNCTION__)  . '() must extend by class ' . get_class($this), E_USER_ERROR);
+    }
+
+    /**
+     * Decrypts a block
+     *
+     * @access private
+     * @param string $in
+     * @return string
+     * @internal Must be extended by the child Crypt_* class
+     */
+    function _decryptBlock($in)
+    {
+        user_error((version_compare(PHP_VERSION, '5.0.0', '>=')  ? __METHOD__ 
: __FUNCTION__)  . '() must extend by class ' . get_class($this), E_USER_ERROR);
+    }
+
+    /**
+     * Setup the key (expansion)
+     *
+     * Only used if $engine == CRYPT_ENGINE_INTERNAL
+     *
+     * @see self::_setup()
+     * @access private
+     * @internal Must be extended by the child Crypt_* class
+     */
+    function _setupKey()
+    {
+        user_error((version_compare(PHP_VERSION, '5.0.0', '>=')  ? __METHOD__ 
: __FUNCTION__)  . '() must extend by class ' . get_class($this), E_USER_ERROR);
+    }
+
+    /**
+     * Setup the CRYPT_ENGINE_INTERNAL $engine
+     *
+     * (re)init, if necessary, the internal cipher $engine and flush all 
$buffers
+     * Used (only) if $engine == CRYPT_ENGINE_INTERNAL
+     *
+     * _setup() will be called each time if $changed === true
+     * typically this happens when using one or more of following public 
methods:
+     *
+     * - setKey()
+     *
+     * - setIV()
+     *
+     * - disableContinuousBuffer()
+     *
+     * - First run of encrypt() / decrypt() with no init-settings
+     *
+     * @see self::setKey()
+     * @see self::setIV()
+     * @see self::disableContinuousBuffer()
+     * @access private
+     * @internal _setup() is always called before en/decryption.
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function _setup()
+    {
+        $this->_clearBuffers();
+        $this->_setupKey();
+
+        if ($this->use_inline_crypt) {
+            $this->_setupInlineCrypt();
+        }
+    }
+
+    /**
+     * Setup the CRYPT_ENGINE_MCRYPT $engine
+     *
+     * (re)init, if necessary, the (ext)mcrypt resources and flush all $buffers
+     * Used (only) if $engine = CRYPT_ENGINE_MCRYPT
+     *
+     * _setupMcrypt() will be called each time if $changed === true
+     * typically this happens when using one or more of following public 
methods:
+     *
+     * - setKey()
+     *
+     * - setIV()
+     *
+     * - disableContinuousBuffer()
+     *
+     * - First run of encrypt() / decrypt()
+     *
+     * @see self::setKey()
+     * @see self::setIV()
+     * @see self::disableContinuousBuffer()
+     * @access private
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function _setupMcrypt()
+    {
+        $this->_clearBuffers();
+        $this->enchanged = $this->dechanged = true;
+
+        if (!isset($this->enmcrypt)) {
+            static $mcrypt_modes = array(
+                CRYPT_MODE_CTR    => 'ctr',
+                CRYPT_MODE_ECB    => MCRYPT_MODE_ECB,
+                CRYPT_MODE_CBC    => MCRYPT_MODE_CBC,
+                CRYPT_MODE_CFB    => 'ncfb',
+                CRYPT_MODE_OFB    => MCRYPT_MODE_NOFB,
+                CRYPT_MODE_STREAM => MCRYPT_MODE_STREAM,
+            );
+
+            $this->demcrypt = @mcrypt_module_open($this->cipher_name_mcrypt, 
'', $mcrypt_modes[$this->mode], '');
+            $this->enmcrypt = @mcrypt_module_open($this->cipher_name_mcrypt, 
'', $mcrypt_modes[$this->mode], '');
+
+            // we need the $ecb mcrypt resource (only) in MODE_CFB with 
enableContinuousBuffer()
+            // to workaround mcrypt's broken ncfb implementation in buffered 
mode
+            // see: {@link http://phpseclib.sourceforge.net/cfb-demo.phps}
+            if ($this->mode == CRYPT_MODE_CFB) {
+                $this->ecb = @mcrypt_module_open($this->cipher_name_mcrypt, 
'', MCRYPT_MODE_ECB, '');
+            }
+        } // else should mcrypt_generic_deinit be called?
+
+        if ($this->mode == CRYPT_MODE_CFB) {
+            @mcrypt_generic_init($this->ecb, $this->key, str_repeat("\0", 
$this->block_size));
+        }
+    }
+
+    /**
+     * Pads a string
+     *
+     * Pads a string using the RSA PKCS padding standards so that its length 
is a multiple of the blocksize.
