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::Sign message signing by hand.
13 use bitcoin::blockdata::script::{Script,Builder};
14 use bitcoin::blockdata::opcodes;
15 use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction, SigHashType};
16 use bitcoin::util::bip143;
18 use bitcoin::hashes::{Hash, HashEngine};
19 use bitcoin::hashes::sha256::Hash as Sha256;
20 use bitcoin::hashes::ripemd160::Hash as Ripemd160;
21 use bitcoin::hash_types::{Txid, PubkeyHash};
23 use ln::{PaymentHash, PaymentPreimage};
24 use ln::msgs::DecodeError;
25 use util::ser::{Readable, Writeable, Writer};
28 use bitcoin::hash_types::WPubkeyHash;
29 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
30 use bitcoin::secp256k1::{Secp256k1, Signature, Message};
31 use bitcoin::secp256k1::Error as SecpError;
32 use bitcoin::secp256k1;
37 use util::transaction_utils::sort_outputs;
38 use ln::channel::INITIAL_COMMITMENT_NUMBER;
42 pub(crate) const MAX_HTLCS: u16 = 483;
44 pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
45 pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
48 pub(crate) enum HTLCType {
54 /// Check if a given tx witnessScript len matchs one of a pre-signed HTLC
55 pub(crate) fn scriptlen_to_htlctype(witness_script_len: usize) -> Option<HTLCType> {
56 if witness_script_len == 133 {
57 Some(HTLCType::OfferedHTLC)
58 } else if witness_script_len >= 136 && witness_script_len <= 139 {
59 Some(HTLCType::AcceptedHTLC)
66 // Various functions for key derivation and transaction creation for use within channels. Primarily
67 // used in Channel and ChannelMonitor.
69 /// Build the commitment secret from the seed and the commitment number
70 pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
71 let mut res: [u8; 32] = commitment_seed.clone();
74 if idx & (1 << bitpos) == (1 << bitpos) {
75 res[bitpos / 8] ^= 1 << (bitpos & 7);
76 res = Sha256::hash(&res).into_inner();
82 /// Implements the per-commitment secret storage scheme from
83 /// [BOLT 3](https://github.com/lightningnetwork/lightning-rfc/blob/dcbf8583976df087c79c3ce0b535311212e6812d/03-transactions.md#efficient-per-commitment-secret-storage).
85 /// Allows us to keep track of all of the revocation secrets of counterarties in just 50*32 bytes
88 pub(crate) struct CounterpartyCommitmentSecrets {
89 old_secrets: [([u8; 32], u64); 49],
92 impl PartialEq for CounterpartyCommitmentSecrets {
93 fn eq(&self, other: &Self) -> bool {
94 for (&(ref secret, ref idx), &(ref o_secret, ref o_idx)) in self.old_secrets.iter().zip(other.old_secrets.iter()) {
95 if secret != o_secret || idx != o_idx {
103 impl CounterpartyCommitmentSecrets {
104 pub(crate) fn new() -> Self {
105 Self { old_secrets: [([0; 32], 1 << 48); 49], }
109 fn place_secret(idx: u64) -> u8 {
111 if idx & (1 << i) == (1 << i) {
118 pub(crate) fn get_min_seen_secret(&self) -> u64 {
119 //TODO This can be optimized?
120 let mut min = 1 << 48;
121 for &(_, idx) in self.old_secrets.iter() {
130 fn derive_secret(secret: [u8; 32], bits: u8, idx: u64) -> [u8; 32] {
131 let mut res: [u8; 32] = secret;
133 let bitpos = bits - 1 - i;
134 if idx & (1 << bitpos) == (1 << bitpos) {
135 res[(bitpos / 8) as usize] ^= 1 << (bitpos & 7);
136 res = Sha256::hash(&res).into_inner();
142 pub(crate) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), ()> {
143 let pos = Self::place_secret(idx);
145 let (old_secret, old_idx) = self.old_secrets[i as usize];
146 if Self::derive_secret(secret, pos, old_idx) != old_secret {
150 if self.get_min_seen_secret() <= idx {
153 self.old_secrets[pos as usize] = (secret, idx);
157 /// Can only fail if idx is < get_min_seen_secret
158 pub(crate) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
159 for i in 0..self.old_secrets.len() {
160 if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
161 return Some(Self::derive_secret(self.old_secrets[i].0, i as u8, idx))
164 assert!(idx < self.get_min_seen_secret());
169 impl Writeable for CounterpartyCommitmentSecrets {
170 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
171 for &(ref secret, ref idx) in self.old_secrets.iter() {
172 writer.write_all(secret)?;
173 writer.write_all(&byte_utils::be64_to_array(*idx))?;
175 write_tlv_fields!(writer, {}, {});
179 impl Readable for CounterpartyCommitmentSecrets {
180 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
181 let mut old_secrets = [([0; 32], 1 << 48); 49];
182 for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
183 *secret = Readable::read(reader)?;
184 *idx = Readable::read(reader)?;
186 read_tlv_fields!(reader, {}, {});
187 Ok(Self { old_secrets })
191 /// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key)
192 /// from the base secret and the per_commitment_point.
194 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
195 /// generated (ie our own).
196 pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, SecpError> {
197 let mut sha = Sha256::engine();
198 sha.input(&per_commitment_point.serialize());
199 sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize());
200 let res = Sha256::from_engine(sha).into_inner();
202 let mut key = base_secret.clone();
203 key.add_assign(&res)?;
207 /// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key)
208 /// from the base point and the per_commitment_key. This is the public equivalent of
209 /// derive_private_key - using only public keys to derive a public key instead of private keys.
211 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
212 /// generated (ie our own).
213 pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, SecpError> {
214 let mut sha = Sha256::engine();
215 sha.input(&per_commitment_point.serialize());
216 sha.input(&base_point.serialize());
217 let res = Sha256::from_engine(sha).into_inner();
219 let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?);
220 base_point.combine(&hashkey)
223 /// Derives a per-commitment-transaction revocation key from its constituent parts.
225 /// Only the cheating participant owns a valid witness to propagate a revoked
226 /// commitment transaction, thus per_commitment_secret always come from cheater
227 /// and revocation_base_secret always come from punisher, which is the broadcaster
228 /// of the transaction spending with this key knowledge.
230 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
231 /// generated (ie our own).
