<?php
/**
* Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.
*
* Uses hash() or mhash() if available and an internal implementation, otherwise. Currently supports the following:
*
* md2, md5, md5-96, sha1, sha1-96, sha256, sha256-96, sha384, and sha512, sha512-96
*
* If {@link self::setKey() setKey()} is called, {@link self::hash() hash()} will return the HMAC as opposed to
* the hash. If no valid algorithm is provided, sha1 will be used.
*
* PHP version 5
*
* {@internal The variable names are the same as those in
* {@link http://tools.ietf.org/html/rfc2104#section-2 RFC2104}.}}
*
* Here's a short example of how to use this library:
* <code>
* <?php
* include 'phpseclib/autoload.php';
*
* $hash = new \phpseclib\Crypt\Hash('sha1');
*
* $hash->setKey('abcdefg');
*
* echo base64_encode($hash->hash('abcdefg'));
* ?>
* </code>
*
* @category Crypt
* @package Hash
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2007 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib\Crypt;
use phpseclib\Math\BigInteger;
/**
* Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions.
*
* @package Hash
* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
class Hash
{
/**#@+
* @access private
* @see \phpseclib\Crypt\Hash::__construct()
*/
/**
* Toggles the internal implementation
*/
const MODE_INTERNAL = 1;
/**
* Toggles the mhash() implementation, which has been deprecated on PHP 5.3.0+.
*/
const MODE_MHASH = 2;
/**
* Toggles the hash() implementation, which works on PHP 5.1.2+.
*/
const MODE_HASH = 3;
/**#@-*/
/**
* Hash Parameter
*
* @see self::setHash()
* @var int
* @access private
*/
var $hashParam;
/**
* Byte-length of compression blocks / key (Internal HMAC)
*
* @see self::setAlgorithm()
* @var int
* @access private
*/
var $b;
/**
* Byte-length of hash output (Internal HMAC)
*
* @see self::setHash()
* @var int
* @access private
*/
var $l = false;
/**
* Hash Algorithm
*
* @see self::setHash()
* @var string
* @access private
*/
var $hash;
/**
* Key
*
* @see self::setKey()
* @var string
* @access private
*/
var $key = false;
/**
* Outer XOR (Internal HMAC)
*
* @see self::setKey()
* @var string
* @access private
*/
var $opad;
/**
* Inner XOR (Internal HMAC)
*
* @see self::setKey()
* @var string
* @access private
*/
var $ipad;
/**
* Default Constructor.
*
* @param string $hash
* @return \phpseclib\Crypt\Hash
* @access public
*/
function __construct($hash = 'sha1')
{
if (!defined('CRYPT_HASH_MODE')) {
switch (true) {
case extension_loaded('hash'):
define('CRYPT_HASH_MODE', self::MODE_HASH);
break;
case extension_loaded('mhash'):
define('CRYPT_HASH_MODE', self::MODE_MHASH);
break;
default:
define('CRYPT_HASH_MODE', self::MODE_INTERNAL);
}
}
$this->setHash($hash);
}
/**
* Sets the key for HMACs
*
* Keys can be of any length.
*
* @access public
* @param string $key
*/
function setKey($key = false)
{
$this->key = $key;
}
/**
* Gets the hash function.
*
* As set by the constructor or by the setHash() method.
*
* @access public
* @return string
*/
function getHash()
{
return $this->hashParam;
}
/**
* Sets the hash function.
*
* @access public
* @param string $hash
*/
function setHash($hash)
{
$this->hashParam = $hash = strtolower($hash);
switch ($hash) {
case 'md5-96':
case 'sha1-96':
case 'sha256-96':
case 'sha512-96':
$hash = substr($hash, 0, -3);
$this->l = 12; // 96 / 8 = 12
break;
case 'md2':
case 'md5':
$this->l = 16;
break;
case 'sha1':
$this->l = 20;
break;
case 'sha256':
$this->l = 32;
break;
case 'sha384':
$this->l = 48;
break;
case 'sha512':
$this->l = 64;
}
switch ($hash) {
case 'md2':
$mode = CRYPT_HASH_MODE == self::MODE_HASH && in_array('md2', hash_algos()) ?
