BitWasp\Bitcoin\Key\Deterministic\HierarchicalKey

Complexity

Total Complexity

33

Size/Duplication

Total Lines	300
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	14

Test Coverage

Coverage

98.88%

Importance

Changes	1
Bugs	0	Features	1

18 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	14	2
A	getDepth()	0	4	1
A	getSequence()	0	4	1
A	getFingerprint()	0	8	2
A	getChildFingerprint()	0	4	1
A	getChainCode()	0	4	1
A	getPrivateKey()	0	8	2
A	getPublicKey()	0	8	2
A	toPublic()	0	8	2
A	isPrivate()	0	4	1
A	isHardened()	0	5	1
A	deriveChild()	0	22	3
A	getHmacSeed()	0	18	3
B	deriveFromList()	0	13	5
A	derivePath()	0	5	1
A	toExtendedKey()	0	8	2
A	toExtendedPrivateKey()	0	8	2
A	toExtendedPublicKey()	0	5	1

<?php

namespace BitWasp\Bitcoin\Key\Deterministic;

use BitWasp\Bitcoin\Bitcoin;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\KeyInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Key\PrivateKeyInterface;
use BitWasp\Bitcoin\Crypto\EcAdapter\Impl\PhpEcc\Key\PublicKey;
use BitWasp\Buffertools\Buffer;
use BitWasp\Bitcoin\Crypto\EcAdapter\Adapter\EcAdapterInterface;
use BitWasp\Bitcoin\Serializer\Key\HierarchicalKey\ExtendedKeySerializer;
use BitWasp\Bitcoin\Serializer\Key\HierarchicalKey\HexExtendedKeySerializer;
use BitWasp\Buffertools\Buffertools;
use BitWasp\Buffertools\Parser;
use BitWasp\Bitcoin\Crypto\Hash;
use BitWasp\Bitcoin\Network\NetworkInterface;

class HierarchicalKey
{
    /**
     * @var EcAdapterInterface
     */
    private $ecAdapter;

    /**
     * @var int|string
     */
    private $depth;

    /**
     * @var int|string
     */
    private $parentFingerprint;

    /**
     * @var int|string
     */
    private $sequence;

    /**
     * @var int|string
     */
    private $chainCode;

    /**
     * @var KeyInterface
     */
    private $key;

    /**
     * @param EcAdapterInterface $ecAdapter
     * @param integer|string $depth
     * @param integer|string $parentFingerprint
     * @param integer|string $sequence
     * @param integer|string $chainCode
     * @param KeyInterface $key
     * @throws \Exception
     */
    public function __construct(EcAdapterInterface $ecAdapter, $depth, $parentFingerprint, $sequence, $chainCode, KeyInterface $key)
    {
        if (!$key->isCompressed()) {
            throw new \InvalidArgumentException('A HierarchicalKey must always be compressed');
        }

        $this->ecAdapter = $ecAdapter;
        $this->depth = $depth;
        $this->sequence = $sequence;
        $this->parentFingerprint = $parentFingerprint;
        $this->chainCode = $chainCode;
        $this->key = $key;

    }

    /**
     * Return the depth of this key. This is limited to 256 sequential derivations.
     *
     * @return int
     */
    public function getDepth()
    {
        return $this->depth;
    }

    /**
     * Get the sequence number for this address. Hardened keys are
     * created with sequence > 0x80000000. a sequence number lower
     * than this can be derived with the public key.
     *
     * @return int
     */
    public function getSequence()
    {
        return $this->sequence;
    }

    /**
     * Get the fingerprint of the parent key. For master keys, this is 00000000.
     *
     * @return string
     */
    public function getFingerprint()
    {
        if ($this->getDepth() === 0) {
            return 0;
        }

        return $this->parentFingerprint;
    }

    /**
     * Return the fingerprint to be used for child keys.
     * @return string
     */
    public function getChildFingerprint()
    {
        return $this->getPublicKey()->getPubKeyHash()->slice(0, 4)->getInt();
    }

    /**
     * Return the chain code - a deterministic 'salt' for HMAC-SHA512
     * in child derivations
     *
     * @return integer
     */
    public function getChainCode()
    {
        return $this->chainCode;
    }

    /**
     * @return PrivateKeyInterface
     */
    public function getPrivateKey()
    {
        if ($this->key->isPrivate()) {
            return $this->key;
        }

        throw new \RuntimeException('Unable to get private key, not known');
    }

    /**
     * Get the public key the private key or public key.
     *
     * @return PublicKey
     */
    public function getPublicKey()
    {
        if ($this->isPrivate()) {
            return $this->getPrivateKey()->getPublicKey();
        } else {
            return $this->key;
        }
    }