232 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> {
233 let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret);
234 let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
236 let rev_append_commit_hash_key = {
237 let mut sha = Sha256::engine();
238 sha.input(&countersignatory_revocation_base_point.serialize());
239 sha.input(&per_commitment_point.serialize());
241 Sha256::from_engine(sha).into_inner()
243 let commit_append_rev_hash_key = {
244 let mut sha = Sha256::engine();
245 sha.input(&per_commitment_point.serialize());
246 sha.input(&countersignatory_revocation_base_point.serialize());
248 Sha256::from_engine(sha).into_inner()
251 let mut countersignatory_contrib = countersignatory_revocation_base_secret.clone();
252 countersignatory_contrib.mul_assign(&rev_append_commit_hash_key)?;
253 let mut broadcaster_contrib = per_commitment_secret.clone();
254 broadcaster_contrib.mul_assign(&commit_append_rev_hash_key)?;
255 countersignatory_contrib.add_assign(&broadcaster_contrib[..])?;
256 Ok(countersignatory_contrib)
259 /// Derives a per-commitment-transaction revocation public key from its constituent parts. This is
260 /// the public equivalend of derive_private_revocation_key - using only public keys to derive a
261 /// public key instead of private keys.
263 /// Only the cheating participant owns a valid witness to propagate a revoked
264 /// commitment transaction, thus per_commitment_point always come from cheater
265 /// and revocation_base_point always come from punisher, which is the broadcaster
266 /// of the transaction spending with this key knowledge.
268 /// Note that this is infallible iff we trust that at least one of the two input keys are randomly
269 /// generated (ie our own).
270 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> {
271 let rev_append_commit_hash_key = {
272 let mut sha = Sha256::engine();
273 sha.input(&countersignatory_revocation_base_point.serialize());
274 sha.input(&per_commitment_point.serialize());
276 Sha256::from_engine(sha).into_inner()
278 let commit_append_rev_hash_key = {
279 let mut sha = Sha256::engine();
280 sha.input(&per_commitment_point.serialize());
281 sha.input(&countersignatory_revocation_base_point.serialize());
283 Sha256::from_engine(sha).into_inner()
286 let mut countersignatory_contrib = countersignatory_revocation_base_point.clone();
287 countersignatory_contrib.mul_assign(&secp_ctx, &rev_append_commit_hash_key)?;
288 let mut broadcaster_contrib = per_commitment_point.clone();
289 broadcaster_contrib.mul_assign(&secp_ctx, &commit_append_rev_hash_key)?;
290 countersignatory_contrib.combine(&broadcaster_contrib)
293 /// The set of public keys which are used in the creation of one commitment transaction.
294 /// These are derived from the channel base keys and per-commitment data.
296 /// A broadcaster key is provided from potential broadcaster of the computed transaction.
297 /// A countersignatory key is coming from a protocol participant unable to broadcast the
300 /// These keys are assumed to be good, either because the code derived them from
301 /// channel basepoints via the new function, or they were obtained via
302 /// CommitmentTransaction.trust().keys() because we trusted the source of the
303 /// pre-calculated keys.
304 #[derive(PartialEq, Clone)]
305 pub struct TxCreationKeys {
306 /// The broadcaster's per-commitment public key which was used to derive the other keys.
307 pub per_commitment_point: PublicKey,
308 /// The revocation key which is used to allow the broadcaster of the commitment
309 /// transaction to provide their counterparty the ability to punish them if they broadcast
311 pub revocation_key: PublicKey,
312 /// Broadcaster's HTLC Key
313 pub broadcaster_htlc_key: PublicKey,
314 /// Countersignatory's HTLC Key
315 pub countersignatory_htlc_key: PublicKey,
316 /// Broadcaster's Payment Key (which isn't allowed to be spent from for some delay)
317 pub broadcaster_delayed_payment_key: PublicKey,
320 impl_writeable_tlv_based!(TxCreationKeys, {
321 (0, per_commitment_point),
323 (4, broadcaster_htlc_key),
324 (6, countersignatory_htlc_key),
325 (8, broadcaster_delayed_payment_key),
328 /// One counterparty's public keys which do not change over the life of a channel.
329 #[derive(Clone, PartialEq)]
330 pub struct ChannelPublicKeys {
331 /// The public key which is used to sign all commitment transactions, as it appears in the
332 /// on-chain channel lock-in 2-of-2 multisig output.
333 pub funding_pubkey: PublicKey,
334 /// The base point which is used (with derive_public_revocation_key) to derive per-commitment
335 /// revocation keys. This is combined with the per-commitment-secret generated by the
336 /// counterparty to create a secret which the counterparty can reveal to revoke previous
338 pub revocation_basepoint: PublicKey,
339 /// The public key on which the non-broadcaster (ie the countersignatory) receives an immediately
340 /// spendable primary channel balance on the broadcaster's commitment transaction. This key is
341 /// static across every commitment transaction.
342 pub payment_point: PublicKey,
343 /// The base point which is used (with derive_public_key) to derive a per-commitment payment
344 /// public key which receives non-HTLC-encumbered funds which are only available for spending
345 /// after some delay (or can be claimed via the revocation path).
346 pub delayed_payment_basepoint: PublicKey,
347 /// The base point which is used (with derive_public_key) to derive a per-commitment public key
348 /// which is used to encumber HTLC-in-flight outputs.
349 pub htlc_basepoint: PublicKey,
352 impl_writeable_tlv_based!(ChannelPublicKeys, {
354 (2, revocation_basepoint),
356 (6, 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 /// The maximum length of a script returned by get_revokeable_redeemscript.
388 // Calculated as 6 bytes of opcodes, 1 byte push plus 2 bytes for contest_delay, and two public
389 // keys of 33 bytes (+ 1 push).
390 pub const REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH: usize = 6 + 3 + 34*2;
392 /// A script either spendable by the revocation
393 /// key or the broadcaster_delayed_payment_key and satisfying the relative-locktime OP_CSV constrain.
394 /// Encumbering a `to_holder` output on a commitment transaction or 2nd-stage HTLC transactions.
