1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Various utilities for building scripts and deriving keys related to channels. These are
11 //! largely of interest for those implementing chain::keysinterface::ChannelKeys message signing
14 use bitcoin::blockdata::script::{Script,Builder};
15 use bitcoin::blockdata::opcodes;
16 use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction, SigHashType};
17 use bitcoin::util::bip143;
19 use bitcoin::hashes::{Hash, HashEngine};
20 use bitcoin::hashes::sha256::Hash as Sha256;
21 use bitcoin::hashes::ripemd160::Hash as Ripemd160;
22 use bitcoin::hash_types::{Txid, PubkeyHash};
24 use ln::channelmanager::{PaymentHash, PaymentPreimage};
25 use ln::msgs::DecodeError;
26 use util::ser::{Readable, Writeable, Writer, MAX_BUF_SIZE};
29 use bitcoin::hash_types::WPubkeyHash;
30 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
31 use bitcoin::secp256k1::{Secp256k1, Signature, Message};
32 use bitcoin::secp256k1::Error as SecpError;
33 use bitcoin::secp256k1;
37 use util::transaction_utils::sort_outputs;
38 use ln::channel::INITIAL_COMMITMENT_NUMBER;
43 const HTLC_OUTPUT_IN_COMMITMENT_SIZE: usize = 1 + 8 + 4 + 32 + 5;
45 pub(crate) const MAX_HTLCS: u16 = 483;
47 // This checks that the buffer size is greater than the maximum possible size for serialized HTLCS
48 const _EXCESS_BUFFER_SIZE: usize = MAX_BUF_SIZE - MAX_HTLCS as usize * HTLC_OUTPUT_IN_COMMITMENT_SIZE;
50 pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
51 pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
54 pub(crate) enum HTLCType {
60 /// Check if a given tx witnessScript len matchs one of a pre-signed HTLC
61 pub(crate) fn scriptlen_to_htlctype(witness_script_len: usize) -> Option<HTLCType> {
62 if witness_script_len == 133 {
63 Some(HTLCType::OfferedHTLC)
64 } else if witness_script_len >= 136 && witness_script_len <= 139 {
65 Some(HTLCType::AcceptedHTLC)
72 // Various functions for key derivation and transaction creation for use within channels. Primarily
73 // used in Channel and ChannelMonitor.
75 /// Build the commitment secret from the seed and the commitment number
76 pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
77 let mut res: [u8; 32] = commitment_seed.clone();
80 if idx & (1 << bitpos) == (1 << bitpos) {
81 res[bitpos / 8] ^= 1 << (bitpos & 7);
82 res = Sha256::hash(&res).into_inner();
88 /// Implements the per-commitment secret storage scheme from
89 /// [BOLT 3](https://github.com/lightningnetwork/lightning-rfc/blob/dcbf8583976df087c79c3ce0b535311212e6812d/03-transactions.md#efficient-per-commitment-secret-storage).
91 /// Allows us to keep track of all of the revocation secrets of counterarties in just 50*32 bytes
94 pub(crate) struct CounterpartyCommitmentSecrets {
95 old_secrets: [([u8; 32], u64); 49],
98 impl PartialEq for CounterpartyCommitmentSecrets {
99 fn eq(&self, other: &Self) -> bool {
100 for (&(ref secret, ref idx), &(ref o_secret, ref o_idx)) in self.old_secrets.iter().zip(other.old_secrets.iter()) {
101 if secret != o_secret || idx != o_idx {
109 impl CounterpartyCommitmentSecrets {
110 pub(crate) fn new() -> Self {
111 Self { old_secrets: [([0; 32], 1 << 48); 49], }
115 fn place_secret(idx: u64) -> u8 {
117 if idx & (1 << i) == (1 << i) {
124 pub(crate) fn get_min_seen_secret(&self) -> u64 {
125 //TODO This can be optimized?
126 let mut min = 1 << 48;
127 for &(_, idx) in self.old_secrets.iter() {
136 fn derive_secret(secret: [u8; 32], bits: u8, idx: u64) -> [u8; 32] {
137 let mut res: [u8; 32] = secret;
139 let bitpos = bits - 1 - i;
140 if idx & (1 << bitpos) == (1 << bitpos) {
141 res[(bitpos / 8) as usize] ^= 1 << (bitpos & 7);
142 res = Sha256::hash(&res).into_inner();
148 pub(crate) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
149 let pos = Self::place_secret(idx);
151 let (old_secret, old_idx) = self.old_secrets[i as usize];
152 if Self::derive_secret(secret, pos, old_idx) != old_secret {
156 if self.get_min_seen_secret() <= idx {
159 self.old_secrets[pos as usize] = (secret, idx);
163 /// Can only fail if idx is < get_min_seen_secret
164 pub(crate) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
165 for i in 0..self.old_secrets.len() {
166 if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
167 return Some(Self::derive_secret(self.old_secrets[i].0, i as u8, idx))
170 assert!(idx < self.get_min_seen_secret());
175 impl Writeable for CounterpartyCommitmentSecrets {
176 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
177 for &(ref secret, ref idx) in self.old_secrets.iter() {
178 writer.write_all(secret)?;
179 writer.write_all(&byte_utils::be64_to_array(*idx))?;
184 impl Readable for CounterpartyCommitmentSecrets {
185 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
186 let mut old_secrets = [([0; 32], 1 << 48); 49];
187 for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
188 *secret = Readable::read(reader)?;
189 *idx = Readable::read(reader)?;
192 Ok(Self { old_secrets })
196 /// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key)
197 /// from the base secret and the per_commitment_point.
199 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
200 /// generated (ie our own).
201 pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, SecpError> {
202 let mut sha = Sha256::engine();
203 sha.input(&per_commitment_point.serialize());
204 sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize());
205 let res = Sha256::from_engine(sha).into_inner();
207 let mut key = base_secret.clone();
208 key.add_assign(&res)?;
212 /// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key)
213 /// from the base point and the per_commitment_key. This is the public equivalent of
214 /// derive_private_key - using only public keys to derive a public key instead of private keys.
216 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
217 /// generated (ie our own).
218 pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, SecpError> {
219 let mut sha = Sha256::engine();
220 sha.input(&per_commitment_point.serialize());
221 sha.input(&base_point.serialize());
222 let res = Sha256::from_engine(sha).into_inner();
224 let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?);
225 base_point.combine(&hashkey)
228 /// Derives a per-commitment-transaction revocation key from its constituent parts.
