<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Crypt\Key\Derivation;
/**
* Scrypt key derivation function
*
* @see http://www.tarsnap.com/scrypt.html
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01
*/
abstract class Scrypt
{
/**
* Execute the scrypt algorithm
*
* @param string $password
* @param string $salt
* @param int $n CPU cost
* @param int $r Memory cost
* @param int $p parallelization cost
* @param int $length size of the output key
* @return string
*/
public static function calc($password, $salt, $n, $r, $p, $length)
{
if ($n == 0 || ($n & ($n - 1)) != 0) {
throw new Exception\InvalidArgumentException("N must be > 0 and a power of 2");
}
if ($n > PHP_INT_MAX / 128 / $r) {
throw new Exception\InvalidArgumentException("Parameter n is too large");
}
if ($r > PHP_INT_MAX / 128 / $p) {
throw new Exception\InvalidArgumentException("Parameter r is too large");
}
if (extension_loaded('Scrypt')) {
if ($length < 16) {
throw new Exception\InvalidArgumentException("Key length is too low, must be greater or equal to 16");
}
return self::hex2bin(scrypt($password, $salt, $n, $r, $p, $length));
}
$b = Pbkdf2::calc('sha256', $password, $salt, 1, $p * 128 * $r);
$s = '';
for ($i = 0; $i < $p; $i++) {
$s .= self::scryptROMix(substr($b, $i * 128 * $r, 128 * $r), $n, $r);
}
return Pbkdf2::calc('sha256', $password, $s, 1, $length);
}
/**
* scryptROMix
*
* @param string $b
* @param int $n
* @param int $r
* @return string
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01#section-4
*/
protected static function scryptROMix($b, $n, $r)
{
$x = $b;
$v = array();
for ($i = 0; $i < $n; $i++) {
$v[$i] = $x;
$x = self::scryptBlockMix($x, $r);
}
for ($i = 0; $i < $n; $i++) {
$j = self::integerify($x) % $n;
$t = $x ^ $v[$j];
$x = self::scryptBlockMix($t, $r);
}
return $x;
}
/**
* scryptBlockMix
*
* @param string $b
* @param int $r
* @return string
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01#section-3
*/
protected static function scryptBlockMix($b, $r)
{
$x = substr($b, -64);
$even = '';
$odd = '';
$len = 2 * $r;
for ($i = 0; $i < $len; $i++) {
if (PHP_INT_SIZE === 4) {
$x = self::salsa208Core32($x ^ substr($b, 64 * $i, 64));
} else {
$x = self::salsa208Core64($x ^ substr($b, 64 * $i, 64));
}
if ($i % 2 == 0) {
$even .= $x;
} else {
$odd .= $x;
}
}
return $even . $odd;
}
/**
* Salsa 20/8 core (32 bit version)
*
* @param string $b
* @return string
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01#section-2
* @see http://cr.yp.to/salsa20.html
*/
protected static function salsa208Core32($b)
{
$b32 = array();
for ($i = 0; $i < 16; $i++) {
list(, $b32[$i]) = unpack("V", substr($b, $i * 4, 4));
}
$x = $b32;
for ($i = 0; $i < 8; $i += 2) {
$a = ($x[ 0] + $x[12]);
$x[ 4] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[ 4] + $x[ 0]);
$x[ 8] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 8] + $x[ 4]);
$x[12] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[12] + $x[ 8]);
$x[ 0] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[ 5] + $x[ 1]);
$x[ 9] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[ 9] + $x[ 5]);
$x[13] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[13] + $x[ 9]);
$x[ 1] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[ 1] + $x[13]);
$x[ 5] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[10] + $x[ 6]);
$x[14] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[14] + $x[10]);
$x[ 2] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 2] + $x[14]);
$x[ 6] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[ 6] + $x[ 2]);
$x[10] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[15] + $x[11]);
$x[ 3] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[ 3] + $x[15]);
$x[ 7] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 7] + $x[ 3]);
$x[11] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[11] + $x[ 7]);
$x[15] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[ 0] + $x[ 3]);
$x[ 1] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[ 1] + $x[ 0]);
$x[ 2] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 2] + $x[ 1]);
$x[ 3] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[ 3] + $x[ 2]);
$x[ 0] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[ 5] + $x[ 4]);
$x[ 6] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[ 6] + $x[ 5]);
$x[ 7] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 7] + $x[ 6]);
$x[ 4] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[ 4] + $x[ 7]);
