+// 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::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;
/// Allows us to keep track of all of the revocation secrets of counterarties in just 50*32 bytes
/// or so.
#[derive(Clone)]
-pub(super) struct CounterpartyCommitmentSecrets {
+pub(crate) struct CounterpartyCommitmentSecrets {
old_secrets: [([u8; 32], u64); 49],
}
}
impl CounterpartyCommitmentSecrets {
- pub(super) fn new() -> Self {
+ pub(crate) fn new() -> Self {
Self { old_secrets: [([0; 32], 1 << 48); 49], }
}
48
}
- pub(super) fn get_min_seen_secret(&self) -> u64 {
+ pub(crate) fn get_min_seen_secret(&self) -> u64 {
//TODO This can be optimized?
let mut min = 1 << 48;
for &(_, idx) in self.old_secrets.iter() {
res
}
- pub(super) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
+ pub(crate) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
let pos = Self::place_secret(idx);
for i in 0..pos {
let (old_secret, old_idx) = self.old_secrets[i as usize];
}
/// Can only fail if idx is < get_min_seen_secret
- pub(super) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
+ pub(crate) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
for i in 0..self.old_secrets.len() {
if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
return Some(Self::derive_secret(self.old_secrets[i].0, i as u8, idx))
}
}
-/// 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)
-pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
+/// 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, SecpError> {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).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, SecpError> {
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.
+///
+/// Only the cheating participant owns a valid witness to propagate a revoked
+/// commitment transaction, thus per_commitment_secret always come from cheater
+/// and revocation_base_secret always come from punisher, which is the broadcaster
+/// of the transaction spending with this key knowledge.
+///
/// 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> {
- let revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &revocation_base_secret);
+pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) -> Result<SecretKey, SecpError> {
+ let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret);
let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
let rev_append_commit_hash_key = {
let mut sha = Sha256::engine();
- sha.input(&revocation_base_point.serialize());
+ sha.input(&countersignatory_revocation_base_point.serialize());
sha.input(&per_commitment_point.serialize());
Sha256::from_engine(sha).into_inner()
let commit_append_rev_hash_key = {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
- sha.input(&revocation_base_point.serialize());
+ sha.input(&countersignatory_revocation_base_point.serialize());
Sha256::from_engine(sha).into_inner()
};
- let mut part_a = revocation_base_secret.clone();
- part_a.mul_assign(&rev_append_commit_hash_key)?;
- let mut part_b = per_commitment_secret.clone();
- part_b.mul_assign(&commit_append_rev_hash_key)?;
- part_a.add_assign(&part_b[..])?;
- Ok(part_a)
+ let mut countersignatory_contrib = countersignatory_revocation_base_secret.clone();
+ countersignatory_contrib.mul_assign(&rev_append_commit_hash_key)?;
+ let mut broadcaster_contrib = per_commitment_secret.clone();
+ broadcaster_contrib.mul_assign(&commit_append_rev_hash_key)?;
+ countersignatory_contrib.add_assign(&broadcaster_contrib[..])?;
+ Ok(countersignatory_contrib)
}
-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.
+///
+/// Only the cheating participant owns a valid witness to propagate a revoked
+/// commitment transaction, thus per_commitment_point always come from cheater
+/// and revocation_base_point always come from punisher, which is the broadcaster
+/// of the transaction spending with this key knowledge.
+///
+/// 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, countersignatory_revocation_base_point: &PublicKey) -> Result<PublicKey, SecpError> {
let rev_append_commit_hash_key = {
let mut sha = Sha256::engine();
- sha.input(&revocation_base_point.serialize());
+ sha.input(&countersignatory_revocation_base_point.serialize());
sha.input(&per_commitment_point.serialize());
Sha256::from_engine(sha).into_inner()
let commit_append_rev_hash_key = {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
- sha.input(&revocation_base_point.serialize());
+ sha.input(&countersignatory_revocation_base_point.serialize());
Sha256::from_engine(sha).into_inner()
};
- let mut part_a = revocation_base_point.clone();
- part_a.mul_assign(&secp_ctx, &rev_append_commit_hash_key)?;
- let mut part_b = per_commitment_point.clone();
- part_b.mul_assign(&secp_ctx, &commit_append_rev_hash_key)?;
- part_a.combine(&part_b)
+ let mut countersignatory_contrib = countersignatory_revocation_base_point.clone();
+ countersignatory_contrib.mul_assign(&secp_ctx, &rev_append_commit_hash_key)?;
+ let mut broadcaster_contrib = per_commitment_point.clone();
+ broadcaster_contrib.mul_assign(&secp_ctx, &commit_append_rev_hash_key)?;
+ countersignatory_contrib.combine(&broadcaster_contrib)
}
/// 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.
