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 //! Provides keys to LDK and defines some useful objects describing spendable on-chain outputs.
12 //! The provided output descriptors follow a custom LDK data format and are currently not fully
13 //! compatible with Bitcoin Core output descriptors.
15 use bitcoin::blockdata::locktime::absolute::LockTime;
16 use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn};
17 use bitcoin::blockdata::script::{Script, ScriptBuf, Builder};
18 use bitcoin::blockdata::opcodes;
19 use bitcoin::ecdsa::Signature as EcdsaSignature;
20 use bitcoin::network::constants::Network;
21 use bitcoin::psbt::PartiallySignedTransaction;
22 use bitcoin::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
24 use bitcoin::sighash::EcdsaSighashType;
26 use bitcoin::bech32::u5;
27 use bitcoin::hashes::{Hash, HashEngine};
28 use bitcoin::hashes::sha256::Hash as Sha256;
29 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
30 use bitcoin::hash_types::WPubkeyHash;
33 use bitcoin::secp256k1::All;
34 use bitcoin::secp256k1::{KeyPair, PublicKey, Scalar, Secp256k1, SecretKey, Signing};
35 use bitcoin::secp256k1::ecdh::SharedSecret;
36 use bitcoin::secp256k1::ecdsa::{RecoverableSignature, Signature};
37 use bitcoin::secp256k1::schnorr;
38 use bitcoin::{secp256k1, Sequence, Witness, Txid};
40 use crate::util::transaction_utils;
41 use crate::util::crypto::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
42 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
43 use crate::chain::transaction::OutPoint;
44 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
45 use crate::ln::{chan_utils, PaymentPreimage};
46 use crate::ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
47 use crate::ln::channel_keys::{DelayedPaymentBasepoint, DelayedPaymentKey, HtlcKey, HtlcBasepoint, RevocationKey, RevocationBasepoint};
48 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
50 use crate::ln::msgs::PartialSignatureWithNonce;
51 use crate::ln::script::ShutdownScript;
52 use crate::offers::invoice::UnsignedBolt12Invoice;
53 use crate::offers::invoice_request::UnsignedInvoiceRequest;
55 use crate::prelude::*;
56 use core::convert::TryInto;
58 use core::sync::atomic::{AtomicUsize, Ordering};
60 use musig2::types::{PartialSignature, PublicNonce, SecretNonce};
61 use crate::io::{self, Error};
62 use crate::ln::features::ChannelTypeFeatures;
63 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
64 use crate::sign::ecdsa::{EcdsaChannelSigner, WriteableEcdsaChannelSigner};
66 use crate::sign::taproot::TaprootChannelSigner;
67 use crate::util::atomic_counter::AtomicCounter;
68 use crate::util::chacha20::ChaCha20;
69 use crate::util::invoice::construct_invoice_preimage;
71 pub(crate) mod type_resolver;
77 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
78 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
80 /// This is not exported to bindings users as we just use `[u8; 32]` directly
81 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
82 pub struct KeyMaterial(pub [u8; 32]);
84 /// Information about a spendable output to a P2WSH script.
86 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
87 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
88 pub struct DelayedPaymentOutputDescriptor {
89 /// The outpoint which is spendable.
90 pub outpoint: OutPoint,
91 /// Per commitment point to derive the delayed payment key by key holder.
92 pub per_commitment_point: PublicKey,
93 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
94 /// the witness_script.
95 pub to_self_delay: u16,
96 /// The output which is referenced by the given outpoint.
98 /// The revocation point specific to the commitment transaction which was broadcast. Used to
99 /// derive the witnessScript for this output.
100 pub revocation_pubkey: RevocationKey,
101 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
102 /// This may be useful in re-deriving keys used in the channel to spend the output.
103 pub channel_keys_id: [u8; 32],
104 /// The value of the channel which this output originated from, possibly indirectly.
105 pub channel_value_satoshis: u64,
107 impl DelayedPaymentOutputDescriptor {
108 /// The maximum length a well-formed witness spending one of these should have.
109 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
111 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
112 // redeemscript push length.
113 pub const MAX_WITNESS_LENGTH: u64 = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH as u64 + 1;
116 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
117 (0, outpoint, required),
118 (2, per_commitment_point, required),
119 (4, to_self_delay, required),
120 (6, output, required),
121 (8, revocation_pubkey, required),
122 (10, channel_keys_id, required),
123 (12, channel_value_satoshis, required),
126 pub(crate) const P2WPKH_WITNESS_WEIGHT: u64 = 1 /* num stack items */ +
128 73 /* sig including sighash flag */ +
129 1 /* pubkey length */ +
132 /// Information about a spendable output to our "payment key".
134 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
135 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
136 pub struct StaticPaymentOutputDescriptor {
137 /// The outpoint which is spendable.
138 pub outpoint: OutPoint,
139 /// The output which is referenced by the given outpoint.
141 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
142 /// This may be useful in re-deriving keys used in the channel to spend the output.
143 pub channel_keys_id: [u8; 32],
144 /// The value of the channel which this transactions spends.
145 pub channel_value_satoshis: u64,
146 /// The necessary channel parameters that need to be provided to the re-derived signer through
147 /// [`ChannelSigner::provide_channel_parameters`].
149 /// Added as optional, but always `Some` if the descriptor was produced in v0.0.117 or later.
150 pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
152 impl StaticPaymentOutputDescriptor {
153 /// Returns the `witness_script` of the spendable output.
