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tgseclib/phpseclib/Crypt/Base.php

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Crypt_Base Crypt_Base() implementation
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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
/**
* Base Class for all Crypt_* cipher classes
*
* PHP versions 4 and 5
*
* 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 <terrafrost@php.net>
* @author Hans-Juergen Petrich <petrich@tronic-media.com>
* @copyright MMVII Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @version 1.0
* @link http://phpseclib.sourceforge.net
*/
/**#@+
* @access public
* @see Crypt_Base::encrypt()
* @see Crypt_Base::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);
/**
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* Encrypt / decrypt using streaming mode.
*
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*/
define('CRYPT_MODE_STREAM', 5);
/**#@-*/
/**#@+
* @access private
* @see Crypt_Base::Crypt_Base()
*/
/**
* Base value for the internal implementation $engine switch
*/
define('CRYPT_MODE_INTERNAL', 1);
/**
* Base value for the mcrypt implementation $engine switch
*/
define('CRYPT_MODE_MCRYPT', 2);
/**#@-*/
/**
* Base Class for all Crypt_* cipher classes
*
* @author Jim Wigginton <terrafrost@php.net>
* @author Hans-Juergen Petrich <petrich@tronic-media.com>
* @version 1.0.0
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* @access public
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* @package Crypt_Base
*/
class Crypt_Base {
/**
* The Encryption Mode
*
* @see Crypt_Base::Crypt_Base()
* @var Integer
* @access private
*/
var $mode;
/**
* The Block Length of the block cipher
*
* @var Integer
* @access private
*/
var $block_size = 16;
/**
* The Key
*
* @see Crypt_Base::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_Base::setIV()
* @var String
* @access private
*/
var $iv;
/**
* A "sliding" Initialization Vector
*
* @see Crypt_Base::enableContinuousBuffer()
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* @see Crypt_Base::_clearBuffers()
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* @var String
* @access private
*/
var $encryptIV;
/**
* A "sliding" Initialization Vector
*
* @see Crypt_Base::enableContinuousBuffer()
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* @see Crypt_Base::_clearBuffers()
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* @var String
* @access private
*/
var $decryptIV;
/**
* Continuous Buffer status
*
* @see Crypt_Base::enableContinuousBuffer()
* @var Boolean
* @access private
*/
var $continuousBuffer = false;
/**
* Encryption buffer for CTR, OFB and CFB modes
*
* @see Crypt_Base::encrypt()
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* @see Crypt_Base::_clearBuffers()
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* @var Array
* @access private
*/
var $enbuffer;
/**
* Decryption buffer for CTR, OFB and CFB modes
*
* @see Crypt_Base::decrypt()
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* @see Crypt_Base::_clearBuffers()
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* @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 Crypt_Base::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 Crypt_Base::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 Boolean
* @access private
*/
var $enchanged = true;
/**
* Does the demcrypt resource need to be (re)initialized?
*
* @see Crypt_Twofish::setKey()
* @see Crypt_Twofish::setIV()
* @var Boolean
* @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 Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
* @see Crypt_Base::_mcryptSetup()
* @var Resource
* @access private
*/
var $ecb;
/**
* Optimizing value while CFB-encrypting
*
* Only relevant if $continuousBuffer enabled
* and $engine == CRYPT_MODE_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 choosen 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 Crypt_Base::encrypt()
* @var Integer
* @access private
*/
var $cfb_init_len = 600;
/**
* Does internal cipher state need to be (re)initialized?
*
* @see setKey()
* @see setIV()
* @see disableContinuousBuffer()
* @var Boolean
* @access private
*/
var $changed = true;
/**
* Padding status
*
* @see Crypt_Base::enablePadding()
* @var Boolean
* @access private
*/
var $padding = true;
/**
* Is the mode one that is paddable?
