+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
//! Various utilities for building scripts and deriving keys related to channels. These are
//! largely of interest for those implementing chain::keysinterface::ChannelKeys message signing
//! by hand.
use bitcoin::blockdata::script::{Script,Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction, SigHashType};
-use bitcoin::consensus::encode::{self, Decodable, Encodable};
+use bitcoin::consensus::encode::{Decodable, Encodable};
+use bitcoin::consensus::encode;
use bitcoin::util::bip143;
-use bitcoin_hashes::{Hash, HashEngine};
-use bitcoin_hashes::sha256::Hash as Sha256;
-use bitcoin_hashes::ripemd160::Hash as Ripemd160;
-use bitcoin_hashes::hash160::Hash as Hash160;
-use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::hashes::ripemd160::Hash as Ripemd160;
+use bitcoin::hash_types::{Txid, PubkeyHash};
use ln::channelmanager::{PaymentHash, PaymentPreimage};
use ln::msgs::DecodeError;
use util::ser::{Readable, Writeable, Writer, WriterWriteAdaptor};
use util::byte_utils;
-use secp256k1::key::{SecretKey, PublicKey};
-use secp256k1::{Secp256k1, Signature};
-use secp256k1;
+use bitcoin::secp256k1::key::{SecretKey, PublicKey};
+use bitcoin::secp256k1::{Secp256k1, Signature};
+use bitcoin::secp256k1::Error as SecpError;
+use bitcoin::secp256k1;
use std::{cmp, mem};
// Various functions for key derivation and transaction creation for use within channels. Primarily
// used in Channel and ChannelMonitor.
-pub(super) fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
+/// Build the commitment secret from the seed and the commitment number
+pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
let mut res: [u8; 32] = commitment_seed.clone();
for i in 0..48 {
let bitpos = 47 - i;
}
}
-/// Derives a per-commitment-transaction private key (eg an htlc key or payment key) from the base
-/// private key for that type of key and the per_commitment_point (available in TxCreationKeys)
+/// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key)
+/// from the base secret and the per_commitment_point.
+///
+/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
+/// generated (ie our own).
pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
Ok(key)
}
-pub(super) fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
+/// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key)
+/// from the base point and the per_commitment_key. This is the public equivalent of
+/// derive_private_key - using only public keys to derive a public key instead of private keys.
+///
+/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
+/// generated (ie our own).
+pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
sha.input(&base_point.serialize());
base_point.combine(&hashkey)
}
-/// Derives a revocation key from its constituent parts.
+/// Derives a per-commitment-transaction revocation key from its constituent parts.
+///
/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
/// generated (ie our own).
-pub(super) fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
+pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
let revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &revocation_base_secret);
let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
Ok(part_a)
}
-pub(super) fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, revocation_base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
+/// Derives a per-commitment-transaction revocation public key from its constituent parts. This is
+/// the public equivalend of derive_private_revocation_key - using only public keys to derive a
+/// public key instead of private keys.
+///
+/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
+/// generated (ie our own).
+pub fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, revocation_base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
let rev_append_commit_hash_key = {
let mut sha = Sha256::engine();
sha.input(&revocation_base_point.serialize());
/// The set of public keys which are used in the creation of one commitment transaction.
/// These are derived from the channel base keys and per-commitment data.
+///
+/// These keys are assumed to be good, either because the code derived them from
+/// channel basepoints via the new function, or they were obtained via
+/// PreCalculatedTxCreationKeys.trust_key_derivation because we trusted the source of the
+/// pre-calculated keys.
#[derive(PartialEq, Clone)]
pub struct TxCreationKeys {
/// The per-commitment public key which was used to derive the other keys.
pub per_commitment_point: PublicKey,
/// The revocation key which is used to allow the owner of the commitment transaction to
/// provide their counterparty the ability to punish them if they broadcast an old state.
- pub(crate) revocation_key: PublicKey,
+ pub revocation_key: PublicKey,
/// A's HTLC Key
- pub(crate) a_htlc_key: PublicKey,
+ pub a_htlc_key: PublicKey,
/// B's HTLC Key
- pub(crate) b_htlc_key: PublicKey,
+ pub b_htlc_key: PublicKey,
/// A's Payment Key (which isn't allowed to be spent from for some delay)
- pub(crate) a_delayed_payment_key: PublicKey,
- /// B's Payment Key
- pub(crate) b_payment_key: PublicKey,
+ pub a_delayed_payment_key: PublicKey,
}
impl_writeable!(TxCreationKeys, 33*6,
- { per_commitment_point, revocation_key, a_htlc_key, b_htlc_key, a_delayed_payment_key, b_payment_key });
+ { per_commitment_point, revocation_key, a_htlc_key, b_htlc_key, a_delayed_payment_key });
+
+/// The per-commitment point and a set of pre-calculated public keys used for transaction creation
+/// in the signer.
