EcAdapter::recoverYfromX() - Code Metrics - Inspection of "Unify phpecc & ecadapter" - Bit-Wasp/bitcoin-php - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#318)

by thomas

created 2016-06-17 21:48 UTC

EcAdapter::recoverYfromX() B

↳ Parent: Project

Complexity

Conditions	3
Paths	3

Size

Total Lines	29
Code Lines	17

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	18
CRAP Score	3

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	3
eloc	17
c	1
b	0
f	0
nc	3
nop	2
dl	0
loc	29
ccs	18
cts	18
cp	1
crap	3
rs	8.8571

<?php

namespace BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Adapter;

use BitWasp\Bitcoin\Crypto\EcAdapter\Adapter\EcAdapterInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\CompactSignatureInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\SignatureInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PublicKey;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\Signature;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PublicKeyInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PrivateKeyInterface;
use BitWasp\Bitcoin\Crypto\Random\RbgInterface;
use BitWasp\Bitcoin\Crypto\Random\Rfc6979;
use BitWasp\Bitcoin\Math\Math;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PrivateKey;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\CompactSignature;
use BitWasp\Buffertools\BufferInterface;
use Mdanter\Ecc\Crypto\Signature\Signer;
use Mdanter\Ecc\Primitives\GeneratorPoint;
use Mdanter\Ecc\Primitives\PointInterface;

class EcAdapter implements EcAdapterInterface
{
    /**
     * @var Math
     */
    private $math;

    /**
     * @var GeneratorPoint
     */
    private $generator;

    /**
     * @param Math $math
     * @param GeneratorPoint $generator
     */
    public function __construct(Math $math, GeneratorPoint $generator)
    {
        $this->math = $math;
        $this->generator = $generator;
    }

    /**
     * @return Math
     */
    public function getMath()
    {
        return $this->math;
    }

    /**
     * @return GeneratorPoint
     */
    public function getGenerator()
    {
        return $this->generator;
    }

    /**
     * @param \GMP $scalar
     * @param bool|false $compressed
     * @return PrivateKey
     */
    public function getPrivateKey(\GMP $scalar, $compressed = false)
    {
        return new PrivateKey($this, $scalar, $compressed);
    }

    /**
     * @param PointInterface $point
     * @param bool|false $compressed
     * @return PublicKey
     */
    public function getPublicKey(PointInterface $point, $compressed = false)
    {
        return new PublicKey($this, $point, $compressed);
    }

    /**
     * @param \GMP $r
     * @param \GMP $s
     * @return Signature
     */
    public function getSignature(\GMP $r, \GMP $s)
    {
        return new Signature($this, $r, $s);
    }

    /**
     * @param BufferInterface $messageHash
     * @param PublicKey $publicKey
     * @param Signature $signature
     * @return bool
     */
    private function doVerify(BufferInterface $messageHash, PublicKey $publicKey, Signature $signature)
    {
        $hash = gmp_init($messageHash->getHex(), 16);
        $signer = new Signer($this->math);
        return $signer->verify($publicKey, $signature, $hash);
    }

    /**
     * @param BufferInterface $messageHash
     * @param PublicKeyInterface $publicKey
     * @param SignatureInterface $signature
     * @return bool
     */
    public function verify(BufferInterface $messageHash, PublicKeyInterface $publicKey, SignatureInterface $signature)
    {
        /** @var PublicKey $publicKey */
        /** @var Signature $signature */
        return $this->doVerify($messageHash, $publicKey, $signature);

    }

    /**
     * @param BufferInterface $messageHash
     * @param PrivateKey $privateKey
     * @param RbgInterface|null $rbg
     * @return Signature
     */
    private function doSign(BufferInterface $messageHash, PrivateKey $privateKey, RbgInterface $rbg = null)
    {
        $rbg = $rbg ?: new Rfc6979($this, $privateKey, $messageHash);
        $randomK = gmp_init($rbg->bytes(32)->getHex(), 16);
        $hash = gmp_init($messageHash->getHex(), 16);

        $signer = new Signer($this->math);
        $signature = $signer->sign($privateKey, $hash, $randomK);
        $s = $signature->getS();