self::MODE_HASH : self::MODE_INTERNAL;
break;
case 'sha384':
case 'sha512':
$mode = CRYPT_HASH_MODE == self::MODE_MHASH ? self::MODE_INTERNAL : CRYPT_HASH_MODE;
break;
default:
$mode = CRYPT_HASH_MODE;
}
switch ($mode) {
case self::MODE_MHASH:
switch ($hash) {
case 'md5':
$this->hash = MHASH_MD5;
break;
case 'sha256':
$this->hash = MHASH_SHA256;
break;
case 'sha1':
default:
$this->hash = MHASH_SHA1;
}
return;
case self::MODE_HASH:
switch ($hash) {
case 'md5':
$this->hash = 'md5';
return;
case 'md2':
case 'sha256':
case 'sha384':
case 'sha512':
$this->hash = $hash;
return;
case 'sha1':
default:
$this->hash = 'sha1';
}
return;
}
switch ($hash) {
case 'md2':
$this->b = 16;
$this->hash = array($this, '_md2');
break;
case 'md5':
$this->b = 64;
$this->hash = array($this, '_md5');
break;
case 'sha256':
$this->b = 64;
$this->hash = array($this, '_sha256');
break;
case 'sha384':
case 'sha512':
$this->b = 128;
$this->hash = array($this, '_sha512');
break;
case 'sha1':
default:
$this->b = 64;
$this->hash = array($this, '_sha1');
}
$this->ipad = str_repeat(chr(0x36), $this->b);
$this->opad = str_repeat(chr(0x5C), $this->b);
}
/**
* Compute the HMAC.
*
* @access public
* @param string $text
* @return string
*/
function hash($text)
{
$mode = is_array($this->hash) ? self::MODE_INTERNAL : CRYPT_HASH_MODE;
if (!empty($this->key) || is_string($this->key)) {
switch ($mode) {
case self::MODE_MHASH:
$output = mhash($this->hash, $text, $this->key);
break;
case self::MODE_HASH:
$output = hash_hmac($this->hash, $text, $this->key, true);
break;
case self::MODE_INTERNAL:
/* "Applications that use keys longer than B bytes will first hash the key using H and then use the
resultant L byte string as the actual key to HMAC."
-- http://tools.ietf.org/html/rfc2104#section-2 */
$key = strlen($this->key) > $this->b ? call_user_func($this->hash, $this->key) : $this->key;
$key = str_pad($key, $this->b, chr(0)); // step 1
$temp = $this->ipad ^ $key; // step 2
$temp .= $text; // step 3
$temp = call_user_func($this->hash, $temp); // step 4
$output = $this->opad ^ $key; // step 5
$output.= $temp; // step 6
$output = call_user_func($this->hash, $output); // step 7
}
} else {
switch ($mode) {
case self::MODE_MHASH:
$output = mhash($this->hash, $text);
break;
case self::MODE_HASH:
$output = hash($this->hash, $text, true);
break;
case self::MODE_INTERNAL:
$output = call_user_func($this->hash, $text);
}
}
return substr($output, 0, $this->l);
}
/**
* Returns the hash length (in bytes)
*
* @access public
* @return int
*/
function getLength()
{
return $this->l;
}
/**
* Wrapper for MD5
*
* @access private
* @param string $m
*/
function _md5($m)
{
return pack('H*', md5($m));
}
/**
* Wrapper for SHA1
*
* @access private
* @param string $m
*/
function _sha1($m)
{
return pack('H*', sha1($m));
}
/**
* Pure-PHP implementation of MD2
*
* See {@link http://tools.ietf.org/html/rfc1319 RFC1319}.
*
* @access private
* @param string $m
*/
function _md2($m)
{
static $s = array(
41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
31, 26, 219, 153, 141, 51, 159, 17, 131, 20
);
// Step 1. Append Padding Bytes
$pad = 16 - (strlen($m) & 0xF);
$m.= str_repeat(chr($pad), $pad);
$length = strlen($m);
// Step 2. Append Checksum
$c = str_repeat(chr(0), 16);
$l = chr(0);
for ($i = 0; $i < $length; $i+= 16) {
for ($j = 0; $j < 16; $j++) {
// RFC1319 incorrectly states that C[j] should be set to S[c xor L]
//$c[$j] = chr($s[ord($m[$i + $j] ^ $l)]);
// per <http://www.rfc-editor.org/errata_search.php?rfc=1319>, however, C[j] should be set to S[c xor L] xor C[j]
$c[$j] = chr($s[ord($m[$i + $j] ^ $l)] ^ ord($c[$j]));
$l = $c[$j];
}
}
$m.= $c;
$length+= 16;
// Step 3. Initialize MD Buffer
$x = str_repeat(chr(0), 48);
// Step 4. Process Message in 16-Byte Blocks
for ($i = 0; $i < $length; $i+= 16) {
for ($j = 0; $j < 16; $j++) {
$x[$j + 16] = $m[$i + $j];
$x[$j + 32] = $x[$j + 16] ^ $x[$j];
}
$t = chr(0);
for ($j = 0; $j < 18; $j++) {
for ($k = 0; $k < 48; $k++) {
$x[$k] = $t = $x[$k] ^ chr($s[ord($t)]);
//$t = $x[$k] = $x[$k] ^ chr($s[ord($t)]);
}
$t = chr(ord($t) + $j);
}
}
// Step 5. Output
return substr($x, 0, 16);
}
/**
* Pure-PHP implementation of SHA256
*
* See {@link http://en.wikipedia.org/wiki/SHA_hash_functions#SHA-256_.28a_SHA-2_variant.29_pseudocode SHA-256 (a SHA-2 variant) pseudocode - Wikipedia}.