395 pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, contest_delay: u16, broadcaster_delayed_payment_key: &PublicKey) -> Script {
396 let res = Builder::new().push_opcode(opcodes::all::OP_IF)
397 .push_slice(&revocation_key.serialize())
398 .push_opcode(opcodes::all::OP_ELSE)
399 .push_int(contest_delay as i64)
400 .push_opcode(opcodes::all::OP_CSV)
401 .push_opcode(opcodes::all::OP_DROP)
402 .push_slice(&broadcaster_delayed_payment_key.serialize())
403 .push_opcode(opcodes::all::OP_ENDIF)
404 .push_opcode(opcodes::all::OP_CHECKSIG)
406 debug_assert!(res.len() <= REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH);
410 #[derive(Clone, PartialEq)]
411 /// Information about an HTLC as it appears in a commitment transaction
412 pub struct HTLCOutputInCommitment {
413 /// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction).
414 /// Note that this is not the same as whether it is ountbound *from us*. To determine that you
415 /// need to compare this value to whether the commitment transaction in question is that of
416 /// the counterparty or our own.
418 /// The value, in msat, of the HTLC. The value as it appears in the commitment transaction is
419 /// this divided by 1000.
420 pub amount_msat: u64,
421 /// The CLTV lock-time at which this HTLC expires.
422 pub cltv_expiry: u32,
423 /// The hash of the preimage which unlocks this HTLC.
424 pub payment_hash: PaymentHash,
425 /// The position within the commitment transactions' outputs. This may be None if the value is
426 /// below the dust limit (in which case no output appears in the commitment transaction and the
427 /// value is spent to additional transaction fees).
428 pub transaction_output_index: Option<u32>,
431 impl_writeable_tlv_based!(HTLCOutputInCommitment, {
437 (8, transaction_output_index)
441 pub(crate) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, broadcaster_htlc_key: &PublicKey, countersignatory_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
442 let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
444 Builder::new().push_opcode(opcodes::all::OP_DUP)
445 .push_opcode(opcodes::all::OP_HASH160)
446 .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
447 .push_opcode(opcodes::all::OP_EQUAL)
448 .push_opcode(opcodes::all::OP_IF)
449 .push_opcode(opcodes::all::OP_CHECKSIG)
450 .push_opcode(opcodes::all::OP_ELSE)
451 .push_slice(&countersignatory_htlc_key.serialize()[..])
452 .push_opcode(opcodes::all::OP_SWAP)
453 .push_opcode(opcodes::all::OP_SIZE)
455 .push_opcode(opcodes::all::OP_EQUAL)
456 .push_opcode(opcodes::all::OP_NOTIF)
457 .push_opcode(opcodes::all::OP_DROP)
459 .push_opcode(opcodes::all::OP_SWAP)
460 .push_slice(&broadcaster_htlc_key.serialize()[..])
462 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
463 .push_opcode(opcodes::all::OP_ELSE)
464 .push_opcode(opcodes::all::OP_HASH160)
465 .push_slice(&payment_hash160)
466 .push_opcode(opcodes::all::OP_EQUALVERIFY)
467 .push_opcode(opcodes::all::OP_CHECKSIG)
468 .push_opcode(opcodes::all::OP_ENDIF)
469 .push_opcode(opcodes::all::OP_ENDIF)
472 Builder::new().push_opcode(opcodes::all::OP_DUP)
473 .push_opcode(opcodes::all::OP_HASH160)
474 .push_slice(&PubkeyHash::hash(&revocation_key.serialize())[..])
475 .push_opcode(opcodes::all::OP_EQUAL)
476 .push_opcode(opcodes::all::OP_IF)
477 .push_opcode(opcodes::all::OP_CHECKSIG)
478 .push_opcode(opcodes::all::OP_ELSE)
479 .push_slice(&countersignatory_htlc_key.serialize()[..])
480 .push_opcode(opcodes::all::OP_SWAP)
481 .push_opcode(opcodes::all::OP_SIZE)
483 .push_opcode(opcodes::all::OP_EQUAL)
484 .push_opcode(opcodes::all::OP_IF)
485 .push_opcode(opcodes::all::OP_HASH160)
486 .push_slice(&payment_hash160)
487 .push_opcode(opcodes::all::OP_EQUALVERIFY)
489 .push_opcode(opcodes::all::OP_SWAP)
490 .push_slice(&broadcaster_htlc_key.serialize()[..])
492 .push_opcode(opcodes::all::OP_CHECKMULTISIG)
493 .push_opcode(opcodes::all::OP_ELSE)
494 .push_opcode(opcodes::all::OP_DROP)
495 .push_int(htlc.cltv_expiry as i64)
496 .push_opcode(opcodes::all::OP_CLTV)
497 .push_opcode(opcodes::all::OP_DROP)
498 .push_opcode(opcodes::all::OP_CHECKSIG)
499 .push_opcode(opcodes::all::OP_ENDIF)
500 .push_opcode(opcodes::all::OP_ENDIF)
505 /// Gets the witness redeemscript for an HTLC output in a commitment transaction. Note that htlc
506 /// does not need to have its previous_output_index filled.
508 pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Script {
509 get_htlc_redeemscript_with_explicit_keys(htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key)
512 /// Gets the redeemscript for a funding output from the two funding public keys.
513 /// Note that the order of funding public keys does not matter.
514 pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &PublicKey) -> Script {
515 let broadcaster_funding_key = broadcaster.serialize();
516 let countersignatory_funding_key = countersignatory.serialize();
518 let builder = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2);
519 if broadcaster_funding_key[..] < countersignatory_funding_key[..] {
520 builder.push_slice(&broadcaster_funding_key)
521 .push_slice(&countersignatory_funding_key)
523 builder.push_slice(&countersignatory_funding_key)
524 .push_slice(&broadcaster_funding_key)
525 }.push_opcode(opcodes::all::OP_PUSHNUM_2).push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script()
528 /// panics if htlc.transaction_output_index.is_none()!
529 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 {
530 let mut txins: Vec<TxIn> = Vec::new();
532 previous_output: OutPoint {
533 txid: prev_hash.clone(),
534 vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"),
536 script_sig: Script::new(),
541 let total_fee = if htlc.offered {
542 feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000
544 feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000
547 let mut txouts: Vec<TxOut> = Vec::new();
549 script_pubkey: get_revokeable_redeemscript(revocation_key, contest_delay, broadcaster_delayed_payment_key).to_v0_p2wsh(),
550 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)
555 lock_time: if htlc.offered { htlc.cltv_expiry } else { 0 },
561 /// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction).
562 /// The fields are organized by holder/counterparty.