230 /// Only the cheating participant owns a valid witness to propagate a revoked
231 /// commitment transaction, thus per_commitment_secret always come from cheater
232 /// and revocation_base_secret always come from punisher, which is the broadcaster
233 /// of the transaction spending with this key knowledge.
235 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
236 /// generated (ie our own).
237 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> {
238 let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret);
239 let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
241 let rev_append_commit_hash_key = {
242 let mut sha = Sha256::engine();
243 sha.input(&countersignatory_revocation_base_point.serialize());
244 sha.input(&per_commitment_point.serialize());
246 Sha256::from_engine(sha).into_inner()
248 let commit_append_rev_hash_key = {
249 let mut sha = Sha256::engine();
250 sha.input(&per_commitment_point.serialize());
251 sha.input(&countersignatory_revocation_base_point.serialize());
253 Sha256::from_engine(sha).into_inner()
256 let mut countersignatory_contrib = countersignatory_revocation_base_secret.clone();
257 countersignatory_contrib.mul_assign(&rev_append_commit_hash_key)?;
258 let mut broadcaster_contrib = per_commitment_secret.clone();
259 broadcaster_contrib.mul_assign(&commit_append_rev_hash_key)?;
260 countersignatory_contrib.add_assign(&broadcaster_contrib[..])?;
261 Ok(countersignatory_contrib)
264 /// Derives a per-commitment-transaction revocation public key from its constituent parts. This is
265 /// the public equivalend of derive_private_revocation_key - using only public keys to derive a
266 /// public key instead of private keys.
268 /// Only the cheating participant owns a valid witness to propagate a revoked
269 /// commitment transaction, thus per_commitment_point always come from cheater
270 /// and revocation_base_point always come from punisher, which is the broadcaster
271 /// of the transaction spending with this key knowledge.
273 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
274 /// generated (ie our own).
275 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> {
276 let rev_append_commit_hash_key = {
277 let mut sha = Sha256::engine();
278 sha.input(&countersignatory_revocation_base_point.serialize());
279 sha.input(&per_commitment_point.serialize());
281 Sha256::from_engine(sha).into_inner()
283 let commit_append_rev_hash_key = {
284 let mut sha = Sha256::engine();
285 sha.input(&per_commitment_point.serialize());
286 sha.input(&countersignatory_revocation_base_point.serialize());
288 Sha256::from_engine(sha).into_inner()
291 let mut countersignatory_contrib = countersignatory_revocation_base_point.clone();
292 countersignatory_contrib.mul_assign(&secp_ctx, &rev_append_commit_hash_key)?;
293 let mut broadcaster_contrib = per_commitment_point.clone();
294 broadcaster_contrib.mul_assign(&secp_ctx, &commit_append_rev_hash_key)?;
295 countersignatory_contrib.combine(&broadcaster_contrib)
298 /// The set of public keys which are used in the creation of one commitment transaction.
299 /// These are derived from the channel base keys and per-commitment data.
301 /// A broadcaster key is provided from potential broadcaster of the computed transaction.
302 /// A countersignatory key is coming from a protocol participant unable to broadcast the
305 /// These keys are assumed to be good, either because the code derived them from
306 /// channel basepoints via the new function, or they were obtained via
307 /// CommitmentTransaction.trust().keys() because we trusted the source of the
308 /// pre-calculated keys.
309 #[derive(PartialEq, Clone)]
310 pub struct TxCreationKeys {
311 /// The broadcaster's per-commitment public key which was used to derive the other keys.
312 pub per_commitment_point: PublicKey,
313 /// The revocation key which is used to allow the broadcaster of the commitment
314 /// transaction to provide their counterparty the ability to punish them if they broadcast
316 pub revocation_key: PublicKey,
317 /// Broadcaster's HTLC Key
318 pub broadcaster_htlc_key: PublicKey,
319 /// Countersignatory's HTLC Key
320 pub countersignatory_htlc_key: PublicKey,
321 /// Broadcaster's Payment Key (which isn't allowed to be spent from for some delay)
322 pub broadcaster_delayed_payment_key: PublicKey,
324 impl_writeable!(TxCreationKeys, 33*6,
325 { per_commitment_point, revocation_key, broadcaster_htlc_key, countersignatory_htlc_key, broadcaster_delayed_payment_key });
327 /// One counterparty's public keys which do not change over the life of a channel.
328 #[derive(Clone, PartialEq)]
329 pub struct ChannelPublicKeys {
330 /// The public key which is used to sign all commitment transactions, as it appears in the
331 /// on-chain channel lock-in 2-of-2 multisig output.
332 pub funding_pubkey: PublicKey,
333 /// The base point which is used (with derive_public_revocation_key) to derive per-commitment
334 /// revocation keys. This is combined with the per-commitment-secret generated by the
335 /// counterparty to create a secret which the counterparty can reveal to revoke previous
337 pub revocation_basepoint: PublicKey,
338 /// The public key on which the non-broadcaster (ie the countersignatory) receives an immediately
339 /// spendable primary channel balance on the broadcaster's commitment transaction. This key is
340 /// static across every commitment transaction.
341 pub payment_point: PublicKey,
342 /// The base point which is used (with derive_public_key) to derive a per-commitment payment
343 /// public key which receives non-HTLC-encumbered funds which are only available for spending
344 /// after some delay (or can be claimed via the revocation path).
345 pub delayed_payment_basepoint: PublicKey,
346 /// The base point which is used (with derive_public_key) to derive a per-commitment public key
347 /// which is used to encumber HTLC-in-flight outputs.
348 pub htlc_basepoint: PublicKey,
351 impl_writeable!(ChannelPublicKeys, 33*5, {
353 revocation_basepoint,
355 delayed_payment_basepoint,
360 impl TxCreationKeys {
361 /// Create per-state keys from channel base points and the per-commitment point.
362 /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
363 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> {
365 per_commitment_point: per_commitment_point.clone(),
366 revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base)?,
367 broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base)?,
368 countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base)?,
369 broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base)?,
373 /// Generate per-state keys from channel static keys.