*
* @access private
* @param string $m
*/
function _sha256($m)
{
if (extension_loaded('suhosin')) {
return pack('H*', sha256($m));
}
// Initialize variables
$hash = array(
0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
);
// Initialize table of round constants
// (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311)
static $k = array(
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
);
// Pre-processing
$length = strlen($m);
// to round to nearest 56 mod 64, we'll add 64 - (length + (64 - 56)) % 64
$m.= str_repeat(chr(0), 64 - (($length + 8) & 0x3F));
$m[$length] = chr(0x80);
// we don't support hashing strings 512MB long
$m.= pack('N2', 0, $length << 3);
// Process the message in successive 512-bit chunks
$chunks = str_split($m, 64);
foreach ($chunks as $chunk) {
$w = array();
for ($i = 0; $i < 16; $i++) {
extract(unpack('Ntemp', $this->_string_shift($chunk, 4)));
$w[] = $temp;
}
// Extend the sixteen 32-bit words into sixty-four 32-bit words
for ($i = 16; $i < 64; $i++) {
// @codingStandardsIgnoreStart
$s0 = $this->_rightRotate($w[$i - 15], 7) ^
$this->_rightRotate($w[$i - 15], 18) ^
$this->_rightShift( $w[$i - 15], 3);
$s1 = $this->_rightRotate($w[$i - 2], 17) ^
$this->_rightRotate($w[$i - 2], 19) ^
$this->_rightShift( $w[$i - 2], 10);
// @codingStandardsIgnoreEnd
$w[$i] = $this->_add($w[$i - 16], $s0, $w[$i - 7], $s1);
}
// Initialize hash value for this chunk
list($a, $b, $c, $d, $e, $f, $g, $h) = $hash;
// Main loop
for ($i = 0; $i < 64; $i++) {
$s0 = $this->_rightRotate($a, 2) ^
$this->_rightRotate($a, 13) ^
$this->_rightRotate($a, 22);
$maj = ($a & $b) ^
($a & $c) ^
($b & $c);
$t2 = $this->_add($s0, $maj);
$s1 = $this->_rightRotate($e, 6) ^
$this->_rightRotate($e, 11) ^
$this->_rightRotate($e, 25);
$ch = ($e & $f) ^
($this->_not($e) & $g);
$t1 = $this->_add($h, $s1, $ch, $k[$i], $w[$i]);
$h = $g;
$g = $f;
$f = $e;
$e = $this->_add($d, $t1);
$d = $c;
$c = $b;
$b = $a;
$a = $this->_add($t1, $t2);
}
// Add this chunk's hash to result so far
$hash = array(
$this->_add($hash[0], $a),
$this->_add($hash[1], $b),
$this->_add($hash[2], $c),
$this->_add($hash[3], $d),
$this->_add($hash[4], $e),
$this->_add($hash[5], $f),
$this->_add($hash[6], $g),
$this->_add($hash[7], $h)
);
}
// Produce the final hash value (big-endian)
return pack('N8', $hash[0], $hash[1], $hash[2], $hash[3], $hash[4], $hash[5], $hash[6], $hash[7]);
}
/**
* Pure-PHP implementation of SHA384 and SHA512
*
* @access private
* @param string $m
*/
function _sha512($m)
{
static $init384, $init512, $k;
if (!isset($k)) {
// Initialize variables
$init384 = array( // initial values for SHA384
'cbbb9d5dc1059ed8', '629a292a367cd507', '9159015a3070dd17', '152fecd8f70e5939',
'67332667ffc00b31', '8eb44a8768581511', 'db0c2e0d64f98fa7', '47b5481dbefa4fa4'
);
$init512 = array( // initial values for SHA512
'6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1',
'510e527fade682d1', '9b05688c2b3e6c1f', '1f83d9abfb41bd6b', '5be0cd19137e2179'
);
for ($i = 0; $i < 8; $i++) {
$init384[$i] = new BigInteger($init384[$i], 16);
$init384[$i]->setPrecision(64);
$init512[$i] = new BigInteger($init512[$i], 16);