564 /// Normally, this is converted to the broadcaster/countersignatory-organized DirectedChannelTransactionParameters
565 /// before use, via the as_holder_broadcastable and as_counterparty_broadcastable functions.
567 pub struct ChannelTransactionParameters {
568 /// Holder public keys
569 pub holder_pubkeys: ChannelPublicKeys,
570 /// The contest delay selected by the holder, which applies to counterparty-broadcast transactions
571 pub holder_selected_contest_delay: u16,
572 /// Whether the holder is the initiator of this channel.
573 /// This is an input to the commitment number obscure factor computation.
574 pub is_outbound_from_holder: bool,
575 /// The late-bound counterparty channel transaction parameters.
576 /// These parameters are populated at the point in the protocol where the counterparty provides them.
577 pub counterparty_parameters: Option<CounterpartyChannelTransactionParameters>,
578 /// The late-bound funding outpoint
579 pub funding_outpoint: Option<chain::transaction::OutPoint>,
582 /// Late-bound per-channel counterparty data used to build transactions.
584 pub struct CounterpartyChannelTransactionParameters {
585 /// Counter-party public keys
586 pub pubkeys: ChannelPublicKeys,
587 /// The contest delay selected by the counterparty, which applies to holder-broadcast transactions
588 pub selected_contest_delay: u16,
591 impl ChannelTransactionParameters {
592 /// Whether the late bound parameters are populated.
593 pub fn is_populated(&self) -> bool {
594 self.counterparty_parameters.is_some() && self.funding_outpoint.is_some()
597 /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
598 /// given that the holder is the broadcaster.
600 /// self.is_populated() must be true before calling this function.
601 pub fn as_holder_broadcastable(&self) -> DirectedChannelTransactionParameters {
602 assert!(self.is_populated(), "self.late_parameters must be set before using as_holder_broadcastable");
603 DirectedChannelTransactionParameters {
605 holder_is_broadcaster: true
609 /// Convert the holder/counterparty parameters to broadcaster/countersignatory-organized parameters,
610 /// given that the counterparty is the broadcaster.
612 /// self.is_populated() must be true before calling this function.
613 pub fn as_counterparty_broadcastable(&self) -> DirectedChannelTransactionParameters {
614 assert!(self.is_populated(), "self.late_parameters must be set before using as_counterparty_broadcastable");
615 DirectedChannelTransactionParameters {
617 holder_is_broadcaster: false
622 impl_writeable_tlv_based!(CounterpartyChannelTransactionParameters, {
624 (2, selected_contest_delay),
627 impl_writeable_tlv_based!(ChannelTransactionParameters, {
629 (2, holder_selected_contest_delay),
630 (4, is_outbound_from_holder),
632 (6, counterparty_parameters),
633 (8, funding_outpoint),
636 /// Static channel fields used to build transactions given per-commitment fields, organized by
637 /// broadcaster/countersignatory.
639 /// This is derived from the holder/counterparty-organized ChannelTransactionParameters via the
640 /// as_holder_broadcastable and as_counterparty_broadcastable functions.
641 pub struct DirectedChannelTransactionParameters<'a> {
642 /// The holder's channel static parameters
643 inner: &'a ChannelTransactionParameters,
644 /// Whether the holder is the broadcaster
645 holder_is_broadcaster: bool,
648 impl<'a> DirectedChannelTransactionParameters<'a> {
649 /// Get the channel pubkeys for the broadcaster
650 pub fn broadcaster_pubkeys(&self) -> &ChannelPublicKeys {
651 if self.holder_is_broadcaster {
652 &self.inner.holder_pubkeys
654 &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
658 /// Get the channel pubkeys for the countersignatory
659 pub fn countersignatory_pubkeys(&self) -> &ChannelPublicKeys {
660 if self.holder_is_broadcaster {
661 &self.inner.counterparty_parameters.as_ref().unwrap().pubkeys
663 &self.inner.holder_pubkeys
667 /// Get the contest delay applicable to the transactions.
668 /// Note that the contest delay was selected by the countersignatory.
669 pub fn contest_delay(&self) -> u16 {
670 let counterparty_parameters = self.inner.counterparty_parameters.as_ref().unwrap();
671 if self.holder_is_broadcaster { counterparty_parameters.selected_contest_delay } else { self.inner.holder_selected_contest_delay }
674 /// Whether the channel is outbound from the broadcaster.
676 /// The boolean representing the side that initiated the channel is
677 /// an input to the commitment number obscure factor computation.
678 pub fn is_outbound(&self) -> bool {
679 if self.holder_is_broadcaster { self.inner.is_outbound_from_holder } else { !self.inner.is_outbound_from_holder }
682 /// The funding outpoint
683 pub fn funding_outpoint(&self) -> OutPoint {
684 self.inner.funding_outpoint.unwrap().into_bitcoin_outpoint()
688 /// Information needed to build and sign a holder's commitment transaction.
690 /// The transaction is only signed once we are ready to broadcast.
692 pub struct HolderCommitmentTransaction {
693 inner: CommitmentTransaction,
694 /// Our counterparty's signature for the transaction
695 pub counterparty_sig: Signature,
696 /// All non-dust counterparty HTLC signatures, in the order they appear in the transaction
697 pub counterparty_htlc_sigs: Vec<Signature>,
698 // Which order the signatures should go in when constructing the final commitment tx witness.
699 // The user should be able to reconstruct this themselves, so we don't bother to expose it.