+///
+/// A broadcaster key is provided from potential broadcaster of the computed transaction.
+/// A countersignatory key is coming from a protocol participant unable to broadcast the
+/// transaction.
+///
+/// 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.
+ /// The broadcaster's 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,
- /// A's HTLC Key
- pub(crate) a_htlc_key: PublicKey,
- /// B's HTLC Key
- pub(crate) 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,
+ /// The revocation key which is used to allow the broadcaster of the commitment
+ /// transaction to provide their counterparty the ability to punish them if they broadcast
+ /// an old state.
+ pub revocation_key: PublicKey,
+ /// Broadcaster's HTLC Key
+ pub broadcaster_htlc_key: PublicKey,
+ /// Countersignatory's HTLC Key
+ pub countersignatory_htlc_key: PublicKey,
+ /// Broadcaster's Payment Key (which isn't allowed to be spent from for some delay)
+ pub broadcaster_delayed_payment_key: PublicKey,
}
impl_writeable!(TxCreationKeys, 33*6,
- { per_commitment_point, revocation_key, a_htlc_key, b_htlc_key, a_delayed_payment_key });
+ { per_commitment_point, revocation_key, broadcaster_htlc_key, countersignatory_htlc_key, broadcaster_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 on which the non-broadcaster (ie the countersignatory) receives an immediately
+ /// spendable primary channel balance on the broadcaster's commitment transaction. 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_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, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_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)?,
+ revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base)?,
+ broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base)?,
+ countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base)?,
+ broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_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 broadcaster_delayed_payment_key and satisfying the relative-locktime OP_CSV constrain.
+/// Encumbering a `to_holder` output on a commitment transaction or 2nd-stage HTLC transactions.
+pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, contest_delay: u16, broadcaster_delayed_payment_key: &PublicKey) -> Script {
Builder::new().push_opcode(opcodes::all::OP_IF)
.push_slice(&revocation_key.serialize())
.push_opcode(opcodes::all::OP_ELSE)
- .push_int(to_self_delay as i64)
+ .push_int(contest_delay as i64)
.push_opcode(opcodes::all::OP_CSV)
.push_opcode(opcodes::all::OP_DROP)
- .push_slice(&delayed_payment_key.serialize())
+ .push_slice(&broadcaster_delayed_payment_key.serialize())
.push_opcode(opcodes::all::OP_ENDIF)
.push_opcode(opcodes::all::OP_CHECKSIG)
.into_script()
/// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction).
/// Note that this is not the same as whether it is ountbound *from us*. To determine that you
/// need to compare this value to whether the commitment transaction in question is that of
- /// the remote party or our own.
+ /// the counterparty or our own.
pub offered: bool,
/// The value, in msat, of the HTLC. The value as it appears in the commitment transaction is
/// this divided by 1000.
});
#[inline]
-pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
+pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, broadcaster_htlc_key: &PublicKey, countersignatory_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
if htlc.offered {
Builder::new().push_opcode(opcodes::all::OP_DUP)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
.push_opcode(opcodes::all::OP_ELSE)
- .push_slice(&b_htlc_key.serialize()[..])
+ .push_slice(&countersignatory_htlc_key.serialize()[..])
.push_opcode(opcodes::all::OP_SWAP)
.push_opcode(opcodes::all::OP_SIZE)
.push_int(32)
.push_opcode(opcodes::all::OP_DROP)
.push_int(2)
.push_opcode(opcodes::all::OP_SWAP)
- .push_slice(&a_htlc_key.serialize()[..])
+ .push_slice(&broadcaster_htlc_key.serialize()[..])
.push_int(2)
.push_opcode(opcodes::all::OP_CHECKMULTISIG)
.push_opcode(opcodes::all::OP_ELSE)
.push_opcode(opcodes::all::OP_IF)
.push_opcode(opcodes::all::OP_CHECKSIG)
.push_opcode(opcodes::all::OP_ELSE)
- .push_slice(&b_htlc_key.serialize()[..])
+ .push_slice(&countersignatory_htlc_key.serialize()[..])