374 /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
375 pub fn from_channel_static_keys<T: secp256k1::Signing + secp256k1::Verification>(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TxCreationKeys, SecpError> {
376 TxCreationKeys::derive_new(
378 &per_commitment_point,
379 &broadcaster_keys.delayed_payment_basepoint,
380 &broadcaster_keys.htlc_basepoint,
381 &countersignatory_keys.revocation_basepoint,
382 &countersignatory_keys.htlc_basepoint,
387 /// A script either spendable by the revocation
388 /// key or the broadcaster_delayed_payment_key and satisfying the relative-locktime OP_CSV constrain.
389 /// Encumbering a `to_holder` output on a commitment transaction or 2nd-stage HTLC transactions.
390 pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, contest_delay: u16, broadcaster_delayed_payment_key: &PublicKey) -> Script {
391 Builder::new().push_opcode(opcodes::all::OP_IF)
392 .push_slice(&revocation_key.serialize())
393 .push_opcode(opcodes::all::OP_ELSE)
394 .push_int(contest_delay as i64)
395 .push_opcode(opcodes::all::OP_CSV)
396 .push_opcode(opcodes::all::OP_DROP)
397 .push_slice(&broadcaster_delayed_payment_key.serialize())
398 .push_opcode(opcodes::all::OP_ENDIF)
399 .push_opcode(opcodes::all::OP_CHECKSIG)
403 #[derive(Clone, PartialEq)]
404 /// Information about an HTLC as it appears in a commitment transaction
405 pub struct HTLCOutputInCommitment {
406 /// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction).
407 /// Note that this is not the same as whether it is ountbound *from us*. To determine that you
408 /// need to compare this value to whether the commitment transaction in question is that of
409 /// the counterparty or our own.
411 /// The value, in msat, of the HTLC. The value as it appears in the commitment transaction is
412 /// this divided by 1000.
413 pub amount_msat: u64,
414 /// The CLTV lock-time at which this HTLC expires.
415 pub cltv_expiry: u32,
416 /// The hash of the preimage which unlocks this HTLC.
417 pub payment_hash: PaymentHash,
418 /// The position within the commitment transactions' outputs. This may be None if the value is
419 /// below the dust limit (in which case no output appears in the commitment transaction and the
420 /// value is spent to additional transaction fees).
421 pub transaction_output_index: Option<u32>,
424 impl_writeable!(HTLCOutputInCommitment, HTLC_OUTPUT_IN_COMMITMENT_SIZE, {
429 transaction_output_index
433 pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, broadcaster_htlc_key: &PublicKey, countersignatory_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
434 let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
436 Builder::new().push_opcode(opcodes::all::OP_DUP)
437 .push_opcode(opcodes::all::OP_HASH160)
438 .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
439 .push_opcode(opcodes::all::OP_EQUAL)
440 .push_opcode(opcodes::all::OP_IF)
441 .push_opcode(opcodes::all::OP_CHECKSIG)
442 .push_opcode(opcodes::all::OP_ELSE)
443 .push_slice(&countersignatory_htlc_key.serialize()[..])
444 .push_opcode(opcodes::all::OP_SWAP)
445 .push_opcode(opcodes::all::OP_SIZE)
447 .push_opcode(opcodes::all::OP_EQUAL)
448 .push_opcode(opcodes::all::OP_NOTIF)
449 .push_opcode(opcodes::all::OP_DROP)
451 .push_opcode(opcodes::all::OP_SWAP)
452 .push_slice(&broadcaster_htlc_key.serialize()[..])
454 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
455 .push_opcode(opcodes::all::OP_ELSE)
456 .push_opcode(opcodes::all::OP_HASH160)
457 .push_slice(&payment_hash160)
458 .push_opcode(opcodes::all::OP_EQUALVERIFY)
459 .push_opcode(opcodes::all::OP_CHECKSIG)
460 .push_opcode(opcodes::all::OP_ENDIF)
461 .push_opcode(opcodes::all::OP_ENDIF)
464 Builder::new().push_opcode(opcodes::all::OP_DUP)
465 .push_opcode(opcodes::all::OP_HASH160)
466 .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
467 .push_opcode(opcodes::all::OP_EQUAL)
468 .push_opcode(opcodes::all::OP_IF)
469 .push_opcode(opcodes::all::OP_CHECKSIG)
470 .push_opcode(opcodes::all::OP_ELSE)
471 .push_slice(&countersignatory_htlc_key.serialize()[..])
472 .push_opcode(opcodes::all::OP_SWAP)
473 .push_opcode(opcodes::all::OP_SIZE)
475 .push_opcode(opcodes::all::OP_EQUAL)
476 .push_opcode(opcodes::all::OP_IF)
477 .push_opcode(opcodes::all::OP_HASH160)
478 .push_slice(&payment_hash160)
479 .push_opcode(opcodes::all::OP_EQUALVERIFY)
481 .push_opcode(opcodes::all::OP_SWAP)
482 .push_slice(&broadcaster_htlc_key.serialize()[..])
484 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
485 .push_opcode(opcodes::all::OP_ELSE)
486 .push_opcode(opcodes::all::OP_DROP)
487 .push_int(htlc.cltv_expiry as i64)
488 .push_opcode(opcodes::all::OP_CLTV)
489 .push_opcode(opcodes::all::OP_DROP)
490 .push_opcode(opcodes::all::OP_CHECKSIG)
491 .push_opcode(opcodes::all::OP_ENDIF)
492 .push_opcode(opcodes::all::OP_ENDIF)
497 /// Gets the witness redeemscript for an HTLC output in a commitment transaction. Note that htlc
498 /// does not need to have its previous_output_index filled.
500 pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Script {
501 get_htlc_redeemscript_with_explicit_keys(htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key)
504 /// Gets the redeemscript for a funding output from the two funding public keys.
505 /// Note that the order of funding public keys does not matter.
506 pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &PublicKey) -> Script {
507 let broadcaster_funding_key = broadcaster.serialize();
508 let countersignatory_funding_key = countersignatory.serialize();
510 let builder = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2);
511 if broadcaster_funding_key[..] < countersignatory_funding_key[..] {
512 builder.push_slice(&broadcaster_funding_key)
513 .push_slice(&countersignatory_funding_key)
515 builder.push_slice(&countersignatory_funding_key)
516 .push_slice(&broadcaster_funding_key)
517 }.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
520 /// panics if htlc.transaction_output_index.is_none()!