700 holder_sig_first: bool,
703 impl Deref for HolderCommitmentTransaction {
704 type Target = CommitmentTransaction;
706 fn deref(&self) -> &Self::Target { &self.inner }
709 impl PartialEq for HolderCommitmentTransaction {
710 // We dont care whether we are signed in equality comparison
711 fn eq(&self, o: &Self) -> bool {
712 self.inner == o.inner
716 impl_writeable_tlv_based!(HolderCommitmentTransaction, {
718 (2, counterparty_sig),
719 (4, holder_sig_first),
721 (6, counterparty_htlc_sigs),
724 impl HolderCommitmentTransaction {
726 pub fn dummy() -> Self {
727 let secp_ctx = Secp256k1::new();
728 let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
729 let dummy_sig = secp_ctx.sign(&secp256k1::Message::from_slice(&[42; 32]).unwrap(), &SecretKey::from_slice(&[42; 32]).unwrap());
731 let keys = TxCreationKeys {
732 per_commitment_point: dummy_key.clone(),
733 revocation_key: dummy_key.clone(),
734 broadcaster_htlc_key: dummy_key.clone(),
735 countersignatory_htlc_key: dummy_key.clone(),
736 broadcaster_delayed_payment_key: dummy_key.clone(),
738 let channel_pubkeys = ChannelPublicKeys {
739 funding_pubkey: dummy_key.clone(),
740 revocation_basepoint: dummy_key.clone(),
741 payment_point: dummy_key.clone(),
742 delayed_payment_basepoint: dummy_key.clone(),
743 htlc_basepoint: dummy_key.clone()
745 let channel_parameters = ChannelTransactionParameters {
746 holder_pubkeys: channel_pubkeys.clone(),
747 holder_selected_contest_delay: 0,
748 is_outbound_from_holder: false,
749 counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: channel_pubkeys.clone(), selected_contest_delay: 0 }),
750 funding_outpoint: Some(chain::transaction::OutPoint { txid: Default::default(), index: 0 })
752 let mut htlcs_with_aux: Vec<(_, ())> = Vec::new();
753 let inner = CommitmentTransaction::new_with_auxiliary_htlc_data(0, 0, 0, keys, 0, &mut htlcs_with_aux, &channel_parameters.as_counterparty_broadcastable());
754 HolderCommitmentTransaction {
756 counterparty_sig: dummy_sig,
757 counterparty_htlc_sigs: Vec::new(),
758 holder_sig_first: false
762 /// Create a new holder transaction with the given counterparty signatures.
763 /// The funding keys are used to figure out which signature should go first when building the transaction for broadcast.
764 pub fn new(commitment_tx: CommitmentTransaction, counterparty_sig: Signature, counterparty_htlc_sigs: Vec<Signature>, holder_funding_key: &PublicKey, counterparty_funding_key: &PublicKey) -> Self {
766 inner: commitment_tx,
768 counterparty_htlc_sigs,
769 holder_sig_first: holder_funding_key.serialize()[..] < counterparty_funding_key.serialize()[..],
773 pub(crate) fn add_holder_sig(&self, funding_redeemscript: &Script, holder_sig: Signature) -> Transaction {
774 // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
775 let mut tx = self.inner.built.transaction.clone();
776 tx.input[0].witness.push(Vec::new());
778 if self.holder_sig_first {
779 tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
780 tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
782 tx.input[0].witness.push(self.counterparty_sig.serialize_der().to_vec());
783 tx.input[0].witness.push(holder_sig.serialize_der().to_vec());
785 tx.input[0].witness[1].push(SigHashType::All as u8);
786 tx.input[0].witness[2].push(SigHashType::All as u8);
788 tx.input[0].witness.push(funding_redeemscript.as_bytes().to_vec());
793 /// A pre-built Bitcoin commitment transaction and its txid.
795 pub struct BuiltCommitmentTransaction {
796 /// The commitment transaction
797 pub transaction: Transaction,
798 /// The txid for the commitment transaction.
800 /// This is provided as a performance optimization, instead of calling transaction.txid()
805 impl_writeable_tlv_based!(BuiltCommitmentTransaction, {
810 impl BuiltCommitmentTransaction {
811 /// Get the SIGHASH_ALL sighash value of the transaction.
813 /// This can be used to verify a signature.
814 pub fn get_sighash_all(&self, funding_redeemscript: &Script, channel_value_satoshis: u64) -> Message {
815 let sighash = &bip143::SigHashCache::new(&self.transaction).signature_hash(0, funding_redeemscript, channel_value_satoshis, SigHashType::All)[..];
816 hash_to_message!(sighash)
819 /// Sign a transaction, either because we are counter-signing the counterparty's transaction or
820 /// because we are about to broadcast a holder transaction.
821 pub fn sign<T: secp256k1::Signing>(&self, funding_key: &SecretKey, funding_redeemscript: &Script, channel_value_satoshis: u64, secp_ctx: &Secp256k1<T>) -> Signature {
822 let sighash = self.get_sighash_all(funding_redeemscript, channel_value_satoshis);
823 secp_ctx.sign(&sighash, funding_key)
827 /// This class tracks the per-transaction information needed to build a commitment transaction and to
828 /// actually build it and sign. It is used for holder transactions that we sign only when needed
829 /// and for transactions we sign for the counterparty.
831 /// This class can be used inside a signer implementation to generate a signature given the relevant
834 pub struct CommitmentTransaction {
835 commitment_number: u64,
836 to_broadcaster_value_sat: u64,
837 to_countersignatory_value_sat: u64,
839 htlcs: Vec<HTLCOutputInCommitment>,
840 // A cache of the parties' pubkeys required to construct the transaction, see doc for trust()
841 keys: TxCreationKeys,
842 // For access to the pre-built transaction, see doc for trust()
843 built: BuiltCommitmentTransaction,
846 impl PartialEq for CommitmentTransaction {
847 fn eq(&self, o: &Self) -> bool {
848 let eq = self.commitment_number == o.commitment_number &&
849 self.to_broadcaster_value_sat == o.to_broadcaster_value_sat &&
850 self.to_countersignatory_value_sat == o.to_countersignatory_value_sat &&
851 self.feerate_per_kw == o.feerate_per_kw &&
852 self.htlcs == o.htlcs &&
855 debug_assert_eq!(self.built.transaction, o.built.transaction);
856 debug_assert_eq!(self.built.txid, o.built.txid);
862 impl_writeable_tlv_based!(CommitmentTransaction, {
863 (0, commitment_number),
864 (2, to_broadcaster_value_sat),
865 (4, to_countersignatory_value_sat),
873 impl CommitmentTransaction {
874 /// Construct an object of the class while assigning transaction output indices to HTLCs.
876 /// Populates HTLCOutputInCommitment.transaction_output_index in htlcs_with_aux.
878 /// The generic T allows the caller to match the HTLC output index with auxiliary data.
879 /// This auxiliary data is not stored in this object.
881 /// Only include HTLCs that are above the dust limit for the channel.