*
* @see Crypt_Base::Crypt_Base()
* @var Boolean
* @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_MODE_MCRYPT (fast, php-extension: mcrypt, extension_loaded('mcrypt') required)
* - CRYPT_MODE_INTERNAL (slower, pure php-engine, no php-extension required)
*
* In the pipeline... maybe. But currently not available:
* - CRYPT_MODE_OPENSSL (very fast, php-extension: openssl, extension_loaded('openssl') required)
*
* If possible, CRYPT_MODE_MCRYPT will be used for each cipher.
* Otherwise CRYPT_MODE_INTERNAL
*
* @see Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
* @var Integer
* @access private
*/
var $engine;
/**
* The mcrypt specific name of the cipher
*
* Only used if $engine == CRYPT_MODE_MCRYPT
*
* @link http://www.php.net/mcrypt_module_open
* @link http://www.php.net/mcrypt_list_algorithms
* @see Crypt_Base::_mcryptSetup()
* @var String
* @access private
*/
var $cipher_name_mcrypt;
/**
* The default password key_size used by setPassword()
*
* @see Crypt_Base::setPassword()
* @var Integer
* @access private
*/
var $password_key_size = 32;
/**
* The default salt used by setPassword()
*
* @see Crypt_Base::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 Crypt_Base::Crypt_Base()
* @var String
* @access private
*/
var $const_namespace;
/**
* The name of the performance-optimized callback function
*
* Used by encrypt() / decrypt()
* only if $engine == CRYPT_MODE_INTERNAL
*
* @see Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
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* @see Crypt_Base::_inlineCryptSetup()
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* @see Crypt_Base::$use_inline_crypt
* @var Callback
* @access private
*/
var $inline_crypt;
/**
* Holds whether performance-optimized $inline_crypt() can/should be used.
*
* @see Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
* @see Crypt_Base::inline_crypt
* @var mixed
* @access private
*/
var $use_inline_crypt;
/**
* 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 choosen cipher, for example for AES: CRYPT_AES_MODE_ECB or CRYPT_AES_MODE_CBC ...)
*
* If not explictly set, CRYPT_MODE_CBC will be used.
*
* @param optional Integer $mode
* @access public
*/
function Crypt_Base($mode = CRYPT_MODE_CBC)
{
$const_crypt_mode = 'CRYPT_' . $this->const_namespace . '_MODE';
// Determining the availibility of mcrypt support for the cipher
if (!defined($const_crypt_mode)) {
switch (true) {
case extension_loaded('mcrypt') && in_array($this->cipher_name_mcrypt, mcrypt_list_algorithms()):
define($const_crypt_mode, CRYPT_MODE_MCRYPT);
break;
default:
define($const_crypt_mode, CRYPT_MODE_INTERNAL);
}
}
// Determining which internal $engine should be used.
// The fastes possible first.
switch (true) {
case empty($this->cipher_name_mcrypt): // The cipher module has no mcrypt-engine support at all so we force CRYPT_MODE_INTERNAL
$this->engine = CRYPT_MODE_INTERNAL;
break;
case constant($const_crypt_mode) == CRYPT_MODE_MCRYPT:
$this->engine = CRYPT_MODE_MCRYPT;
break;
default:
$this->engine = CRYPT_MODE_INTERNAL;
}
// $mode dependent settings
switch ($mode) {
case CRYPT_MODE_ECB:
$this->paddable = true;
$this->mode = $mode;
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;
$this->mode = CRYPT_MODE_CBC;
}
// Determining whether inline crypting can be used by the cipher
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if ($this->use_inline_crypt !== false && function_exists('create_function')) {
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$this->use_inline_crypt = true;
}
}
/**
* 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 explictly set, it'll be assumed
* to be all zero's.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @access public
* @param String $iv
*/
function setIV($iv)
{
if ($this->mode == CRYPT_MODE_ECB) {
return;
}
if ($this->iv === $iv) {
return;
}
$this->iv = $iv;
$this->changed = true;
}
/**
* 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.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @access public
* @param String $key
*/
function setKey($key)
{
if ($this->key === $key) {
return;
}
$this->key = $key;
$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, $count, $dkLen
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @param String $password
* @param optional String $method
* @access public
*/
function setPassword($password, $method = 'pbkdf2')
{
$key = '';
switch ($method) {
default: // 'pbkdf2'
$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
$dkLen = isset($func_args[5]) ? $func_args[5] : $this->password_key_size;
if (!class_exists('Crypt_Hash')) {
require_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;
}
}
$this->setKey(substr($key, 0, $dkLen));
}
/**
* 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.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see Crypt_Base::decrypt()
* @access public
* @param String $plaintext
* @return String $cipertext
*/
function encrypt($plaintext)
{
if ($this->engine == CRYPT_MODE_MCRYPT) {
if ($this->changed) {
$this->_mcryptSetup();
$this->changed = false;
}
if ($this->enchanged) {
mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
$this->enchanged = false;
}
// re: http://phpseclib.sourceforge.net/cfb-demo.phps
// using mcrypt's default handing of CFB the above would output two different things. using phpseclib's
// rewritten CFB implementation the above outputs the same thing twice.
