Developer
<?php
/**
* Pure-PHP implementation of RC2.
*
* Uses mcrypt, if available, and an internal implementation, otherwise.
*
* PHP version 5
*
* Useful resources are as follows:
*
* - {@link http://tools.ietf.org/html/rfc2268}
*
* Here's a short example of how to use this library:
* <code>
* <?php
* include 'vendor/autoload.php';
*
* $rc2 = new \phpseclib3\Crypt\RC2('ctr');
*
* $rc2->setKey('abcdefgh');
*
* $plaintext = str_repeat('a', 1024);
*
* echo $rc2->decrypt($rc2->encrypt($plaintext));
* ?>
* </code>
*
* @author Patrick Monnerat <pm@datasphere.ch>
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib3\Crypt;
use phpseclib3\Crypt\Common\BlockCipher;
use phpseclib3\Exception\BadModeException;
/**
* Pure-PHP implementation of RC2.
*
*/
class RC2 extends BlockCipher
{
/**
* Block Length of the cipher
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::block_size
* @var int
*/
protected $block_size = 8;
/**
* The Key
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::key
* @see self::setKey()
* @var string
*/
protected $key;
/**
* The Original (unpadded) Key
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::key
* @see self::setKey()
* @see self::encrypt()
* @see self::decrypt()
* @var string
*/
private $orig_key;
/**
* Key Length (in bytes)
*
* @see \phpseclib3\Crypt\RC2::setKeyLength()
* @var int
*/
protected $key_length = 16; // = 128 bits
/**
* The mcrypt specific name of the cipher
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::cipher_name_mcrypt
* @var string
*/
protected $cipher_name_mcrypt = 'rc2';
/**
* Optimizing value while CFB-encrypting
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::cfb_init_len
* @var int
*/
protected $cfb_init_len = 500;
/**
* The key length in bits.
*
* {@internal Should be in range [1..1024].}
*
* {@internal Changing this value after setting the key has no effect.}
*
* @see self::setKeyLength()
* @see self::setKey()
* @var int
*/
private $default_key_length = 1024;
/**
* The key length in bits.
*
* {@internal Should be in range [1..1024].}
*
* @see self::isValidEnine()
* @see self::setKey()
* @var int
*/
private $current_key_length;
/**
* The Key Schedule
*
* @see self::setupKey()
* @var array
*/
private $keys;
/**
* Key expansion randomization table.
* Twice the same 256-value sequence to save a modulus in key expansion.
*
* @see self::setKey()
* @var array
*/
private static $pitable = [
0xD9, 0x78, 0xF9, 0xC4, 0x19, 0xDD, 0xB5, 0xED,
0x28, 0xE9, 0xFD, 0x79, 0x4A, 0xA0, 0xD8, 0x9D,
0xC6, 0x7E, 0x37, 0x83, 0x2B, 0x76, 0x53, 0x8E,
0x62, 0x4C, 0x64, 0x88, 0x44, 0x8B, 0xFB, 0xA2,
0x17, 0x9A, 0x59, 0xF5, 0x87, 0xB3, 0x4F, 0x13,
0x61, 0x45, 0x6D, 0x8D, 0x09, 0x81, 0x7D, 0x32,
0xBD, 0x8F, 0x40, 0xEB, 0x86, 0xB7, 0x7B, 0x0B,
0xF0, 0x95, 0x21, 0x22, 0x5C, 0x6B, 0x4E, 0x82,