        // if s is less than half the curve order, invert s
        if (!$this->validateSignatureElement($s, true)) {
            $s = $this->math->sub($this->generator->getOrder(), $s);
        }

        return new Signature($this, $signature->getR(), $s);
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
    }

    /**
     * @param BufferInterface $messageHash
     * @param PrivateKeyInterface $privateKey
     * @param RbgInterface $rbg
     * @return SignatureInterface
     * @throws \BitWasp\Bitcoin\Exceptions\RandomBytesFailure
     */
    public function sign(BufferInterface $messageHash, PrivateKeyInterface $privateKey, RbgInterface $rbg = null)
    {
        /** @var PrivateKey $privateKey */
        return $this->doSign($messageHash, $privateKey, $rbg);
    }

    /**
     * @param BufferInterface $messageHash
     * @param CompactSignatureInterface $signature
     * @return PublicKey
     * @throws \Exception
     */
    public function recover(BufferInterface $messageHash, CompactSignatureInterface $signature)
    {
        $math = $this->getMath();
        $G = $this->getGenerator();

        $zero = gmp_init(0);
        $one = gmp_init(1);

        $r = $signature->getR();
        $s = $signature->getS();
        $recGMP = gmp_init($signature->getRecoveryId(), 10);
        $isYEven = $math->cmp($math->bitwiseAnd($recGMP, $one), $zero) !== 0;
        $isSecondKey = $math->cmp($math->bitwiseAnd($recGMP, gmp_init(2)), $zero) !== 0;
        $curve = $G->getCurve();

        // Precalculate (p + 1) / 4 where p is the field order
        $p_over_four = $math->div($math->add($curve->getPrime(), $one), gmp_init(4));

        // 1.1 Compute x
        if (!$isSecondKey) {
            $x = $r;
        } else {
            $x = $math->add($r, $G->getOrder());
        }

        // 1.3 Convert x to point
        $alpha = $math->mod($math->add($math->add($math->pow($x, 3), $math->mul($curve->getA(), $x)), $curve->getB()), $curve->getPrime());
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}
        $beta = $math->powmod($alpha, $p_over_four, $curve->getPrime());

        // If beta is even, but y isn't or vice versa, then convert it,
        // otherwise we're done and y == beta.
        if ($math->isEven($beta) === $isYEven) {
            $y = $math->sub($curve->getPrime(), $beta);
        } else {
            $y = $beta;
        }

        // 1.4 Check that nR is at infinity (implicitly done in constructor)
        $R = $G->getCurve()->getPoint($x, $y);
/**
 * @return array|string
 */
function returnsDifferentValues($x) {
    if ($x) {
        return 'foo';
    }

    return array();
}

$x = returnsDifferentValues($y);
if (is_array($x)) {
    // $x is an array.
}

        $point_negate = function (PointInterface $p) use ($math, $G) {
            return $G->getCurve()->getPoint($p->getX(), $math->mul($p->getY(), gmp_init('-1', 10)));
        };

        // 1.6.1 Compute a candidate public key Q = r^-1 (sR - eG)
        $rInv = $math->inverseMod($r, $G->getOrder());
        $eGNeg = $point_negate($G->mul(gmp_init($messageHash->getInt())));
        $Q = $R->mul($s)->add($eGNeg)->mul($rInv);

        // 1.6.2 Test Q as a public key
        $Qk = new PublicKey($this, $Q, $signature->isCompressed());
        if ($this->verify($messageHash, $Qk, $signature->convert())) {
            return $Qk;
        }

        throw new \Exception('Unable to recover public key');
    }

    /**
     * Attempt to calculate the public key recovery param by trial and error
     *
     * @param \GMP $r
     * @param \GMP $s
     * @param BufferInterface $messageHash
     * @param PublicKey $publicKey
     * @return int
     * @throws \Exception
     */
    public function calcPubKeyRecoveryParam(\GMP $r, \GMP $s, BufferInterface $messageHash, PublicKey $publicKey)
    {
        $Q = $publicKey->getPoint();
        for ($i = 0; $i < 4; $i++) {
            try {
                $recover = $this->recover($messageHash, new CompactSignature($this, $r, $s, $i, $publicKey->isCompressed()));
                if ($Q->equals($recover->getPoint())) {
                    return $i;
                }
            } catch (\Exception $e) {
                continue;
            }
        }