.push_opcode(opcodes::all::OP_SWAP)
.push_opcode(opcodes::all::OP_SIZE)
.push_int(32)
.push_opcode(opcodes::all::OP_EQUALVERIFY)
.push_int(2)
.push_opcode(opcodes::all::OP_SWAP)
- .push_slice(&a_htlc_key.serialize()[..])
+ .push_slice(&broadcaster_htlc_key.serialize()[..])
.push_int(2)
.push_opcode(opcodes::all::OP_CHECKMULTISIG)
.push_opcode(opcodes::all::OP_ELSE)
}
}
-/// note here that 'a_revocation_key' is generated using b_revocation_basepoint and a's
-/// commitment secret. 'htlc' does *not* need to have its previous_output_index filled.
+/// Gets the witness redeemscript for an HTLC output in a commitment transaction. Note that htlc
+/// does not need to have its previous_output_index filled.
#[inline]
pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Script {
- get_htlc_redeemscript_with_explicit_keys(htlc, &keys.a_htlc_key, &keys.b_htlc_key, &keys.revocation_key)
+ get_htlc_redeemscript_with_explicit_keys(htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key)
}
/// Gets the redeemscript for a funding output from the two funding public keys.
/// Note that the order of funding public keys does not matter.
-pub fn make_funding_redeemscript(a: &PublicKey, b: &PublicKey) -> Script {
- let our_funding_key = a.serialize();
- let their_funding_key = b.serialize();
+pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &PublicKey) -> Script {
+ let broadcaster_funding_key = broadcaster.serialize();
+ let countersignatory_funding_key = countersignatory.serialize();
let builder = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2);
- if our_funding_key[..] < their_funding_key[..] {
- builder.push_slice(&our_funding_key)
- .push_slice(&their_funding_key)
+ if broadcaster_funding_key[..] < countersignatory_funding_key[..] {
+ builder.push_slice(&broadcaster_funding_key)
+ .push_slice(&countersignatory_funding_key)
} else {
- builder.push_slice(&their_funding_key)
- .push_slice(&our_funding_key)
+ builder.push_slice(&countersignatory_funding_key)
+ .push_slice(&broadcaster_funding_key)
}.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
}
/// panics if htlc.transaction_output_index.is_none()!
-pub fn build_htlc_transaction(prev_hash: &Txid, 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, contest_delay: u16, htlc: &HTLCOutputInCommitment, broadcaster_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();
txouts.push(TxOut {
- script_pubkey: get_revokeable_redeemscript(revocation_key, to_self_delay, a_delayed_payment_key).to_v0_p2wsh(),
+ script_pubkey: get_revokeable_redeemscript(revocation_key, contest_delay, broadcaster_delayed_payment_key).to_v0_p2wsh(),
value: htlc.amount_msat / 1000 - total_fee //TODO: BOLT 3 does not specify if we should add amount_msat before dividing or if we should divide by 1000 before subtracting (as we do here)
});
}
#[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.
-pub struct LocalCommitmentTransaction {
+/// We use this to track holder commitment transactions and put off signing them until we are ready
+/// to broadcast. This class can be used inside a signer implementation to generate a signature
+/// given the relevant secret key.
+pub struct HolderCommitmentTransaction {
// 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,
// so we're probably most of the way there.
/// The commitment transaction itself, in unsigned form.
pub unsigned_tx: Transaction,
/// Our counterparty's signature for the transaction, above.
- pub their_sig: Signature,
+ pub counterparty_sig: Signature,
// 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,
+ holder_sig_first: bool,
+ pub(crate) 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,
- /// The HTLCs and remote htlc signatures which were included in this commitment transaction.
+ pub feerate_per_kw: u32,
+ /// The HTLCs and counterparty htlc signatures which were included in this commitment transaction.
///
/// Note that this includes all HTLCs, including ones which were considered dust and not
/// actually included in the transaction as it appears on-chain, but who's value is burned as
- /// fees and not included in the to_local or to_remote outputs.
+ /// fees and not included in the to_holder or to_counterparty outputs.