$x[ 5] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[10] + $x[ 9]);
$x[11] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[11] + $x[10]);
$x[ 8] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[ 8] + $x[11]);
$x[ 9] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[ 9] + $x[ 8]);
$x[10] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
$a = ($x[15] + $x[14]);
$x[12] ^= ($a << 7) | ($a >> 25) & 0x7f;
$a = ($x[12] + $x[15]);
$x[13] ^= ($a << 9) | ($a >> 23) & 0x1ff;
$a = ($x[13] + $x[12]);
$x[14] ^= ($a << 13) | ($a >> 19) & 0x1fff;
$a = ($x[14] + $x[13]);
$x[15] ^= ($a << 18) | ($a >> 14) & 0x3ffff;
}
for ($i = 0; $i < 16; $i++) {
$b32[$i] = $b32[$i] + $x[$i];
}
$result = '';
for ($i = 0; $i < 16; $i++) {
$result .= pack("V", $b32[$i]);
}
return $result;
}
/**
* Salsa 20/8 core (64 bit version)
*
* @param string $b
* @return string
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01#section-2
* @see http://cr.yp.to/salsa20.html
*/
protected static function salsa208Core64($b)
{
$b32 = array();
for ($i = 0; $i < 16; $i++) {
list(, $b32[$i]) = unpack("V", substr($b, $i * 4, 4));
}
$x = $b32;
for ($i = 0; $i < 8; $i += 2) {
$a = ($x[ 0] + $x[12]) & 0xffffffff;
$x[ 4] ^= ($a << 7) | ($a >> 25);
$a = ($x[ 4] + $x[ 0]) & 0xffffffff;
$x[ 8] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 8] + $x[ 4]) & 0xffffffff;
$x[12] ^= ($a << 13) | ($a >> 19);
$a = ($x[12] + $x[ 8]) & 0xffffffff;
$x[ 0] ^= ($a << 18) | ($a >> 14);
$a = ($x[ 5] + $x[ 1]) & 0xffffffff;
$x[ 9] ^= ($a << 7) | ($a >> 25);
$a = ($x[ 9] + $x[ 5]) & 0xffffffff;
$x[13] ^= ($a << 9) | ($a >> 23);
$a = ($x[13] + $x[ 9]) & 0xffffffff;
$x[ 1] ^= ($a << 13) | ($a >> 19);
$a = ($x[ 1] + $x[13]) & 0xffffffff;
$x[ 5] ^= ($a << 18) | ($a >> 14);
$a = ($x[10] + $x[ 6]) & 0xffffffff;
$x[14] ^= ($a << 7) | ($a >> 25);
$a = ($x[14] + $x[10]) & 0xffffffff;
$x[ 2] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 2] + $x[14]) & 0xffffffff;
$x[ 6] ^= ($a << 13) | ($a >> 19);
$a = ($x[ 6] + $x[ 2]) & 0xffffffff;
$x[10] ^= ($a << 18) | ($a >> 14);
$a = ($x[15] + $x[11]) & 0xffffffff;
$x[ 3] ^= ($a << 7) | ($a >> 25);
$a = ($x[ 3] + $x[15]) & 0xffffffff;
$x[ 7] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 7] + $x[ 3]) & 0xffffffff;
$x[11] ^= ($a << 13) | ($a >> 19);
$a = ($x[11] + $x[ 7]) & 0xffffffff;
$x[15] ^= ($a << 18) | ($a >> 14);
$a = ($x[ 0] + $x[ 3]) & 0xffffffff;
$x[ 1] ^= ($a << 7) | ($a >> 25);
$a = ($x[ 1] + $x[ 0]) & 0xffffffff;
$x[ 2] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 2] + $x[ 1]) & 0xffffffff;
$x[ 3] ^= ($a << 13) | ($a >> 19);
$a = ($x[ 3] + $x[ 2]) & 0xffffffff;
$x[ 0] ^= ($a << 18) | ($a >> 14);
$a = ($x[ 5] + $x[ 4]) & 0xffffffff;
$x[ 6] ^= ($a << 7) | ($a >> 25);
$a = ($x[ 6] + $x[ 5]) & 0xffffffff;
$x[ 7] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 7] + $x[ 6]) & 0xffffffff;
$x[ 4] ^= ($a << 13) | ($a >> 19);
$a = ($x[ 4] + $x[ 7]) & 0xffffffff;
$x[ 5] ^= ($a << 18) | ($a >> 14);
$a = ($x[10] + $x[ 9]) & 0xffffffff;
$x[11] ^= ($a << 7) | ($a >> 25);
$a = ($x[11] + $x[10]) & 0xffffffff;
$x[ 8] ^= ($a << 9) | ($a >> 23);
$a = ($x[ 8] + $x[11]) & 0xffffffff;
$x[ 9] ^= ($a << 13) | ($a >> 19);
$a = ($x[ 9] + $x[ 8]) & 0xffffffff;
$x[10] ^= ($a << 18) | ($a >> 14);
$a = ($x[15] + $x[14]) & 0xffffffff;
$x[12] ^= ($a << 7) | ($a >> 25);
$a = ($x[12] + $x[15]) & 0xffffffff;
$x[13] ^= ($a << 9) | ($a >> 23);
$a = ($x[13] + $x[12]) & 0xffffffff;
$x[14] ^= ($a << 13) | ($a >> 19);
$a = ($x[14] + $x[13]) & 0xffffffff;
$x[15] ^= ($a << 18) | ($a >> 14);
}
for ($i = 0; $i < 16; $i++) {
$b32[$i] = ($b32[$i] + $x[$i]) & 0xffffffff;
}
$result = '';
for ($i = 0; $i < 16; $i++) {
$result .= pack("V", $b32[$i]);
}
return $result;
}
/**
* Integerify
*
* Integerify (B[0] ... B[2 * r - 1]) is defined as the result
* of interpreting B[2 * r - 1] as a little-endian integer.
* Each block B is a string of 64 bytes.
*
* @param string $b
* @return int
* @see https://tools.ietf.org/html/draft-josefsson-scrypt-kdf-01#section-4
*/
protected static function integerify($b)
{
$v = 'v';
if (PHP_INT_SIZE === 8) {
$v = 'V';
}
list(,$n) = unpack($v, substr($b, -64));
return $n;
}
/**
* Convert hex string in a binary string
*
* @param string $hex
* @return string
*/
protected static function hex2bin($hex)
{
if (version_compare(PHP_VERSION, '5.4') >= 0) {
return hex2bin($hex);
}
$len = strlen($hex);
$result = '';
for ($i = 0; $i < $len; $i+=2) {
$result .= chr(hexdec($hex[$i] . $hex[$i+1]));
}
return $result;
}
}