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<?php
/**
* EC Public Key
*
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2015 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib3\Crypt\EC;
use phpseclib3\Common\Functions\Strings;
use phpseclib3\Crypt\Common;
use phpseclib3\Crypt\EC;
use phpseclib3\Crypt\EC\BaseCurves\Montgomery as MontgomeryCurve;
use phpseclib3\Crypt\EC\BaseCurves\TwistedEdwards as TwistedEdwardsCurve;
use phpseclib3\Crypt\EC\Curves\Ed25519;
use phpseclib3\Crypt\EC\Formats\Keys\PKCS1;
use phpseclib3\Crypt\EC\Formats\Signature\ASN1 as ASN1Signature;
use phpseclib3\Crypt\Hash;
use phpseclib3\Exception\UnsupportedOperationException;
use phpseclib3\Math\BigInteger;
/**
* EC Public Key
*
* @author Jim Wigginton <terrafrost@php.net>
*/
final class PublicKey extends EC implements Common\PublicKey
{
use Common\Traits\Fingerprint;
/**
* Verify a signature
*
* @see self::verify()
* @param string $message
* @param string $signature
* @return mixed
*/
public function verify($message, $signature)
{
if ($this->curve instanceof MontgomeryCurve) {
throw new UnsupportedOperationException('Montgomery Curves cannot be used to create signatures');
}
$shortFormat = $this->shortFormat;
$format = $this->sigFormat;
if ($format === false) {
return false;
}
$order = $this->curve->getOrder();
if ($this->curve instanceof TwistedEdwardsCurve) {
if ($shortFormat == 'SSH2') {
list(, $signature) = Strings::unpackSSH2('ss', $signature);
}
if ($this->curve instanceof Ed25519 && self::$engines['libsodium'] && !isset($this->context)) {
return sodium_crypto_sign_verify_detached($signature, $message, $this->toString('libsodium'));
}
$curve = $this->curve;
if (strlen($signature) != 2 * $curve::SIZE) {
return false;
}
$R = substr($signature, 0, $curve::SIZE);
$S = substr($signature, $curve::SIZE);
try {
$R = PKCS1::extractPoint($R, $curve);
$R = $this->curve->convertToInternal($R);
} catch (\Exception $e) {
return false;
}
$S = strrev($S);
$S = new BigInteger($S, 256);
if ($S->compare($order) >= 0) {
return false;
}
$A = $curve->encodePoint($this->QA);
if ($curve instanceof Ed25519) {
$dom2 = !isset($this->context) ? '' :
'SigEd25519 no Ed25519 collisions' . "\0" . chr(strlen($this->context)) . $this->context;
} else {
$context = isset($this->context) ? $this->context : '';
$dom2 = 'SigEd448' . "\0" . chr(strlen($context)) . $context;
}
$hash = new Hash($curve::HASH);
$k = $hash->hash($dom2 . substr($signature, 0, $curve::SIZE) . $A . $message);
$k = strrev($k);
$k = new BigInteger($k, 256);
list(, $k) = $k->divide($order);
$qa = $curve->convertToInternal($this->QA);
$lhs = $curve->multiplyPoint($curve->getBasePoint(), $S);
$rhs = $curve->multiplyPoint($qa, $k);
$rhs = $curve->addPoint($rhs, $R);
$rhs = $curve->convertToAffine($rhs);
return $lhs[0]->equals($rhs[0]) && $lhs[1]->equals($rhs[1]);
}
$params = $format::load($signature);
if ($params === false || count($params) != 2) {
return false;
}
extract($params);
if (self::$engines['OpenSSL'] && in_array($this->hash->getHash(), openssl_get_md_methods())) {
$sig = $format != 'ASN1' ? ASN1Signature::save($r, $s) : $signature;
$result = openssl_verify($message, $sig, $this->toString('PKCS8', ['namedCurve' => false]), $this->hash->getHash());
if ($result != -1) {
return (bool) $result;
}
}
$n_1 = $order->subtract(self::$one);
if (!$r->between(self::$one, $n_1) || !$s->between(self::$one, $n_1)) {
return false;
}
$e = $this->hash->hash($message);
$e = new BigInteger($e, 256);
$Ln = $this->hash->getLength() - $order->getLength();
$z = $Ln > 0 ? $e->bitwise_rightShift($Ln) : $e;
$w = $s->modInverse($order);
list(, $u1) = $z->multiply($w)->divide($order);
list(, $u2) = $r->multiply($w)->divide($order);
$u1 = $this->curve->convertInteger($u1);
$u2 = $this->curve->convertInteger($u2);
list($x1, $y1) = $this->curve->multiplyAddPoints(
[$this->curve->getBasePoint(), $this->QA],
[$u1, $u2]
);
$x1 = $x1->toBigInteger();
list(, $x1) = $x1->divide($order);
return $x1->equals($r);
}
/**
* Returns the public key
*
* @param string $type
* @param array $options optional
* @return string
*/
public function toString($type, array $options = [])
{
$type = self::validatePlugin('Keys', $type, 'savePublicKey');
return $type::savePublicKey($this->curve, $this->QA, $options);
}
}
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