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tgseclib/phpseclib/Crypt/Common/SymmetricKey.php

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<?php
/**
* Base Class for all \phpseclib\Crypt\* cipher classes
*
* PHP version 5
*
* Internally for phpseclib developers:
* If you plan to add a new cipher class, please note following rules:
*
* - The new \phpseclib\Crypt\* cipher class should extend \phpseclib\Crypt\Common\SymmetricKey
*
* - 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 \phpseclib\Crypt\Common\SymmetricKey
* 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
*
* @category Crypt
* @package Base
* @author Jim Wigginton <terrafrost@php.net>
* @author Hans-Juergen Petrich <petrich@tronic-media.com>
* @copyright 2007 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib\Crypt\Common;
use phpseclib\Crypt\Hash;
use phpseclib\Common\Functions\Strings;
use phpseclib\Math\BigInteger;
/**
* Base Class for all \phpseclib\Crypt\* cipher classes
*
* @package Base
* @author Jim Wigginton <terrafrost@php.net>
* @author Hans-Juergen Petrich <petrich@tronic-media.com>
*/
abstract class SymmetricKey
{
/**#@+
* @access public
* @see \phpseclib\Crypt\Common\SymmetricKey::encrypt()
* @see \phpseclib\Crypt\Common\SymmetricKey::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
*/
const 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
*/
const 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
*/
const 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
*/
const 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
*/
const MODE_OFB = 4;
/**
* Encrypt / decrypt using streaming mode.
*/
const MODE_STREAM = 5;
/**#@-*/
/**
* Mode Map
*
* @access private
* @see \phpseclib\Crypt\Common\SymmetricKey::__construct()
*/
const MODE_MAP = [
'ctr' => self::MODE_CTR,
'ecb' => self::MODE_ECB,
'cbc' => self::MODE_CBC,
'cfb' => self::MODE_CFB,
'ofb' => self::MODE_OFB,
'stream' => self::MODE_STREAM
];
/**#@+
* @access private
* @see \phpseclib\Crypt\Common\SymmetricKey::__construct()
*/
/**
* Base value for the internal implementation $engine switch
*/
const ENGINE_INTERNAL = 1;
/**
* Base value for the eval() implementation $engine switch
*/
const ENGINE_EVAL = 2;
/**
* Base value for the mcrypt implementation $engine switch
*/
const ENGINE_MCRYPT = 3;
/**
* Base value for the mcrypt implementation $engine switch
*/
const ENGINE_OPENSSL = 4;
/**#@-*/
/**
* Engine Reverse Map
*
* @access private
* @see \phpseclib\Crypt\Common\SymmetricKey::getEngine()
*/
const ENGINE_MAP = [
self::ENGINE_INTERNAL => 'PHP',
self::ENGINE_EVAL => 'Eval',
self::ENGINE_MCRYPT => 'mcrypt',
self::ENGINE_OPENSSL => 'OpenSSL'
];
/**
* The Encryption Mode
*
* @see self::__construct()
* @var int
* @access private
*/
protected $mode;
/**
* The Block Length of the block cipher
*
* @var int
* @access private
*/
protected $block_size = 16;
/**
* The Key
*
* @see self::setKey()
* @var string
* @access private
*/
protected $key = false;
/**
* The Initialization Vector
*
* @see self::setIV()
* @var string
* @access private
*/
private $iv = false;
/**
* A "sliding" Initialization Vector
*
* @see self::enableContinuousBuffer()
* @see self::clearBuffers()
* @var string
* @access private
*/
protected $encryptIV;
/**
* A "sliding" Initialization Vector
*
* @see self::enableContinuousBuffer()
* @see self::clearBuffers()
* @var string
* @access private
*/
protected $decryptIV;
/**
* Continuous Buffer status
*
* @see self::enableContinuousBuffer()
* @var bool
* @access private
*/
protected $continuousBuffer = false;
/**
* Encryption buffer for CTR, OFB and CFB modes
*
* @see self::encrypt()
* @see self::clearBuffers()
* @var array
* @access private
*/
private $enbuffer;
/**
* Decryption buffer for CTR, OFB and CFB modes
*
* @see self::decrypt()
* @see self::clearBuffers()
* @var array
* @access private
*/
private $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
*/
private $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
*/
private $demcrypt;
/**
* Does the enmcrypt resource need to be (re)initialized?
*
* @see \phpseclib\Crypt\Twofish::setKey()
* @see \phpseclib\Crypt\Twofish::setIV()
* @var bool
* @access private
*/
private $enchanged = true;
/**
* Does the demcrypt resource need to be (re)initialized?