0x54, 0xD6, 0x65, 0x93, 0xCE, 0x60, 0xB2, 0x1C,
0x73, 0x56, 0xC0, 0x14, 0xA7, 0x8C, 0xF1, 0xDC,
0x12, 0x75, 0xCA, 0x1F, 0x3B, 0xBE, 0xE4, 0xD1,
0x42, 0x3D, 0xD4, 0x30, 0xA3, 0x3C, 0xB6, 0x26,
0x6F, 0xBF, 0x0E, 0xDA, 0x46, 0x69, 0x07, 0x57,
0x27, 0xF2, 0x1D, 0x9B, 0xBC, 0x94, 0x43, 0x03,
0xF8, 0x11, 0xC7, 0xF6, 0x90, 0xEF, 0x3E, 0xE7,
0x06, 0xC3, 0xD5, 0x2F, 0xC8, 0x66, 0x1E, 0xD7,
0x08, 0xE8, 0xEA, 0xDE, 0x80, 0x52, 0xEE, 0xF7,
0x84, 0xAA, 0x72, 0xAC, 0x35, 0x4D, 0x6A, 0x2A,
0x96, 0x1A, 0xD2, 0x71, 0x5A, 0x15, 0x49, 0x74,
0x4B, 0x9F, 0xD0, 0x5E, 0x04, 0x18, 0xA4, 0xEC,
0xC2, 0xE0, 0x41, 0x6E, 0x0F, 0x51, 0xCB, 0xCC,
0x24, 0x91, 0xAF, 0x50, 0xA1, 0xF4, 0x70, 0x39,
0x99, 0x7C, 0x3A, 0x85, 0x23, 0xB8, 0xB4, 0x7A,
0xFC, 0x02, 0x36, 0x5B, 0x25, 0x55, 0x97, 0x31,
0x2D, 0x5D, 0xFA, 0x98, 0xE3, 0x8A, 0x92, 0xAE,
0x05, 0xDF, 0x29, 0x10, 0x67, 0x6C, 0xBA, 0xC9,
0xD3, 0x00, 0xE6, 0xCF, 0xE1, 0x9E, 0xA8, 0x2C,
0x63, 0x16, 0x01, 0x3F, 0x58, 0xE2, 0x89, 0xA9,
0x0D, 0x38, 0x34, 0x1B, 0xAB, 0x33, 0xFF, 0xB0,
0xBB, 0x48, 0x0C, 0x5F, 0xB9, 0xB1, 0xCD, 0x2E,
0xC5, 0xF3, 0xDB, 0x47, 0xE5, 0xA5, 0x9C, 0x77,
0x0A, 0xA6, 0x20, 0x68, 0xFE, 0x7F, 0xC1, 0xAD,
0xD9, 0x78, 0xF9, 0xC4, 0x19, 0xDD, 0xB5, 0xED,
0x28, 0xE9, 0xFD, 0x79, 0x4A, 0xA0, 0xD8, 0x9D,
0xC6, 0x7E, 0x37, 0x83, 0x2B, 0x76, 0x53, 0x8E,
0x62, 0x4C, 0x64, 0x88, 0x44, 0x8B, 0xFB, 0xA2,
0x17, 0x9A, 0x59, 0xF5, 0x87, 0xB3, 0x4F, 0x13,
0x61, 0x45, 0x6D, 0x8D, 0x09, 0x81, 0x7D, 0x32,
0xBD, 0x8F, 0x40, 0xEB, 0x86, 0xB7, 0x7B, 0x0B,
0xF0, 0x95, 0x21, 0x22, 0x5C, 0x6B, 0x4E, 0x82,
0x54, 0xD6, 0x65, 0x93, 0xCE, 0x60, 0xB2, 0x1C,
0x73, 0x56, 0xC0, 0x14, 0xA7, 0x8C, 0xF1, 0xDC,
0x12, 0x75, 0xCA, 0x1F, 0x3B, 0xBE, 0xE4, 0xD1,
0x42, 0x3D, 0xD4, 0x30, 0xA3, 0x3C, 0xB6, 0x26,
0x6F, 0xBF, 0x0E, 0xDA, 0x46, 0x69, 0x07, 0x57,
0x27, 0xF2, 0x1D, 0x9B, 0xBC, 0x94, 0x43, 0x03,
0xF8, 0x11, 0xC7, 0xF6, 0x90, 0xEF, 0x3E, 0xE7,
0x06, 0xC3, 0xD5, 0x2F, 0xC8, 0x66, 0x1E, 0xD7,
0x08, 0xE8, 0xEA, 0xDE, 0x80, 0x52, 0xEE, 0xF7,
0x84, 0xAA, 0x72, 0xAC, 0x35, 0x4D, 0x6A, 0x2A,
0x96, 0x1A, 0xD2, 0x71, 0x5A, 0x15, 0x49, 0x74,
0x4B, 0x9F, 0xD0, 0x5E, 0x04, 0x18, 0xA4, 0xEC,
0xC2, 0xE0, 0x41, 0x6E, 0x0F, 0x51, 0xCB, 0xCC,
0x24, 0x91, 0xAF, 0x50, 0xA1, 0xF4, 0x70, 0x39,
0x99, 0x7C, 0x3A, 0x85, 0x23, 0xB8, 0xB4, 0x7A,
0xFC, 0x02, 0x36, 0x5B, 0x25, 0x55, 0x97, 0x31,
0x2D, 0x5D, 0xFA, 0x98, 0xE3, 0x8A, 0x92, 0xAE,
0x05, 0xDF, 0x29, 0x10, 0x67, 0x6C, 0xBA, 0xC9,
0xD3, 0x00, 0xE6, 0xCF, 0xE1, 0x9E, 0xA8, 0x2C,
0x63, 0x16, 0x01, 0x3F, 0x58, 0xE2, 0x89, 0xA9,
0x0D, 0x38, 0x34, 0x1B, 0xAB, 0x33, 0xFF, 0xB0,
0xBB, 0x48, 0x0C, 0x5F, 0xB9, 0xB1, 0xCD, 0x2E,
0xC5, 0xF3, 0xDB, 0x47, 0xE5, 0xA5, 0x9C, 0x77,
0x0A, 0xA6, 0x20, 0x68, 0xFE, 0x7F, 0xC1, 0xAD
];
/**
* Inverse key expansion randomization table.