        throw new \Exception('Failed to find valid recovery factor');
    }

    /**
     * @param BufferInterface $messageHash
     * @param PrivateKey $privateKey
     * @param RbgInterface|null $rbg
     * @return CompactSignature
     * @throws \Exception
     */
    private function doSignCompact(BufferInterface $messageHash, PrivateKey $privateKey, RbgInterface $rbg = null)
    {
        $sign = $this->sign($messageHash, $privateKey, $rbg);

        // calculate the recovery param
        // there should be a way to get this when signing too, but idk how ...
        return new CompactSignature(
            $this,
            $sign->getR(),
            $sign->getS(),
            $this->calcPubKeyRecoveryParam($sign->getR(), $sign->getS(), $messageHash, $privateKey->getPublicKey()),
            $privateKey->isCompressed()
        );
    }

    /**
     * @param PrivateKeyInterface $privateKey
     * @param BufferInterface $messageHash
     * @param RbgInterface $rbg
     * @return CompactSignature
     */
    public function signCompact(BufferInterface $messageHash, PrivateKeyInterface $privateKey, RbgInterface $rbg = null)
    {
        /** @var PrivateKey $privateKey */
        return $this->doSignCompact($messageHash, $privateKey, $rbg);
    }

    /**
     * @param BufferInterface $privateKey
     * @return bool
     */
    public function validatePrivateKey(BufferInterface $privateKey)
    {
        $math = $this->math;
        $scalar = gmp_init($privateKey->getInt(), 10);
        return $math->cmp($scalar, gmp_init(0)) > 0 && $math->cmp($scalar, $this->getGenerator()->getOrder()) < 0;
    }

    /**
     * @param \GMP $element
     * @param bool $half
     * @return bool
     */
    public function validateSignatureElement(\GMP $element, $half = false)
    {
        $math = $this->getMath();
        $against = $this->getGenerator()->getOrder();
        if ($half) {
            $against = $math->rightShift($against, 1);
        }

        return $math->cmp($element, $against) < 0 && $math->cmp($element, gmp_init(0)) !== 0;
    }

    /**
     * @param BufferInterface $publicKey
     * @return PublicKeyInterface
     * @throws \Exception
     */
    public function publicKeyFromBuffer(BufferInterface $publicKey)
    {
        $prefix = $publicKey->slice(0, 1)->getBinary();
        $size = $publicKey->getSize();
        if ($prefix == PublicKey::KEY_UNCOMPRESSED) {
            if ($size !== PublicKey::LENGTH_UNCOMPRESSED) {
                throw new \Exception('Invalid length for uncompressed key');
            }
            $compressed = false;
        } else if ($prefix === PublicKey::KEY_COMPRESSED_EVEN || $prefix === PublicKey::KEY_COMPRESSED_ODD) {
            if ($size !== PublicKey::LENGTH_COMPRESSED) {
                throw new \Exception('Invalid length for compressed key');
            }
            $compressed = true;
        } else {
            throw new \Exception('Unknown public key prefix');
        }

        $x = gmp_init($publicKey->slice(1, 32)->getInt(), 10);
        $curve = $this->generator->getCurve();
        $y = $compressed
            ? $curve->recoverYfromX($prefix === PublicKey::KEY_COMPRESSED_ODD, $x)
            : gmp_init($publicKey->slice(33, 32)->getInt(), 10);

        return new PublicKey(
            $this,
            $curve->getPoint($x, $y),
            $compressed
        );
    }
}