if ($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 $ciphertext;
}
if ($this->paddable) {
$plaintext = $this->_pad($plaintext);
}
$ciphertext = mcrypt_generic($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, $plaintext);
}
if ($this->paddable) {
$plaintext = $this->_pad($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['encrypted'])) {
for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
$block = substr($plaintext, $i, $block_size);
if (strlen($block) > strlen($buffer['encrypted'])) {
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$buffer['encrypted'].= $this->_encryptBlock($this->_generateXor($block_size, $xor));
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}
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$key = $this->_stringShift($buffer['encrypted'], $block_size);
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$ciphertext.= $block ^ $key;
}
} else {
for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
$block = substr($plaintext, $i, $block_size);
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$key = $this->_encryptBlock($this->_generateXor($block_size, $xor));
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$ciphertext.= $block ^ $key;
}
}
if ($this->continuousBuffer) {
$this->encryptIV = $xor;
if ($start = strlen($plaintext) % $block_size) {
$buffer['encrypted'] = substr($key, $start) . $buffer['encrypted'];
}
}
break;
case CRYPT_MODE_CFB:
// cfb loosely routines inspired by openssl's:
// http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1
if ($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_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'].= $xor;
}
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$key = $this->_stringShift($buffer['xor'], $block_size);
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$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.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see Crypt_Base::encrypt()
* @access public
* @param String $ciphertext
* @return String $plaintext
*/
function decrypt($ciphertext)
{
if ($this->engine == CRYPT_MODE_MCRYPT) {
$block_size = $this->block_size;
if ($this->changed) {
$this->_mcryptSetup();
$this->changed = false;
}
if ($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 $plaintext;
}
if ($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($ciphertext) + ($block_size - strlen($ciphertext) % $block_size) % $block_size, chr(0));
}
$plaintext = mdecrypt_generic($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 = $this->block_size;
if ($this->paddable) {
// we pad with chr(0) since that's what mcrypt_generic does [...]
$ciphertext = str_pad($ciphertext, strlen($ciphertext) + ($block_size - strlen($ciphertext) % $block_size) % $block_size, chr(0));
}
$buffer = &$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($buffer['ciphertext'])) {
CS and method namings
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$buffer['ciphertext'].= $this->_encryptBlock($this->_generateXor($block_size, $xor));
Crypt_Base Crypt_Base() implementation
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}
CS and method namings
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$key = $this->_stringShift($buffer['ciphertext'], $block_size);
Crypt_Base Crypt_Base() implementation
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$plaintext.= $block ^ $key;
}
} else {
for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
$block = substr($ciphertext, $i, $block_size);
CS and method namings
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$key = $this->_encryptBlock($this->_generateXor($block_size, $xor));
Crypt_Base Crypt_Base() implementation
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$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'].= $xor;
}
CS and method namings
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$key = $this->_stringShift($buffer['xor'], $block_size);
Crypt_Base Crypt_Base() implementation
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$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) : $plaintext;
}
CS and method namings
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/**
* Pad "packets".
*
* Block ciphers working by encrypting between their specified [$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 Crypt_Base::disablePadding()
* @access public
*/
function enablePadding()
{
$this->padding = true;
}
/**
* Do not pad packets.