521 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 {
522 let mut txins: Vec<TxIn> = Vec::new();
524 previous_output: OutPoint {
525 txid: prev_hash.clone(),
526 vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"),
528 script_sig: Script::new(),
533 let total_fee = if htlc.offered {
534 feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000
536 feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000
539 let mut txouts: Vec<TxOut> = Vec::new();
541 script_pubkey: get_revokeable_redeemscript(revocation_key, contest_delay, broadcaster_delayed_payment_key).to_v0_p2wsh(),
542 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)
547 lock_time: if htlc.offered { htlc.cltv_expiry } else { 0 },
553 /// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction).
554 /// The fields are organized by holder/counterparty.
556 /// Normally, this is converted to the broadcaster/countersignatory-organized DirectedChannelTransactionParameters
557 /// before use, via the as_holder_broadcastable and as_counterparty_broadcastable functions.
559 pub struct ChannelTransactionParameters {
560 /// Holder public keys
561 pub holder_pubkeys: ChannelPublicKeys,
562 /// The contest delay selected by the holder, which applies to counterparty-broadcast transactions
563 pub holder_selected_contest_delay: u16,
564 /// Whether the holder is the initiator of this channel.
565 /// This is an input to the commitment number obscure factor computation.
566 pub is_outbound_from_holder: bool,
567 /// The late-bound counterparty channel transaction parameters.
568 /// These parameters are populated at the point in the protocol where the counterparty provides them.
569 pub counterparty_parameters: Option<CounterpartyChannelTransactionParameters>,
570 /// The late-bound funding outpoint
571 pub funding_outpoint: Option<chain::transaction::OutPoint>,
574 /// Late-bound per-channel counterparty data used to build transactions.
576 pub struct CounterpartyChannelTransactionParameters {
577 /// Counter-party public keys
578 pub pubkeys: ChannelPublicKeys,
579 /// The contest delay selected by the counterparty, which applies to holder-broadcast transactions
580 pub selected_contest_delay: u16,
583 impl ChannelTransactionParameters {
584 /// Whether the late bound parameters are populated.
585 pub fn is_populated(&self) -> bool {
586 self.counterparty_parameters.is_some() && self.funding_outpoint.is_some()
589 /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
590 /// given that the holder is the broadcaster.
592 /// self.is_populated() must be true before calling this function.
593 pub fn as_holder_broadcastable(&self) -> DirectedChannelTransactionParameters {
594 assert!(self.is_populated(), "self.late_parameters must be set before using as_holder_broadcastable");
595 DirectedChannelTransactionParameters {
597 holder_is_broadcaster: true
601 /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
602 /// given that the counterparty is the broadcaster.
604 /// self.is_populated() must be true before calling this function.
605 pub fn as_counterparty_broadcastable(&self) -> DirectedChannelTransactionParameters {
606 assert!(self.is_populated(), "self.late_parameters must be set before using as_counterparty_broadcastable");
607 DirectedChannelTransactionParameters {
609 holder_is_broadcaster: false
614 impl_writeable!(CounterpartyChannelTransactionParameters, 0, {
616 selected_contest_delay
619 impl_writeable!(ChannelTransactionParameters, 0, {
621 holder_selected_contest_delay,
622 is_outbound_from_holder,
623 counterparty_parameters,
627 /// Static channel fields used to build transactions given per-commitment fields, organized by
628 /// broadcaster/countersignatory.
630 /// This is derived from the holder/counterparty-organized ChannelTransactionParameters via the
631 /// as_holder_broadcastable and as_counterparty_broadcastable functions.
632 pub struct DirectedChannelTransactionParameters<'a> {
633 /// The holder's channel static parameters
634 inner: &'a ChannelTransactionParameters,
635 /// Whether the holder is the broadcaster
636 holder_is_broadcaster: bool,
639 impl<'a> DirectedChannelTransactionParameters<'a> {
640 /// Get the channel pubkeys for the broadcaster
641 pub fn broadcaster_pubkeys(&self) -> &ChannelPublicKeys {
642 if self.holder_is_broadcaster {
643 &self.inner.holder_pubkeys
645 &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
649 /// Get the channel pubkeys for the countersignatory
650 pub fn countersignatory_pubkeys(&self) -> &ChannelPublicKeys {
651 if self.holder_is_broadcaster {
652 &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
654 &self.inner.holder_pubkeys
658 /// Get the contest delay applicable to the transactions.
659 /// Note that the contest delay was selected by the countersignatory.
660 pub fn contest_delay(&self) -> u16 {
661 let counterparty_parameters = self.inner.counterparty_parameters.as_ref().unwrap();
662 if self.holder_is_broadcaster { counterparty_parameters.selected_contest_delay } else { self.inner.holder_selected_contest_delay }
665 /// Whether the channel is outbound from the broadcaster.
667 /// The boolean representing the side that initiated the channel is
668 /// an input to the commitment number obscure factor computation.
669 pub fn is_outbound(&self) -> bool {
670 if self.holder_is_broadcaster { self.inner.is_outbound_from_holder } else { !self.inner.is_outbound_from_holder }
673 /// The funding outpoint
674 pub fn funding_outpoint(&self) -> OutPoint {
675 self.inner.funding_outpoint.unwrap().into_bitcoin_outpoint()
679 /// Information needed to build and sign a holder's commitment transaction.
681 /// The transaction is only signed once we are ready to broadcast.
683 pub struct HolderCommitmentTransaction {
684 inner: CommitmentTransaction,
685 /// Our counterparty's signature for the transaction
686 pub counterparty_sig: Signature,
687 /// All non-dust counterparty HTLC signatures, in the order they appear in the transaction
688 pub counterparty_htlc_sigs: Vec<Signature>,
689 // Which order the signatures should go in when constructing the final commitment tx witness.
690 // The user should be able to reconstruct this themselves, so we don't bother to expose it.