+     * $this->block_size - (strlen($text) % $this->block_size) bytes are 
added, each of which is equal to
+     * chr($this->block_size - (strlen($text) % $this->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 self::_unpad()
+     * @param string $text
+     * @access private
+     * @return string
+     */
+    function _pad($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 self::_pad()
+     * @param string $text
+     * @access private
+     * @return string
+     */
+    function _unpad($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);
+    }
+
+    /**
+     * Clears internal buffers
+     *
+     * Clearing/resetting the internal buffers is done everytime
+     * after disableContinuousBuffer() or on cipher $engine (re)init
+     * ie after setKey() or setIV()
+     *
+     * @access public
+     * @internal Could, but not must, extend by the child Crypt_* class
+     */
+    function _clearBuffers()
+    {
+        $this->enbuffer = $this->debuffer = array('ciphertext' => '', 'xor' => 
'', 'pos' => 0, 'enmcrypt_init' => true);
+
+        // mcrypt's handling of invalid's $iv:
+        // $this->encryptIV = $this->decryptIV = strlen($this->iv) == 
$this->block_size ? $this->iv : str_repeat("\0", $this->block_size);
+        $this->encryptIV = $this->decryptIV = str_pad(substr($this->iv, 0, 
$this->block_size), $this->block_size, "\0");
+
+        if (!$this->skip_key_adjustment) {
+            $this->key = str_pad(substr($this->key, 0, $this->key_length), 
$this->key_length, "\0");
+        }
+    }
+
+    /**
+     * String Shift
+     *
+     * Inspired by array_shift
+     *
+     * @param string $string
+     * @param int $index
+     * @access private
+     * @return string
+     */
+    function _string_shift(&$string, $index = 1)
+    {
+        $substr = substr($string, 0, $index);
+        $string = substr($string, $index);
+        return $substr;
+    }
+
+    /**
+     * String Pop
+     *
+     * Inspired by array_pop
+     *
+     * @param string $string
+     * @param int $index
+     * @access private
+     * @return string
+     */
+    function _string_pop(&$string, $index = 1)
+    {
+        $substr = substr($string, -$index);
+        $string = substr($string, 0, -$index);
+        return $substr;
+    }
+
+    /**
+     * Increment the current string
+     *
+     * @see self::decrypt()
+     * @see self::encrypt()
+     * @param string $var
+     * @access private
+     */
+    function _increment_str(&$var)
+    {
+        for ($i = 4; $i <= strlen($var); $i+= 4) {
+            $temp = substr($var, -$i, 4);
+            switch ($temp) {
+                case "\xFF\xFF\xFF\xFF":
+                    $var = substr_replace($var, "\x00\x00\x00\x00", -$i, 4);
+                    break;
+                case "\x7F\xFF\xFF\xFF":
+                    $var = substr_replace($var, "\x80\x00\x00\x00", -$i, 4);
+                    return;
+                default:
+                    $temp = unpack('Nnum', $temp);
+                    $var = substr_replace($var, pack('N', $temp['num'] + 1), 
-$i, 4);
+                    return;
+            }
+        }
+
+        $remainder = strlen($var) % 4;
+
+        if ($remainder == 0) {
+            return;
+        }
+
+        $temp = unpack('Nnum', str_pad(substr($var, 0, $remainder), 4, "\0", 
STR_PAD_LEFT));
+        $temp = substr(pack('N', $temp['num'] + 1), -$remainder);
+        $var = substr_replace($var, $temp, 0, $remainder);
+    }
+
+    /**
+     * Setup the performance-optimized function for de/encrypt()
+     *
+     * Stores the created (or existing) callback function-name
+     * in $this->inline_crypt
+     *
+     * Internally for phpseclib developers:
+     *
+     *     _setupInlineCrypt() would be called only if:
+     *
+     *     - $engine == CRYPT_ENGINE_INTERNAL and
+     *
+     *     - $use_inline_crypt === true
+     *
+     *     - each time on _setup(), after(!) _setupKey()
+     *
+     *
+     *     This ensures that _setupInlineCrypt() has always a
+     *     full ready2go initializated internal cipher $engine state
+     *     where, for example, the keys allready expanded,
+     *     keys/block_size calculated and such.
+     *
+     *     It is, each time if called, the responsibility of 
_setupInlineCrypt():
+     *
+     *     - to set $this->inline_crypt to a valid and fully working callback 
function
+     *       as a (faster) replacement for encrypt() / decrypt()
+     *
+     *     - NOT to create unlimited callback functions (for memory reasons!)
+     *       no matter how often _setupInlineCrypt() would be called. At some
+     *       point of amount they must be generic re-useable.