1		<?php
2
3		namespace BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Adapter;
4
5		use BitWasp\Bitcoin\Crypto\EcAdapter\Adapter\EcAdapterInterface;
6		use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\CompactSignatureInterface;
7		use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\SignatureInterface;
8		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PublicKey;
9		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\Signature;
10		use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PublicKeyInterface;
11		use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PrivateKeyInterface;
12		use BitWasp\Bitcoin\Crypto\Random\RbgInterface;
13		use BitWasp\Bitcoin\Crypto\Random\Rfc6979;
14		use BitWasp\Bitcoin\Math\Math;
15		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PrivateKey;
16		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\CompactSignature;
17		use BitWasp\Buffertools\BufferInterface;
18		use Mdanter\Ecc\Crypto\Signature\Signer;
19		use Mdanter\Ecc\Primitives\GeneratorPoint;
20		use Mdanter\Ecc\Primitives\PointInterface;
21
22		class EcAdapter implements EcAdapterInterface
23		{
24		/**
25		* @var Math
26		*/
27		private $math;
28
29		/**
30		* @var GeneratorPoint
31		*/
32		private $generator;
33
34		/**
35		* @param Math $math
36		* @param GeneratorPoint $generator
37		*/
38	19	public function __construct(Math $math, GeneratorPoint $generator)
39		{
40	19	$this->math = $math;
41	19	$this->generator = $generator;
42	19	}
43
44		/**
45		* @return Math
46		*/
47	614	public function getMath()
48		{
49	614	return $this->math;
50		}
51
52		/**
53		* @return GeneratorPoint
54		*/
55	169	public function getGenerator()
56		{
57	169	return $this->generator;
58		}
59
60		/**
61		* @param \GMP $scalar
62		* @param bool\|false $compressed
63		* @return PrivateKey
64		*/
65	125	public function getPrivateKey(\GMP $scalar, $compressed = false)
66		{
67	125	return new PrivateKey($this, $scalar, $compressed);
68		}
69
70		/**
71		* @param PointInterface $point
72		* @param bool\|false $compressed
73		* @return PublicKey
74		*/
75	105	public function getPublicKey(PointInterface $point, $compressed = false)
76		{
77	105	return new PublicKey($this, $point, $compressed);
78		}
79
80		/**
81		* @param \GMP $r
82		* @param \GMP $s
83		* @return Signature
84		*/
85		public function getSignature(\GMP $r, \GMP $s)
86		{
87		return new Signature($this, $r, $s);
88		}
89
90		/**
91		* @param BufferInterface $messageHash
92		* @param PublicKey $publicKey
93		* @param Signature $signature
94		* @return bool
95		*/
96	47	private function doVerify(BufferInterface $messageHash, PublicKey $publicKey, Signature $signature)
97		{
98	47	$hash = gmp_init($messageHash->getHex(), 16);
99	47	$signer = new Signer($this->math);
100	47	return $signer->verify($publicKey, $signature, $hash);
101		}
102
103		/**
104		* @param BufferInterface $messageHash
105		* @param PublicKeyInterface $publicKey
106		* @param SignatureInterface $signature
107		* @return bool
108		*/
109	47	public function verify(BufferInterface $messageHash, PublicKeyInterface $publicKey, SignatureInterface $signature)
110		{
111		/** @var PublicKey $publicKey */
112		/** @var Signature $signature */
113	47	return $this->doVerify($messageHash, $publicKey, $signature);
		0 ignored issues – show Compatibility introduced 2015-11-21 03:53 UTC by Report Bug Copy Issue Report `$publicKey` of type `object<BitWasp\Bitcoin\C...Key\PublicKeyInterface>` is not a sub-type of `object<BitWasp\Bitcoin\C...l\PhpEcc\Key\PublicKey>`. It seems like you assume a concrete implementation of the interface `BitWasp\Bitcoin\Crypto\E...\Key\PublicKeyInterface` to be always present. This check looks for parameters that are defined as one type in their type hint or doc comment but seem to be used as a narrower type, i.e an implementation of an interface or a subclass. Consider changing the type of the parameter or doing an instanceof check before assuming your parameter is of the expected type. Loading history...