*
* @see \phpseclib\Crypt\Twofish::setKey()
* @see \phpseclib\Crypt\Twofish::setIV()
* @var bool
* @access private
*/
private $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
*/
private $ecb;
/**
* Optimizing value while CFB-encrypting
*
* Only relevant if $continuousBuffer enabled
* and $engine == self::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
*/
protected $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
*/
protected $changed = true;
/**
* Padding status
*
* @see self::enablePadding()
* @var bool
* @access private
*/
private $padding = true;
/**
* Is the mode one that is paddable?
*
* @see self::__construct()
* @var bool
* @access private
*/
private $paddable = false;
/**
* Holds which crypt engine internaly should be use,
* which will be determined automatically on __construct()
*
* Currently available $engines are:
* - self::ENGINE_OPENSSL (very fast, php-extension: openssl, extension_loaded('openssl') required)
* - self::ENGINE_MCRYPT (fast, php-extension: mcrypt, extension_loaded('mcrypt') required)
* - self::ENGINE_EVAL (medium, pure php-engine, no php-extension required)
* - self::ENGINE_INTERNAL (slower, pure php-engine, no php-extension required)
*
* @see self::setEngine()
* @see self::encrypt()
* @see self::decrypt()
* @var int
* @access private
*/
protected $engine;
/**
* Holds the preferred crypt engine
*
* @see self::setEngine()
* @see self::setPreferredEngine()
* @var int
* @access private
*/
private $preferredEngine;
/**
* The mcrypt specific name of the cipher
*
* Only used if $engine == self::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
*/
protected $cipher_name_mcrypt;
/**
* The openssl specific name of the cipher
*
* Only used if $engine == self::ENGINE_OPENSSL
*
* @link http://www.php.net/openssl-get-cipher-methods
* @var string
* @access private
*/
protected $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
*/
protected $cipher_name_openssl_ecb;
/**
* The default salt used by setPassword()
*
* @see self::setPassword()
* @var string
* @access private
*/
private $password_default_salt = 'phpseclib/salt';
/**
* The name of the performance-optimized callback function
*
* Used by encrypt() / decrypt()
* only if $engine == self::ENGINE_INTERNAL
*
* @see self::encrypt()
* @see self::decrypt()
* @see self::setupInlineCrypt()
* @see self::$use_inline_crypt
* @var Callback
* @access private
*/
protected $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
*/
protected $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
*/
private $openssl_emulate_ctr = false;
/**
* Don't truncate / null pad key
*
* @see self::clearBuffers()
* @var bool
* @access private
*/
private $skip_key_adjustment = false;
/**
* Has the key length explicitly been set or should it be derived from the key, itself?
*
* @see self::setKeyLength()
* @var bool
* @access private
*/
protected $explicit_key_length = false;
/**
* Default Constructor.
*
* $mode could be:
*
* - ecb
*
* - cbc
*
* - ctr
*
* - cfb
*
* - ofb
*
* @param int $mode
* @access public
* @throws \InvalidArgumentException if an invalid / unsupported mode is provided
*/
public function __construct($mode)
{
$mode = strtolower($mode);
// necessary because of 5.6 compatability; we can't do isset(self::MODE_MAP[$mode]) in 5.6
$map = self::MODE_MAP;
if (!isset($map[$mode])) {
throw new \InvalidArgumentException('No valid mode has been specified');
}
$mode = self::MODE_MAP[$mode];
// $mode dependent settings
switch ($mode) {
case self::MODE_ECB:
case self::MODE_CBC:
$this->paddable = true;
break;
case self::MODE_CTR:
case self::MODE_CFB:
case self::MODE_OFB:
case self::MODE_STREAM:
$this->paddable = false;
break;
default:
throw new \InvalidArgumentException('No valid mode has been specified');
}
$this->mode = $mode;
}
/**
* Sets the initialization vector.
*
* setIV() is not required when self::MODE_ECB (or ie for AES: \phpseclib\Crypt\AES::MODE_ECB) is being used.
*
* @access public
* @param string $iv
* @throws \LengthException if the IV length isn't equal to the block size
* @throws \InvalidArgumentException if an IV is provided when one shouldn't be
* @internal Can be overwritten by a sub class, but does not have to be
*/
public function setIV($iv)
{
if ($this->mode == self::MODE_ECB) {
throw new \InvalidArgumentException('This mode does not require an IV.');
}
if (!$this->usesIV()) {
throw new \InvalidArgumentException('This algorithm does not use an IV.');
}
if (strlen($iv) != $this->block_size) {
throw new \LengthException('Received initialization vector of size ' . strlen($iv) . ', but size ' . $this->block_size . ' is required');
}
$this->iv = $iv;
$this->changed = true;
}
/**
* Returns whether or not the algorithm uses an IV
*
* @access public
* @return bool
*/
public function usesIV()
{
return true;
}
/**
* Returns the current key length in bits
*
* @access public
* @return int
*/
public function getKeyLength()
{
return $this->key_length << 3;
}
/**
* Returns the current block length in bits
*
* @access public
* @return int
*/
public function getBlockLength()
{
return $this->block_size << 3;
}
/**
* Returns the current block length in bytes
*
* @access public
* @return int
*/
public function getBlockLengthInBytes()
{
return $this->block_size;
}
/**
* Sets the key length.