155 /// Note that this will only return `Some` for [`StaticPaymentOutputDescriptor`]s that
156 /// originated from an anchor outputs channel, as they take the form of a P2WSH script.
157 pub fn witness_script(&self) -> Option<ScriptBuf> {
158 self.channel_transaction_parameters.as_ref()
159 .and_then(|channel_params|
160 if channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx() {
161 let payment_point = channel_params.holder_pubkeys.payment_point;
162 Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
169 /// The maximum length a well-formed witness spending one of these should have.
170 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
172 pub fn max_witness_length(&self) -> u64 {
173 if self.channel_transaction_parameters.as_ref()
174 .map(|channel_params| channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx())
177 let witness_script_weight = 1 /* pubkey push */ + 33 /* pubkey */ +
178 1 /* OP_CHECKSIGVERIFY */ + 1 /* OP_1 */ + 1 /* OP_CHECKSEQUENCEVERIFY */;
179 1 /* num witness items */ + 1 /* sig push */ + 73 /* sig including sighash flag */ +
180 1 /* witness script push */ + witness_script_weight
182 P2WPKH_WITNESS_WEIGHT
186 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
187 (0, outpoint, required),
188 (2, output, required),
189 (4, channel_keys_id, required),
190 (6, channel_value_satoshis, required),
191 (7, channel_transaction_parameters, option),
194 /// Describes the necessary information to spend a spendable output.
196 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
197 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
198 /// to spend on-chain. The information needed to do this is provided in this enum, including the
199 /// outpoint describing which `txid` and output `index` is available, the full output which exists
200 /// at that `txid`/`index`, and any keys or other information required to sign.
202 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
203 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
204 pub enum SpendableOutputDescriptor {
205 /// An output to a script which was provided via [`SignerProvider`] directly, either from
206 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
207 /// know how to spend it. No secret keys are provided as LDK was never given any key.
208 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
209 /// on-chain using the payment preimage or after it has timed out.
211 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
212 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
214 /// The outpoint which is spendable.
216 /// The output which is referenced by the given outpoint.
218 /// The `channel_keys_id` for the channel which this output came from.
220 /// For channels which were generated on LDK 0.0.119 or later, this is the value which was
221 /// passed to the [`SignerProvider::get_destination_script`] call which provided this
224 /// For channels which were generated prior to LDK 0.0.119, no such argument existed,
225 /// however this field may still be filled in if such data is available.
226 channel_keys_id: Option<[u8; 32]>
228 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
231 /// The witness in the spending input should be:
233 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
236 /// Note that the `nSequence` field in the spending input must be set to
237 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
238 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
239 /// the outpoint confirms, see [BIP
240 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
241 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
244 /// These are generally the result of a "revocable" output to us, spendable only by us unless
245 /// it is an output from an old state which we broadcast (which should never happen).
247 /// To derive the delayed payment key which is used to sign this input, you must pass the
248 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
249 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
250 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The DelayedPaymentKey can be
251 /// generated without the secret key using [`DelayedPaymentKey::from_basepoint`] and only the
252 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
254 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
255 /// used in the witness script generation), you must pass the counterparty
256 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
257 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
258 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
259 /// [`RevocationKey`].
261 /// The witness script which is hashed and included in the output `script_pubkey` may be
262 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
263 /// as explained above), our delayed payment pubkey (derived as explained above), and the
264 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
265 /// [`chan_utils::get_revokeable_redeemscript`].
266 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
267 /// An output spendable exclusively by our payment key (i.e., the private key that corresponds
268 /// to the `payment_point` in [`ChannelSigner::pubkeys`]). The output type depends on the
269 /// channel type negotiated.
271 /// On an anchor outputs channel, the witness in the spending input is:
273 /// <BIP 143 signature> <witness script>
276 /// Otherwise, it is:
278 /// <BIP 143 signature> <payment key>
281 /// These are generally the result of our counterparty having broadcast the current state,
282 /// allowing us to claim the non-HTLC-encumbered outputs immediately, or after one confirmation
283 /// in the case of anchor outputs channels.
284 StaticPaymentOutput(StaticPaymentOutputDescriptor),
287 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
288 (0, StaticOutput) => {
289 (0, outpoint, required),
290 (1, channel_keys_id, option),
291 (2, output, required),
294 (1, DelayedPaymentOutput),
295 (2, StaticPaymentOutput),
298 impl SpendableOutputDescriptor {
299 /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
300 /// [`PartiallySignedTransaction`] which spends the given descriptor.
302 /// Note that this does not include any signatures, just the information required to
303 /// construct the transaction and sign it.
305 /// This is not exported to bindings users as there is no standard serialization for an input.
306 /// See [`Self::create_spendable_outputs_psbt`] instead.
307 pub fn to_psbt_input(&self) -> bitcoin::psbt::Input {
309 SpendableOutputDescriptor::StaticOutput { output, .. } => {
310 // Is a standard P2WPKH, no need for witness script
311 bitcoin::psbt::Input {
312 witness_utxo: Some(output.clone()),
316 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
317 // TODO we could add the witness script as well
318 bitcoin::psbt::Input {
319 witness_utxo: Some(descriptor.output.clone()),
323 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
324 // TODO we could add the witness script as well
325 bitcoin::psbt::Input {
326 witness_utxo: Some(descriptor.output.clone()),
333 /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
334 /// the given outputs, plus an output to the given change destination (if sufficient
335 /// change value remains). The PSBT will have a feerate, at least, of the given value.
337 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
338 /// transaction will have a locktime of 0. It it recommended to set this to the current block
339 /// height to avoid fee sniping, unless you have some specific reason to use a different
342 /// Returns the PSBT and expected max transaction weight.