+     *
+     *     - the code of _setupInlineCrypt() it self,
+     *       and the generated callback code,
+     *       must be, in following order:
+     *       - 100% safe
+     *       - 100% compatible to encrypt()/decrypt()
+     *       - using only php5+ features/lang-constructs/php-extensions if
+     *         compatibility (down to php4) or fallback is provided
+     *       - readable/maintainable/understandable/commented and... 
not-cryptic-styled-code :-)
+     *       - >= 10% faster than encrypt()/decrypt() [which is, by the way,
+     *         the reason for the existence of _setupInlineCrypt() :-)]
+     *       - memory-nice
+     *       - short (as good as possible)
+     *
+     * Note: - _setupInlineCrypt() is using _createInlineCryptFunction() to 
create the full callback function code.
+     *       - In case of using inline crypting, _setupInlineCrypt() must 
extend by the child Crypt_* class.
+     *       - The following variable names are reserved:
+     *         - $_*  (all variable names prefixed with an underscore)
+     *         - $self (object reference to it self. Do not use $this, but 
$self instead)
+     *         - $in (the content of $in has to en/decrypt by the generated 
code)
+     *       - The callback function should not use the 'return' statement, 
but en/decrypt'ing the content of $in only
+     *
+     *
+     * @see self::_setup()
+     * @see self::_createInlineCryptFunction()
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @access private
+     * @internal If a Crypt_* class providing inline crypting it must extend 
_setupInlineCrypt()
+     */
+    function _setupInlineCrypt()
+    {
+        // If, for any reason, an extending Crypt_Base() Crypt_* class
+        // not using inline crypting then it must be ensured that: 
$this->use_inline_crypt = false
+        // ie in the class var declaration of $use_inline_crypt in general for 
the Crypt_* class,
+        // in the constructor at object instance-time
+        // or, if it's runtime-specific, at runtime
+
+        $this->use_inline_crypt = false;
+    }
+
+    /**
+     * Creates the performance-optimized function for en/decrypt()
+     *
+     * Internally for phpseclib developers:
+     *
+     *    _createInlineCryptFunction():
+     *
+     *    - merge the $cipher_code [setup'ed by _setupInlineCrypt()]
+     *      with the current [$this->]mode of operation code
+     *
+     *    - create the $inline function, which called by encrypt() / decrypt()
+     *      as its replacement to speed up the en/decryption operations.
+     *
+     *    - return the name of the created $inline callback function
+     *
+     *    - used to speed up en/decryption
+     *
+     *
+     *
+     *    The main reason why can speed up things [up to 50%] this way are:
+     *
+     *    - using variables more effective then regular.
+     *      (ie no use of expensive arrays but integers $k_0, $k_1 ...
+     *      or even, for example, the pure $key[] values hardcoded)
+     *
+     *    - avoiding 1000's of function calls of ie _encryptBlock()
+     *      but inlining the crypt operations.
+     *      in the mode of operation for() loop.
+     *
+     *    - full loop unroll the (sometimes key-dependent) rounds
+     *      avoiding this way ++$i counters and runtime-if's etc...
+     *
+     *    The basic code architectur of the generated $inline en/decrypt()
+     *    lambda function, in pseudo php, is:
+     *
+     *    <code>
+     *    
+----------------------------------------------------------------------------------------------+
+     *    | callback $inline = create_function:                                
                          |
+     *    | lambda_function_0001_crypt_ECB($action, $text)                     
                          |
+     *    | {                                                                  
                          |
+     *    |     INSERT PHP CODE OF:                                            
                          |
+     *    |     $cipher_code['init_crypt'];                  // general init 
code.                       |
+     *    |                                                  // ie: $sbox'es 
declarations used for       |
+     *    |                                                  //     encrypt 
and decrypt'ing.             |
+     *    |                                                                    
                          |
+     *    |     switch ($action) {                                             
                          |
+     *    |         case 'encrypt':                                            
                          |
+     *    |             INSERT PHP CODE OF:                                    
                          |
+     *    |             $cipher_code['init_encrypt'];       // encrypt 
sepcific init code.               |
+     *    |                                                    ie: specified 
$key or $box                |
+     *    |                                                        
declarations for encrypt'ing.         |
+     *    |                                                                    
                          |
+     *    |             foreach ($ciphertext) {                                
                          |
+     *    |                 $in = $block_size of $ciphertext;                  
                          |
+     *    |                                                                    
                          |
+     *    |                 INSERT PHP CODE OF:                                
                          |
+     *    |                 $cipher_code['encrypt_block'];  // encrypt's 
(string) $in, which is always:  |
+     *    |                                                 // strlen($in) == 
$this->block_size          |
+     *    |                                                 // here comes the 
cipher algorithm in action |
+     *    |                                                 // for encryption. 
