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<?php
/**
* secp192r1
*
* This is the NIST P-192 curve
*
* PHP version 5 and 7
*
* @category Crypt
* @package EC
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2017 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://pear.php.net/package/Math_BigInteger
*/
namespace phpseclib3\Crypt\EC\Curves;
use phpseclib3\Crypt\EC\BaseCurves\Prime;
use phpseclib3\Math\BigInteger;
class secp192r1 extends Prime
{
public function __construct()
{
$modulo = new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFF', 16);
$this->setModulo($modulo);
// algorithm 2.27 from http://diamond.boisestate.edu/~liljanab/MATH308/GuideToECC.pdf#page=66
/* in theory this should be faster than regular modular reductions save for one small issue.
to convert to / from base-2**8 with BCMath you have to call bcmul() and bcdiv() a lot.
to convert to / from base-2**8 with PHP64 you have to call base256_rshift() a lot.
in short, converting to / from base-2**8 is pretty expensive and that expense is
enough to offset whatever else might be gained by a simplified reduction algorithm.
now, if PHP supported unsigned integers things might be different. no bit-shifting
would be required for the PHP engine and it'd be a lot faster. but as is, BigInteger
uses base-2**31 or base-2**26 depending on whether or not the system is has a 32-bit
or a 64-bit OS.
*/
/*
$m_length = $this->getLengthInBytes();
$this->setReduction(function($c) use ($m_length) {
$cBytes = $c->toBytes();
$className = $this->className;
if (strlen($cBytes) > 2 * $m_length) {
list(, $r) = $c->divide($className::$modulo);
return $r;
}
$c = str_pad($cBytes, 48, "\0", STR_PAD_LEFT);
$c = array_reverse(str_split($c, 8));
$null = "\0\0\0\0\0\0\0\0";
$s1 = new BigInteger($c[2] . $c[1] . $c[0], 256);
$s2 = new BigInteger($null . $c[3] . $c[3], 256);
$s3 = new BigInteger($c[4] . $c[4] . $null, 256);
$s4 = new BigInteger($c[5] . $c[5] . $c[5], 256);
$r = $s1->add($s2)->add($s3)->add($s4);
while ($r->compare($className::$modulo) >= 0) {
$r = $r->subtract($className::$modulo);
}
return $r;
});
*/
$this->setCoefficients(
new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFC', 16),
new BigInteger('64210519E59C80E70FA7E9AB72243049FEB8DEECC146B9B1', 16)
);
$this->setBasePoint(
new BigInteger('188DA80EB03090F67CBF20EB43A18800F4FF0AFD82FF1012', 16),
new BigInteger('07192B95FFC8DA78631011ED6B24CDD573F977A11E794811', 16)
);
$this->setOrder(new BigInteger('FFFFFFFFFFFFFFFFFFFFFFFF99DEF836146BC9B1B4D22831', 16));
}
}
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