691 holder_sig_first: bool,
694 impl Deref for HolderCommitmentTransaction {
695 type Target = CommitmentTransaction;
697 fn deref(&self) -> &Self::Target { &self.inner }
700 impl PartialEq for HolderCommitmentTransaction {
701 // We dont care whether we are signed in equality comparison
702 fn eq(&self, o: &Self) -> bool {
703 self.inner == o.inner
707 impl_writeable!(HolderCommitmentTransaction, 0, {
708 inner, counterparty_sig, counterparty_htlc_sigs, holder_sig_first
711 impl HolderCommitmentTransaction {
713 pub fn dummy() -> Self {
714 let secp_ctx = Secp256k1::new();
715 let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
716 let dummy_sig = secp_ctx.sign(&secp256k1::Message::from_slice(&[42; 32]).unwrap(), &SecretKey::from_slice(&[42; 32]).unwrap());
718 let keys = TxCreationKeys {
719 per_commitment_point: dummy_key.clone(),
720 revocation_key: dummy_key.clone(),
721 broadcaster_htlc_key: dummy_key.clone(),
722 countersignatory_htlc_key: dummy_key.clone(),
723 broadcaster_delayed_payment_key: dummy_key.clone(),
725 let channel_pubkeys = ChannelPublicKeys {
726 funding_pubkey: dummy_key.clone(),
727 revocation_basepoint: dummy_key.clone(),
728 payment_point: dummy_key.clone(),
729 delayed_payment_basepoint: dummy_key.clone(),
730 htlc_basepoint: dummy_key.clone()
732 let channel_parameters = ChannelTransactionParameters {
733 holder_pubkeys: channel_pubkeys.clone(),
734 holder_selected_contest_delay: 0,
735 is_outbound_from_holder: false,
736 counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: channel_pubkeys.clone(), selected_contest_delay: 0 }),
737 funding_outpoint: Some(chain::transaction::OutPoint { txid: Default::default(), index: 0 })
739 let mut htlcs_with_aux: Vec<(_, ())> = Vec::new();
740 let inner = CommitmentTransaction::new_with_auxiliary_htlc_data(0, 0, 0, keys, 0, &mut htlcs_with_aux, &channel_parameters.as_counterparty_broadcastable());
741 HolderCommitmentTransaction {
743 counterparty_sig: dummy_sig,
744 counterparty_htlc_sigs: Vec::new(),
745 holder_sig_first: false
749 /// Create a new holder transaction with the given counterparty signatures.
750 /// The funding keys are used to figure out which signature should go first when building the transaction for broadcast.
751 pub fn new(commitment_tx: CommitmentTransaction, counterparty_sig: Signature, counterparty_htlc_sigs: Vec<Signature>, holder_funding_key: &PublicKey, counterparty_funding_key: &PublicKey) -> Self {
753 inner: commitment_tx,
755 counterparty_htlc_sigs,
756 holder_sig_first: holder_funding_key.serialize()[..] < counterparty_funding_key.serialize()[..],
760 pub(crate) fn add_holder_sig(&self, funding_redeemscript: &Script, holder_sig: Signature) -> Transaction {
761 // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
762 let mut tx = self.inner.built.transaction.clone();
763 tx.input[0].witness.push(Vec::new());
765 if self.holder_sig_first {
766 tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
767 tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
769 tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
770 tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
772 tx.input[0].witness[1].push(SigHashType::All as u8);
773 tx.input[0].witness[2].push(SigHashType::All as u8);
775 tx.input[0].witness.push(funding_redeemscript.as_bytes().to_vec());
780 /// A pre-built Bitcoin commitment transaction and its txid.
782 pub struct BuiltCommitmentTransaction {
783 /// The commitment transaction
784 pub transaction: Transaction,
785 /// The txid for the commitment transaction.
787 /// This is provided as a performance optimization, instead of calling transaction.txid()
792 impl_writeable!(BuiltCommitmentTransaction, 0, { transaction, txid });
794 impl BuiltCommitmentTransaction {
795 /// Get the SIGHASH_ALL sighash value of the transaction.
797 /// This can be used to verify a signature.
798 pub fn get_sighash_all(&self, funding_redeemscript: &Script, channel_value_satoshis: u64) -> Message {
799 let sighash = &bip143::SigHashCache::new(&self.transaction).signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..];
800 hash_to_message!(sighash)
803 /// Sign a transaction, either because we are counter-signing the counterparty's transaction or
804 /// because we are about to broadcast a holder transaction.
805 pub fn sign<T: secp256k1::Signing>(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) -> Signature {
806 let sighash = self.get_sighash_all(funding_redeemscript, channel_value_satoshis);
807 secp_ctx.sign(&sighash, funding_key)
811 /// This class tracks the per-transaction information needed to build a commitment transaction and to
812 /// actually build it and sign. It is used for holder transactions that we sign only when needed
813 /// and for transactions we sign for the counterparty.
815 /// This class can be used inside a signer implementation to generate a signature given the relevant
818 pub struct CommitmentTransaction {
819 commitment_number: u64,
820 to_broadcaster_value_sat: u64,
821 to_countersignatory_value_sat: u64,
823 htlcs: Vec<HTLCOutputInCommitment>,
824 // A cache of the parties' pubkeys required to construct the transaction, see doc for trust()
825 keys: TxCreationKeys,
826 // For access to the pre-built transaction, see doc for trust()
827 built: BuiltCommitmentTransaction,
830 impl PartialEq for CommitmentTransaction {
831 fn eq(&self, o: &Self) -> bool {
832 let eq = self.commitment_number == o.commitment_number &&
833 self.to_broadcaster_value_sat == o.to_broadcaster_value_sat &&
834 self.to_countersignatory_value_sat == o.to_countersignatory_value_sat &&
835 self.feerate_per_kw == o.feerate_per_kw &&
836 self.htlcs == o.htlcs &&
839 debug_assert_eq!(self.built.transaction, o.built.transaction);
840 debug_assert_eq!(self.built.txid, o.built.txid);
846 impl Writeable for Vec<HTLCOutputInCommitment> {
848 fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
849 (self.len() as u16).write(w)?;
850 for e in self.iter() {
857 impl Readable for Vec<HTLCOutputInCommitment> {
859 fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
860 let len: u16 = Readable::read(r)?;
861 let byte_size = (len as usize)
862 .checked_mul(HTLC_OUTPUT_IN_COMMITMENT_SIZE)
863 .ok_or(DecodeError::BadLengthDescriptor)?;
864 if byte_size > MAX_BUF_SIZE {
865 return Err(DecodeError::BadLengthDescriptor);
867 let mut ret = Vec::with_capacity(len as usize);
868 for _ in 0..len { ret.push(HTLCOutputInCommitment::read(r)?); }
873 impl_writeable!(CommitmentTransaction, 0, {
875 to_broadcaster_value_sat,
876 to_countersignatory_value_sat,
883 impl CommitmentTransaction {
884 /// Construct an object of the class while assigning transaction output indices to HTLCs.
886 /// Populates HTLCOutputInCommitment.transaction_output_index in htlcs_with_aux.
888 /// The generic T allows the caller to match the HTLC output index with auxiliary data.