344 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
345 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
346 /// does not match the one we can spend.
348 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
349 pub fn create_spendable_outputs_psbt(descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>) -> Result<(PartiallySignedTransaction, u64), ()> {
350 let mut input = Vec::with_capacity(descriptors.len());
351 let mut input_value = 0;
352 let mut witness_weight = 0;
353 let mut output_set = HashSet::with_capacity(descriptors.len());
354 for outp in descriptors {
356 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
357 if !output_set.insert(descriptor.outpoint) { return Err(()); }
359 if descriptor.channel_transaction_parameters.as_ref()
360 .map(|channel_params| channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx())
363 Sequence::from_consensus(1)
368 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
369 script_sig: ScriptBuf::new(),
371 witness: Witness::new(),
373 witness_weight += descriptor.max_witness_length();
374 #[cfg(feature = "grind_signatures")]
375 { witness_weight -= 1; } // Guarantees a low R signature
376 input_value += descriptor.output.value;
378 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
379 if !output_set.insert(descriptor.outpoint) { return Err(()); }
381 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
382 script_sig: ScriptBuf::new(),
383 sequence: Sequence(descriptor.to_self_delay as u32),
384 witness: Witness::new(),
386 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
387 #[cfg(feature = "grind_signatures")]
388 { witness_weight -= 1; } // Guarantees a low R signature
389 input_value += descriptor.output.value;
391 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
392 if !output_set.insert(*outpoint) { return Err(()); }
394 previous_output: outpoint.into_bitcoin_outpoint(),
395 script_sig: ScriptBuf::new(),
396 sequence: Sequence::ZERO,
397 witness: Witness::new(),
399 witness_weight += 1 + 73 + 34;
400 #[cfg(feature = "grind_signatures")]
401 { witness_weight -= 1; } // Guarantees a low R signature
402 input_value += output.value;
405 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
407 let mut tx = Transaction {
409 lock_time: locktime.unwrap_or(LockTime::ZERO),
413 let expected_max_weight =
414 transaction_utils::maybe_add_change_output(&mut tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
416 let psbt_inputs = descriptors.iter().map(|d| d.to_psbt_input()).collect::<Vec<_>>();
417 let psbt = PartiallySignedTransaction {
419 outputs: vec![Default::default(); tx.output.len()],
421 xpub: Default::default(),
423 proprietary: Default::default(),
424 unknown: Default::default(),
426 Ok((psbt, expected_max_weight))
430 /// The parameters required to derive a channel signer via [`SignerProvider`].
431 #[derive(Clone, Debug, PartialEq, Eq)]
432 pub struct ChannelDerivationParameters {
433 /// The value in satoshis of the channel we're attempting to spend the anchor output of.
434 pub value_satoshis: u64,
435 /// The unique identifier to re-derive the signer for the associated channel.
436 pub keys_id: [u8; 32],
437 /// The necessary channel parameters that need to be provided to the re-derived signer through
438 /// [`ChannelSigner::provide_channel_parameters`].
439 pub transaction_parameters: ChannelTransactionParameters,
442 impl_writeable_tlv_based!(ChannelDerivationParameters, {
443 (0, value_satoshis, required),
444 (2, keys_id, required),
445 (4, transaction_parameters, required),
448 /// A descriptor used to sign for a commitment transaction's HTLC output.
449 #[derive(Clone, Debug, PartialEq, Eq)]
450 pub struct HTLCDescriptor {
451 /// The parameters required to derive the signer for the HTLC input.
452 pub channel_derivation_parameters: ChannelDerivationParameters,
453 /// The txid of the commitment transaction in which the HTLC output lives.
454 pub commitment_txid: Txid,
455 /// The number of the commitment transaction in which the HTLC output lives.
456 pub per_commitment_number: u64,
457 /// The key tweak corresponding to the number of the commitment transaction in which the HTLC
458 /// output lives. This tweak is applied to all the basepoints for both parties in the channel to
459 /// arrive at unique keys per commitment.
461 /// See <https://github.com/lightning/bolts/blob/master/03-transactions.md#keys> for more info.
462 pub per_commitment_point: PublicKey,
463 /// The feerate to use on the HTLC claiming transaction. This is always `0` for HTLCs
464 /// originating from a channel supporting anchor outputs, otherwise it is the channel's
465 /// negotiated feerate at the time the commitment transaction was built.
466 pub feerate_per_kw: u32,
467 /// The details of the HTLC as it appears in the commitment transaction.
468 pub htlc: HTLCOutputInCommitment,
469 /// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
471 pub preimage: Option<PaymentPreimage>,
472 /// The counterparty's signature required to spend the HTLC output.
473 pub counterparty_sig: Signature
476 impl_writeable_tlv_based!(HTLCDescriptor, {
477 (0, channel_derivation_parameters, required),
478 (1, feerate_per_kw, (default_value, 0)),
479 (2, commitment_txid, required),
480 (4, per_commitment_number, required),
481 (6, per_commitment_point, required),
483 (10, preimage, option),
484 (12, counterparty_sig, required),
487 impl HTLCDescriptor {
488 /// Returns the outpoint of the HTLC output in the commitment transaction. This is the outpoint
489 /// being spent by the HTLC input in the HTLC transaction.
490 pub fn outpoint(&self) -> bitcoin::OutPoint {
492 txid: self.commitment_txid,
493 vout: self.htlc.transaction_output_index.unwrap(),
497 /// Returns the UTXO to be spent by the HTLC input, which can be obtained via
498 /// [`Self::unsigned_tx_input`].