+/// The pre-calculated keys are an optimization, because ChannelKeys has enough
+/// information to re-derive them.
+pub struct PreCalculatedTxCreationKeys(TxCreationKeys);
+
+impl PreCalculatedTxCreationKeys {
+ /// Create a new PreCalculatedTxCreationKeys from TxCreationKeys
+ pub fn new(keys: TxCreationKeys) -> Self {
+ PreCalculatedTxCreationKeys(keys)
+ }
+
+ /// The pre-calculated transaction creation public keys.
+ /// An external validating signer should not trust these keys.
+ pub fn trust_key_derivation(&self) -> &TxCreationKeys {
+ &self.0
+ }
+
+ /// The transaction per-commitment point
+ pub fn per_commitment_point(&self) -> &PublicKey {
+ &self.0.per_commitment_point
+ }
+}
/// One counterparty's public keys which do not change over the life of a channel.
#[derive(Clone, PartialEq)]
/// on-chain channel lock-in 2-of-2 multisig output.
pub funding_pubkey: PublicKey,
/// The base point which is used (with derive_public_revocation_key) to derive per-commitment
- /// revocation keys. The per-commitment revocation private key is then revealed by the owner of
- /// a commitment transaction so that their counterparty can claim all available funds if they
- /// broadcast an old state.
+ /// revocation keys. This is combined with the per-commitment-secret generated by the
+ /// counterparty to create a secret which the counterparty can reveal to revoke previous
+ /// states.
pub revocation_basepoint: PublicKey,
- /// The base point which is used (with derive_public_key) to derive a per-commitment payment
- /// public key which receives immediately-spendable non-HTLC-encumbered funds.
- pub payment_basepoint: PublicKey,
+ /// The public key which receives our immediately spendable primary channel balance in
+ /// remote-broadcasted commitment transactions. This key is static across every commitment
+ /// transaction.
+ pub payment_point: PublicKey,
/// The base point which is used (with derive_public_key) to derive a per-commitment payment
/// public key which receives non-HTLC-encumbered funds which are only available for spending
/// after some delay (or can be claimed via the revocation path).
impl_writeable!(ChannelPublicKeys, 33*5, {
funding_pubkey,
revocation_basepoint,
- payment_basepoint,
+ payment_point,
delayed_payment_basepoint,
htlc_basepoint
});
impl TxCreationKeys {
- pub(crate) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
+ /// Create a new TxCreationKeys from channel base points and the per-commitment point
+ pub fn derive_new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, SecpError> {
Ok(TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,
a_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_htlc_base)?,
b_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_htlc_base)?,
a_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_delayed_payment_base)?,
- b_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_payment_base)?,
})
}
}
-/// Gets the "to_local" output redeemscript, ie the script which is time-locked or spendable by
-/// the revocation key
-pub(super) fn get_revokeable_redeemscript(revocation_key: &PublicKey, to_self_delay: u16, delayed_payment_key: &PublicKey) -> Script {
+/// A script either spendable by the revocation
+/// key or the delayed_payment_key and satisfying the relative-locktime OP_CSV constrain.
+/// Encumbering a `to_local` output on a commitment transaction or 2nd-stage HTLC transactions.
+pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, to_self_delay: u16, delayed_payment_key: &PublicKey) -> Script {
Builder::new().push_opcode(opcodes::all::OP_IF)
.push_slice(&revocation_key.serialize())
.push_opcode(opcodes::all::OP_ELSE)
if htlc.offered {
Builder::new().push_opcode(opcodes::all::OP_DUP)
.push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
+ .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
.push_opcode(opcodes::all::OP_EQUAL)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
} else {
Builder::new().push_opcode(opcodes::all::OP_DUP)
.push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
+ .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
.push_opcode(opcodes::all::OP_EQUAL)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
}
/// panics if htlc.transaction_output_index.is_none()!
-pub fn build_htlc_transaction(prev_hash: &Sha256dHash, feerate_per_kw: u64, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
+pub fn build_htlc_transaction(prev_hash: &Txid, feerate_per_kw: u32, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
let mut txins: Vec<TxIn> = Vec::new();
txins.push(TxIn {
previous_output: OutPoint {
});
let total_fee = if htlc.offered {
- feerate_per_kw * HTLC_TIMEOUT_TX_WEIGHT / 1000
+ feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000
} else {
- feerate_per_kw * HTLC_SUCCESS_TX_WEIGHT / 1000
+ feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000
};
let mut txouts: Vec<TxOut> = Vec::new();
#[derive(Clone)]
/// We use this to track local commitment transactions and put off signing them until we are ready
-/// to broadcast. Eventually this will require a signer which is possibly external, but for now we
-/// just pass in the SecretKeys required.