*
* Keys with explicitly set lengths need to be treated accordingly
*
* @access public
* @param int $length
*/
public function setKeyLength($length)
{
$this->explicit_key_length = $length >> 3;
if (is_string($this->key) && strlen($this->key) != $this->explicit_key_length) {
$this->key = false;
throw new \LengthException('Key has already been set and is not ' .$this->explicit_key_length . ' bytes long');
}
}
/**
* 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 $key
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function setKey($key)
{
if ($this->explicit_key_length !== false && strlen($key) != $this->explicit_key_length) {
throw new \LengthException('Key length has already been set to ' . $this->explicit_key_length . ' bytes and this key is ' . strlen($key) . ' bytes');
}
$this->key = $key;
$this->key_length = strlen($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 $method
* @throws \LengthException if pbkdf1 is being used and the derived key length exceeds the hash length
* @return bool
* @access public
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function setPassword($password, $method = 'pbkdf2')
{
$key = '';
$method = strtolower($method);
switch ($method) {
case 'pkcs12': // from https://tools.ietf.org/html/rfc7292#appendix-B.2
case 'pbkdf1':
case 'pbkdf2':
$func_args = func_get_args();
// Hash function
$hash = isset($func_args[2]) ? strtolower($func_args[2]) : 'sha1';
$hashObj = new Hash();
$hashObj->setHash($hash);
// 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 {
$key_length = $this->explicit_key_length !== false ? $this->explicit_key_length : $this->key_length;
$dkLen = $method == 'pbkdf1' ? 2 * $key_length : $key_length;
}
switch (true) {
case $method == 'pkcs12':
/*
In this specification, however, all passwords are created from
BMPStrings with a NULL terminator. This means that each character in
the original BMPString is encoded in 2 bytes in big-endian format
(most-significant byte first). There are no Unicode byte order
marks. The 2 bytes produced from the last character in the BMPString
are followed by 2 additional bytes with the value 0x00.
-- https://tools.ietf.org/html/rfc7292#appendix-B.1
*/
$password = "\0". chunk_split($password, 1, "\0") . "\0";
/*
This standard specifies 3 different values for the ID byte mentioned
above:
1. If ID=1, then the pseudorandom bits being produced are to be used
as key material for performing encryption or decryption.
2. If ID=2, then the pseudorandom bits being produced are to be used
as an IV (Initial Value) for encryption or decryption.
3. If ID=3, then the pseudorandom bits being produced are to be used
as an integrity key for MACing.
*/
// Construct a string, D (the "diversifier"), by concatenating v/8
// copies of ID.
$blockLength = $hashObj->getBlockLengthInBytes();
$d1 = str_repeat(chr(1), $blockLength);
$d2 = str_repeat(chr(2), $blockLength);
$s = '';
if (strlen($salt)) {
while (strlen($s) < $blockLength) {
$s.= $salt;
}
}
$s = substr($s, 0, $blockLength);
$p = '';
if (strlen($password)) {
while (strlen($p) < $blockLength) {
$p.= $password;
}
}
$p = substr($p, 0, $blockLength);
$i = $s . $p;
$this->setKey(self::pkcs12helper($dkLen, $hashObj, $i, $d1, $count));
if ($this->usesIV()) {
$this->setIV(self::pkcs12helper($this->block_size, $hashObj, $i, $d2, $count));
}
return true;
case $method == 'pbkdf1':
if ($dkLen > $hashObj->getLengthInBytes()) {
throw new \LengthException('Derived key length cannot be longer than the hash length');
}
$t = $password . $salt;
for ($i = 0; $i < $count; ++$i) {
$t = $hashObj->hash($t);
}
$key = substr($t, 0, $dkLen);
$this->setKey(substr($key, 0, $dkLen >> 1));
if ($this->usesIV()) {
$this->setIV(substr($key, $dkLen >> 1));
}
return true;
case !function_exists('hash_pbkdf2'):
case !function_exists('hash_algos'):
case !in_array($hash, hash_algos()):
$i = 1;
$hashObj->setKey($password);
while (strlen($key) < $dkLen) {
$f = $u = $hashObj->hash($salt . pack('N', $i++));
for ($j = 2; $j <= $count; ++$j) {
$u = $hashObj->hash($u);
$f^= $u;
}
$key.= $f;
}
$key = substr($key, 0, $dkLen);
break;
default:
$key = hash_pbkdf2($hash, $password, $salt, $count, $dkLen, true);
}
break;
default:
throw new \InvalidArgumentException($method . ' is not a supported password hashing method');
}
$this->setKey($key);
return true;
}
/**
* PKCS#12 KDF Helper Function
*
* As discussed here:
*
* {@link https://tools.ietf.org/html/rfc7292#appendix-B}
*
* @see self::setPassword()
* @access private
* @param int $n
* @param \phpseclib\Crypt\Hash $hashObj
* @param string $i
* @param string $d
* @param int $count
* @return string $a
*/
private static function pkcs12helper($n, $hashObj, $i, $d, $count)
{
static $one;
if (!isset($one)) {
$one = new BigInteger(1);
}
$blockLength = $hashObj->getBlockLength() >> 3;
