/**
* @param EcAdapterInterface $ecAdapter
* @param $int
* @param bool $compressed
* @throws InvalidPrivateKey
*/
public function __construct(EcAdapterInterface $ecAdapter, $int, $compressed = false)
{
$buffer = Buffer::hex($ecAdapter->getMath()->decHex($int), 32);
if (false === $ecAdapter->validatePrivateKey($buffer)) {
throw new InvalidPrivateKey('Invalid private key - must be less than curve order.');
}
$this->ecAdapter = $ecAdapter;
$this->secretMultiplier = $int;
$this->setCompressed($compressed);
}
/**
* Derive a child key
*
* @param $sequence
* @return HierarchicalKey
* @throws \Exception
*/
public function deriveChild($sequence)
{
$chain = Buffer::hex($this->ecAdapter->getMath()->decHex($this->getChainCode()), 32);
$hash = Hash::hmac('sha512', $this->getHmacSeed($sequence), $chain);
$offset = $hash->slice(0, 32);
$chain = $hash->slice(32);
if (false === $this->ecAdapter->validatePrivateKey($offset)) {
return $this->deriveChild($sequence + 1);
}
return new HierarchicalKey($this->ecAdapter, $this->getDepth() + 1, $this->getChildFingerprint(), $sequence, $chain->getInt(), $this->isPrivate() ? $this->ecAdapter->privateKeyAdd($this->getPrivateKey(), $offset->getInt()) : $this->ecAdapter->publicKeyAdd($this->getPublicKey(), $offset->getInt()));
}