889 /// This auxiliary data is not stored in this object.
891 /// Only include HTLCs that are above the dust limit for the channel.
893 /// (C-not exported) due to the generic though we likely should expose a version without
894 pub fn new_with_auxiliary_htlc_data<T>(commitment_number: u64, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, keys: TxCreationKeys, feerate_per_kw: u32, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> CommitmentTransaction {
895 // Sort outputs and populate output indices while keeping track of the auxiliary data
896 let (outputs, htlcs) = Self::internal_build_outputs(&keys, to_broadcaster_value_sat, to_countersignatory_value_sat, htlcs_with_aux, channel_parameters).unwrap();
898 let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(commitment_number, channel_parameters);
899 let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
900 let txid = transaction.txid();
901 CommitmentTransaction {
903 to_broadcaster_value_sat,
904 to_countersignatory_value_sat,
908 built: BuiltCommitmentTransaction {
915 fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters) -> Result<BuiltCommitmentTransaction, ()> {
916 let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(self.commitment_number, channel_parameters);
918 let mut htlcs_with_aux = self.htlcs.iter().map(|h| (h.clone(), ())).collect();
919 let (outputs, _) = Self::internal_build_outputs(keys, self.to_broadcaster_value_sat, self.to_countersignatory_value_sat, &mut htlcs_with_aux, channel_parameters)?;
921 let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
922 let txid = transaction.txid();
923 let built_transaction = BuiltCommitmentTransaction {
927 Ok(built_transaction)
930 fn make_transaction(obscured_commitment_transaction_number: u64, txins: Vec<TxIn>, outputs: Vec<TxOut>) -> Transaction {
933 lock_time: ((0x20 as u32) << 8 * 3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
939 // This is used in two cases:
940 // - initial sorting of outputs / HTLCs in the constructor, in which case T is auxiliary data the
941 // caller needs to have sorted together with the HTLCs so it can keep track of the output index
942 // - building of a bitcoin transaction during a verify() call, in which case T is just ()
943 fn internal_build_outputs<T>(keys: &TxCreationKeys, to_broadcaster_value_sat: u64, to_countersignatory_value_sat: u64, htlcs_with_aux: &mut Vec<(HTLCOutputInCommitment, T)>, channel_parameters: &DirectedChannelTransactionParameters) -> Result<(Vec<TxOut>, Vec<HTLCOutputInCommitment>), ()> {
944 let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
945 let contest_delay = channel_parameters.contest_delay();
947 let mut txouts: Vec<(TxOut, Option<&mut HTLCOutputInCommitment>)> = Vec::new();
949 if to_countersignatory_value_sat > 0 {
950 let script = script_for_p2wpkh(&countersignatory_pubkeys.payment_point);
953 script_pubkey: script.clone(),
954 value: to_countersignatory_value_sat,
960 if to_broadcaster_value_sat > 0 {
961 let redeem_script = get_revokeable_redeemscript(
962 &keys.revocation_key,
964 &keys.broadcaster_delayed_payment_key,
968 script_pubkey: redeem_script.to_v0_p2wsh(),
969 value: to_broadcaster_value_sat,
975 let mut htlcs = Vec::with_capacity(htlcs_with_aux.len());
976 for (htlc, _) in htlcs_with_aux {
977 let script = chan_utils::get_htlc_redeemscript(&htlc, &keys);
979 script_pubkey: script.to_v0_p2wsh(),
980 value: htlc.amount_msat / 1000,
982 txouts.push((txout, Some(htlc)));
985 // Sort output in BIP-69 order (amount, scriptPubkey). Tie-breaks based on HTLC
986 // CLTV expiration height.
987 sort_outputs(&mut txouts, |a, b| {
988 if let &Some(ref a_htlcout) = a {
989 if let &Some(ref b_htlcout) = b {
990 a_htlcout.cltv_expiry.cmp(&b_htlcout.cltv_expiry)
991 // Note that due to hash collisions, we have to have a fallback comparison
992 // here for fuzztarget mode (otherwise at least chanmon_fail_consistency
994 .then(a_htlcout.payment_hash.0.cmp(&b_htlcout.payment_hash.0))
995 // For non-HTLC outputs, if they're copying our SPK we don't really care if we
996 // close the channel due to mismatches - they're doing something dumb:
997 } else { cmp::Ordering::Equal }
998 } else { cmp::Ordering::Equal }
1001 let mut outputs = Vec::with_capacity(txouts.len());
1002 for (idx, out) in txouts.drain(..).enumerate() {
1003 if let Some(htlc) = out.1 {
1004 htlc.transaction_output_index = Some(idx as u32);
1005 htlcs.push(htlc.clone());
1007 outputs.push(out.0);
1009 Ok((outputs, htlcs))
1012 fn internal_build_inputs(commitment_number: u64, channel_parameters: &DirectedChannelTransactionParameters) -> (u64, Vec<TxIn>) {
1013 let broadcaster_pubkeys = channel_parameters.broadcaster_pubkeys();
1014 let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
1015 let commitment_transaction_number_obscure_factor = get_commitment_transaction_number_obscure_factor(
1016 &broadcaster_pubkeys.payment_point,
1017 &countersignatory_pubkeys.payment_point,
1018 channel_parameters.is_outbound(),
1021 let obscured_commitment_transaction_number =
1022 commitment_transaction_number_obscure_factor ^ (INITIAL_COMMITMENT_NUMBER - commitment_number);
1025 let mut ins: Vec<TxIn> = Vec::new();
1027 previous_output: channel_parameters.funding_outpoint(),
1028 script_sig: Script::new(),
1029 sequence: ((0x80 as u32) << 8 * 3)
1030 | ((obscured_commitment_transaction_number >> 3 * 8) as u32),
1031 witness: Vec::new(),
1035 (obscured_commitment_transaction_number, txins)
1038 /// The backwards-counting commitment number
1039 pub fn commitment_number(&self) -> u64 {
1040 self.commitment_number
1043 /// The value to be sent to the broadcaster
1044 pub fn to_broadcaster_value_sat(&self) -> u64 {
1045 self.to_broadcaster_value_sat
1048 /// The value to be sent to the counterparty
1049 pub fn to_countersignatory_value_sat(&self) -> u64 {
1050 self.to_countersignatory_value_sat
1053 /// The feerate paid per 1000-weight-unit in this commitment transaction.