$init512[$i]->setPrecision(64);
}
// Initialize table of round constants
// (first 64 bits of the fractional parts of the cube roots of the first 80 primes 2..409)
$k = array(
'428a2f98d728ae22', '7137449123ef65cd', 'b5c0fbcfec4d3b2f', 'e9b5dba58189dbbc',
'3956c25bf348b538', '59f111f1b605d019', '923f82a4af194f9b', 'ab1c5ed5da6d8118',
'd807aa98a3030242', '12835b0145706fbe', '243185be4ee4b28c', '550c7dc3d5ffb4e2',
'72be5d74f27b896f', '80deb1fe3b1696b1', '9bdc06a725c71235', 'c19bf174cf692694',
'e49b69c19ef14ad2', 'efbe4786384f25e3', '0fc19dc68b8cd5b5', '240ca1cc77ac9c65',
'2de92c6f592b0275', '4a7484aa6ea6e483', '5cb0a9dcbd41fbd4', '76f988da831153b5',
'983e5152ee66dfab', 'a831c66d2db43210', 'b00327c898fb213f', 'bf597fc7beef0ee4',
'c6e00bf33da88fc2', 'd5a79147930aa725', '06ca6351e003826f', '142929670a0e6e70',
'27b70a8546d22ffc', '2e1b21385c26c926', '4d2c6dfc5ac42aed', '53380d139d95b3df',
'650a73548baf63de', '766a0abb3c77b2a8', '81c2c92e47edaee6', '92722c851482353b',
'a2bfe8a14cf10364', 'a81a664bbc423001', 'c24b8b70d0f89791', 'c76c51a30654be30',
'd192e819d6ef5218', 'd69906245565a910', 'f40e35855771202a', '106aa07032bbd1b8',
'19a4c116b8d2d0c8', '1e376c085141ab53', '2748774cdf8eeb99', '34b0bcb5e19b48a8',
'391c0cb3c5c95a63', '4ed8aa4ae3418acb', '5b9cca4f7763e373', '682e6ff3d6b2b8a3',
'748f82ee5defb2fc', '78a5636f43172f60', '84c87814a1f0ab72', '8cc702081a6439ec',
'90befffa23631e28', 'a4506cebde82bde9', 'bef9a3f7b2c67915', 'c67178f2e372532b',
'ca273eceea26619c', 'd186b8c721c0c207', 'eada7dd6cde0eb1e', 'f57d4f7fee6ed178',
'06f067aa72176fba', '0a637dc5a2c898a6', '113f9804bef90dae', '1b710b35131c471b',
'28db77f523047d84', '32caab7b40c72493', '3c9ebe0a15c9bebc', '431d67c49c100d4c',
'4cc5d4becb3e42b6', '597f299cfc657e2a', '5fcb6fab3ad6faec', '6c44198c4a475817'
);
for ($i = 0; $i < 80; $i++) {
$k[$i] = new BigInteger($k[$i], 16);
}
}
$hash = $this->l == 48 ? $init384 : $init512;
// Pre-processing
$length = strlen($m);
// to round to nearest 112 mod 128, we'll add 128 - (length + (128 - 112)) % 128
$m.= str_repeat(chr(0), 128 - (($length + 16) & 0x7F));
$m[$length] = chr(0x80);
// we don't support hashing strings 512MB long
$m.= pack('N4', 0, 0, 0, $length << 3);
// Process the message in successive 1024-bit chunks
$chunks = str_split($m, 128);
foreach ($chunks as $chunk) {
$w = array();
for ($i = 0; $i < 16; $i++) {
$temp = new BigInteger($this->_string_shift($chunk, 8), 256);
$temp->setPrecision(64);
$w[] = $temp;
}
// Extend the sixteen 32-bit words into eighty 32-bit words
for ($i = 16; $i < 80; $i++) {
$temp = array(
$w[$i - 15]->bitwise_rightRotate(1),
$w[$i - 15]->bitwise_rightRotate(8),
$w[$i - 15]->bitwise_rightShift(7)
);
$s0 = $temp[0]->bitwise_xor($temp[1]);
$s0 = $s0->bitwise_xor($temp[2]);
$temp = array(
$w[$i - 2]->bitwise_rightRotate(19),
$w[$i - 2]->bitwise_rightRotate(61),
$w[$i - 2]->bitwise_rightShift(6)
);
$s1 = $temp[0]->bitwise_xor($temp[1]);
$s1 = $s1->bitwise_xor($temp[2]);
$w[$i] = $w[$i - 16]->copy();
$w[$i] = $w[$i]->add($s0);
$w[$i] = $w[$i]->add($w[$i - 7]);
$w[$i] = $w[$i]->add($s1);
}
// Initialize hash value for this chunk
$a = $hash[0]->copy();