$c = ceil($n / $hashObj->getLengthInBytes());
$a = '';
for ($j = 1; $j <= $c; $j++) {
$ai = $d . $i;
for ($k = 0; $k < $count; $k++) {
$ai = $hashObj->hash($ai);
}
$b = '';
while (strlen($b) < $blockLength) {
$b.= $ai;
}
$b = substr($b, 0, $blockLength);
$b = new BigInteger($b, 256);
$newi = '';
for ($k = 0; $k < strlen($i); $k+= $blockLength) {
$temp = substr($i, $k, $blockLength);
$temp = new BigInteger($temp, 256);
$temp->setPrecision($blockLength << 3);
$temp = $temp->add($b);
$temp = $temp->add($one);
$newi.= $temp->toBytes(false);
}
$i = $newi;
$a.= $ai;
}
return substr($a, 0, $n);
}
/**
* 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 $ciphertext
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function encrypt($plaintext)
{
if ($this->paddable) {
$plaintext = $this->pad($plaintext);
}
if ($this->engine === self::ENGINE_OPENSSL) {
if ($this->changed) {
$this->clearBuffers();
$this->changed = false;
}
switch ($this->mode) {
case self::MODE_STREAM:
return openssl_encrypt($plaintext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
case self::MODE_ECB:
return openssl_encrypt($plaintext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
case self::MODE_CBC:
$result = openssl_encrypt($plaintext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $this->encryptIV);
if ($this->continuousBuffer) {
$this->encryptIV = substr($result, -$this->block_size);
}
return $result;
case self::MODE_CTR:
return $this->openssl_ctr_process($plaintext, $this->encryptIV, $this->enbuffer);
case self::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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
$iv = Strings::pop($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
$iv = substr($ciphertext, -$this->block_size);
}
return $ciphertext;
case self::MODE_OFB:
return $this->openssl_ofb_process($plaintext, $this->encryptIV, $this->enbuffer);
}
}
if ($this->engine === self::ENGINE_MCRYPT) {
if ($this->changed) {
$this->setupMcrypt();
$this->changed = false;
}
if ($this->enchanged) {
@mcrypt_generic_init($this->enmcrypt, $this->key, $this->getIV($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 == self::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, $this->getIV($this->encryptIV));
}
return $ciphertext;
}
if ($this->changed) {
$this->setup();
$this->changed = false;
}
if ($this->engine === self::ENGINE_EVAL) {
$inline = $this->inline_crypt;
return $inline('encrypt', $plaintext);
}
$buffer = &$this->enbuffer;
$block_size = $this->block_size;
$ciphertext = '';
switch ($this->mode) {
case self::MODE_ECB:
for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
$ciphertext.= $this->encryptBlock(substr($plaintext, $i, $block_size));
}
break;
case self::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 self::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);
$key = Strings::shift($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) . $buffer['ciphertext'];
}
}
break;
case self::MODE_CFB:
// cfb loosely routines inspired by openssl's:
// {@link http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1}
if ($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 self::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;
}
$key = Strings::shift($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 self::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 $plaintext
* @throws \LengthException if we're inside a block cipher and the ciphertext length is not a multiple of the block size
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function decrypt($ciphertext)
{
if ($this->paddable && strlen($ciphertext) % $this->block_size) {
throw new \LengthException('The ciphertext length (' . strlen($ciphertext) . ') needs to be a multiple of the block size (' . $this->block_size . ')');
}
if ($this->engine === self::ENGINE_OPENSSL) {
if ($this->changed) {
$this->clearBuffers();
$this->changed = false;
}
switch ($this->mode) {
case self::MODE_STREAM:
$plaintext = openssl_decrypt($ciphertext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
break;
case self::MODE_ECB:
$plaintext = openssl_decrypt($ciphertext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
break;
case self::MODE_CBC:
$offset = $this->block_size;
$plaintext = openssl_decrypt($ciphertext, $this->cipher_name_openssl, $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $this->decryptIV);
if ($this->continuousBuffer) {
$this->decryptIV = substr($ciphertext, -$offset, $this->block_size);
}
break;
case self::MODE_CTR:
$plaintext = $this->openssl_ctr_process($ciphertext, $this->decryptIV, $this->debuffer);
break;
case self::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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
if ($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
$iv = substr($ciphertext, -$this->block_size);
}
break;