1054 pub fn feerate_per_kw(&self) -> u32 {
1058 /// The non-dust HTLCs (direction, amt, height expiration, hash, transaction output index)
1059 /// which were included in this commitment transaction in output order.
1060 /// The transaction index is always populated.
1062 /// (C-not exported) as we cannot currently convert Vec references to/from C, though we should
1063 /// expose a less effecient version which creates a Vec of references in the future.
1064 pub fn htlcs(&self) -> &Vec<HTLCOutputInCommitment> {
1068 /// Trust our pre-built transaction and derived transaction creation public keys.
1070 /// Applies a wrapper which allows access to these fields.
1072 /// This should only be used if you fully trust the builder of this object. It should not
1073 /// be used by an external signer - instead use the verify function.
1074 pub fn trust(&self) -> TrustedCommitmentTransaction {
1075 TrustedCommitmentTransaction { inner: self }
1078 /// Verify our pre-built transaction and derived transaction creation public keys.
1080 /// Applies a wrapper which allows access to these fields.
1082 /// An external validating signer must call this method before signing
1083 /// or using the built transaction.
1084 pub fn verify<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TrustedCommitmentTransaction, ()> {
1085 // This is the only field of the key cache that we trust
1086 let per_commitment_point = self.keys.per_commitment_point;
1087 let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap();
1088 if keys != self.keys {
1091 let tx = self.internal_rebuild_transaction(&keys, channel_parameters)?;
1092 if self.built.transaction != tx.transaction || self.built.txid != tx.txid {
1095 Ok(TrustedCommitmentTransaction { inner: self })
1099 /// A wrapper on CommitmentTransaction indicating that the derived fields (the built bitcoin
1100 /// transaction and the transaction creation keys) are trusted.
1102 /// See trust() and verify() functions on CommitmentTransaction.
1104 /// This structure implements Deref.
1105 pub struct TrustedCommitmentTransaction<'a> {
1106 inner: &'a CommitmentTransaction,
1109 impl<'a> Deref for TrustedCommitmentTransaction<'a> {
1110 type Target = CommitmentTransaction;
1112 fn deref(&self) -> &Self::Target { self.inner }
1115 impl<'a> TrustedCommitmentTransaction<'a> {
1116 /// The transaction ID of the built Bitcoin transaction
1117 pub fn txid(&self) -> Txid {
1118 self.inner.built.txid
1121 /// The pre-built Bitcoin commitment transaction
1122 pub fn built_transaction(&self) -> &BuiltCommitmentTransaction {
1126 /// The pre-calculated transaction creation public keys.
1127 pub fn keys(&self) -> &TxCreationKeys {
1131 /// Get a signature for each HTLC which was included in the commitment transaction (ie for
1132 /// which HTLCOutputInCommitment::transaction_output_index.is_some()).
1134 /// The returned Vec has one entry for each HTLC, and in the same order.
1135 pub fn get_htlc_sigs<T: secp256k1::Signing>(&self, htlc_base_key: &SecretKey, channel_parameters: &DirectedChannelTransactionParameters, secp_ctx: &Secp256k1<T>) -> Result<Vec<Signature>, ()> {
1136 let inner = self.inner;
1137 let keys = &inner.keys;
1138 let txid = inner.built.txid;
1139 let mut ret = Vec::with_capacity(inner.htlcs.len());
1140 let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
1142 for this_htlc in inner.htlcs.iter() {
1143 assert!(this_htlc.transaction_output_index.is_some());
1144 let htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
1146 let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key);
1148 let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.amount_msat / 1000, SigHashType::All)[..]);
1149 ret.push(secp_ctx.sign(&sighash, &holder_htlc_key));
1154 /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the holder HTLC transaction signature.
1155 pub(crate) fn get_signed_htlc_tx(&self, channel_parameters: &DirectedChannelTransactionParameters, htlc_index: usize, counterparty_signature: &Signature, signature: &Signature, preimage: &Option<PaymentPreimage>) -> Transaction {
1156 let inner = self.inner;
1157 let keys = &inner.keys;
1158 let txid = inner.built.txid;
1159 let this_htlc = &inner.htlcs[htlc_index];
1160 assert!(this_htlc.transaction_output_index.is_some());
1161 // if we don't have preimage for an HTLC-Success, we can't generate an HTLC transaction.
1162 if !this_htlc.offered && preimage.is_none() { unreachable!(); }
1163 // Further, we should never be provided the preimage for an HTLC-Timeout transaction.
1164 if this_htlc.offered && preimage.is_some() { unreachable!(); }
1166 let mut htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
1168 let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key);
1170 // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
1171 htlc_tx.input[0].witness.push(Vec::new());
1173 htlc_tx.input[0].witness.push(counterparty_signature.serialize_der().to_vec());
1174 htlc_tx.input[0].witness.push(signature.serialize_der().to_vec());
1175 htlc_tx.input[0].witness[1].push(SigHashType::All as u8);
1176 htlc_tx.input[0].witness[2].push(SigHashType::All as u8);
1178 if this_htlc.offered {
1179 // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
1180 htlc_tx.input[0].witness.push(Vec::new());
1182 htlc_tx.input[0].witness.push(preimage.unwrap().0.to_vec());
1185 htlc_tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec());
1190 /// Get the transaction number obscure factor
1191 pub fn get_commitment_transaction_number_obscure_factor(
1192 broadcaster_payment_basepoint: &PublicKey,
1193 countersignatory_payment_basepoint: &PublicKey,
1194 outbound_from_broadcaster: bool,
1196 let mut sha = Sha256::engine();
1198 if outbound_from_broadcaster {
1199 sha.input(&broadcaster_payment_basepoint.serialize());
1200 sha.input(&countersignatory_payment_basepoint.serialize());
1202 sha.input(&countersignatory_payment_basepoint.serialize());
1203 sha.input(&broadcaster_payment_basepoint.serialize());
1205 let res = Sha256::from_engine(sha).into_inner();
1207 ((res[26] as u64) << 5 * 8)
1208 | ((res[27] as u64) << 4 * 8)
1209 | ((res[28] as u64) << 3 * 8)
1210 | ((res[29] as u64) << 2 * 8)
1211 | ((res[30] as u64) << 1 * 8)
1212 | ((res[31] as u64) << 0 * 8)
1215 fn script_for_p2wpkh(key: &PublicKey) -> Script {
1216 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1217 .push_slice(&WPubkeyHash::hash(&key.serialize())[..])