*
* @see self::setKey()
* @var array
*/
private static $invpitable = [
0xD1, 0xDA, 0xB9, 0x6F, 0x9C, 0xC8, 0x78, 0x66,
0x80, 0x2C, 0xF8, 0x37, 0xEA, 0xE0, 0x62, 0xA4,
0xCB, 0x71, 0x50, 0x27, 0x4B, 0x95, 0xD9, 0x20,
0x9D, 0x04, 0x91, 0xE3, 0x47, 0x6A, 0x7E, 0x53,
0xFA, 0x3A, 0x3B, 0xB4, 0xA8, 0xBC, 0x5F, 0x68,
0x08, 0xCA, 0x8F, 0x14, 0xD7, 0xC0, 0xEF, 0x7B,
0x5B, 0xBF, 0x2F, 0xE5, 0xE2, 0x8C, 0xBA, 0x12,
0xE1, 0xAF, 0xB2, 0x54, 0x5D, 0x59, 0x76, 0xDB,
0x32, 0xA2, 0x58, 0x6E, 0x1C, 0x29, 0x64, 0xF3,
0xE9, 0x96, 0x0C, 0x98, 0x19, 0x8D, 0x3E, 0x26,
0xAB, 0xA5, 0x85, 0x16, 0x40, 0xBD, 0x49, 0x67,
0xDC, 0x22, 0x94, 0xBB, 0x3C, 0xC1, 0x9B, 0xEB,
0x45, 0x28, 0x18, 0xD8, 0x1A, 0x42, 0x7D, 0xCC,
0xFB, 0x65, 0x8E, 0x3D, 0xCD, 0x2A, 0xA3, 0x60,
0xAE, 0x93, 0x8A, 0x48, 0x97, 0x51, 0x15, 0xF7,
0x01, 0x0B, 0xB7, 0x36, 0xB1, 0x2E, 0x11, 0xFD,
0x84, 0x2D, 0x3F, 0x13, 0x88, 0xB3, 0x34, 0x24,
0x1B, 0xDE, 0xC5, 0x1D, 0x4D, 0x2B, 0x17, 0x31,
0x74, 0xA9, 0xC6, 0x43, 0x6D, 0x39, 0x90, 0xBE,
0xC3, 0xB0, 0x21, 0x6B, 0xF6, 0x0F, 0xD5, 0x99,
0x0D, 0xAC, 0x1F, 0x5C, 0x9E, 0xF5, 0xF9, 0x4C,
0xD6, 0xDF, 0x89, 0xE4, 0x8B, 0xFF, 0xC7, 0xAA,
0xE7, 0xED, 0x46, 0x25, 0xB6, 0x06, 0x5E, 0x35,
0xB5, 0xEC, 0xCE, 0xE8, 0x6C, 0x30, 0x55, 0x61,
0x4A, 0xFE, 0xA0, 0x79, 0x03, 0xF0, 0x10, 0x72,
0x7C, 0xCF, 0x52, 0xA6, 0xA7, 0xEE, 0x44, 0xD3,
0x9A, 0x57, 0x92, 0xD0, 0x5A, 0x7A, 0x41, 0x7F,
0x0E, 0x00, 0x63, 0xF2, 0x4F, 0x05, 0x83, 0xC9,
0xA1, 0xD4, 0xDD, 0xC4, 0x56, 0xF4, 0xD2, 0x77,
0x81, 0x09, 0x82, 0x33, 0x9F, 0x07, 0x86, 0x75,
0x38, 0x4E, 0x69, 0xF1, 0xAD, 0x23, 0x73, 0x87,
0x70, 0x02, 0xC2, 0x1E, 0xB8, 0x0A, 0xFC, 0xE6
];
/**
* Default Constructor.