case self::MODE_OFB:
$plaintext = $this->openssl_ofb_process($ciphertext, $this->decryptIV, $this->debuffer);
}
return $this->paddable ? $this->unpad($plaintext) : $plaintext;
}
if ($this->engine === self::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, $this->getIV($this->decryptIV));
$this->dechanged = false;
}
if ($this->mode == self::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, $this->getIV($this->decryptIV));
}
return $this->paddable ? $this->unpad($plaintext) : $plaintext;
}
if ($this->changed) {
$this->setup();
$this->changed = false;
}
if ($this->engine === self::ENGINE_EVAL) {
$inline = $this->inline_crypt;
return $inline('decrypt', $ciphertext);
}
$block_size = $this->block_size;
$buffer = &$this->debuffer;
$plaintext = '';
switch ($this->mode) {
case self::MODE_ECB:
for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
$plaintext.= $this->decryptBlock(substr($ciphertext, $i, $block_size));
}
break;
case self::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 self::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);
$key = Strings::shift($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) . $buffer['ciphertext'];
}
}
break;
case self::MODE_CFB:
if ($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 self::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;
}
$key = Strings::shift($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 self::MODE_STREAM:
$plaintext = $this->decryptBlock($ciphertext);
break;
}
return $this->paddable ? $this->unpad($plaintext) : $plaintext;
}
/**
* Get the IV
*
* mcrypt requires an IV even if ECB is used
*
* @see self::encrypt()
* @see self::decrypt()
* @param string $iv
* @return string
* @access private
*/
public function getIV($iv)
{
return $this->mode == self::MODE_ECB ? str_repeat("\0", $this->block_size) : $iv;
}
/**
* 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 SymmetricKey::encrypt()
* and SymmetricKey::decrypt(). Also, OpenSSL doesn't implement CTR for all of it's symmetric ciphers so this
* function will emulate CTR with ECB when necesary.
*
* @see self::encrypt()
* @see self::decrypt()
* @param string $plaintext
* @param string $encryptIV
* @param array $buffer
* @return string
* @access private
*/
private function openssl_ctr_process($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'])) {
$buffer['ciphertext'].= openssl_encrypt($xor, $this->cipher_name_openssl_ecb, $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
}
$this->increment_str($xor);
$otp = Strings::shift($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
$this->increment_str($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 = $plaintext ^ Strings::shift($buffer['ciphertext'], strlen($plaintext));
$plaintext = substr($plaintext, strlen($ciphertext));
if (!strlen($plaintext)) {
return $ciphertext;
}
}
$overflow = strlen($plaintext) % $block_size;
if ($overflow) {
$plaintext2 = Strings::pop($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $encryptIV);
$temp = Strings::pop($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $encryptIV);
$temp = Strings::pop($ciphertext, $block_size);
if ($this->continuousBuffer) {
$encryptIV = $temp;
}
}
if ($this->continuousBuffer) {
$encryptIV = openssl_decrypt($encryptIV, $this->cipher_name_openssl_ecb, $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
if ($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 SymmetricKey::encrypt()
* and SymmetricKey::decrypt().
*
* @see self::encrypt()
* @see self::decrypt()
* @param string $plaintext
* @param string $encryptIV
* @param array $buffer
* @return string
* @access private
*/
private function openssl_ofb_process($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, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $encryptIV);
$xor = Strings::pop($ciphertext, $block_size);
if ($this->continuousBuffer) {
$encryptIV = $xor;
}
$ciphertext.= Strings::shift($xor, $overflow) ^ substr($plaintext, -$overflow);
if ($this->continuousBuffer) {
$buffer['xor'] = $xor;
}
} else {
$ciphertext = openssl_encrypt($plaintext, $this->cipher_name_openssl, $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $encryptIV);
if ($this->continuousBuffer) {
$encryptIV = substr($ciphertext, -$block_size) ^ substr($plaintext, -$block_size);
}
}
}
return $ciphertext;
}
/**
* phpseclib <-> OpenSSL Mode Mapper
*
* May need to be overwritten by classes extending this one in some cases
*
* @return int
* @access private
*/
protected function openssl_translate_mode()
{
switch ($this->mode) {
case self::MODE_ECB:
return 'ecb';
case self::MODE_CBC:
return 'cbc';
case self::MODE_CTR:
return 'ctr';
case self::MODE_CFB:
return 'cfb';
case self::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
*/
public function enablePadding()
{
$this->padding = true;
}
/**
* Do not pad packets.