114		}
115
116		/**
117		* @param BufferInterface $messageHash
118		* @param PrivateKey $privateKey
119		* @param RbgInterface\|null $rbg
120		* @return Signature
121		*/
122	46	private function doSign(BufferInterface $messageHash, PrivateKey $privateKey, RbgInterface $rbg = null)
123		{
124	46	$rbg = $rbg ?: new Rfc6979($this, $privateKey, $messageHash);
125	46	$randomK = gmp_init($rbg->bytes(32)->getHex(), 16);
126	46	$hash = gmp_init($messageHash->getHex(), 16);
127
128	46	$signer = new Signer($this->math);
129	46	$signature = $signer->sign($privateKey, $hash, $randomK);
130	46	$s = $signature->getS();
131
132		// if s is less than half the curve order, invert s
133	46	if (!$this->validateSignatureElement($s, true)) {
134	23	$s = $this->math->sub($this->generator->getOrder(), $s);
135	11	}
136
137	46	return new Signature($this, $signature->getR(), $s);
		0 ignored issues – show Bug introduced 2016-06-17 22:20 UTC by Report Bug Copy Issue Report It seems like `$s` defined by `$this->math->sub($this->...erator->getOrder(), $s)` on line `134` can also be of type `resource`; however, `BitWasp\Bitcoin\Crypto\E...ignature::__construct()` does only seem to accept `object<GMP>`, maybe add an additional type check? If a method or function can return multiple different values and unless you are sure that you only can receive a single value in this context, we recommend to add an additional type check: /** * @return array\|string */ function returnsDifferentValues($x) { if ($x) { return 'foo'; } return array(); } $x = returnsDifferentValues($y); if (is_array($x)) { // $x is an array. } If this a common case that PHP Analyzer should handle natively, please let us know by opening an issue. Loading history...
138		}
139
140		/**
141		* @param BufferInterface $messageHash
142		* @param PrivateKeyInterface $privateKey
143		* @param RbgInterface $rbg
144		* @return SignatureInterface
145		* @throws \BitWasp\Bitcoin\Exceptions\RandomBytesFailure
146		*/
147	46	public function sign(BufferInterface $messageHash, PrivateKeyInterface $privateKey, RbgInterface $rbg = null)
148		{
149		/** @var PrivateKey $privateKey */
150	46	return $this->doSign($messageHash, $privateKey, $rbg);
151		}
152
153		/**
154		* @param BufferInterface $messageHash
155		* @param CompactSignatureInterface $signature
156		* @return PublicKey
157		* @throws \Exception
158		*/
159	17	public function recover(BufferInterface $messageHash, CompactSignatureInterface $signature)
160		{
161	17	$math = $this->getMath();
162	17	$G = $this->getGenerator();
163
164	17	$zero = gmp_init(0);
165	17	$one = gmp_init(1);
166
167	17	$r = $signature->getR();
168	17	$s = $signature->getS();
169	17	$recGMP = gmp_init($signature->getRecoveryId(), 10);
170	17	$isYEven = $math->cmp($math->bitwiseAnd($recGMP, $one), $zero) !== 0;
171	17	$isSecondKey = $math->cmp($math->bitwiseAnd($recGMP, gmp_init(2)), $zero) !== 0;
172	17	$curve = $G->getCurve();
173
174		// Precalculate (p + 1) / 4 where p is the field order
175	17	$p_over_four = $math->div($math->add($curve->getPrime(), $one), gmp_init(4));
176
177		// 1.1 Compute x
178	17	if (!$isSecondKey) {
179	17	$x = $r;
180	9	} else {
181	3	$x = $math->add($r, $G->getOrder());
182		}
183
184		// 1.3 Convert x to point
185	17	$alpha = $math->mod($math->add($math->add($math->pow($x, 3), $math->mul($curve->getA(), $x)), $curve->getB()), $curve->getPrime());
		0 ignored issues – show Bug introduced 2016-06-17 17:50 UTC by Report Bug Copy Issue Report It seems like `$x` defined by `$math->add($r, $G->getOrder())` on line `181` can also be of type `resource`; however, `Mdanter\Ecc\Math\GmpMath::pow()` does only seem to accept `object<GMP>`, maybe add an additional type check? If a method or function can return multiple different values and unless you are sure that you only can receive a single value in this context, we recommend to add an additional type check: /** * @return array\|string / function returnsDifferentValues($x) { if ($x) { return 'foo'; } return array(); } $x = returnsDifferentValues($y); if (is_array($x)) { // $x is an array. } If this a common case that PHP Analyzer should handle natively, please let us know by opening an issue. Loading history... Bug introduced 2016-06-17 17:50 UTC by Report Bug Copy Issue Report It seems like `$x` defined by `$math->add($r, $G->getOrder())` on line `181` can also be of type `resource`; however, `Mdanter\Ecc\Math\GmpMath::mul()` does only seem to accept `object<GMP>`, maybe add an additional type check? If a method or function can return multiple different values and unless you are sure that you only can receive a single value in this context, we recommend to add an additional type check: /* * @return array\|string */ function returnsDifferentValues($x) { if ($x) { return 'foo'; } return array(); } $x = returnsDifferentValues($y); if (is_array($x)) { // $x is an array. } If this a common case that PHP Analyzer should handle natively, please let us know by opening an issue. Loading history...
186	17	$beta = $math->powmod($alpha, $p_over_four, $curve->getPrime());
187
188		// If beta is even, but y isn't or vice versa, then convert it,
189		// otherwise we're done and y == beta.
190	17	if ($math->isEven($beta) === $isYEven) {
191	11	$y = $math->sub($curve->getPrime(), $beta);
192	6	} else {
193	11	$y = $beta;
194		}
195
196		// 1.4 Check that nR is at infinity (implicitly done in constructor)
197	17	$R = $G->getCurve()->getPoint($x, $y);
		0 ignored issues – show Bug introduced 2016-06-17 17:50 UTC by Report Bug Copy Issue Report It seems like `$x` defined by `$math->add($r, $G->getOrder())` on line `181` can also be of type `resource`; however, `Mdanter\Ecc\Primitives\C...FpInterface::getPoint()` does only seem to accept `object<GMP>`, maybe add an additional type check? If a method or function can return multiple different values and unless you are sure that you only can receive a single value in this context, we recommend to add an additional type check: /** * @return array\|string */ function returnsDifferentValues($x) { if ($x) { return 'foo'; } return array(); } $x = returnsDifferentValues($y); if (is_array($x)) { // $x is an array. } If this a common case that PHP Analyzer should handle natively, please let us know by opening an issue. Loading history...
198
199	17	$point_negate = function (PointInterface $p) use ($math, $G) {
200	17	return $G->getCurve()->getPoint($p->getX(), $math->mul($p->getY(), gmp_init('-1', 10)));
201	17	};
202
203		// 1.6.1 Compute a candidate public key Q = r^-1 (sR - eG)
204	17	$rInv = $math->inverseMod($r, $G->getOrder());
205	17	$eGNeg = $point_negate($G->mul(gmp_init($messageHash->getInt())));
206	17	$Q = $R->mul($s)->add($eGNeg)->mul($rInv);
207
208		// 1.6.2 Test Q as a public key
209	17	$Qk = new PublicKey($this, $Q, $signature->isCompressed());
210	17	if ($this->verify($messageHash, $Qk, $signature->convert())) {
211	14	return $Qk;
212		}
213
214	3	throw new \Exception('Unable to recover public key');
215		}
216
217		/**
218		* Attempt to calculate the public key recovery param by trial and error
219		*
220		* @param \GMP $r
221		* @param \GMP $s
222		* @param BufferInterface $messageHash
223		* @param PublicKey $publicKey
224		* @return int
225		* @throws \Exception
226		*/
227	15	public function calcPubKeyRecoveryParam(\GMP $r, \GMP $s, BufferInterface $messageHash, PublicKey $publicKey)