*
* @param string $mode
* @throws \InvalidArgumentException if an invalid / unsupported mode is provided
*/
public function __construct($mode)
{
parent::__construct($mode);
if ($this->mode == self::MODE_STREAM) {
throw new BadModeException('Block ciphers cannot be ran in stream mode');
}
}
/**
* Test for engine validity
*
* This is mainly just a wrapper to set things up for \phpseclib3\Crypt\Common\SymmetricKey::isValidEngine()
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::__construct()
* @param int $engine
* @return bool
*/
protected function isValidEngineHelper($engine)
{
switch ($engine) {
case self::ENGINE_OPENSSL:
if ($this->current_key_length != 128 || strlen($this->orig_key) < 16) {
return false;
}
// quoting https://www.openssl.org/news/openssl-3.0-notes.html, OpenSSL 3.0.1
// "Moved all variations of the EVP ciphers CAST5, BF, IDEA, SEED, RC2, RC4, RC5, and DES to the legacy provider"
// in theory openssl_get_cipher_methods() should catch this but, on GitHub Actions, at least, it does not
if (defined('OPENSSL_VERSION_TEXT') && version_compare(preg_replace('#OpenSSL (\d+\.\d+\.\d+) .*#', '$1', OPENSSL_VERSION_TEXT), '3.0.1', '>=')) {
return false;
}
$this->cipher_name_openssl_ecb = 'rc2-ecb';
$this->cipher_name_openssl = 'rc2-' . $this->openssl_translate_mode();
}
return parent::isValidEngineHelper($engine);
}
/**
* Sets the key length.
*
* Valid key lengths are 8 to 1024.
* Calling this function after setting the key has no effect until the next
* \phpseclib3\Crypt\RC2::setKey() call.
*
* @param int $length in bits
* @throws \LengthException if the key length isn't supported
*/
public function setKeyLength($length)
{
if ($length < 8 || $length > 1024) {
throw new \LengthException('Key size of ' . $length . ' bits is not supported by this algorithm. Only keys between 1 and 1024 bits, inclusive, are supported');
}
$this->default_key_length = $this->current_key_length = $length;
$this->explicit_key_length = $length >> 3;
}
/**
* Returns the current key length
*
* @return int
*/
public function getKeyLength()
{
return $this->current_key_length;
}
/**
* Sets the key.
*
* Keys can be of any length. RC2, itself, uses 8 to 1024 bit keys (eg.
* strlen($key) <= 128), however, we only use the first 128 bytes if $key
* has more then 128 bytes in it, and set $key to a single null byte if
* it is empty.
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::setKey()
* @param string $key
* @param int|boolean $t1 optional Effective key length in bits.
* @throws \LengthException if the key length isn't supported
*/
public function setKey($key, $t1 = false)
{
$this->orig_key = $key;
if ($t1 === false) {
$t1 = $this->default_key_length;
}
if ($t1 < 1 || $t1 > 1024) {
throw new \LengthException('Key size of ' . $length . ' bits is not supported by this algorithm. Only keys between 1 and 1024 bits, inclusive, are supported');
}
$this->current_key_length = $t1;
if (strlen($key) < 1 || strlen($key) > 128) {
throw new \LengthException('Key of size ' . strlen($key) . ' not supported by this algorithm. Only keys of sizes between 8 and 1024 bits, inclusive, are supported');
}
$t = strlen($key);
// The mcrypt RC2 implementation only supports effective key length
// of 1024 bits. It is however possible to handle effective key
// lengths in range 1..1024 by expanding the key and applying
// inverse pitable mapping to the first byte before submitting it
// to mcrypt.
// Key expansion.
$l = array_values(unpack('C*', $key));
$t8 = ($t1 + 7) >> 3;
$tm = 0xFF >> (8 * $t8 - $t1);
// Expand key.