*
* @see self::enablePadding()
* @access public
*/
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($plaintext, 16, 16)));
* </code>
*
* With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different
* outputs. The reason is due to the fact that the initialization vector's change after every encryption /
* decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.
*
* Put another way, when the continuous buffer is enabled, the state of the \phpseclib\Crypt\*() object changes after each
* encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that
* continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),
* however, they are also less intuitive and more likely to cause you problems.
*
* @see self::disableContinuousBuffer()
* @access public
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function enableContinuousBuffer()
{
if ($this->mode == self::MODE_ECB) {
return;
}
$this->continuousBuffer = true;
$this->setEngine();
}
/**
* Treat consecutive packets as if they are a discontinuous buffer.
*
* The default behavior.
*
* @see self::enableContinuousBuffer()
* @access public
* @internal Could, but not must, extend by the child Crypt_* class
*/
public function disableContinuousBuffer()
{
if ($this->mode == self::MODE_ECB) {
return;
}
if (!$this->continuousBuffer) {
return;
}
$this->continuousBuffer = false;
$this->changed = true;
$this->setEngine();
}
/**
* Test for engine validity
*
* @see self::__construct()
* @param int $engine
* @access private
* @return bool
*/
protected function isValidEngineHelper($engine)
{
switch ($engine) {
case self::ENGINE_OPENSSL:
if ($this->mode == self::MODE_STREAM && $this->continuousBuffer) {
return false;
}
$this->openssl_emulate_ctr = false;
$result = $this->cipher_name_openssl &&
extension_loaded('openssl');
if (!$result) {
return false;
}
$methods = openssl_get_cipher_methods();
if (in_array($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 self::MODE_CTR:
if (in_array($this->cipher_name_openssl_ecb, $methods)) {
$this->openssl_emulate_ctr = true;
return true;
}
}
return false;
case self::ENGINE_MCRYPT:
return $this->cipher_name_mcrypt &&
extension_loaded('mcrypt') &&
in_array($this->cipher_name_mcrypt, @mcrypt_list_algorithms());
case self::ENGINE_EVAL:
return method_exists($this, 'setupInlineCrypt');
case self::ENGINE_INTERNAL:
return true;
}
return false;
}
/**
* Test for engine validity
*
* @see self::__construct()
* @param string $engine
* @access public
* @return bool
*/
public function isValidEngine($engine)
{
static $reverseMap;
if (!isset($reverseMap)) {
$reverseMap = array_map('strtolower', self::ENGINE_MAP);
$reverseMap = array_flip($reverseMap);
}
$engine = strtolower($engine);
if (!isset($reverseMap[$engine])) {
return false;
}
return $this->isValidEngineHelper($reverseMap[$engine]);
}
/**
* Sets the preferred crypt engine
*
* Currently, $engine could be:
*
* - OpenSSL [very fast]
*
* - mcrypt [fast]
*
* - Eval [slow]
*
* - PHP [slowest]
*
* If the preferred crypt engine is not available the fastest available one will be used
*
* @see self::__construct()
* @param int $engine
* @access public
*/
public function setPreferredEngine($engine)
{
static $reverseMap;
if (!isset($reverseMap)) {
$reverseMap = array_map('strtolower', self::ENGINE_MAP);
$reverseMap = array_flip($reverseMap);
}
$engine = strtolower($engine);
$this->preferredEngine = isset($reverseMap[$engine]) ? $reverseMap[$engine] : self::ENGINE_OPENSSL;
$this->setEngine();
}
/**
* Returns the engine currently being utilized
*
* @see self::setEngine()
* @access public
*/
public function getEngine()
{
return self::ENGINE_MAP[$this->engine];
}
/**
* Sets the engine as appropriate
*
* @see self::__construct()
* @access private
*/
protected function setEngine()
{
$this->engine = null;
$candidateEngines = [
$this->preferredEngine,
self::ENGINE_OPENSSL,
self::ENGINE_MCRYPT,
self::ENGINE_EVAL
];
foreach ($candidateEngines as $engine) {
if ($this->isValidEngineHelper($engine)) {
$this->engine = $engine;
break;
}
}
if (!$this->engine) {
$this->engine = self::ENGINE_INTERNAL;
}
if ($this->engine != self::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
*
* Note: Must be extended by the child \phpseclib\Crypt\* class
*
* @access private
* @param string $in
* @return string
*/
abstract protected function encryptBlock($in);
/**
* Decrypts a block
*
* Note: Must be extended by the child \phpseclib\Crypt\* class
*
* @access private
* @param string $in
* @return string
*/