1223 use super::CounterpartyCommitmentSecrets;
1227 fn test_per_commitment_storage() {
1228 // Test vectors from BOLT 3:
1229 let mut secrets: Vec<[u8; 32]> = Vec::new();
1232 macro_rules! test_secrets {
1234 let mut idx = 281474976710655;
1235 for secret in secrets.iter() {
1236 assert_eq!(monitor.get_secret(idx).unwrap(), *secret);
1239 assert_eq!(monitor.get_min_seen_secret(), idx + 1);
1240 assert!(monitor.get_secret(idx).is_none());
1245 // insert_secret correct sequence
1246 monitor = CounterpartyCommitmentSecrets::new();
1249 secrets.push([0; 32]);
1250 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1251 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1254 secrets.push([0; 32]);
1255 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1256 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1259 secrets.push([0; 32]);
1260 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1261 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1264 secrets.push([0; 32]);
1265 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1266 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1269 secrets.push([0; 32]);
1270 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1271 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1274 secrets.push([0; 32]);
1275 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1276 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1279 secrets.push([0; 32]);
1280 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1281 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1284 secrets.push([0; 32]);
1285 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1286 monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap();
1291 // insert_secret #1 incorrect
1292 monitor = CounterpartyCommitmentSecrets::new();
1295 secrets.push([0; 32]);
1296 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1297 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1300 secrets.push([0; 32]);
1301 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1302 assert!(monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).is_err());
1306 // insert_secret #2 incorrect (#1 derived from incorrect)
1307 monitor = CounterpartyCommitmentSecrets::new();
1310 secrets.push([0; 32]);
1311 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1312 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1315 secrets.push([0; 32]);
1316 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("dddc3a8d14fddf2b68fa8c7fbad2748274937479dd0f8930d5ebb4ab6bd866a3").unwrap());
1317 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1320 secrets.push([0; 32]);
1321 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1322 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1325 secrets.push([0; 32]);
1326 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1327 assert!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).is_err());
1331 // insert_secret #3 incorrect
1332 monitor = CounterpartyCommitmentSecrets::new();
1335 secrets.push([0; 32]);
1336 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1337 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1340 secrets.push([0; 32]);
1341 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1342 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1345 secrets.push([0; 32]);
1346 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c51a18b13e8527e579ec56365482c62f180b7d5760b46e9477dae59e87ed423a").unwrap());
1347 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1350 secrets.push([0; 32]);
1351 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1352 assert!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).is_err());
1356 // insert_secret #4 incorrect (1,2,3 derived from incorrect)
1357 monitor = CounterpartyCommitmentSecrets::new();
1360 secrets.push([0; 32]);
1361 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1362 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1365 secrets.push([0; 32]);
1366 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("dddc3a8d14fddf2b68fa8c7fbad2748274937479dd0f8930d5ebb4ab6bd866a3").unwrap());
1367 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1370 secrets.push([0; 32]);
1371 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c51a18b13e8527e579ec56365482c62f180b7d5760b46e9477dae59e87ed423a").unwrap());
1372 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1375 secrets.push([0; 32]);
1376 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("ba65d7b0ef55a3ba300d4e87af29868f394f8f138d78a7011669c79b37b936f4").unwrap());
1377 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1380 secrets.push([0; 32]);
1381 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1382 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1385 secrets.push([0; 32]);
1386 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1387 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1390 secrets.push([0; 32]);
1391 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1392 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1395 secrets.push([0; 32]);
1396 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1397 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1401 // insert_secret #5 incorrect
1402 monitor = CounterpartyCommitmentSecrets::new();
1405 secrets.push([0; 32]);
1406 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1407 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1410 secrets.push([0; 32]);
1411 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1412 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1415 secrets.push([0; 32]);
1416 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1417 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1420 secrets.push([0; 32]);
1421 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1422 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1425 secrets.push([0; 32]);
1426 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("631373ad5f9ef654bb3dade742d09504c567edd24320d2fcd68e3cc47e2ff6a6").unwrap());
1427 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1430 secrets.push([0; 32]);
1431 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1432 assert!(monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).is_err());
1436 // insert_secret #6 incorrect (5 derived from incorrect)
1437 monitor = CounterpartyCommitmentSecrets::new();
1440 secrets.push([0; 32]);
1441 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1442 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1445 secrets.push([0; 32]);
1446 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1447 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1450 secrets.push([0; 32]);
1451 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1452 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1455 secrets.push([0; 32]);
1456 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1457 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1460 secrets.push([0; 32]);
1461 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("631373ad5f9ef654bb3dade742d09504c567edd24320d2fcd68e3cc47e2ff6a6").unwrap());
1462 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1465 secrets.push([0; 32]);
1466 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("b7e76a83668bde38b373970155c868a653304308f9896692f904a23731224bb1").unwrap());
1467 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1470 secrets.push([0; 32]);
1471 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1472 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1475 secrets.push([0; 32]);
1476 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1477 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1481 // insert_secret #7 incorrect
1482 monitor = CounterpartyCommitmentSecrets::new();
1485 secrets.push([0; 32]);
1486 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1487 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1490 secrets.push([0; 32]);
1491 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1492 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1495 secrets.push([0; 32]);
1496 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1497 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1500 secrets.push([0; 32]);
1501 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1502 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1505 secrets.push([0; 32]);
1506 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1507 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1510 secrets.push([0; 32]);
1511 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1512 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1515 secrets.push([0; 32]);
1516 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("e7971de736e01da8ed58b94c2fc216cb1dca9e326f3a96e7194fe8ea8af6c0a3").unwrap());
1517 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1520 secrets.push([0; 32]);
1521 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1522 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1526 // insert_secret #8 incorrect
1527 monitor = CounterpartyCommitmentSecrets::new();
1530 secrets.push([0; 32]);
1531 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1532 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1535 secrets.push([0; 32]);
1536 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1537 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1540 secrets.push([0; 32]);
1541 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1542 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1545 secrets.push([0; 32]);
1546 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1547 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1550 secrets.push([0; 32]);
1551 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1552 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1555 secrets.push([0; 32]);
1556 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1557 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1560 secrets.push([0; 32]);
1561 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1562 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1565 secrets.push([0; 32]);
1566 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a7efbc61aac46d34f77778bac22c8a20c6a46ca460addc49009bda875ec88fa4").unwrap());
1567 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());