$pitable = self::$pitable;
for ($i = $t; $i < 128; $i++) {
$l[$i] = $pitable[$l[$i - 1] + $l[$i - $t]];
}
$i = 128 - $t8;
$l[$i] = $pitable[$l[$i] & $tm];
while ($i--) {
$l[$i] = $pitable[$l[$i + 1] ^ $l[$i + $t8]];
}
// Prepare the key for mcrypt.
$l[0] = self::$invpitable[$l[0]];
array_unshift($l, 'C*');
$this->key = pack(...$l);
$this->key_length = strlen($this->key);
$this->changed = $this->nonIVChanged = true;
$this->setEngine();
}
/**
* Encrypts a message.
*
* Mostly a wrapper for \phpseclib3\Crypt\Common\SymmetricKey::encrypt, with some additional OpenSSL handling code
*
* @see self::decrypt()
* @param string $plaintext
* @return string $ciphertext
*/
public function encrypt($plaintext)
{
if ($this->engine == self::ENGINE_OPENSSL) {
$temp = $this->key;
$this->key = $this->orig_key;
$result = parent::encrypt($plaintext);
$this->key = $temp;
return $result;
}
return parent::encrypt($plaintext);
}
/**
* Decrypts a message.
*
* Mostly a wrapper for \phpseclib3\Crypt\Common\SymmetricKey::decrypt, with some additional OpenSSL handling code
*
* @see self::encrypt()
* @param string $ciphertext
* @return string $plaintext
*/
public function decrypt($ciphertext)
{
if ($this->engine == self::ENGINE_OPENSSL) {
$temp = $this->key;
$this->key = $this->orig_key;
$result = parent::decrypt($ciphertext);
$this->key = $temp;
return $result;
}
return parent::decrypt($ciphertext);
}
/**
* Encrypts a block
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::encryptBlock()
* @see \phpseclib3\Crypt\Common\SymmetricKey::encrypt()
* @param string $in
* @return string
*/
protected function encryptBlock($in)
{
list($r0, $r1, $r2, $r3) = array_values(unpack('v*', $in));
$keys = $this->keys;
$limit = 20;
$actions = [$limit => 44, 44 => 64];
$j = 0;
for (;;) {
// Mixing round.
$r0 = (($r0 + $keys[$j++] + ((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF) << 1;
$r0 |= $r0 >> 16;
$r1 = (($r1 + $keys[$j++] + ((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF) << 2;
$r1 |= $r1 >> 16;
$r2 = (($r2 + $keys[$j++] + ((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF) << 3;
$r2 |= $r2 >> 16;
$r3 = (($r3 + $keys[$j++] + ((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF) << 5;
$r3 |= $r3 >> 16;
if ($j === $limit) {
if ($limit === 64) {
break;
}
// Mashing round.
$r0 += $keys[$r3 & 0x3F];
$r1 += $keys[$r0 & 0x3F];
$r2 += $keys[$r1 & 0x3F];
$r3 += $keys[$r2 & 0x3F];
$limit = $actions[$limit];
}
}
return pack('vvvv', $r0, $r1, $r2, $r3);
}
/**
* Decrypts a block
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::decryptBlock()
* @see \phpseclib3\Crypt\Common\SymmetricKey::decrypt()
* @param string $in
* @return string
*/
protected function decryptBlock($in)
{
list($r0, $r1, $r2, $r3) = array_values(unpack('v*', $in));
$keys = $this->keys;
$limit = 44;
$actions = [$limit => 20, 20 => 0];
$j = 64;
for (;;) {
// R-mixing round.
$r3 = ($r3 | ($r3 << 16)) >> 5;
$r3 = ($r3 - $keys[--$j] - ((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF;
$r2 = ($r2 | ($r2 << 16)) >> 3;
$r2 = ($r2 - $keys[--$j] - ((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF;
$r1 = ($r1 | ($r1 << 16)) >> 2;
$r1 = ($r1 - $keys[--$j] - ((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF;
$r0 = ($r0 | ($r0 << 16)) >> 1;
$r0 = ($r0 - $keys[--$j] - ((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF;
if ($j === $limit) {
if ($limit === 0) {
break;
}
// R-mashing round.
$r3 = ($r3 - $keys[$r2 & 0x3F]) & 0xFFFF;
$r2 = ($r2 - $keys[$r1 & 0x3F]) & 0xFFFF;
$r1 = ($r1 - $keys[$r0 & 0x3F]) & 0xFFFF;
$r0 = ($r0 - $keys[$r3 & 0x3F]) & 0xFFFF;
$limit = $actions[$limit];
}
}
return pack('vvvv', $r0, $r1, $r2, $r3);
}
/**
* Creates the key schedule
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::setupKey()
*/
protected function setupKey()
{
if (!isset($this->key)) {
$this->setKey('');
}
// Key has already been expanded in \phpseclib3\Crypt\RC2::setKey():
// Only the first value must be altered.