883 /// (C-not exported) due to the generic though we likely should expose a version without
884 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 {
885 // Sort outputs and populate output indices while keeping track of the auxiliary data
886 let (outputs, htlcs) = Self::internal_build_outputs(&keys, to_broadcaster_value_sat, to_countersignatory_value_sat, htlcs_with_aux, channel_parameters).unwrap();
888 let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(commitment_number, channel_parameters);
889 let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
890 let txid = transaction.txid();
891 CommitmentTransaction {
893 to_broadcaster_value_sat,
894 to_countersignatory_value_sat,
898 built: BuiltCommitmentTransaction {
905 fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters) -> Result<BuiltCommitmentTransaction, ()> {
906 let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(self.commitment_number, channel_parameters);
908 let mut htlcs_with_aux = self.htlcs.iter().map(|h| (h.clone(), ())).collect();
909 let (outputs, _) = Self::internal_build_outputs(keys, self.to_broadcaster_value_sat, self.to_countersignatory_value_sat, &mut htlcs_with_aux, channel_parameters)?;
911 let transaction = Self::make_transaction(obscured_commitment_transaction_number, txins, outputs);
912 let txid = transaction.txid();
913 let built_transaction = BuiltCommitmentTransaction {
917 Ok(built_transaction)
920 fn make_transaction(obscured_commitment_transaction_number: u64, txins: Vec<TxIn>, outputs: Vec<TxOut>) -> Transaction {
923 lock_time: ((0x20 as u32) << 8 * 3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
929 // This is used in two cases:
930 // - initial sorting of outputs / HTLCs in the constructor, in which case T is auxiliary data the
931 // caller needs to have sorted together with the HTLCs so it can keep track of the output index
932 // - building of a bitcoin transaction during a verify() call, in which case T is just ()
933 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>), ()> {
934 let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
935 let contest_delay = channel_parameters.contest_delay();
937 let mut txouts: Vec<(TxOut, Option<&mut HTLCOutputInCommitment>)> = Vec::new();
939 if to_countersignatory_value_sat > 0 {
940 let script = script_for_p2wpkh(&countersignatory_pubkeys.payment_point);
943 script_pubkey: script.clone(),
944 value: to_countersignatory_value_sat,
950 if to_broadcaster_value_sat > 0 {
951 let redeem_script = get_revokeable_redeemscript(
952 &keys.revocation_key,
954 &keys.broadcaster_delayed_payment_key,
958 script_pubkey: redeem_script.to_v0_p2wsh(),
959 value: to_broadcaster_value_sat,
965 let mut htlcs = Vec::with_capacity(htlcs_with_aux.len());
966 for (htlc, _) in htlcs_with_aux {
967 let script = chan_utils::get_htlc_redeemscript(&htlc, &keys);
969 script_pubkey: script.to_v0_p2wsh(),
970 value: htlc.amount_msat / 1000,
972 txouts.push((txout, Some(htlc)));
975 // Sort output in BIP-69 order (amount, scriptPubkey). Tie-breaks based on HTLC
976 // CLTV expiration height.
977 sort_outputs(&mut txouts, |a, b| {
978 if let &Some(ref a_htlcout) = a {
979 if let &Some(ref b_htlcout) = b {
980 a_htlcout.cltv_expiry.cmp(&b_htlcout.cltv_expiry)
981 // Note that due to hash collisions, we have to have a fallback comparison
982 // here for fuzztarget mode (otherwise at least chanmon_fail_consistency
984 .then(a_htlcout.payment_hash.0.cmp(&b_htlcout.payment_hash.0))
985 // For non-HTLC outputs, if they're copying our SPK we don't really care if we
986 // close the channel due to mismatches - they're doing something dumb:
987 } else { cmp::Ordering::Equal }
988 } else { cmp::Ordering::Equal }
991 let mut outputs = Vec::with_capacity(txouts.len());
992 for (idx, out) in txouts.drain(..).enumerate() {
993 if let Some(htlc) = out.1 {
994 htlc.transaction_output_index = Some(idx as u32);
995 htlcs.push(htlc.clone());
1002 fn internal_build_inputs(commitment_number: u64, channel_parameters: &DirectedChannelTransactionParameters) -> (u64, Vec<TxIn>) {
1003 let broadcaster_pubkeys = channel_parameters.broadcaster_pubkeys();
1004 let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
1005 let commitment_transaction_number_obscure_factor = get_commitment_transaction_number_obscure_factor(
1006 &broadcaster_pubkeys.payment_point,
1007 &countersignatory_pubkeys.payment_point,
1008 channel_parameters.is_outbound(),
1011 let obscured_commitment_transaction_number =
1012 commitment_transaction_number_obscure_factor ^ (INITIAL_COMMITMENT_NUMBER - commitment_number);
1015 let mut ins: Vec<TxIn> = Vec::new();
1017 previous_output: channel_parameters.funding_outpoint(),
1018 script_sig: Script::new(),
1019 sequence: ((0x80 as u32) << 8 * 3)
1020 | ((obscured_commitment_transaction_number >> 3 * 8) as u32),
1021 witness: Vec::new(),
1025 (obscured_commitment_transaction_number, txins)
1028 /// The backwards-counting commitment number
1029 pub fn commitment_number(&self) -> u64 {
1030 self.commitment_number
1033 /// The value to be sent to the broadcaster
1034 pub fn to_broadcaster_value_sat(&self) -> u64 {
1035 self.to_broadcaster_value_sat
1038 /// The value to be sent to the counterparty
1039 pub fn to_countersignatory_value_sat(&self) -> u64 {
1040 self.to_countersignatory_value_sat
1043 /// The feerate paid per 1000-weight-unit in this commitment transaction.
1044 pub fn feerate_per_kw(&self) -> u32 {
1048 /// The non-dust HTLCs (direction, amt, height expiration, hash, transaction output index)
1049 /// which were included in this commitment transaction in output order.
1050 /// The transaction index is always populated.
1052 /// (C-not exported) as we cannot currently convert Vec references to/from C, though we should
1053 /// expose a less effecient version which creates a Vec of references in the future.
1054 pub fn htlcs(&self) -> &Vec<HTLCOutputInCommitment> {
1058 /// Trust our pre-built transaction and derived transaction creation public keys.
1060 /// Applies a wrapper which allows access to these fields.
1062 /// This should only be used if you fully trust the builder of this object. It should not
1063 /// be used by an external signer - instead use the verify function.
1064 pub fn trust(&self) -> TrustedCommitmentTransaction {
1065 TrustedCommitmentTransaction { inner: self }
1068 /// Verify our pre-built transaction and derived transaction creation public keys.
1070 /// Applies a wrapper which allows access to these fields.
1072 /// An external validating signer must call this method before signing
1073 /// or using the built transaction.
1074 pub fn verify<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TrustedCommitmentTransaction, ()> {
1075 // This is the only field of the key cache that we trust
1076 let per_commitment_point = self.keys.per_commitment_point;
1077 let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap();
1078 if keys != self.keys {
1081 let tx = self.internal_rebuild_transaction(&keys, channel_parameters)?;
1082 if self.built.transaction != tx.transaction || self.built.txid != tx.txid {
1085 Ok(TrustedCommitmentTransaction { inner: self })
1089 /// A wrapper on CommitmentTransaction indicating that the derived fields (the built bitcoin
1090 /// transaction and the transaction creation keys) are trusted.
1092 /// See trust() and verify() functions on CommitmentTransaction.
1094 /// This structure implements Deref.
1095 pub struct TrustedCommitmentTransaction<'a> {
1096 inner: &'a CommitmentTransaction,
1099 impl<'a> Deref for TrustedCommitmentTransaction<'a> {
1100 type Target = CommitmentTransaction;
1102 fn deref(&self) -> &Self::Target { self.inner }
1105 impl<'a> TrustedCommitmentTransaction<'a> {
1106 /// The transaction ID of the built Bitcoin transaction
1107 pub fn txid(&self) -> Txid {
1108 self.inner.built.txid
1111 /// The pre-built Bitcoin commitment transaction
1112 pub fn built_transaction(&self) -> &BuiltCommitmentTransaction {
1116 /// The pre-calculated transaction creation public keys.
1117 pub fn keys(&self) -> &TxCreationKeys {
1121 /// Get a signature for each HTLC which was included in the commitment transaction (ie for
1122 /// which HTLCOutputInCommitment::transaction_output_index.is_some()).
1124 /// The returned Vec has one entry for each HTLC, and in the same order.
1125 pub fn get_htlc_sigs<T: secp256k1::Signing>(&self, htlc_base_key: &SecretKey, channel_parameters: &DirectedChannelTransactionParameters, secp_ctx: &Secp256k1<T>) -> Result<Vec<Signature>, ()> {
1126 let inner = self.inner;
1127 let keys = &inner.keys;
1128 let txid = inner.built.txid;
1129 let mut ret = Vec::with_capacity(inner.htlcs.len());
1130 let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
1132 for this_htlc in inner.htlcs.iter() {
1133 assert!(this_htlc.transaction_output_index.is_some());
1134 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);
1136 let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key);
1138 let sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, this_htlc.amount_msat / 1000, SigHashType::All)[..]);
1139 ret.push(secp_ctx.sign(&sighash, &holder_htlc_key));
1144 /// Gets a signed HTLC transaction given a preimage (for !htlc.offered) and the holder HTLC transaction signature.
1145 pub(crate) fn get_signed_htlc_tx(&self, channel_parameters: &DirectedChannelTransactionParameters, htlc_index: usize, counterparty_signature: &Signature, signature: &Signature, preimage: &Option<PaymentPreimage>) -> Transaction {
1146 let inner = self.inner;
1147 let keys = &inner.keys;
1148 let txid = inner.built.txid;
1149 let this_htlc = &inner.htlcs[htlc_index];
1150 assert!(this_htlc.transaction_output_index.is_some());
1151 // if we don't have preimage for an HTLC-Success, we can't generate an HTLC transaction.
1152 if !this_htlc.offered && preimage.is_none() { unreachable!(); }
1153 // Further, we should never be provided the preimage for an HTLC-Timeout transaction.
1154 if this_htlc.offered && preimage.is_some() { unreachable!(); }
1156 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);
1158 let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key);
1160 // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element.
1161 htlc_tx.input[0].witness.push(Vec::new());
1163 htlc_tx.input[0].witness.push(counterparty_signature.serialize_der().to_vec());
1164 htlc_tx.input[0].witness.push(signature.serialize_der().to_vec());
1165 htlc_tx.input[0].witness[1].push(SigHashType::All as u8);
1166 htlc_tx.input[0].witness[2].push(SigHashType::All as u8);
1168 if this_htlc.offered {
1169 // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
1170 htlc_tx.input[0].witness.push(Vec::new());
1172 htlc_tx.input[0].witness.push(preimage.unwrap().0.to_vec());
1175 htlc_tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec());
1180 /// Get the transaction number obscure factor
1181 pub fn get_commitment_transaction_number_obscure_factor(
1182 broadcaster_payment_basepoint: &PublicKey,
1183 countersignatory_payment_basepoint: &PublicKey,
1184 outbound_from_broadcaster: bool,
1186 let mut sha = Sha256::engine();
1188 if outbound_from_broadcaster {
1189 sha.input(&broadcaster_payment_basepoint.serialize());
1190 sha.input(&countersignatory_payment_basepoint.serialize());
1192 sha.input(&countersignatory_payment_basepoint.serialize());
1193 sha.input(&broadcaster_payment_basepoint.serialize());
1195 let res = Sha256::from_engine(sha).into_inner();
1197 ((res[26] as u64) << 5 * 8)
1198 | ((res[27] as u64) << 4 * 8)
1199 | ((res[28] as u64) << 3 * 8)
1200 | ((res[29] as u64) << 2 * 8)
1201 | ((res[30] as u64) << 1 * 8)
1202 | ((res[31] as u64) << 0 * 8)
1205 fn script_for_p2wpkh(key: &PublicKey) -> Script {
1206 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1207 .push_slice(&WPubkeyHash::hash(&key.serialize())[..])
1213 use super::CounterpartyCommitmentSecrets;
1218 fn test_per_commitment_storage() {
1219 // Test vectors from BOLT 3:
1220 let mut secrets: Vec<[u8; 32]> = Vec::new();
1223 macro_rules! test_secrets {
1225 let mut idx = 281474976710655;
1226 for secret in secrets.iter() {
1227 assert_eq!(monitor.get_secret(idx).unwrap(), *secret);
1230 assert_eq!(monitor.get_min_seen_secret(), idx + 1);
1231 assert!(monitor.get_secret(idx).is_none());
1236 // insert_secret correct sequence
1237 monitor = CounterpartyCommitmentSecrets::new();
1240 secrets.push([0; 32]);
1241 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1242 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1245 secrets.push([0; 32]);
1246 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1247 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1250 secrets.push([0; 32]);
1251 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1252 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1255 secrets.push([0; 32]);
1256 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1257 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1260 secrets.push([0; 32]);
1261 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1262 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1265 secrets.push([0; 32]);
1266 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1267 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1270 secrets.push([0; 32]);
1271 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1272 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1275 secrets.push([0; 32]);
1276 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1277 monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap();
1282 // insert_secret #1 incorrect
1283 monitor = CounterpartyCommitmentSecrets::new();
1286 secrets.push([0; 32]);
1287 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1288 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1291 secrets.push([0; 32]);
1292 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1293 assert!(monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).is_err());
1297 // insert_secret #2 incorrect (#1 derived from incorrect)
1298 monitor = CounterpartyCommitmentSecrets::new();
1301 secrets.push([0; 32]);
1302 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1303 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1306 secrets.push([0; 32]);
1307 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("dddc3a8d14fddf2b68fa8c7fbad2748274937479dd0f8930d5ebb4ab6bd866a3").unwrap());
1308 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1311 secrets.push([0; 32]);
1312 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1313 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1316 secrets.push([0; 32]);
1317 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1318 assert!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).is_err());
1322 // insert_secret #3 incorrect
1323 monitor = CounterpartyCommitmentSecrets::new();
1326 secrets.push([0; 32]);
1327 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1328 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1331 secrets.push([0; 32]);
1332 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1333 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1336 secrets.push([0; 32]);
1337 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c51a18b13e8527e579ec56365482c62f180b7d5760b46e9477dae59e87ed423a").unwrap());
1338 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1341 secrets.push([0; 32]);
1342 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1343 assert!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).is_err());
1347 // insert_secret #4 incorrect (1,2,3 derived from incorrect)
1348 monitor = CounterpartyCommitmentSecrets::new();
1351 secrets.push([0; 32]);
1352 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("02a40c85b6f28da08dfdbe0926c53fab2de6d28c10301f8f7c4073d5e42e3148").unwrap());
1353 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1356 secrets.push([0; 32]);
1357 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("dddc3a8d14fddf2b68fa8c7fbad2748274937479dd0f8930d5ebb4ab6bd866a3").unwrap());
1358 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1361 secrets.push([0; 32]);
1362 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c51a18b13e8527e579ec56365482c62f180b7d5760b46e9477dae59e87ed423a").unwrap());
1363 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1366 secrets.push([0; 32]);
1367 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("ba65d7b0ef55a3ba300d4e87af29868f394f8f138d78a7011669c79b37b936f4").unwrap());
1368 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1371 secrets.push([0; 32]);
1372 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1373 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1376 secrets.push([0; 32]);
1377 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1378 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1381 secrets.push([0; 32]);
1382 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1383 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1386 secrets.push([0; 32]);
1387 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1388 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1392 // insert_secret #5 incorrect
1393 monitor = CounterpartyCommitmentSecrets::new();
1396 secrets.push([0; 32]);
1397 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1398 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1401 secrets.push([0; 32]);
1402 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1403 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1406 secrets.push([0; 32]);
1407 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1408 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1411 secrets.push([0; 32]);
1412 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1413 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1416 secrets.push([0; 32]);
1417 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("631373ad5f9ef654bb3dade742d09504c567edd24320d2fcd68e3cc47e2ff6a6").unwrap());
1418 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1421 secrets.push([0; 32]);
1422 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1423 assert!(monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).is_err());
1427 // insert_secret #6 incorrect (5 derived from incorrect)
1428 monitor = CounterpartyCommitmentSecrets::new();
1431 secrets.push([0; 32]);
1432 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1433 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1436 secrets.push([0; 32]);
1437 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1438 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1441 secrets.push([0; 32]);
1442 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1443 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1446 secrets.push([0; 32]);
1447 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1448 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1451 secrets.push([0; 32]);
1452 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("631373ad5f9ef654bb3dade742d09504c567edd24320d2fcd68e3cc47e2ff6a6").unwrap());
1453 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1456 secrets.push([0; 32]);
1457 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("b7e76a83668bde38b373970155c868a653304308f9896692f904a23731224bb1").unwrap());
1458 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1461 secrets.push([0; 32]);
1462 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1463 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1466 secrets.push([0; 32]);
1467 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1468 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1472 // insert_secret #7 incorrect
1473 monitor = CounterpartyCommitmentSecrets::new();
1476 secrets.push([0; 32]);
1477 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1478 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1481 secrets.push([0; 32]);
1482 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1483 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1486 secrets.push([0; 32]);
1487 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1488 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1491 secrets.push([0; 32]);
1492 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1493 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1496 secrets.push([0; 32]);
1497 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1498 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1501 secrets.push([0; 32]);
1502 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1503 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1506 secrets.push([0; 32]);
1507 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("e7971de736e01da8ed58b94c2fc216cb1dca9e326f3a96e7194fe8ea8af6c0a3").unwrap());
1508 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1511 secrets.push([0; 32]);
1512 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
1513 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());
1517 // insert_secret #8 incorrect
1518 monitor = CounterpartyCommitmentSecrets::new();
1521 secrets.push([0; 32]);
1522 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
1523 monitor.provide_secret(281474976710655, secrets.last().unwrap().clone()).unwrap();
1526 secrets.push([0; 32]);
1527 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
1528 monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap();
1531 secrets.push([0; 32]);
1532 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
1533 monitor.provide_secret(281474976710653, secrets.last().unwrap().clone()).unwrap();
1536 secrets.push([0; 32]);
1537 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
1538 monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap();
1541 secrets.push([0; 32]);
1542 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c65716add7aa98ba7acb236352d665cab17345fe45b55fb879ff80e6bd0c41dd").unwrap());
1543 monitor.provide_secret(281474976710651, secrets.last().unwrap().clone()).unwrap();
1546 secrets.push([0; 32]);
1547 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
1548 monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap();
1551 secrets.push([0; 32]);
1552 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a5a64476122ca0925fb344bdc1854c1c0a59fc614298e50a33e331980a220f32").unwrap());
1553 monitor.provide_secret(281474976710649, secrets.last().unwrap().clone()).unwrap();
1556 secrets.push([0; 32]);
1557 secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a7efbc61aac46d34f77778bac22c8a20c6a46ca460addc49009bda875ec88fa4").unwrap());
1558 assert!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).is_err());