PowerOfTwo.php — JetBackup – Backup, Restore & Migrate 3.1.23.3

backup / src / JetBackup / 3rdparty / phpseclib3 / Math / BigInteger / Engines / PHP / Reductions / PowerOfTwo.php

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PowerOfTwo.php

52 lines

1	<?php
2
3	/**
4	* PHP Power of Two Modular Exponentiation Engine
5	*
6	* PHP version 5 and 7
7	*
8	* @author Jim Wigginton <terrafrost@php.net>
9	* @copyright 2017 Jim Wigginton
10	* @license http://www.opensource.org/licenses/mit-license.html MIT License
11	* @link http://pear.php.net/package/Math_BigInteger
12	*/
13
14	declare(strict_types=1);
15
16	namespace phpseclib3\Math\BigInteger\Engines\PHP\Reductions;
17
18	use phpseclib3\Math\BigInteger\Engines\PHP\Base;
19
20	/**
21	* PHP Power Of Two Modular Exponentiation Engine
22	*
23	* @author Jim Wigginton <terrafrost@php.net>
24	*/
25	abstract class PowerOfTwo extends Base
26	{
27	/**
28	* Prepare a number for use in Montgomery Modular Reductions
29	*/
30	protected static function prepareReduce(array $x, array $n, string $class): array
31	{
32	return self::reduce($x, $n, $class);
33	}
34
35	/**
36	* Power Of Two Reduction
37	*/
38	protected static function reduce(array $x, array $n, string $class): array
39	{
40	$lhs = new $class();
41	$lhs->value = $x;
42	$rhs = new $class();
43	$rhs->value = $n;
44
45	$temp = new $class();
46	$temp->value = [1];
47
48	$result = $lhs->bitwise_and($rhs->subtract($temp));
49	return $result->value;
50	}
51	}
52