                          |
+     *    |                                                 // 
$cipher_code['encrypt_block'] has to      |
+     *    |                                                 // encrypt the 
content of the $in variable   |
+     *    |                                                                    
                          |
+     *    |                 $plaintext .= $in;                                 
                          |
+     *    |             }                                                      
                          |
+     *    |             return $plaintext;                                     
                          |
+     *    |                                                                    
                          |
+     *    |         case 'decrypt':                                            
                          |
+     *    |             INSERT PHP CODE OF:                                    
                          |
+     *    |             $cipher_code['init_decrypt'];       // decrypt 
sepcific init code                |
+     *    |                                                    ie: specified 
$key or $box                |
+     *    |                                                        
declarations for decrypt'ing.         |
+     *    |             foreach ($plaintext) {                                 
                          |
+     *    |                 $in = $block_size of $plaintext;                   
                          |
+     *    |                                                                    
                          |
+     *    |                 INSERT PHP CODE OF:                                
                          |
+     *    |                 $cipher_code['decrypt_block'];  // decrypt's 
(string) $in, which is always   |
+     *    |                                                 // strlen($in) == 
$this->block_size          |
+     *    |                                                 // here comes the 
cipher algorithm in action |
+     *    |                                                 // for decryption. 
                          |
+     *    |                                                 // 
$cipher_code['decrypt_block'] has to      |
+     *    |                                                 // decrypt the 
content of the $in variable   |
+     *    |                 $ciphertext .= $in;                                
                          |
+     *    |             }                                                      
                          |
+     *    |             return $ciphertext;                                    
                          |
+     *    |     }                                                              
                          |
+     *    | }                                                                  
                          |
+     *    
+----------------------------------------------------------------------------------------------+
+     *    </code>
+     *
+     *    See also the Crypt_*::_setupInlineCrypt()'s for
+     *    productive inline $cipher_code's how they works.
+     *
+     *    Structure of:
+     *    <code>
+     *    $cipher_code = array(
+     *        'init_crypt'    => (string) '', // optional
+     *        'init_encrypt'  => (string) '', // optional
+     *        'init_decrypt'  => (string) '', // optional
+     *        'encrypt_block' => (string) '', // required
+     *        'decrypt_block' => (string) ''  // required
+     *    );
+     *    </code>
+     *
+     * @see self::_setupInlineCrypt()
+     * @see self::encrypt()
+     * @see self::decrypt()
+     * @param array $cipher_code
+     * @access private
+     * @return string (the name of the created callback function)
+     */
+    function _createInlineCryptFunction($cipher_code)
+    {
+        $block_size = $this->block_size;
+
+        // optional
+        $init_crypt    = isset($cipher_code['init_crypt'])    ? 
$cipher_code['init_crypt']    : '';
+        $init_encrypt  = isset($cipher_code['init_encrypt'])  ? 
$cipher_code['init_encrypt']  : '';
+        $init_decrypt  = isset($cipher_code['init_decrypt'])  ? 
$cipher_code['init_decrypt']  : '';
+        // required
+        $encrypt_block = $cipher_code['encrypt_block'];
+        $decrypt_block = $cipher_code['decrypt_block'];
+
+        // Generating mode of operation inline code,
+        // merged with the $cipher_code algorithm
+        // for encrypt- and decryption.
+        switch ($this->mode) {
+            case CRYPT_MODE_ECB:
+                $encrypt = $init_encrypt . '
+                    $_ciphertext = "";
+                    $_plaintext_len = strlen($_text);
+
+                    for ($_i = 0; $_i < $_plaintext_len; $_i+= 
'.$block_size.') {
+                        $in = substr($_text, $_i, '.$block_size.');
+                        '.$encrypt_block.'
+                        $_ciphertext.= $in;
+                    }
+
+                    return $_ciphertext;
+                    ';
+
+                $decrypt = $init_decrypt . '
+                    $_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.');
+                        '.$decrypt_block.'
+                        $_plaintext.= $in;
+                    }
+
+                    return $self->_unpad($_plaintext);
+                    ';
+                break;
+            case CRYPT_MODE_CTR:
+                $encrypt = $init_encrypt . '
+                    $_ciphertext = "";
+                    $_plaintext_len = strlen($_text);
+                    $_xor = $self->encryptIV;
+                    $_buffer = &$self->enbuffer;
+                    if (strlen($_buffer["ciphertext"])) {
+                        for ($_i = 0; $_i < $_plaintext_len; $_i+= 
'.$block_size.') {
+                            $_block = substr($_text, $_i, '.$block_size.');
+                            if (strlen($_block) > 
strlen($_buffer["ciphertext"])) {
+                                $in = $_xor;
+                                '.$encrypt_block.'
+                                $self->_increment_str($_xor);
+                                $_buffer["ciphertext"].= $in;
+                            }
+                            $_key = 
$self->_string_shift($_buffer["ciphertext"], '.$block_size.');
+                            $_ciphertext.= $_block ^ $_key;
+                        }
+                    } else {

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