499 pub fn previous_utxo<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
501 script_pubkey: self.witness_script(secp).to_v0_p2wsh(),
502 value: self.htlc.amount_msat / 1000,
506 /// Returns the unsigned transaction input spending the HTLC output in the commitment
508 pub fn unsigned_tx_input(&self) -> TxIn {
509 chan_utils::build_htlc_input(
510 &self.commitment_txid, &self.htlc, &self.channel_derivation_parameters.transaction_parameters.channel_type_features
514 /// Returns the delayed output created as a result of spending the HTLC output in the commitment
516 pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
517 let channel_params = self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
518 let broadcaster_keys = channel_params.broadcaster_pubkeys();
519 let counterparty_keys = channel_params.countersignatory_pubkeys();
520 let broadcaster_delayed_key = DelayedPaymentKey::from_basepoint(
521 secp, &broadcaster_keys.delayed_payment_basepoint, &self.per_commitment_point
523 let counterparty_revocation_key = &RevocationKey::from_basepoint(&secp, &counterparty_keys.revocation_basepoint, &self.per_commitment_point);
524 chan_utils::build_htlc_output(
525 self.feerate_per_kw, channel_params.contest_delay(), &self.htlc,
526 channel_params.channel_type_features(), &broadcaster_delayed_key, &counterparty_revocation_key
530 /// Returns the witness script of the HTLC output in the commitment transaction.
531 pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> ScriptBuf {
532 let channel_params = self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
533 let broadcaster_keys = channel_params.broadcaster_pubkeys();
534 let counterparty_keys = channel_params.countersignatory_pubkeys();
535 let broadcaster_htlc_key = HtlcKey::from_basepoint(
536 secp, &broadcaster_keys.htlc_basepoint, &self.per_commitment_point
538 let counterparty_htlc_key = HtlcKey::from_basepoint(
539 secp, &counterparty_keys.htlc_basepoint, &self.per_commitment_point,
541 let counterparty_revocation_key = &RevocationKey::from_basepoint(&secp, &counterparty_keys.revocation_basepoint, &self.per_commitment_point);
542 chan_utils::get_htlc_redeemscript_with_explicit_keys(
543 &self.htlc, channel_params.channel_type_features(), &broadcaster_htlc_key, &counterparty_htlc_key,
544 &counterparty_revocation_key,
548 /// Returns the fully signed witness required to spend the HTLC output in the commitment
550 pub fn tx_input_witness(&self, signature: &Signature, witness_script: &Script) -> Witness {
551 chan_utils::build_htlc_input_witness(
552 signature, &self.counterparty_sig, &self.preimage, witness_script,
553 &self.channel_derivation_parameters.transaction_parameters.channel_type_features
557 /// Derives the channel signer required to sign the HTLC input.
558 pub fn derive_channel_signer<S: WriteableEcdsaChannelSigner, SP: Deref>(&self, signer_provider: &SP) -> S
560 SP::Target: SignerProvider<EcdsaSigner= S>
562 let mut signer = signer_provider.derive_channel_signer(
563 self.channel_derivation_parameters.value_satoshis,
564 self.channel_derivation_parameters.keys_id,
566 signer.provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
571 /// A trait to handle Lightning channel key material without concretizing the channel type or
572 /// the signature mechanism.
573 pub trait ChannelSigner {
574 /// Gets the per-commitment point for a specific commitment number
576 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
577 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
579 /// Gets the commitment secret for a specific commitment number as part of the revocation process
581 /// An external signer implementation should error here if the commitment was already signed
582 /// and should refuse to sign it in the future.
584 /// May be called more than once for the same index.
586 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
587 // TODO: return a Result so we can signal a validation error
588 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
590 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
592 /// This is required in order for the signer to make sure that releasing a commitment
593 /// secret won't leave us without a broadcastable holder transaction.
594 /// Policy checks should be implemented in this function, including checking the amount
595 /// sent to us and checking the HTLCs.
597 /// The preimages of outbound HTLCs that were fulfilled since the last commitment are provided.
598 /// A validating signer should ensure that an HTLC output is removed only when the matching
599 /// preimage is provided, or when the value to holder is restored.
601 /// Note that all the relevant preimages will be provided, but there may also be additional
602 /// irrelevant or duplicate preimages.
603 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction,
604 outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
606 /// Returns the holder's channel public keys and basepoints.
607 fn pubkeys(&self) -> &ChannelPublicKeys;
609 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
610 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
611 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
612 fn channel_keys_id(&self) -> [u8; 32];
614 /// Set the counterparty static channel data, including basepoints,
615 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
617 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
618 /// instance, LDK will call this method exactly once - either immediately after construction
619 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
620 /// information has been generated.
622 /// channel_parameters.is_populated() MUST be true.
623 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
626 /// Specifies the recipient of an invoice.
628 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
631 /// The invoice should be signed with the local node secret key.
633 /// The invoice should be signed with the phantom node secret key. This secret key must be the
634 /// same for all nodes participating in the [phantom node payment].
636 /// [phantom node payment]: PhantomKeysManager
640 /// A trait that describes a source of entropy.
641 pub trait EntropySource {
642 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
643 /// different value each time it is called.
644 fn get_secure_random_bytes(&self) -> [u8; 32];
647 /// A trait that can handle cryptographic operations at the scope level of a node.
