bip32: replace rust-secp key types with rust-bitcoin key types
We continue to support only compressed keys when doing key derivation, but de/serialization of uncompressed keys will now work, and it will be easier/more consistent to implement PSBT on top of this.
This commit is contained in:
Andrew Poelstra
parent
fc47c477ab
commit
4f74ae61c4
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@ -24,11 +24,11 @@ use std::str::FromStr;
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use byteorder::{BigEndian, ByteOrder, ReadBytesExt};
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use bitcoin_hashes::{hash160, sha512, Hash, HashEngine, Hmac, HmacEngine};
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use secp256k1::key::{PublicKey, SecretKey};
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use secp256k1::{self, Secp256k1};
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use network::constants::Network;
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use util::base58;
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use util::key::{PublicKey, PrivateKey};
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/// A chain code
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pub struct ChainCode([u8; 32]);
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@ -57,8 +57,8 @@ pub struct ExtendedPrivKey {
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pub parent_fingerprint: Fingerprint,
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/// Child number of the key used to derive from parent (0 for master)
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pub child_number: ChildNumber,
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/// Secret key
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pub secret_key: SecretKey,
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/// Private key
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pub private_key: PrivateKey,
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/// Chain code
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pub chain_code: ChainCode
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}
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@ -398,7 +398,13 @@ impl ExtendedPrivKey {
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depth: 0,
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parent_fingerprint: Default::default(),
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child_number: ChildNumber::from_normal_idx(0)?,
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secret_key: SecretKey::from_slice(&hmac_result[..32]).map_err(Error::Ecdsa)?,
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private_key: PrivateKey {
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compressed: true,
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network: network,
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key: secp256k1::SecretKey::from_slice(
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&hmac_result[..32]
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).map_err(Error::Ecdsa)?,
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},
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chain_code: ChainCode::from(&hmac_result[32..]),
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})
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}
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@ -425,27 +431,31 @@ impl ExtendedPrivKey {
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match i {
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ChildNumber::Normal {..} => {
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// Non-hardened key: compute public data and use that
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hmac_engine.input(&PublicKey::from_secret_key(secp, &self.secret_key).serialize()[..]);
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hmac_engine.input(&PublicKey::from_private_key(secp, &self.private_key).key.serialize()[..]);
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}
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ChildNumber::Hardened {..} => {
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// Hardened key: use only secret data to prevent public derivation
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hmac_engine.input(&[0u8]);
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hmac_engine.input(&self.secret_key[..]);
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hmac_engine.input(&self.private_key[..]);
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}
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}
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BigEndian::write_u32(&mut be_n, u32::from(i));
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hmac_engine.input(&be_n);
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let hmac_result: Hmac<sha512::Hash> = Hmac::from_engine(hmac_engine);
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let mut sk = SecretKey::from_slice(&hmac_result[..32]).map_err(Error::Ecdsa)?;
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sk.add_assign(&self.secret_key[..]).map_err(Error::Ecdsa)?;
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let mut sk = PrivateKey {
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compressed: true,
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network: self.network,
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key: secp256k1::SecretKey::from_slice(&hmac_result[..32]).map_err(Error::Ecdsa)?,
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};
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sk.key.add_assign(&self.private_key[..]).map_err(Error::Ecdsa)?;
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Ok(ExtendedPrivKey {
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network: self.network,
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depth: self.depth + 1,
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parent_fingerprint: self.fingerprint(secp),
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child_number: i,
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secret_key: sk,
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private_key: sk,
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chain_code: ChainCode::from(&hmac_result[32..])