+/// to broadcast. This class can be used inside a signer implementation to generate a signature
+/// given the relevant secret key.
pub struct LocalCommitmentTransaction {
// TODO: We should migrate away from providing the transaction, instead providing enough to
// allow the ChannelKeys to construct it from scratch. Luckily we already have HTLC data here,
// Which order the signatures should go in when constructing the final commitment tx witness.
// The user should be able to reconstruc this themselves, so we don't bother to expose it.
our_sig_first: bool,
- /// The key derivation parameters for this commitment transaction
- pub local_keys: TxCreationKeys,
+ pub(crate) local_keys: TxCreationKeys,
/// The feerate paid per 1000-weight-unit in this commitment transaction. This value is
/// controlled by the channel initiator.
- pub feerate_per_kw: u64,
+ pub feerate_per_kw: u32,
/// The HTLCs and remote htlc signatures which were included in this commitment transaction.
///
/// Note that this includes all HTLCs, including ones which were considered dust and not
a_htlc_key: dummy_key.clone(),
b_htlc_key: dummy_key.clone(),
a_delayed_payment_key: dummy_key.clone(),
- b_payment_key: dummy_key.clone(),
},
feerate_per_kw: 0,
per_htlc: Vec::new()
}
/// Generate a new LocalCommitmentTransaction based on a raw commitment transaction,
- /// remote signature and both parties keys
- pub(crate) fn new_missing_local_sig(unsigned_tx: Transaction, their_sig: Signature, our_funding_key: &PublicKey, their_funding_key: &PublicKey, local_keys: TxCreationKeys, feerate_per_kw: u64, htlc_data: Vec<(HTLCOutputInCommitment, Option<Signature>)>) -> LocalCommitmentTransaction {
+ /// remote signature and both parties keys.
+ ///
+ /// The unsigned transaction outputs must be consistent with htlc_data. This function
+ /// only checks that the shape and amounts are consistent, but does not check the scriptPubkey.
+ pub fn new_missing_local_sig(unsigned_tx: Transaction, their_sig: Signature, our_funding_key: &PublicKey, their_funding_key: &PublicKey, local_keys: TxCreationKeys, feerate_per_kw: u32, htlc_data: Vec<(HTLCOutputInCommitment, Option<Signature>)>) -> LocalCommitmentTransaction {
if unsigned_tx.input.len() != 1 { panic!("Tried to store a commitment transaction that had input count != 1!"); }
if unsigned_tx.input[0].witness.len() != 0 { panic!("Tried to store a signed commitment transaction?"); }
+ for htlc in &htlc_data {
+ if let Some(index) = htlc.0.transaction_output_index {
+ let out = &unsigned_tx.output[index as usize];
+ if out.value != htlc.0.amount_msat / 1000 {
+ panic!("HTLC at index {} has incorrect amount", index);
+ }
+ if !out.script_pubkey.is_v0_p2wsh() {
+ panic!("HTLC at index {} doesn't have p2wsh scriptPubkey", index);
+ }
+ }
+ }
+
Self {
unsigned_tx,
their_sig,
}
}
+ /// The pre-calculated transaction creation public keys.
+ /// An external validating signer should not trust these keys.
+ pub fn trust_key_derivation(&self) -> &TxCreationKeys {
+ &self.local_keys
+ }
+
/// Get the txid of the local commitment transaction contained in this
/// LocalCommitmentTransaction
- pub fn txid(&self) -> Sha256dHash {
+ pub fn txid(&self) -> Txid {
self.unsigned_tx.txid()
}
/// ChannelKeys::sign_local_commitment() calls directly.
/// Channel value is amount locked in funding_outpoint.
pub fn get_local_sig<T: secp256k1::Signing>(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) -> Signature {
- let sighash = hash_to_message!(&bip143::SighashComponents::new(&self.unsigned_tx)
- .sighash_all(&self.unsigned_tx.input[0], funding_redeemscript, channel_value_satoshis)[..]);
+ let sighash = hash_to_message!(&bip143::SigHashCache::new(&self.unsigned_tx)
+ .signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..]);
secp_ctx.sign(&sighash, funding_key)
}
let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.local_keys.a_htlc_key, &self.local_keys.b_htlc_key, &self.local_keys.revocation_key);
- let sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, this_htlc.0.amount_msat / 1000)[..]);
+ let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.0.amount_msat / 1000, SigHashType::All)[..]);
ret.push(Some(secp_ctx.sign(&sighash, &our_htlc_key)));
} else {
ret.push(None);
projects / rust-lightning / blobdiff