80 lines
2.3 KiB
PHP
80 lines
2.3 KiB
PHP
<?php
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/**
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* Curve25519
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*
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* PHP version 5 and 7
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*
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2019 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://pear.php.net/package/Math_BigInteger
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*/
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declare(strict_types=1);
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namespace phpseclib3\Crypt\EC\Curves;
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use phpseclib3\Crypt\EC\BaseCurves\Montgomery;
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use phpseclib3\Math\BigInteger;
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class Curve25519 extends Montgomery
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{
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public function __construct()
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{
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// 2^255 - 19
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$this->setModulo(new BigInteger('7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED', 16));
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$this->a24 = $this->factory->newInteger(new BigInteger('121666'));
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$this->p = [$this->factory->newInteger(new BigInteger(9))];
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// 2^252 + 0x14def9dea2f79cd65812631a5cf5d3ed
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$this->setOrder(new BigInteger('1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED', 16));
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/*
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$this->setCoefficients(
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new BigInteger('486662'), // a
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);
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$this->setBasePoint(
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new BigInteger(9),
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new BigInteger('14781619447589544791020593568409986887264606134616475288964881837755586237401')
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);
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*/
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}
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/**
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* Multiply a point on the curve by a scalar
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*
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* Modifies the scalar as described at https://tools.ietf.org/html/rfc7748#page-8
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*/
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public function multiplyPoint(array $p, BigInteger $d): array
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{
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//$r = strrev(sodium_crypto_scalarmult($d->toBytes(), strrev($p[0]->toBytes())));
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//return [$this->factory->newInteger(new BigInteger($r, 256))];
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$d = $d->toBytes();
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$d &= "\xF8" . str_repeat("\xFF", 30) . "\x7F";
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$d = strrev($d);
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$d |= "\x40";
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$d = new BigInteger($d, -256);
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return parent::multiplyPoint($p, $d);
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}
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/**
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* Creates a random scalar multiplier
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*/
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public function createRandomMultiplier(): BigInteger
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{
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return BigInteger::random(256);
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}
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/**
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* Performs range check
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*/
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public function rangeCheck(BigInteger $x): void
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{
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if ($x->getLength() > 256 || $x->isNegative()) {
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throw new \RangeException('x must be a positive integer less than 256 bytes in length');
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}
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}
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}
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