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})
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}
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@ -469,7 +479,7 @@ impl ExtendedPubKey {
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depth: sk.depth,
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parent_fingerprint: sk.parent_fingerprint,
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child_number: sk.child_number,
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public_key: PublicKey::from_secret_key(secp, &sk.secret_key),
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public_key: PublicKey::from_private_key(secp, &sk.private_key),
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chain_code: sk.chain_code
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}
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}
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@ -490,23 +500,27 @@ impl ExtendedPubKey {
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}
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/// Compute the scalar tweak added to this key to get a child key
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pub fn ckd_pub_tweak(&self, i: ChildNumber) -> Result<(SecretKey, ChainCode), Error> {
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pub fn ckd_pub_tweak(&self, i: ChildNumber) -> Result<(PrivateKey, ChainCode), Error> {
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match i {
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ChildNumber::Hardened {..} => {
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Err(Error::CannotDeriveFromHardenedKey)
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}
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ChildNumber::Normal { index: n } => {
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let mut hmac_engine: HmacEngine<sha512::Hash> = HmacEngine::new(&self.chain_code[..]);
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hmac_engine.input(&self.public_key.serialize()[..]);
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hmac_engine.input(&self.public_key.key.serialize()[..]);
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let mut be_n = [0; 4];
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BigEndian::write_u32(&mut be_n, n);
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hmac_engine.input(&be_n);
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let hmac_result: Hmac<sha512::Hash> = Hmac::from_engine(hmac_engine);
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let secret_key = SecretKey::from_slice(&hmac_result[..32])?;
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let private_key = PrivateKey {
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compressed: true,
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network: self.network,
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key: secp256k1::SecretKey::from_slice(&hmac_result[..32])?,
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};
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let chain_code = ChainCode::from(&hmac_result[32..]);
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Ok((secret_key, chain_code))
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Ok((private_key, chain_code))
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}
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}
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}
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@ -519,7 +533,7 @@ impl ExtendedPubKey {
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) -> Result<ExtendedPubKey, Error> {
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let (sk, chain_code) = self.ckd_pub_tweak(i)?;
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let mut pk = self.public_key.clone();
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pk.add_exp_assign(secp, &sk[..]).map_err(Error::Ecdsa)?;
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pk.key.add_exp_assign(secp, &sk[..]).map_err(Error::Ecdsa)?;
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Ok(ExtendedPubKey {
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network: self.network,
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@ -533,7 +547,9 @@ impl ExtendedPubKey {
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/// Returns the HASH160 of the chaincode
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pub fn identifier(&self) -> hash160::Hash {
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hash160::Hash::hash(&self.public_key.serialize())
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let mut engine = hash160::Hash::engine();
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self.public_key.write_into(&mut engine);
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hash160::Hash::from_engine(engine)
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}
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/// Returns the first four bytes of the identifier
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@ -556,7 +572,7 @@ impl fmt::Display for ExtendedPrivKey {
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ret[13..45].copy_from_slice(&self.chain_code[..]);
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ret[45] = 0;
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ret[46..78].copy_from_slice(&self.secret_key[..]);
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ret[46..78].copy_from_slice(&self.private_key[..]);
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fmt.write_str(&base58::check_encode_slice(&ret[..]))
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}
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}
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@ -574,21 +590,29 @@ impl FromStr for ExtendedPrivKey {
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let cn_int: u32 = Cursor::new(&data[9..13]).read_u32::<BigEndian>().unwrap();
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let child_number: ChildNumber = ChildNumber::from(cn_int);
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Ok(ExtendedPrivKey {
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network: if &data[0..4] == [0x04u8, 0x88, 0xAD, 0xE4] {
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let network = if &data[0..4] == [0x04u8, 0x88, 0xAD, 0xE4] {
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Network::Bitcoin
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} else if &data[0..4] == [0x04u8, 0x35, 0x83, 0x94] {
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Network::Testnet
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} else {
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return Err(base58::Error::InvalidVersion((&data[0..4]).to_vec()));
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},
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};
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Ok(ExtendedPrivKey {
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network: network,
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depth: data[4],
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parent_fingerprint: Fingerprint::from(&data[5..9]),
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child_number: child_number,
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chain_code: ChainCode::from(&data[13..45]),
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secret_key: SecretKey::from_slice(
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&data[46..78]).map_err(|e|
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base58::Error::Other(e.to_string()))?
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private_key: PrivateKey {
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compressed: true,
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network: network,
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key: secp256k1::SecretKey::from_slice(
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&data[46..78]
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).map_err(|e|
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base58::Error::Other(e.to_string())
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)?,
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},
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})
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}
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}
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@ -606,7 +630,7 @@ impl fmt::Display for ExtendedPubKey {
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BigEndian::write_u32(&mut ret[9..13], u32::from(self.child_number));
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ret[13..45].copy_from_slice(&self.chain_code[..]);
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ret[45..78].copy_from_slice(&self.public_key.serialize()[..]);
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ret[45..78].copy_from_slice(&self.public_key.key.serialize()[..]);
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fmt.write_str(&base58::check_encode_slice(&ret[..]))
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}
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}
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