abstract protected function decryptBlock($in);
/**
* Setup the key (expansion)
*
* Only used if $engine == self::ENGINE_INTERNAL
*
* Note: Must extend by the child \phpseclib\Crypt\* class
*
* @see self::setup()
* @access private
*/
abstract protected function setupKey();
/**
* Setup the self::ENGINE_INTERNAL $engine
*
* (re)init, if necessary, the internal cipher $engine and flush all $buffers
* Used (only) if $engine == self::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
*/
protected function setup()
{
$this->clearBuffers();
$this->setupKey();
if ($this->engine === self::ENGINE_EVAL) {
$this->setupInlineCrypt();
}
}
/**
* Setup the self::ENGINE_MCRYPT $engine
*
* (re)init, if necessary, the (ext)mcrypt resources and flush all $buffers
* Used (only) if $engine = self::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
*/
private function setupMcrypt()
{
$this->clearBuffers();
$this->enchanged = $this->dechanged = true;
if (!isset($this->enmcrypt)) {
static $mcrypt_modes = [
self::MODE_CTR => 'ctr',
self::MODE_ECB => MCRYPT_MODE_ECB,
self::MODE_CBC => MCRYPT_MODE_CBC,
self::MODE_CFB => 'ncfb',
self::MODE_OFB => MCRYPT_MODE_NOFB,
self::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 == self::MODE_CFB) {
$this->ecb = @mcrypt_module_open($this->cipher_name_mcrypt, '', MCRYPT_MODE_ECB, '');
}
} // else should mcrypt_generic_deinit be called?
if ($this->mode == self::MODE_CFB) {
@mcrypt_generic_init($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 $text
* @throws \LengthException if padding is disabled and the plaintext's length is not a multiple of the block size
* @access private
* @return string
*/
protected function pad($text)
{
$length = strlen($text);
if (!$this->padding) {
if ($length % $this->block_size == 0) {
return $text;
} else {
throw new \LengthException("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size}). Try enabling padding.");
}
}
$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 $text
* @throws \LengthException if the ciphertext's length is not a multiple of the block size
* @access private
* @return string
*/
protected function unpad($text)
{
if (!$this->padding) {
return $text;
}
$length = ord($text[strlen($text) - 1]);
if (!$length || $length > $this->block_size) {
throw new \LengthException("The ciphertext has an invalid padding length ($length) compared to the block size ({$this->block_size})");
}
return substr($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 private
* @internal Could, but not must, extend by the child Crypt_* class
* @throws \UnexpectedValueException when an IV is required but not defined
*/
private function clearBuffers()
{
$this->enbuffer = $this->debuffer = ['ciphertext' => '', 'xor' => '', 'pos' => 0, 'enmcrypt_init' => true];
if ($this->iv === false && !in_array($this->mode, [self::MODE_STREAM, self::MODE_ECB])) {
throw new \UnexpectedValueException('No IV has been defined');
}
$this->encryptIV = $this->decryptIV = $this->iv;
}
/**
* Increment the current string
*
* @see self::decrypt()
* @see self::encrypt()
* @param string $var
* @access private
*/
protected function increment_str(&$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:
*
* - $this->engine === self::ENGINE_EVAL
*
* - 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 \phpseclib\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()
*/
//protected function setupInlineCrypt();
/**
* 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 \phpseclib\Crypt\*::_setupInlineCrypt()'s for
* productive inline $cipher_code's how they works.
*
* Structure of:
* <code>
* $cipher_code = [
* '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 $cipher_code
* @access private
* @return string (the name of the created callback function)
*/
protected function createInlineCryptFunction($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 self::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 $this->unpad($_plaintext);
';
break;
case self::MODE_CTR:
$encrypt = $init_encrypt . '
$_ciphertext = "";
$_plaintext_len = strlen($_text);
$_xor = $this->encryptIV;
$_buffer = &$this->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.'
$this->increment_str($_xor);
$_buffer["ciphertext"].= $in;
}
$_key = \phpseclib\Common\Functions\Strings::shift($_buffer["ciphertext"], '.$block_size.');
$_ciphertext.= $_block ^ $_key;
}
} else {
for ($_i = 0; $_i < $_plaintext_len; $_i+= '.$block_size.') {
$_block = substr($_text, $_i, '.$block_size.');
$in = $_xor;
'.$encrypt_block.'