///
- /// The remote HTLC signatures in the second element will always be set for non-dust HTLCs, ie
+ /// The counterparty HTLC signatures in the second element will always be set for non-dust HTLCs, ie
/// those for which transaction_output_index.is_some().
pub per_htlc: Vec<(HTLCOutputInCommitment, Option<Signature>)>,
}
-impl LocalCommitmentTransaction {
+impl HolderCommitmentTransaction {
#[cfg(test)]
pub fn dummy() -> Self {
let dummy_input = TxIn {
output: Vec::new(),
lock_time: 0,
},
- their_sig: dummy_sig,
- our_sig_first: false,
- local_keys: TxCreationKeys {
+ counterparty_sig: dummy_sig,
+ holder_sig_first: false,
+ keys: TxCreationKeys {
per_commitment_point: dummy_key.clone(),
revocation_key: dummy_key.clone(),
- a_htlc_key: dummy_key.clone(),
- b_htlc_key: dummy_key.clone(),
- a_delayed_payment_key: dummy_key.clone(),
+ broadcaster_htlc_key: dummy_key.clone(),
+ countersignatory_htlc_key: dummy_key.clone(),
+ broadcaster_delayed_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 {
+ /// Generate a new HolderCommitmentTransaction based on a raw commitment transaction,
+ /// counterparty 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_holder_sig(unsigned_tx: Transaction, counterparty_sig: Signature, holder_funding_key: &PublicKey, counterparty_funding_key: &PublicKey, keys: TxCreationKeys, feerate_per_kw: u32, htlc_data: Vec<(HTLCOutputInCommitment, Option<Signature>)>) -> HolderCommitmentTransaction {
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,
- our_sig_first: our_funding_key.serialize()[..] < their_funding_key.serialize()[..],
- local_keys,
+ counterparty_sig,
+ holder_sig_first: holder_funding_key.serialize()[..] < counterparty_funding_key.serialize()[..],
+ keys,
feerate_per_kw,
per_htlc: htlc_data,
}
}
- /// Get the txid of the local commitment transaction contained in this
- /// LocalCommitmentTransaction
+ /// The pre-calculated transaction creation public keys.
+ /// An external validating signer should not trust these keys.
+ pub fn trust_key_derivation(&self) -> &TxCreationKeys {
+ &self.keys
+ }
+
+ /// Get the txid of the holder commitment transaction contained in this
+ /// HolderCommitmentTransaction
pub fn txid(&self) -> Txid {
self.unsigned_tx.txid()
}
- /// Gets our signature for the contained commitment transaction given our funding private key.
+ /// Gets holder signature for the contained commitment transaction given holder funding private key.
///
/// Funding key is your key included in the 2-2 funding_outpoint lock. Should be provided
/// by your ChannelKeys.
/// Funding redeemscript is script locking funding_outpoint. This is the mutlsig script
/// between your own funding key and your counterparty's. Currently, this is provided in
- /// ChannelKeys::sign_local_commitment() calls directly.
+ /// ChannelKeys::sign_holder_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)[..]);
+ pub fn get_holder_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::SigHashCache::new(&self.unsigned_tx)
+ .signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..]);
secp_ctx.sign(&sighash, funding_key)
}
- pub(crate) fn add_local_sig(&self, funding_redeemscript: &Script, our_sig: Signature) -> Transaction {
+ pub(crate) fn add_holder_sig(&self, funding_redeemscript: &Script, holder_sig: Signature) -> Transaction {
let mut tx = self.unsigned_tx.clone();
// First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
tx.input[0].witness.push(Vec::new());
- if self.our_sig_first {
- tx.input[0].witness.push(our_sig.serialize_der().to_vec());
- tx.input[0].witness.push(self.their_sig.serialize_der().to_vec());
+ if self.holder_sig_first {
+ tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
} else {
- tx.input[0].witness.push(self.their_sig.serialize_der().to_vec());
- tx.input[0].witness.push(our_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
+ tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
}
tx.input[0].witness[1].push(SigHashType::All as u8);
tx.input[0].witness[2].push(SigHashType::All as u8);
/// The returned Vec has one entry for each HTLC, and in the same order. For HTLCs which were
/// considered dust and not included, a None entry exists, for all others a signature is
/// included.
- pub fn get_htlc_sigs<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_base_key: &SecretKey, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
+ pub fn get_htlc_sigs<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_base_key: &SecretKey, counterparty_selected_contest_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
let txid = self.txid();
let mut ret = Vec::with_capacity(self.per_htlc.len());
- let our_htlc_key = derive_private_key(secp_ctx, &self.local_keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
+ let holder_htlc_key = derive_private_key(secp_ctx, &self.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
for this_htlc in self.per_htlc.iter() {
if this_htlc.0.transaction_output_index.is_some() {
- let htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, local_csv, &this_htlc.0, &self.local_keys.a_delayed_payment_key, &self.local_keys.revocation_key);
+ let htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, counterparty_selected_contest_delay, &this_htlc.0, &self.keys.broadcaster_delayed_payment_key, &self.keys.revocation_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 htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.keys.broadcaster_htlc_key, &self.keys.countersignatory_htlc_key, &self.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)[..]);
- ret.push(Some(secp_ctx.sign(&sighash, &our_htlc_key)));
+ 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, &holder_htlc_key)));
} else {
ret.push(None);
}
Ok(ret)
}
- /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the local HTLC transaction signature.