$b = $hash[1]->copy();
$c = $hash[2]->copy();
$d = $hash[3]->copy();
$e = $hash[4]->copy();
$f = $hash[5]->copy();
$g = $hash[6]->copy();
$h = $hash[7]->copy();
// Main loop
for ($i = 0; $i < 80; $i++) {
$temp = array(
$a->bitwise_rightRotate(28),
$a->bitwise_rightRotate(34),
$a->bitwise_rightRotate(39)
);
$s0 = $temp[0]->bitwise_xor($temp[1]);
$s0 = $s0->bitwise_xor($temp[2]);
$temp = array(
$a->bitwise_and($b),
$a->bitwise_and($c),
$b->bitwise_and($c)
);
$maj = $temp[0]->bitwise_xor($temp[1]);
$maj = $maj->bitwise_xor($temp[2]);
$t2 = $s0->add($maj);
$temp = array(
$e->bitwise_rightRotate(14),
$e->bitwise_rightRotate(18),
$e->bitwise_rightRotate(41)
);
$s1 = $temp[0]->bitwise_xor($temp[1]);
$s1 = $s1->bitwise_xor($temp[2]);
$temp = array(
$e->bitwise_and($f),
$g->bitwise_and($e->bitwise_not())
);
$ch = $temp[0]->bitwise_xor($temp[1]);
$t1 = $h->add($s1);
$t1 = $t1->add($ch);
$t1 = $t1->add($k[$i]);
$t1 = $t1->add($w[$i]);
$h = $g->copy();
$g = $f->copy();
$f = $e->copy();
$e = $d->add($t1);
$d = $c->copy();
$c = $b->copy();
$b = $a->copy();
$a = $t1->add($t2);
}
// Add this chunk's hash to result so far
$hash = array(
$hash[0]->add($a),
$hash[1]->add($b),
$hash[2]->add($c),
$hash[3]->add($d),
$hash[4]->add($e),
$hash[5]->add($f),
$hash[6]->add($g),
$hash[7]->add($h)
);
}
// Produce the final hash value (big-endian)
// (\phpseclib\Crypt\Hash::hash() trims the output for hashes but not for HMACs. as such, we trim the output here)
$temp = $hash[0]->toBytes() . $hash[1]->toBytes() . $hash[2]->toBytes() . $hash[3]->toBytes() .
$hash[4]->toBytes() . $hash[5]->toBytes();
if ($this->l != 48) {
$temp.= $hash[6]->toBytes() . $hash[7]->toBytes();
}
return $temp;
}
/**
* Right Rotate
*
* @access private
* @param int $int
* @param int $amt
* @see self::_sha256()
* @return int
*/
function _rightRotate($int, $amt)
{
$invamt = 32 - $amt;
$mask = (1 << $invamt) - 1;
return (($int << $invamt) & 0xFFFFFFFF) | (($int >> $amt) & $mask);
}
/**
* Right Shift
*
* @access private
* @param int $int
* @param int $amt
* @see self::_sha256()
* @return int
*/
function _rightShift($int, $amt)
{
$mask = (1 << (32 - $amt)) - 1;
return ($int >> $amt) & $mask;
}
/**
* Not
*
* @access private
* @param int $int
* @see self::_sha256()
* @return int
*/
function _not($int)
{
return ~$int & 0xFFFFFFFF;
}
/**
* Add
*
* _sha256() adds multiple unsigned 32-bit integers. Since PHP doesn't support unsigned integers and since the
* possibility of overflow exists, care has to be taken. BigInteger could be used but this should be faster.
*
* @param int $...
* @return int
* @see self::_sha256()
* @access private
*/
function _add()
{
static $mod;
if (!isset($mod)) {
$mod = pow(2, 32);
}
$result = 0;
$arguments = func_get_args();
foreach ($arguments as $argument) {
$result+= $argument < 0 ? ($argument & 0x7FFFFFFF) + 0x80000000 : $argument;
}
return fmod($result, $mod);
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param string $string
* @param int $index
* @return string
* @access private
*/
function _string_shift(&$string, $index = 1)
{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
}