$this->increment_str($_xor);
$_key = $in;
$_ciphertext.= $_block ^ $_key;
}
}
if ($this->continuousBuffer) {
$this->encryptIV = $_xor;
if ($_start = $_plaintext_len % '.$block_size.') {
$_buffer["ciphertext"] = substr($_key, $_start) . $_buffer["ciphertext"];
}
}
return $_ciphertext;
';
$decrypt = $init_encrypt . '
$_plaintext = "";
$_ciphertext_len = strlen($_text);
$_xor = $this->decryptIV;
$_buffer = &$this->debuffer;
if (strlen($_buffer["ciphertext"])) {
for ($_i = 0; $_i < $_ciphertext_len; $_i+= '.$block_size.') {
$_block = substr($_text, $_i, '.$block_size.');
if (strlen($_block) > strlen($_buffer["ciphertext"])) {
$in = $_xor;
'.$encrypt_block.'
$this->increment_str($_xor);
$_buffer["ciphertext"].= $in;
}
$_key = \phpseclib\Common\Functions\Strings::shift($_buffer["ciphertext"], '.$block_size.');
$_plaintext.= $_block ^ $_key;
}
} else {
for ($_i = 0; $_i < $_ciphertext_len; $_i+= '.$block_size.') {
$_block = substr($_text, $_i, '.$block_size.');
$in = $_xor;
'.$encrypt_block.'
$this->increment_str($_xor);
$_key = $in;
$_plaintext.= $_block ^ $_key;
}
}
if ($this->continuousBuffer) {
$this->decryptIV = $_xor;
if ($_start = $_ciphertext_len % '.$block_size.') {
$_buffer["ciphertext"] = substr($_key, $_start) . $_buffer["ciphertext"];
}
}
return $_plaintext;
';
break;
case self::MODE_CFB:
$encrypt = $init_encrypt . '
$_ciphertext = "";
$_buffer = &$this->enbuffer;
if ($this->continuousBuffer) {
$_iv = &$this->encryptIV;
$_pos = &$_buffer["pos"];
} else {
$_iv = $this->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 = "";
$_buffer = &$this->debuffer;
if ($this->continuousBuffer) {
$_iv = &$this->decryptIV;
$_pos = &$_buffer["pos"];
} else {
$_iv = $this->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 self::MODE_OFB:
$encrypt = $init_encrypt . '
$_ciphertext = "";
$_plaintext_len = strlen($_text);
$_xor = $this->encryptIV;
$_buffer = &$this->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;
}
$_key = \phpseclib\Common\Functions\Strings::shift($_buffer["xor"], '.$block_size.');
$_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 = $_xor;
}
if ($this->continuousBuffer) {
$this->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 = $this->decryptIV;
$_buffer = &$this->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;
}
$_key = \phpseclib\Common\Functions\Strings::shift($_buffer["xor"], '.$block_size.');
$_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 = $_xor;
}
if ($this->continuousBuffer) {
$this->decryptIV = $_xor;
if ($_start = $_ciphertext_len % '.$block_size.') {
$_buffer["xor"] = substr($_key, $_start) . $_buffer["xor"];
}
}
return $_plaintext;
';
break;
case self::MODE_STREAM:
$encrypt = $init_encrypt . '
$_ciphertext = "";
'.$encrypt_block.'
return $_ciphertext;
';
$decrypt = $init_decrypt . '
$_plaintext = "";
'.$decrypt_block.'
return $_plaintext;
';
break;
// case self::MODE_CBC:
default:
$encrypt = $init_encrypt . '
$_ciphertext = "";
$_plaintext_len = strlen($_text);
$in = $this->encryptIV;
for ($_i = 0; $_i < $_plaintext_len; $_i+= '.$block_size.') {
$in = substr($_text, $_i, '.$block_size.') ^ $in;
'.$encrypt_block.'
$_ciphertext.= $in;
}
if ($this->continuousBuffer) {
$this->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 = $this->decryptIV;
for ($_i = 0; $_i < $_ciphertext_len; $_i+= '.$block_size.') {
$in = $_block = substr($_text, $_i, '.$block_size.');
'.$decrypt_block.'
$_plaintext.= $in ^ $_iv;
$_iv = $_block;
}
if ($this->continuousBuffer) {
$this->decryptIV = $_iv;
}
return $this->unpad($_plaintext);
';
break;
}
eval('$func = function ($_action, $_text) { ' . $init_crypt . 'if ($_action == "encrypt") { ' . $encrypt . ' } else { ' . $decrypt . ' }};');
return \Closure::bind($func, $this, static::class);
}
}
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