- pub(crate) fn get_signed_htlc_tx(&self, htlc_index: usize, signature: &Signature, preimage: &Option<PaymentPreimage>, local_csv: u16) -> Transaction {
+ /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the holder HTLC transaction signature.
+ pub(crate) fn get_signed_htlc_tx(&self, htlc_index: usize, signature: &Signature, preimage: &Option<PaymentPreimage>, counterparty_selected_contest_delay: u16) -> Transaction {
let txid = self.txid();
let this_htlc = &self.per_htlc[htlc_index];
assert!(this_htlc.0.transaction_output_index.is_some());
// Further, we should never be provided the preimage for an HTLC-Timeout transaction.
if this_htlc.0.offered && preimage.is_some() { unreachable!(); }
- let mut htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, local_csv, &this_htlc.0, &self.local_keys.a_delayed_payment_key, &self.local_keys.revocation_key);
- // Channel should have checked that we have a remote signature for this HTLC at
+ let mut htlc_tx = build_htlc_transaction(&txid, self.feerate_per_kw, counterparty_selected_contest_delay, &this_htlc.0, &self.keys.broadcaster_delayed_payment_key, &self.keys.revocation_key);
+ // Channel should have checked that we have a counterparty signature for this HTLC at
// creation, and we should have a sensible htlc transaction:
assert!(this_htlc.1.is_some());
- 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 htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc.0, &self.keys.broadcaster_htlc_key, &self.keys.countersignatory_htlc_key, &self.keys.revocation_key);
// First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
htlc_tx.input[0].witness.push(Vec::new());
htlc_tx
}
}
-impl PartialEq for LocalCommitmentTransaction {
+impl PartialEq for HolderCommitmentTransaction {
// We dont care whether we are signed in equality comparison
fn eq(&self, o: &Self) -> bool {
self.txid() == o.txid()
}
}
-impl Writeable for LocalCommitmentTransaction {
+impl Writeable for HolderCommitmentTransaction {
fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
if let Err(e) = self.unsigned_tx.consensus_encode(&mut WriterWriteAdaptor(writer)) {
match e {
encode::Error::Io(e) => return Err(e),
- _ => panic!("local tx must have been well-formed!"),
+ _ => panic!("holder tx must have been well-formed!"),
}
}
- self.their_sig.write(writer)?;
- self.our_sig_first.write(writer)?;
- self.local_keys.write(writer)?;
+ self.counterparty_sig.write(writer)?;
+ self.holder_sig_first.write(writer)?;
+ self.keys.write(writer)?;
self.feerate_per_kw.write(writer)?;
writer.write_all(&byte_utils::be64_to_array(self.per_htlc.len() as u64))?;
for &(ref htlc, ref sig) in self.per_htlc.iter() {
Ok(())
}
}
-impl Readable for LocalCommitmentTransaction {
+impl Readable for HolderCommitmentTransaction {
fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
let unsigned_tx = match Transaction::consensus_decode(reader.by_ref()) {
Ok(tx) => tx,
_ => return Err(DecodeError::InvalidValue),
},
};
- let their_sig = Readable::read(reader)?;
- let our_sig_first = Readable::read(reader)?;
- let local_keys = Readable::read(reader)?;
+ let counterparty_sig = Readable::read(reader)?;
+ let holder_sig_first = Readable::read(reader)?;
+ let keys = Readable::read(reader)?;
let feerate_per_kw = Readable::read(reader)?;
let htlcs_count: u64 = Readable::read(reader)?;
let mut per_htlc = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / mem::size_of::<(HTLCOutputInCommitment, Option<Signature>)>()));
}
Ok(Self {
unsigned_tx,
- their_sig,
- our_sig_first,
- local_keys,
+ counterparty_sig,
+ holder_sig_first,
+ keys,
feerate_per_kw,
per_htlc,
})
projects / rust-lightning / blobdiff