    /**
     * @return HierarchicalKey
     */
    public function toPublic()
    {
        if ($this->isPrivate()) {
            $this->key = $this->getPrivateKey()->getPublicKey();
        }

        return $this;
    }

    /**
     * Return whether this is a private key
     *
     * @return bool
     */
    public function isPrivate()
    {
        return $this->key->isPrivate();
    }

    /**
     * Return whether the key is hardened
     *
     * @return bool
     */
    public function isHardened()
    {
        // (sequence >> 31) == 1 ?
        return $this->ecAdapter->getMath()->getBinaryMath()->isNegative($this->sequence, 32);
    }

    /**
     * Create a buffer containing data to be hashed hashed to yield the child offset
     *
     * @param integer|string $sequence
     * @return Buffer
     * @throws \Exception
     */
    public function getHmacSeed($sequence)
    {
        $hardened = $this->ecAdapter->getMath()->getBinaryMath()->isNegative($sequence, 32);

        if ($hardened) {
            if ($this->isPrivate() === false) {
                throw new \Exception("Can't derive a hardened key without the private key");
            }

            $buffer = Buffertools::concat(new Buffer("\x00"), $this->getPrivateKey()->getBuffer());
        } else {
            $buffer = $this->getPublicKey()->getBuffer();
        }

        return (new Parser($buffer))
            ->writeBytes(4, Buffer::int($sequence, 4))
            ->getBuffer();
    }

    /**
     * Derive a child key
     *
     * @param $sequence
     * @return HierarchicalKey
     * @throws \Exception
     */
    public function deriveChild($sequence)
    {
        $chain = Buffer::int($this->getChainCode(), 32, $this->ecAdapter->getMath());

        $hash = Hash::hmac('sha512', $this->getHmacSeed($sequence), $chain);
        $offset = $hash->slice(0, 32);
        $chain = $hash->slice(32);
        $key = $this->isPrivate() ? $this->getPrivateKey() : $this->getPublicKey();

        if (false === $this->ecAdapter->validatePrivateKey($offset)) {
            return $this->deriveChild($sequence + 1);
        }

        return new HierarchicalKey(
            $this->ecAdapter,
            $this->getDepth() + 1,
            $this->getChildFingerprint(),
            $sequence,
            $chain->getInt(),
            $key->tweakAdd($offset->getInt())
        );
    }

    /**
     * @param array|\stdClass|\Traversable $list
     * @return HierarchicalKey
     */
    public function deriveFromList($list)
    {
        if (!is_array($list) && !$list instanceof \Traversable && !$list instanceof \stdClass) {
            throw new \InvalidArgumentException('List must be an array or \Traversable');
        }

        $key = $this;
        foreach ($list as $sequence) {

The expression $list of type array|object<Traversable>|object<stdClass> is not guaranteed to be traversable. How about adding an additional type check?

            $key = $key->deriveChild($sequence);
        }

        return $key;
    }

    /**
     * Decodes a BIP32 path into actual 32bit sequence numbers and derives the child key
     *
     * @param string $path
     * @return HierarchicalKey
     * @throws \Exception
     */
    public function derivePath($path)
    {
        $sequences = new HierarchicalKeySequence($this->ecAdapter->getMath());
        return $this->deriveFromList($sequences->decodePath($path));
    }

    /**
     * Serializes the instance according to whether it wraps a private or public key.
     * @param NetworkInterface $network
     * @return string
     */
    public function toExtendedKey(NetworkInterface $network = null)
    {
        $network = $network ?: Bitcoin::getNetwork();

        $extendedSerializer = new ExtendedKeySerializer(new HexExtendedKeySerializer($this->ecAdapter, $network));
        $extended = $extendedSerializer->serialize($this);
        return $extended;
    }

    /**
     * Explicitly serialize as a private key. Throws an exception if
     * the key isn't private.
     *
     * @param NetworkInterface $network
     * @return string
     */
    public function toExtendedPrivateKey(NetworkInterface $network = null)
    {
        if (!$this->isPrivate()) {
            throw new \LogicException('Cannot create extended private key from public');
        }

        return $this->toExtendedKey($network);
    }

    /**
     * Explicitly serialize as a public key. This will always work.
     *
     * @param NetworkInterface $network
     * @return string
     */
    public function toExtendedPublicKey(NetworkInterface $network = null)
    {
        $clone = clone($this);
        return $clone->toPublic()->toExtendedKey($network);
    }
}