648 pub trait NodeSigner {
649 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
651 /// If the implementor of this trait supports [phantom node payments], then every node that is
652 /// intended to be included in the phantom invoice route hints must return the same value from
654 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
655 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
656 // nodes, they must share the key that encrypts this payment data.
658 /// This method must return the same value each time it is called.
660 /// [phantom node payments]: PhantomKeysManager
661 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
663 /// Get node id based on the provided [`Recipient`].
665 /// This method must return the same value each time it is called with a given [`Recipient`]
668 /// Errors if the [`Recipient`] variant is not supported by the implementation.
669 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
671 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
672 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
673 /// secret, though this is less efficient.
675 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
676 /// should be resolved to allow LDK to resume forwarding HTLCs.
678 /// Errors if the [`Recipient`] variant is not supported by the implementation.
679 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
683 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
684 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
685 /// blindly signing the hash.
687 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
689 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
691 /// Errors if the [`Recipient`] variant is not supported by the implementation.
692 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()>;
694 /// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
696 /// May be called by a function passed to [`UnsignedInvoiceRequest::sign`] where
697 /// `invoice_request` is the callee.
699 /// Implementors may check that the `invoice_request` is expected rather than blindly signing
700 /// the tagged hash. An `Ok` result should sign `invoice_request.tagged_hash().as_digest()` with
701 /// the node's signing key or an ephemeral key to preserve privacy, whichever is associated with
702 /// [`UnsignedInvoiceRequest::payer_id`].
704 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
705 fn sign_bolt12_invoice_request(
706 &self, invoice_request: &UnsignedInvoiceRequest
707 ) -> Result<schnorr::Signature, ()>;
709 /// Signs the [`TaggedHash`] of a BOLT 12 invoice.
711 /// May be called by a function passed to [`UnsignedBolt12Invoice::sign`] where `invoice` is the
714 /// Implementors may check that the `invoice` is expected rather than blindly signing the tagged
715 /// hash. An `Ok` result should sign `invoice.tagged_hash().as_digest()` with the node's signing
716 /// key or an ephemeral key to preserve privacy, whichever is associated with
717 /// [`UnsignedBolt12Invoice::signing_pubkey`].
719 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
720 fn sign_bolt12_invoice(
721 &self, invoice: &UnsignedBolt12Invoice
722 ) -> Result<schnorr::Signature, ()>;
724 /// Sign a gossip message.
726 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
727 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
728 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
729 /// corresponding channel.
730 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
733 /// A trait that can return signer instances for individual channels.
734 pub trait SignerProvider {
735 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
736 type EcdsaSigner: WriteableEcdsaChannelSigner;
738 /// A type which implements [`TaprootChannelSigner`]
739 type TaprootSigner: TaprootChannelSigner;
741 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::EcdsaSigner`] through
742 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
743 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
744 /// `channel_keys_id`.
746 /// This method must return a different value each time it is called.
747 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
749 /// Derives the private key material backing a `Signer`.
751 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
752 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
753 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
754 /// [`ChannelSigner::channel_keys_id`].
755 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner;
757 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
758 /// This is only called during deserialization of other objects which contain
759 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
760 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
761 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
762 /// you've read all of the provided bytes to ensure no corruption occurred.
764 /// This method is slowly being phased out -- it will only be called when reading objects
765 /// written by LDK versions prior to 0.0.113.
767 /// [`Signer`]: Self::EcdsaSigner
768 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
769 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
770 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError>;
772 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
774 /// If this function returns an error, this will result in a channel failing to open.
776 /// This method should return a different value each time it is called, to avoid linking
777 /// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
778 /// used to derive a unique value for each channel.
779 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
781 /// Get a script pubkey which we will send funds to when closing a channel.
783 /// If this function returns an error, this will result in a channel failing to open or close.
784 /// In the event of a failure when the counterparty is initiating a close, this can result in a
785 /// channel force close.
787 /// This method should return a different value each time it is called, to avoid linking
788 /// on-chain funds across channels as controlled to the same user.
789 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
792 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
794 /// This implementation performs no policy checks and is insufficient by itself as
795 /// a secure external signer.
797 pub struct InMemorySigner {
798 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
799 /// holder's anchor output in a commitment transaction, if one is present.
800 pub funding_key: SecretKey,
801 /// Holder secret key for blinded revocation pubkey.
802 pub revocation_base_key: SecretKey,
803 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
804 pub payment_key: SecretKey,
805 /// Holder secret key used in an HTLC transaction.
806 pub delayed_payment_base_key: SecretKey,
807 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
808 pub htlc_base_key: SecretKey,
810 pub commitment_seed: [u8; 32],
811 /// Holder public keys and basepoints.
812 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
813 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
814 channel_parameters: Option<ChannelTransactionParameters>,
815 /// The total value of this channel.
816 channel_value_satoshis: u64,
817 /// Key derivation parameters.
818 channel_keys_id: [u8; 32],
819 /// Seed from which all randomness produced is derived from.
820 rand_bytes_unique_start: [u8; 32],
821 /// Tracks the number of times we've produced randomness to ensure we don't return the same
823 rand_bytes_index: AtomicCounter,
826 impl PartialEq for InMemorySigner {
827 fn eq(&self, other: &Self) -> bool {
828 self.funding_key == other.funding_key &&
829 self.revocation_base_key == other.revocation_base_key &&
830 self.payment_key == other.payment_key &&
831 self.delayed_payment_base_key == other.delayed_payment_base_key &&
832 self.htlc_base_key == other.htlc_base_key &&
833 self.commitment_seed == other.commitment_seed &&
834 self.holder_channel_pubkeys == other.holder_channel_pubkeys &&
835 self.channel_parameters == other.channel_parameters &&
836 self.channel_value_satoshis == other.channel_value_satoshis &&
837 self.channel_keys_id == other.channel_keys_id
841 impl Clone for InMemorySigner {
842 fn clone(&self) -> Self {
844 funding_key: self.funding_key.clone(),
845 revocation_base_key: self.revocation_base_key.clone(),
846 payment_key: self.payment_key.clone(),
847 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
848 htlc_base_key: self.htlc_base_key.clone(),
849 commitment_seed: self.commitment_seed.clone(),
850 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
851 channel_parameters: self.channel_parameters.clone(),
852 channel_value_satoshis: self.channel_value_satoshis,
853 channel_keys_id: self.channel_keys_id,
854 rand_bytes_unique_start: self.get_secure_random_bytes(),
855 rand_bytes_index: AtomicCounter::new(),
860 impl InMemorySigner {
861 /// Creates a new [`InMemorySigner`].
862 pub fn new<C: Signing>(
863 secp_ctx: &Secp256k1<C>,
864 funding_key: SecretKey,
865 revocation_base_key: SecretKey,
866 payment_key: SecretKey,
867 delayed_payment_base_key: SecretKey,
868 htlc_base_key: SecretKey,
869 commitment_seed: [u8; 32],
870 channel_value_satoshis: u64,
871 channel_keys_id: [u8; 32],
872 rand_bytes_unique_start: [u8; 32],
873 ) -> InMemorySigner {
874 let holder_channel_pubkeys =
875 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
876 &payment_key, &delayed_payment_base_key,
882 delayed_payment_base_key,
885 channel_value_satoshis,
886 holder_channel_pubkeys,
887 channel_parameters: None,
889 rand_bytes_unique_start,
890 rand_bytes_index: AtomicCounter::new(),
894 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
895 funding_key: &SecretKey,
896 revocation_base_key: &SecretKey,
897 payment_key: &SecretKey,
898 delayed_payment_base_key: &SecretKey,
899 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
900 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
902 funding_pubkey: from_secret(&funding_key),
903 revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
904 payment_point: from_secret(&payment_key),
905 delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(&delayed_payment_base_key)),
906 htlc_basepoint: HtlcBasepoint::from(from_secret(&htlc_base_key)),
910 /// Returns the counterparty's pubkeys.
912 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
913 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
914 pub fn counterparty_pubkeys(&self) -> Option<&ChannelPublicKeys> {
915 self.get_channel_parameters()
916 .and_then(|params| params.counterparty_parameters.as_ref().map(|params| ¶ms.pubkeys))
919 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
920 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
921 /// broadcast a transaction.
923 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
924 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
925 pub fn counterparty_selected_contest_delay(&self) -> Option<u16> {
926 self.get_channel_parameters()
927 .and_then(|params| params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay))
930 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
931 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
932 /// if they broadcast a transaction.
934 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
935 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
936 pub fn holder_selected_contest_delay(&self) -> Option<u16> {
937 self.get_channel_parameters().map(|params| params.holder_selected_contest_delay)
940 /// Returns whether the holder is the initiator.
942 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
943 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
944 pub fn is_outbound(&self) -> Option<bool> {
945 self.get_channel_parameters().map(|params| params.is_outbound_from_holder)
950 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
951 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
952 pub fn funding_outpoint(&self) -> Option<&OutPoint> {
953 self.get_channel_parameters().map(|params| params.funding_outpoint.as_ref()).flatten()
956 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
957 /// building transactions.
959 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
960 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
961 pub fn get_channel_parameters(&self) -> Option<&ChannelTransactionParameters> {
962 self.channel_parameters.as_ref()
965 /// Returns the channel type features of the channel parameters. Should be helpful for
966 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
968 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
969 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
970 pub fn channel_type_features(&self) -> Option<&ChannelTypeFeatures> {
971 self.get_channel_parameters().map(|params| ¶ms.channel_type_features)
974 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
975 /// by `descriptor`, returning the witness stack for the input.
977 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
978 /// is not spending the outpoint described by [`descriptor.outpoint`],
979 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
981 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
982 pub fn sign_counterparty_payment_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Witness, ()> {
983 // TODO: We really should be taking the SigHashCache as a parameter here instead of
984 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
985 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
986 // bindings updates to support SigHashCache objects).
987 if spend_tx.input.len() <= input_idx { return Err(()); }
988 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
989 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
991 let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
992 // We cannot always assume that `channel_parameters` is set, so can't just call
993 // `self.channel_parameters()` or anything that relies on it
994 let supports_anchors_zero_fee_htlc_tx = self.channel_type_features()
995 .map(|features| features.supports_anchors_zero_fee_htlc_tx())
998 let witness_script = if supports_anchors_zero_fee_htlc_tx {
999 chan_utils::get_to_countersignatory_with_anchors_redeemscript(&remotepubkey.inner)
1001 ScriptBuf::new_p2pkh(&remotepubkey.pubkey_hash())
1003 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
1004 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
1005 let payment_script = if supports_anchors_zero_fee_htlc_tx {
1006 witness_script.to_v0_p2wsh()
1008 ScriptBuf::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
1011 if payment_script != descriptor.output.script_pubkey { return Err(()); }
1013 let mut witness = Vec::with_capacity(2);
1014 witness.push(remotesig.serialize_der().to_vec());
1015 witness[0].push(EcdsaSighashType::All as u8);
1016 if supports_anchors_zero_fee_htlc_tx {
1017 witness.push(witness_script.to_bytes());
1019 witness.push(remotepubkey.to_bytes());
1024 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
1025 /// described by `descriptor`, returning the witness stack for the input.
1027 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1028 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
1029 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
1030 /// `script_pubkey` does not match the one we can spend.
1032 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
1033 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
1034 pub fn sign_dynamic_p2wsh_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Witness, ()> {
1035 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1036 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1037 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1038 // bindings updates to support SigHashCache objects).
1039 if spend_tx.input.len() <= input_idx { return Err(()); }
1040 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
1041 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
1042 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
1044 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
1045 let delayed_payment_pubkey = DelayedPaymentKey::from_secret_key(&secp_ctx, &delayed_payment_key);
1046 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
1047 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
1048 let local_delayedsig = EcdsaSignature {
1049 sig: sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self),
1050 hash_ty: EcdsaSighashType::All,
1052 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
1054 if descriptor.output.script_pubkey != payment_script { return Err(()); }
1056 Ok(Witness::from_slice(&[
1057 &local_delayedsig.serialize()[..],
1059 witness_script.as_bytes(),
1064 impl EntropySource for InMemorySigner {
1065 fn get_secure_random_bytes(&self) -> [u8; 32] {
1066 let index = self.rand_bytes_index.get_increment();
1067 let mut nonce = [0u8; 16];
1068 nonce[..8].copy_from_slice(&index.to_be_bytes());
1069 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
1073 impl ChannelSigner for InMemorySigner {
1074 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
1075 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
1076 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
1079 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
1080 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
1083 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
1087 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
1089 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
1091 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
1092 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
1093 if self.channel_parameters.is_some() {
1094 // The channel parameters were already set and they match, return early.
1097 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
1098 self.channel_parameters = Some(channel_parameters.clone());
1102 const MISSING_PARAMS_ERR: &'static str = "ChannelSigner::provide_channel_parameters must be called before signing operations";
1104 impl EcdsaChannelSigner for InMemorySigner {
1105 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _inbound_htlc_preimages: Vec<PaymentPreimage>, _outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
1106 let trusted_tx = commitment_tx.trust();
1107 let keys = trusted_tx.keys();
1109 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1110 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1111 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1113 let built_tx = trusted_tx.built_transaction();
1114 let commitment_sig = built_tx.sign_counterparty_commitment(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
1115 let commitment_txid = built_tx.txid;
1117 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
1118 for htlc in commitment_tx.htlcs() {
1119 let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
1120 let holder_selected_contest_delay =
1121 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1122 let chan_type = &channel_parameters.channel_type_features;
1123 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), holder_selected_contest_delay, htlc, chan_type, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
1124 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, chan_type, &keys);
1125 let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
1126 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
1127 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
1128 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
1131 Ok((commitment_sig, htlc_sigs))
1134 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
1138 fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1139 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1140 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1141 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1142 let trusted_tx = commitment_tx.trust();
1143 Ok(trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx))
1146 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
1147 fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1148 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1149 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1150 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1151 let trusted_tx = commitment_tx.trust();
1152 Ok(trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx))
1155 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1156 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1157 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1158 let revocation_pubkey = RevocationKey::from_basepoint(
1159 &secp_ctx, &self.pubkeys().revocation_basepoint, &per_commitment_point,
1161 let witness_script = {
1162 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1163 let holder_selected_contest_delay =
1164 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1165 let counterparty_delayedpubkey = DelayedPaymentKey::from_basepoint(&secp_ctx, &counterparty_keys.delayed_payment_basepoint, &per_commitment_point);
1166 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, holder_selected_contest_delay, &counterparty_delayedpubkey)
1168 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1169 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1170 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1173 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1174 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1175 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1176 let revocation_pubkey = RevocationKey::from_basepoint(
1177 &secp_ctx, &self.pubkeys().revocation_basepoint, &per_commitment_point,
1179 let witness_script = {
1180 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1181 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1182 &secp_ctx, &counterparty_keys.htlc_basepoint, &per_commitment_point,
1184 let holder_htlcpubkey = HtlcKey::from_basepoint(
1185 &secp_ctx, &self.pubkeys().htlc_basepoint, &per_commitment_point,
1187 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1188 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, chan_type, &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
1190 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1191 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1192 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1195 fn sign_holder_htlc_transaction(
1196 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1197 secp_ctx: &Secp256k1<secp256k1::All>
1198 ) -> Result<Signature, ()> {
1199 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1200 let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
1201 input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
1203 let our_htlc_private_key = chan_utils::derive_private_key(
1204 &secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_key
1206 Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash.as_byte_array()), &our_htlc_private_key, &self))
1209 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1210 let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1211 let revocation_pubkey = RevocationKey::from_basepoint(
1212 &secp_ctx, &self.pubkeys().revocation_basepoint, &per_commitment_point,
1214 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1215 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1216 &secp_ctx, &counterparty_keys.htlc_basepoint, &per_commitment_point,
1218 let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &self.pubkeys().htlc_basepoint, &per_commitment_point);