*
* @see Crypt_Base::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($plaintext, 16, 16)));
* </code>
*
* With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different
* outputs. The reason is due to the fact that the initialization vector's change after every encryption /
* decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.
*
* Put another way, when the continuous buffer is enabled, the state of the Crypt_*() object changes after each
* encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that
* continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),
* however, they are also less intuitive and more likely to cause you problems.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see Crypt_Base::disableContinuousBuffer()
* @access public
*/
function enableContinuousBuffer()
{
if ($this->mode == CRYPT_MODE_ECB) {
return;
}
$this->continuousBuffer = true;
}
/**
* Treat consecutive packets as if they are a discontinuous buffer.
*
* The default behavior.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see Crypt_Base::enableContinuousBuffer()
* @access public
*/
function disableContinuousBuffer()
{
if ($this->mode == CRYPT_MODE_ECB) {
return;
}
if (!$this->continuousBuffer) {
return;
}
$this->continuousBuffer = false;
$this->changed = true;
}
Crypt_Base Crypt_Base() implementation
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/**
* Encrypts a block
*
* Note: Must extend by the child Crypt_* class
*
* @access private
* @param String $in
* @return String
*/
function _encryptBlock($in)
{
echo basename(dirname(__FILE__)) . '/' . basename(__FILE__) . ':' . __LINE__ . ' ' . ( version_compare(PHP_VERSION, '5.0.0', '>=') ? __METHOD__ : __FUNCTION__ ) . '() must extend by ' . get_class($this);
}
/**
* Decrypts a block
*
* Note: Must extend by the child Crypt_* class
*
* @access private
* @param String $in
* @return String
*/
function _decryptBlock($in)
{
echo basename(dirname(__FILE__)) . '/' . basename(__FILE__) . ':' . __LINE__ . ' ' . ( version_compare(PHP_VERSION, '5.0.0', '>=') ? __METHOD__ : __FUNCTION__ ) . '() must extend by ' . get_class($this);
}
/**
* Setup the CRYPT_MODE_INTERNAL $engine
*
* (re)init, if necessary, the internal cipher $engine and flush all $buffers
* Used (only) if $engine == CRYPT_MODE_INTERNAL
*
* _setup() will be called each time if $changed === true
* typically this happens when using one or more of following public methods:
* - setKey()
* - setIV()
* - disableContinuousBuffer()
* - First run of encrypt() / decrypt() with no init-settings
*
* Internally: _setup() will, if necessary always called before(!) en/decryption.
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see setKey()
* @see setIV()
* @see disableContinuousBuffer()
* @access private
*/
function _setup()
{
CS and method namings
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$this->_clearBuffers();
Crypt_Base Crypt_Base() implementation
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$this->_setupKey();
if ($this->use_inline_crypt) {
CS and method namings
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$this->_inlineCryptSetup();
Crypt_Base Crypt_Base() implementation
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}
}
/**
* Setup the CRYPT_MODE_MCRYPT $engine
*
* (re)init, if necessary, the (ext)mcrypt resources and flush all $buffers
* Used (only) if $engine = CRYPT_MODE_MCRYPT
*
* _mcryptSetup() will be called each time if $changed === true
* typically this happens when using one or more of following public methods:
* - setKey()
* - setIV()
* - disableContinuousBuffer()
* - First run of encrypt() / decrypt()
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @see setKey()
* @see setIV()
* @see disableContinuousBuffer()
* @access private
*/
function _mcryptSetup()
{
CS and method namings
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$this->_clearBuffers();
Crypt_Base Crypt_Base() implementation
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$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], '');
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));
}
}
/**
* Setup the key (expansion)
*
* Only used if $engine == CRYPT_MODE_INTERNAL
*
* Note: Must extend by the child Crypt_* class
*
* @see Crypt_Base::_setup()
* @access private
*/
function _setupKey()
{
echo basename(dirname(__FILE__)) . '/' . basename(__FILE__) . ':' . __LINE__ . ' ' . ( version_compare(PHP_VERSION, '5.0.0', '>=') ? __METHOD__ : __FUNCTION__ ) . '() must extend by ' . get_class($this);
}
/**
* 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 Crypt_Base::_unpad()
CS and method namings
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* @param String $text
Crypt_Base Crypt_Base() implementation
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* @access private
*/
function _pad($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_Base::_pad()
CS and method namings
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* @param String $text
Crypt_Base Crypt_Base() implementation
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* @access private
*/
function _unpad($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);
}
/**
* Clears internal buffers
*
* Clearing/resetting the internal buffers is done everytime
* after disableContinuousBuffer() or on cipher $engine (re)init
* ie after setKey() or setIV()
*
* Note: Could, but not must, extend by the child Crypt_* class
*
* @access public
*/
CS and method namings
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function _clearBuffers()
Crypt_Base Crypt_Base() implementation
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{
$this->enbuffer = array('encrypted' => '', 'xor' => '', 'pos' => 0, 'enmcrypt_init' => true);