$l = unpack('Ca/Cb/v*', $this->key);
array_unshift($l, self::$pitable[$l['a']] | ($l['b'] << 8));
unset($l['a']);
unset($l['b']);
$this->keys = $l;
}
/**
* Setup the performance-optimized function for de/encrypt()
*
* @see \phpseclib3\Crypt\Common\SymmetricKey::setupInlineCrypt()
*/
protected function setupInlineCrypt()
{
// Init code for both, encrypt and decrypt.
$init_crypt = '$keys = $this->keys;';
$keys = $this->keys;
// $in is the current 8 bytes block which has to be en/decrypt
$encrypt_block = $decrypt_block = '
$in = unpack("v4", $in);
$r0 = $in[1];
$r1 = $in[2];
$r2 = $in[3];
$r3 = $in[4];
';
// Create code for encryption.
$limit = 20;
$actions = [$limit => 44, 44 => 64];
$j = 0;
for (;;) {
// Mixing round.
$encrypt_block .= '
$r0 = (($r0 + ' . $keys[$j++] . ' +
((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF) << 1;
$r0 |= $r0 >> 16;
$r1 = (($r1 + ' . $keys[$j++] . ' +
((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF) << 2;
$r1 |= $r1 >> 16;
$r2 = (($r2 + ' . $keys[$j++] . ' +
((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF) << 3;
$r2 |= $r2 >> 16;
$r3 = (($r3 + ' . $keys[$j++] . ' +
((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF) << 5;
$r3 |= $r3 >> 16;';
if ($j === $limit) {
if ($limit === 64) {
break;
}
// Mashing round.
$encrypt_block .= '
$r0 += $keys[$r3 & 0x3F];
$r1 += $keys[$r0 & 0x3F];
$r2 += $keys[$r1 & 0x3F];
$r3 += $keys[$r2 & 0x3F];';
$limit = $actions[$limit];
}
}
$encrypt_block .= '$in = pack("v4", $r0, $r1, $r2, $r3);';
// Create code for decryption.
$limit = 44;
$actions = [$limit => 20, 20 => 0];
$j = 64;
for (;;) {
// R-mixing round.
$decrypt_block .= '
$r3 = ($r3 | ($r3 << 16)) >> 5;
$r3 = ($r3 - ' . $keys[--$j] . ' -
((($r0 ^ $r1) & $r2) ^ $r0)) & 0xFFFF;
$r2 = ($r2 | ($r2 << 16)) >> 3;
$r2 = ($r2 - ' . $keys[--$j] . ' -
((($r3 ^ $r0) & $r1) ^ $r3)) & 0xFFFF;
$r1 = ($r1 | ($r1 << 16)) >> 2;
$r1 = ($r1 - ' . $keys[--$j] . ' -
((($r2 ^ $r3) & $r0) ^ $r2)) & 0xFFFF;
$r0 = ($r0 | ($r0 << 16)) >> 1;
$r0 = ($r0 - ' . $keys[--$j] . ' -
((($r1 ^ $r2) & $r3) ^ $r1)) & 0xFFFF;';
if ($j === $limit) {
if ($limit === 0) {
break;
}
// R-mashing round.
$decrypt_block .= '
$r3 = ($r3 - $keys[$r2 & 0x3F]) & 0xFFFF;
$r2 = ($r2 - $keys[$r1 & 0x3F]) & 0xFFFF;
$r1 = ($r1 - $keys[$r0 & 0x3F]) & 0xFFFF;
$r0 = ($r0 - $keys[$r3 & 0x3F]) & 0xFFFF;';
$limit = $actions[$limit];
}
}
$decrypt_block .= '$in = pack("v4", $r0, $r1, $r2, $r3);';
// Creates the inline-crypt function
$this->inline_crypt = $this->createInlineCryptFunction(
[
'init_crypt' => $init_crypt,
'encrypt_block' => $encrypt_block,
'decrypt_block' => $decrypt_block
]
);
}
}
Developer
To ensure a smooth integration process and optimal performance, follow these best practices: