EcAdapter::getPrivateKey() - Code Metrics - Inspection of "WIP: PHP7+" - Bit-Wasp/bitcoin-php - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#591)

by thomas

created 2017-12-28 02:07 UTC

EcAdapter::getPrivateKey() A

↳ Parent: EcAdapter

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	2
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	2
nc	1
nop	2
dl	0
loc	4
ccs	2
cts	2
cp	1
crap	1
rs	10
c	0
b	0
f	0

<?php

declare(strict_types=1);

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

use BitWasp\Bitcoin\Crypto\EcAdapter\Adapter\EcAdapterInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PrivateKey;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PublicKey;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\CompactSignature;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PrivateKeyInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PublicKeyInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\CompactSignatureInterface;
use BitWasp\Bitcoin\Math\Math;
use BitWasp\Buffertools\BufferInterface;
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(): Math
    {
        return $this->math;
    }

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

    /**
     * @return \GMP
     */
    public function getOrder(): \GMP
    {
        return $this->generator->getOrder();
    }

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

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

        $one = gmp_init(1);

        $r = $signature->getR();
        $s = $signature->getS();
        $isYEven = ($signature->getRecoveryId() & 1) !== 0;
        $isSecondKey = ($signature->getRecoveryId() & 2) !== 0;
        $curve = $G->getCurve();

        // Precalculate (p + 1) / 4 where p is the field order
        $pOverFour = $math->div($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());
        $beta = $math->powmod($alpha, $pOverFour, $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);

        $pointNegate = 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 = $pointNegate($G->mul($messageHash->getGmp()));
        $Q = $R->mul($s)->add($eGNeg)->mul($rInv);

        // 1.6.2 Test Q as a public key
        $Qk = new PublicKey($this, $Q, $signature->isCompressed());
        if ($Qk->verify($messageHash, $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): int
    {
        $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 $privateKey
     * @return bool
     */
    public function validatePrivateKey(BufferInterface $privateKey): bool
    {
        $math = $this->math;
        $scalar = $privateKey->getGmp();
        return $math->cmp($scalar, gmp_init(0)) > 0 && $math->cmp($scalar, $this->getOrder()) < 0;
    }

    /**
     * @param \GMP $element
     * @param bool $half
     * @return bool
     */
    public function validateSignatureElement(\GMP $element, bool $half = false): bool
    {
        $math = $this->getMath();
        $against = $this->getOrder();
        if ($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): PublicKeyInterface
    {
        $prefix = $publicKey->slice(0, 1)->getBinary();
        $size = $publicKey->getSize();
        $compressed = false;
        if ($prefix === PublicKey::KEY_UNCOMPRESSED || $prefix === "\x06" || $prefix === "\x07") {
            if ($size !== PublicKey::LENGTH_UNCOMPRESSED) {
                throw new \Exception('Invalid length for uncompressed key');
            }
        } 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 = $publicKey->slice(1, 32)->getGmp();
        $curve = $this->generator->getCurve();
        $y = $compressed
            ? $curve->recoverYfromX($prefix === PublicKey::KEY_COMPRESSED_ODD, $x)
            : $publicKey->slice(33, 32)->getGmp();

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


1		<?php
2
3		declare(strict_types=1);
4
5		namespace BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Adapter;
6
7		use BitWasp\Bitcoin\Crypto\EcAdapter\Adapter\EcAdapterInterface;
8		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PrivateKey;
9		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PublicKey;
10		use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Signature\CompactSignature;
11		use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PrivateKeyInterface;
12		use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PublicKeyInterface;
13		use BitWasp\Bitcoin\Crypto\EcAdapter\Signature\CompactSignatureInterface;
14		use BitWasp\Bitcoin\Math\Math;
15		use BitWasp\Buffertools\BufferInterface;
16		use Mdanter\Ecc\Primitives\GeneratorPoint;
17		use Mdanter\Ecc\Primitives\PointInterface;
18
19		class EcAdapter implements EcAdapterInterface
20		{
21		/**
22		* @var Math
23		*/
24		private $math;
25
26		/**
27		* @var GeneratorPoint
28		*/
29		private $generator;
30
31		/**
32		* @param Math $math
33		* @param GeneratorPoint $generator
34		*/
35	4	public function __construct(Math $math, GeneratorPoint $generator)
36		{
37	4	$this->math = $math;
38	4	$this->generator = $generator;
39	4	}
40
41		/**
42		* @return Math
43		*/
44	1316	public function getMath(): Math
45		{
46	1316	return $this->math;
47		}
48
49		/**
50		* @return GeneratorPoint
51		*/
52	176	public function getGenerator()
53		{
54	176	return $this->generator;
55		}
56
57		/**
58		* @return \GMP
59		*/
60	73	public function getOrder(): \GMP
61		{
62	73	return $this->generator->getOrder();
63		}
64
65		/**
66		* @param \GMP $scalar
67		* @param bool\|false $compressed
68		* @return PrivateKeyInterface
69		*/
70	40	public function getPrivateKey(\GMP $scalar, bool $compressed = false): PrivateKeyInterface
71		{
72	40	return new PrivateKey($this, $scalar, $compressed);
73		}
74
75		/**
76		* @param BufferInterface $messageHash
77		* @param CompactSignature\|CompactSignatureInterface $signature
78		* @return PublicKeyInterface
79		* @throws \Exception
80		*/
81	7	public function recover(BufferInterface $messageHash, CompactSignatureInterface $signature): PublicKeyInterface
82		{
83	7	$math = $this->getMath();
84	7	$G = $this->generator;
85
86	7	$one = gmp_init(1);
87
88	7	$r = $signature->getR();
89	7	$s = $signature->getS();
90	7	$isYEven = ($signature->getRecoveryId() & 1) !== 0;
91	7	$isSecondKey = ($signature->getRecoveryId() & 2) !== 0;
92	7	$curve = $G->getCurve();
93
94		// Precalculate (p + 1) / 4 where p is the field order
95	7	$pOverFour = $math->div($math->add($curve->getPrime(), $one), gmp_init(4));
96
97		// 1.1 Compute x
98	7	if (!$isSecondKey) {
99	7	$x = $r;
100		} else {
101	1	$x = $math->add($r, $G->getOrder());
102		}
103
104		// 1.3 Convert x to point
105	7	$alpha = $math->mod($math->add($math->add($math->pow($x, 3), $math->mul($curve->getA(), $x)), $curve->getB()), $curve->getPrime());
106	7	$beta = $math->powmod($alpha, $pOverFour, $curve->getPrime());
107
108		// If beta is even, but y isn't or vice versa, then convert it,
109		// otherwise we're done and y=beta.
110	7	if ($math->isEven($beta) === $isYEven) {
111	6	$y = $math->sub($curve->getPrime(), $beta);
112		} else {
113	6	$y = $beta;
114		}
115
116		// 1.4 Check that nR is at infinity (implicitly done in constructor)
117	7	$R = $G->getCurve()->getPoint($x, $y);
118
119	7	$pointNegate = function (PointInterface $p) use ($math, $G) {
120	7	return $G->getCurve()->getPoint($p->getX(), $math->mul($p->getY(), gmp_init('-1', 10)));
121	7	};
122
123		// 1.6.1 Compute a candidate public key Q = r^-1 (sR - eG)
124	7	$rInv = $math->inverseMod($r, $G->getOrder());
125	7	$eGNeg = $pointNegate($G->mul($messageHash->getGmp()));
126	7	$Q = $R->mul($s)->add($eGNeg)->mul($rInv);
127
128		// 1.6.2 Test Q as a public key
129	7	$Qk = new PublicKey($this, $Q, $signature->isCompressed());
130	7	if ($Qk->verify($messageHash, $signature->convert())) {
131	6	return $Qk;
132		}
133
134	1	throw new \Exception('Unable to recover public key');
135		}
136
137		/**
138		* Attempt to calculate the public key recovery param by trial and error
139		*
140		* @param \GMP $r
141		* @param \GMP $s
142		* @param BufferInterface $messageHash
143		* @param PublicKey $publicKey
144		* @return int
145		* @throws \Exception
146		*/
147	6	public function calcPubKeyRecoveryParam(\GMP $r, \GMP $s, BufferInterface $messageHash, PublicKey $publicKey): int
148		{
149	6	$Q = $publicKey->getPoint();
150	6	for ($i = 0; $i < 4; $i++) {
151		try {
152	6	$recover = $this->recover($messageHash, new CompactSignature($this, $r, $s, $i, $publicKey->isCompressed()));
153	5	if ($Q->equals($recover->getPoint())) {
154	5	return $i;
155		}
156	1	} catch (\Exception $e) {
157	1	continue;
158		}
159		}
160
161	1	throw new \Exception('Failed to find valid recovery factor');
162		}
163
164		/**
165		* @param BufferInterface $privateKey
166		* @return bool
167		*/
168	42	public function validatePrivateKey(BufferInterface $privateKey): bool
169		{
170	42	$math = $this->math;
171	42	$scalar = $privateKey->getGmp();
172	42	return $math->cmp($scalar, gmp_init(0)) > 0 && $math->cmp($scalar, $this->getOrder()) < 0;
173		}
174
175		/**
176		* @param \GMP $element
177		* @param bool $half
178		* @return bool
179		*/
180	35	public function validateSignatureElement(\GMP $element, bool $half = false): bool
181		{
182	35	$math = $this->getMath();
183	35	$against = $this->getOrder();
184	35	if ($half) {
185	35	$against = $math->rightShift($against, 1);
186		}
187
188	35	return $math->cmp($element, $against) < 0 && $math->cmp($element, gmp_init(0)) !== 0;
189		}
190
191		/**
192		* @param BufferInterface $publicKey
193		* @return PublicKeyInterface
194		* @throws \Exception
195		*/
196	187	public function publicKeyFromBuffer(BufferInterface $publicKey): PublicKeyInterface
197		{
198	187	$prefix = $publicKey->slice(0, 1)->getBinary();
199	187	$size = $publicKey->getSize();
200	187	$compressed = false;
201	187	if ($prefix === PublicKey::KEY_UNCOMPRESSED \|\| $prefix === "\x06" \|\| $prefix === "\x07") {
202	74	if ($size !== PublicKey::LENGTH_UNCOMPRESSED) {
203	74	throw new \Exception('Invalid length for uncompressed key');
204		}
205	120	} else if ($prefix === PublicKey::KEY_COMPRESSED_EVEN \|\| $prefix === PublicKey::KEY_COMPRESSED_ODD) {
206	120	if ($size !== PublicKey::LENGTH_COMPRESSED) {
207		throw new \Exception('Invalid length for compressed key');
208		}
209	120	$compressed = true;
210		} else {
211		throw new \Exception('Unknown public key prefix');
212		}
213
214	187	$x = $publicKey->slice(1, 32)->getGmp();
215	187	$curve = $this->generator->getCurve();
216	187	$y = $compressed
217	120	? $curve->recoverYfromX($prefix === PublicKey::KEY_COMPRESSED_ODD, $x)
218	187	: $publicKey->slice(33, 32)->getGmp();
219
220	187	return new PublicKey(
221	187	$this,
222	187	$curve->getPoint($x, $y),
223	187	$compressed,
224	187	$prefix
225		);
226		}
227		}
228

Bit-Wasp / bitcoin-php

Pull Request — master (#591)

EcAdapter::getPrivateKey() A

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