81 lines
3.0 KiB
PHP
81 lines
3.0 KiB
PHP
<?php
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/**
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* secp192r1
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*
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* This is the NIST P-192 curve
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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 2017 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\Prime;
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use phpseclib3\Math\BigInteger;
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class secp192r1 extends Prime
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{
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public function __construct()
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{
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$modulo = new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFF', 16);
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$this->setModulo($modulo);
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// algorithm 2.27 from http://diamond.boisestate.edu/~liljanab/MATH308/GuideToECC.pdf#page=66
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/* in theory this should be faster than regular modular reductions save for one small issue.
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to convert to / from base-2**8 with BCMath you have to call bcmul() and bcdiv() a lot.
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to convert to / from base-2**8 with PHP64 you have to call base256_rshift() a lot.
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in short, converting to / from base-2**8 is pretty expensive and that expense is
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enough to offset whatever else might be gained by a simplified reduction algorithm.
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now, if PHP supported unsigned integers things might be different. no bit-shifting
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would be required for the PHP engine and it'd be a lot faster. but as is, BigInteger
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uses base-2**31 or base-2**26 depending on whether or not the system is has a 32-bit
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or a 64-bit OS.
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*/
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/*
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$m_length = $this->getLengthInBytes();
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$this->setReduction(function($c) use ($m_length) {
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$cBytes = $c->toBytes();
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$className = $this->className;
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if (strlen($cBytes) > 2 * $m_length) {
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list(, $r) = $c->divide($className::$modulo);
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return $r;
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}
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$c = str_pad($cBytes, 48, "\0", STR_PAD_LEFT);
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$c = array_reverse(str_split($c, 8));
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$null = "\0\0\0\0\0\0\0\0";
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$s1 = new BigInteger($c[2] . $c[1] . $c[0], 256);
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$s2 = new BigInteger($null . $c[3] . $c[3], 256);
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$s3 = new BigInteger($c[4] . $c[4] . $null, 256);
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$s4 = new BigInteger($c[5] . $c[5] . $c[5], 256);
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$r = $s1->add($s2)->add($s3)->add($s4);
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while ($r->compare($className::$modulo) >= 0) {
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$r = $r->subtract($className::$modulo);
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}
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return $r;
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});
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*/
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$this->setCoefficients(
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new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFC', 16),
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new BigInteger('64210519E59C80E70FA7E9AB72243049FEB8DEECC146B9B1', 16)
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);
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$this->setBasePoint(
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new BigInteger('188DA80EB03090F67CBF20EB43A18800F4FF0AFD82FF1012', 16),
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new BigInteger('07192B95FFC8DA78631011ED6B24CDD573F977A11E794811', 16)
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);
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$this->setOrder(new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFF99DEF836146BC9B1B4D22831', 16));
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}
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}
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