* setKey('abcdefgh'); * * $plaintext = str_repeat('a', 1024); * * echo $rc2->decrypt($rc2->encrypt($plaintext)); * ?> * * * @author Patrick Monnerat * @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 ] ); } }