$this->debuffer = array('ciphertext' => '', 'xor' => '', 'pos' => 0, 'demcrypt_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");
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param String $string
* @param optional Integer $index
* @return String
* @access private
*/
CS and method namings
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function _stringShift(&$string, $index = 1)
Crypt_Base Crypt_Base() implementation
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{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
/**
* 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_Base::decrypt()
* @see Crypt_Base::encrypt()
* @access public
* @param Integer $length
* @param String $iv
*/
CS and method namings
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function _generateXor($length, &$iv)
Crypt_Base Crypt_Base() implementation
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{
$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;
}
/**
* Setup the performance-optimized function for de/encrypt()
*
* Stores the created (or existing) callback function-name
* in $this->inline_crypt
*
* Internally for phpseclib developers:
CS and method namings
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*
* _inlineCryptSetup() would be called only if:
*
Crypt_Base Crypt_Base() implementation
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* - $engine == CRYPT_MODE_INTERNAL and
CS and method namings
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*
Crypt_Base Crypt_Base() implementation
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* - $use_inline_crypt === true
CS and method namings
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*
Crypt_Base Crypt_Base() implementation
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* - each time on _setup(), after(!) _setupKey()
*
CS and method namings
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*
* This ensures that _inlineCryptSetup() has allways a
Crypt_Base Crypt_Base() implementation
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* full ready2go initializated internal cipher $engine state
* where, for example, the keys allready expanded,
* keys/block_size calculated and such.
*
CS and method namings
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* It is, each time if called, the responsibility of _inlineCryptSetup():
*
Crypt_Base Crypt_Base() implementation
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* - 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!)
CS and method namings
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* no matter how often _inlineCryptSetup() would be called. At some
Crypt_Base Crypt_Base() implementation
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* point of amount they must be generic re-useable.
*
CS and method namings
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* - the code of _inlineCryptSetup() it self,
Crypt_Base Crypt_Base() implementation
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* 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,
CS and method namings
2013-05-25 04:05:24 +02:00
* the reason for the existence of _inlineCryptSetup() :-)]
Crypt_Base Crypt_Base() implementation
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* - memory-nice
* - short (as good as possible)
*
CS and method namings
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* Note: _inlineCryptSetup() is using _createInlineCryptFunction() to create the full callback function code.
Crypt_Base Crypt_Base() implementation
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*
* Note: In case of using inline crypting, it must extend by the child Crypt_* class
*
* @see Crypt_Base::_setup()
CS and method namings
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* @see Crypt_Base::_createInlineCryptFunction()
Crypt_Base Crypt_Base() implementation
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* @see Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
* @access private
*/
CS and method namings
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function _inlineCryptSetup()
Crypt_Base Crypt_Base() implementation
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{
CS and method namings
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// If a Crypt_* class providing inline crypting it must extend _inlineCryptSetup()
Crypt_Base Crypt_Base() implementation
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// 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:
*
CS and method namings
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* _createInlineCryptFunction():
*
* - merge the $cipher_code [setup'ed by _inlineCryptSetup()]
* with the current [$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
*
*
Crypt_Base Crypt_Base() implementation
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*
* The main reason why can speed up things [up to 50%] this way are:
CS and method namings
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*
Crypt_Base Crypt_Base() implementation
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* - 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:
*
CS and method namings
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* <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. |
* | |
* | $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. |
* | $ciphertext .= $in; |
* | } |
* | return $ciphertext; |
* | } |
* | } |
* +----------------------------------------------------------------------------------------------+
* </code>
*
* See also the Crypt_*::_inlineCryptSetup()'s for
Crypt_Base Crypt_Base() implementation
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* productive inline $cipher_code's how they works.
*
* Structure of:
CS and method namings
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* <code>
Crypt_Base Crypt_Base() implementation
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* $cipher_code = array(
* 'init_crypt' => (string) '', // optional
* 'init_encrypt' => (string) '', // optional
* 'init_decrypt' => (string) '', // optional
* 'encrypt_block' => (string) '', // required
* 'decrypt_block' => (string) '' // required
* );
CS and method namings
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* </code>
Crypt_Base Crypt_Base() implementation
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*
CS and method namings
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* @see Crypt_Base::_inlineCryptSetup()
Crypt_Base Crypt_Base() implementation
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* @see Crypt_Base::encrypt()
* @see Crypt_Base::decrypt()
* @param Array $cipher_code
* @access private
* @return String (the name of the created callback function)
*/
CS and method namings
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function _createInlineCryptFunction($cipher_code)
Crypt_Base Crypt_Base() implementation
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{
$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 = "";
$text = $self->_pad($text);
$plaintext_len = strlen($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($buffer["encrypted"])) {
for ($i = 0; $i < $plaintext_len; $i+= '.$block_size.') {
$block = substr($text, $i, '.$block_size.');
if (strlen($block) > strlen($buffer["encrypted"])) {
CS and method namings
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$in = $self->_generateXor('.$block_size.', $xor);
Crypt_Base Crypt_Base() implementation
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'.$encrypt_block.'
$buffer["encrypted"].= $in;
}
CS and method namings
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$key = $self->_stringShift($buffer["encrypted"], '.$block_size.');
Crypt_Base Crypt_Base() implementation
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$ciphertext.= $block ^ $key;
}
} else {
for ($i = 0; $i < $plaintext_len; $i+= '.$block_size.') {
$block = substr($text, $i, '.$block_size.');
CS and method namings
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$in = $self->_generateXor('.$block_size.', $xor);
Crypt_Base Crypt_Base() implementation
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'.$encrypt_block.'
$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_encrypt . '
$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"])) {
CS and method namings
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$in = $self->_generateXor('.$block_size.', $xor);
Crypt_Base Crypt_Base() implementation
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'.$encrypt_block.'
$buffer["ciphertext"].= $in;
}
CS and method namings
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$key = $self->_stringShift($buffer["ciphertext"], '.$block_size.');
Crypt_Base Crypt_Base() implementation
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$plaintext.= $block ^ $key;
}
} else {
for ($i = 0; $i < $ciphertext_len; $i+= '.$block_size.') {
$block = substr($text, $i, '.$block_size.');
CS and method namings
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$in = $self->_generateXor('.$block_size.', $xor);
Crypt_Base Crypt_Base() implementation
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'.$encrypt_block.'
$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_MODE_CFB:
$encrypt = $init_encrypt . '
$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 = $iv;
'.$encrypt_block.';
$iv = $in ^ substr($text, $i, '.$block_size.');
$ciphertext.= $iv;
$len-= '.$block_size.';
$i+= '.$block_size.';
}
if ($len) {
$in = $iv;
'.$encrypt_block.'
$iv = $in;
$block = $iv ^ substr($text, $i);
$iv = substr_replace($iv, $block, 0, $len);
$ciphertext.= $block;
$pos = $len;
}
return $ciphertext;
';
$decrypt = $init_encrypt . '
$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 = $iv;
'.$encrypt_block.'
$iv = $in;
$cb = substr($text, $i, '.$block_size.');
$plaintext.= $iv ^ $cb;
$iv = $cb;
$len-= '.$block_size.';
$i+= '.$block_size.';
}
if ($len) {
$in = $iv;
'.$encrypt_block.'
$iv = $in;
$plaintext.= $iv ^ substr($text, $i);
$iv = substr_replace($iv, substr($text, $i), 0, $len);
$pos = $len;
}
return $plaintext;
';
break;
case CRYPT_MODE_OFB:
$encrypt = $init_encrypt . '
$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 = $xor;
'.$encrypt_block.'
$xor = $in;
$buffer["xor"].= $xor;
}
CS and method namings
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$key = $self->_stringShift($buffer["xor"], '.$block_size.');
Crypt_Base Crypt_Base() implementation
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$ciphertext.= $block ^ $key;
}
} else {
for ($i = 0; $i < $plaintext_len; $i+= '.$block_size.') {
$in = $xor;
'.$encrypt_block.'
$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_encrypt . '
$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 = $xor;
'.$encrypt_block.'
$xor = $in;
$buffer["xor"].= $xor;
}
CS and method namings
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$key = $self->_stringShift($buffer["xor"], '.$block_size.');
Crypt_Base Crypt_Base() implementation
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$plaintext.= $block ^ $key;
}
} else {
for ($i = 0; $i < $ciphertext_len; $i+= '.$block_size.') {
$in = $xor;
'.$encrypt_block.'
$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;
case CRYPT_MODE_STREAM:
$encrypt = $init_encrypt . '
$ciphertext = "";
'.$encrypt_block.'
return $ciphertext;
';
$decrypt = $init_decrypt . '
$plaintext = "";
'.$decrypt_block.'
return $plaintext;
';
break;
// case CRYPT_MODE_CBC:
default:
$encrypt = $init_encrypt . '
$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.') ^ $in;
'.$encrypt_block.'
$ciphertext.= $in;
}
if ($self->continuousBuffer) {
$self->encryptIV = $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);
$iv = $self->decryptIV;
for ($i = 0; $i < $ciphertext_len; $i+= '.$block_size.') {
$in = $block = substr($text, $i, '.$block_size.');
'.$decrypt_block.'
$plaintext.= $in ^ $iv;
$iv = $block;
}
if ($self->continuousBuffer) {
$self->decryptIV = $iv;
}
return $self->_unpad($plaintext);
';
break;
}
// Create the $inline function and return its name as string. Ready to run!
return create_function('$action, &$self, $text', $init_crypt . 'if ($action == "encrypt") { ' . $encrypt . ' } else { ' . $decrypt . ' }');
}
/**
* Holds the lambda_functions table (classwide)
*
* Each name of the lambda function, created from
CS and method namings
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* _inlineCryptSetup() && _createInlineCryptFunction()
Crypt_Base Crypt_Base() implementation
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* is stored, classwide (!), here for reusing.
*
* The string-based index of $function is a classwide
* uniqe value representing, at least, the $mode of
* operation (or more... depends of the optimizing level)
* for which $mode the lambda function was created.
*
* @return Array
* @access private
*/
CS and method namings
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function &_getLambdaFunctions()
Crypt_Base Crypt_Base() implementation
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{
static $functions = array();
return $functions;
}
/**
* Class destructor.
*
* Will be called, automatically, if you're using PHP5. If you're using PHP4, call it yourself. Only really
* needs to be called if mcrypt is being used.
*
* @access public
*/
function __destruct()
{
if ($this->engine == CRYPT_MODE_MCRYPT) {
if (is_resource($this->enmcrypt)) {
mcrypt_module_close($this->enmcrypt);
}
if (is_resource($this->demcrypt)) {
mcrypt_module_close($this->demcrypt);
}
if (is_resource($this->ecb)) {
mcrypt_module_close($this->ecb);
}
}
}
}
// vim: ts=4:sw=4:et:
// vim6: fdl=1:
Reference in New Issue Copy Permalink