228		{
229	15	$Q = $publicKey->getPoint();
230	15	for ($i = 0; $i < 4; $i++) {
231		try {
232	15	$recover = $this->recover($messageHash, new CompactSignature($this, $r, $s, $i, $publicKey->isCompressed()));
233	12	if ($Q->equals($recover->getPoint())) {
234	12	return $i;
235		}
236	5	} catch (\Exception $e) {
237	3	continue;
238		}
239	2	}
240
241	3	throw new \Exception('Failed to find valid recovery factor');
242		}
243
244		/**
245		* @param BufferInterface $messageHash
246		* @param PrivateKey $privateKey
247		* @param RbgInterface\|null $rbg
248		* @return CompactSignature
249		* @throws \Exception
250		*/
251	12	private function doSignCompact(BufferInterface $messageHash, PrivateKey $privateKey, RbgInterface $rbg = null)
252		{
253	12	$sign = $this->sign($messageHash, $privateKey, $rbg);
254
255		// calculate the recovery param
256		// there should be a way to get this when signing too, but idk how ...
257	12	return new CompactSignature(
258	6	$this,
259	12	$sign->getR(),
260	12	$sign->getS(),
261	12	$this->calcPubKeyRecoveryParam($sign->getR(), $sign->getS(), $messageHash, $privateKey->getPublicKey()),
262	12	$privateKey->isCompressed()
263	6	);
264		}
265
266		/**
267		* @param PrivateKeyInterface $privateKey
268		* @param BufferInterface $messageHash
269		* @param RbgInterface $rbg
270		* @return CompactSignature
271		*/
272	12	public function signCompact(BufferInterface $messageHash, PrivateKeyInterface $privateKey, RbgInterface $rbg = null)
273		{
274		/** @var PrivateKey $privateKey */
275	12	return $this->doSignCompact($messageHash, $privateKey, $rbg);
276		}
277
278		/**
279		* @param BufferInterface $privateKey
280		* @return bool
281		*/
282	129	public function validatePrivateKey(BufferInterface $privateKey)
283		{
284	129	$math = $this->math;
285	129	$scalar = gmp_init($privateKey->getInt(), 10);
286	129	return $math->cmp($scalar, gmp_init(0)) > 0 && $math->cmp($scalar, $this->getGenerator()->getOrder()) < 0;
287		}
288
289		/**
290		* @param \GMP $element
291		* @param bool $half
292		* @return bool
293		*/
294	50	public function validateSignatureElement(\GMP $element, $half = false)
295		{
296	50	$math = $this->getMath();
297	50	$against = $this->getGenerator()->getOrder();
298	50	if ($half) {
299	50	$against = $math->rightShift($against, 1);
300	25	}
301
302	50	return $math->cmp($element, $against) < 0 && $math->cmp($element, gmp_init(0)) !== 0;
303		}
304
305		/**
306		* @param BufferInterface $publicKey
307		* @return PublicKeyInterface
308		* @throws \Exception
309		*/
310	158	public function publicKeyFromBuffer(BufferInterface $publicKey)
311		{
312	158	$prefix = $publicKey->slice(0, 1)->getBinary();
313	158	$size = $publicKey->getSize();
314	158	if ($prefix == PublicKey::KEY_UNCOMPRESSED) {
315	60	if ($size !== PublicKey::LENGTH_UNCOMPRESSED) {
316	2	throw new \Exception('Invalid length for uncompressed key');
317		}
318	58	$compressed = false;
319	128	} else if ($prefix === PublicKey::KEY_COMPRESSED_EVEN \|\| $prefix === PublicKey::KEY_COMPRESSED_ODD) {
320	98	if ($size !== PublicKey::LENGTH_COMPRESSED) {
321		throw new \Exception('Invalid length for compressed key');
322		}
323	98	$compressed = true;
324	49	} else {
325	2	throw new \Exception('Unknown public key prefix');
326		}
327
328	154	$x = gmp_init($publicKey->slice(1, 32)->getInt(), 10);
329	154	$curve = $this->generator->getCurve();
330	77	$y = $compressed
331	126	? $curve->recoverYfromX($prefix === PublicKey::KEY_COMPRESSED_ODD, $x)
332	154	: gmp_init($publicKey->slice(33, 32)->getInt(), 10);
333
334	154	return new PublicKey(
335	77	$this,
336	154	$curve->getPoint($x, $y),
337		$compressed
338	77	);
339		}
340		}
341

Bit-Wasp / bitcoin-php

Pull Request — master (#318)

EcAdapter::recoverYfromX() B

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