1219 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1220 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, chan_type, &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
1221 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1222 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1223 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1226 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1227 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1228 let counterparty_funding_key = &self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
1229 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
1230 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
1233 fn sign_holder_anchor_input(
1234 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1235 ) -> Result<Signature, ()> {
1236 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1237 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
1238 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
1240 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1243 fn sign_channel_announcement_with_funding_key(
1244 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
1245 ) -> Result<Signature, ()> {
1246 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1247 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1252 impl TaprootChannelSigner for InMemorySigner {
1253 fn generate_local_nonce_pair(&self, commitment_number: u64, secp_ctx: &Secp256k1<All>) -> PublicNonce {
1257 fn partially_sign_counterparty_commitment(&self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>) -> Result<(PartialSignatureWithNonce, Vec<schnorr::Signature>), ()> {
1261 fn finalize_holder_commitment(&self, commitment_number: u64, commitment_tx: &HolderCommitmentTransaction, counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
1265 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
1269 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
1273 fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
1277 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
1281 fn partially_sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
1285 fn sign_holder_anchor_input(&self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
1290 const SERIALIZATION_VERSION: u8 = 1;
1292 const MIN_SERIALIZATION_VERSION: u8 = 1;
1294 impl WriteableEcdsaChannelSigner for InMemorySigner {}
1296 impl Writeable for InMemorySigner {
1297 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1298 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1300 self.funding_key.write(writer)?;
1301 self.revocation_base_key.write(writer)?;
1302 self.payment_key.write(writer)?;
1303 self.delayed_payment_base_key.write(writer)?;
1304 self.htlc_base_key.write(writer)?;
1305 self.commitment_seed.write(writer)?;
1306 self.channel_parameters.write(writer)?;
1307 self.channel_value_satoshis.write(writer)?;
1308 self.channel_keys_id.write(writer)?;
1310 write_tlv_fields!(writer, {});
1316 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySource {
1317 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1318 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1320 let funding_key = Readable::read(reader)?;
1321 let revocation_base_key = Readable::read(reader)?;
1322 let payment_key = Readable::read(reader)?;
1323 let delayed_payment_base_key = Readable::read(reader)?;
1324 let htlc_base_key = Readable::read(reader)?;
1325 let commitment_seed = Readable::read(reader)?;
1326 let counterparty_channel_data = Readable::read(reader)?;
1327 let channel_value_satoshis = Readable::read(reader)?;
1328 let secp_ctx = Secp256k1::signing_only();
1329 let holder_channel_pubkeys =
1330 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
1331 &payment_key, &delayed_payment_base_key, &htlc_base_key);
1332 let keys_id = Readable::read(reader)?;
1334 read_tlv_fields!(reader, {});
1338 revocation_base_key,
1340 delayed_payment_base_key,
1343 channel_value_satoshis,
1344 holder_channel_pubkeys,
1345 channel_parameters: counterparty_channel_data,
1346 channel_keys_id: keys_id,
1347 rand_bytes_unique_start: entropy_source.get_secure_random_bytes(),
1348 rand_bytes_index: AtomicCounter::new(),
1353 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1354 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1356 /// Your `node_id` is seed/0'.
1357 /// Unilateral closes may use seed/1'.
1358 /// Cooperative closes may use seed/2'.
1359 /// The two close keys may be needed to claim on-chain funds!
1361 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1362 /// [`PhantomKeysManager`] must be used instead.
1364 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1365 /// previously issued invoices and attempts to pay previous invoices will fail.
1366 pub struct KeysManager {
1367 secp_ctx: Secp256k1<secp256k1::All>,
1368 node_secret: SecretKey,
1370 inbound_payment_key: KeyMaterial,
1371 destination_script: ScriptBuf,
1372 shutdown_pubkey: PublicKey,
1373 channel_master_key: ExtendedPrivKey,
1374 channel_child_index: AtomicUsize,
1376 rand_bytes_unique_start: [u8; 32],
1377 rand_bytes_index: AtomicCounter,
1380 starting_time_secs: u64,
1381 starting_time_nanos: u32,
1385 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1386 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1387 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1388 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1389 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1390 /// is to simply use the current time (with very high precision).
1392 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1393 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1394 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1397 /// Note that the seed is required to recover certain on-chain funds independent of
1398 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1399 /// for any channel, and some on-chain during-closing funds.
1401 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1402 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1403 let secp_ctx = Secp256k1::new();
1404 // Note that when we aren't serializing the key, network doesn't matter
1405 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1407 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
1408 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1409 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
1410 Ok(destination_key) => {
1411 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
1412 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1413 .push_slice(&wpubkey_hash.to_byte_array())
1416 Err(_) => panic!("Your RNG is busted"),
1418 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
1419 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
1420 Err(_) => panic!("Your RNG is busted"),
1422 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
1423 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
1424 let mut inbound_pmt_key_bytes = [0; 32];
1425 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1427 let mut rand_bytes_engine = Sha256::engine();
1428 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1429 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1430 rand_bytes_engine.input(seed);
1431 rand_bytes_engine.input(b"LDK PRNG Seed");
1432 let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).to_byte_array();
1434 let mut res = KeysManager {
1438 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1444 channel_child_index: AtomicUsize::new(0),
1446 rand_bytes_unique_start,
1447 rand_bytes_index: AtomicCounter::new(),
1451 starting_time_nanos,
1453 let secp_seed = res.get_secure_random_bytes();
1454 res.secp_ctx.seeded_randomize(&secp_seed);
1457 Err(_) => panic!("Your rng is busted"),
1461 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1462 pub fn get_node_secret_key(&self) -> SecretKey {
1466 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1467 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1468 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1469 let mut unique_start = Sha256::engine();
1470 unique_start.input(params);
1471 unique_start.input(&self.seed);
1473 // We only seriously intend to rely on the channel_master_key for true secure
1474 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1475 // starting_time provided in the constructor) to be unique.
1476 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
1477 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
1478 ).expect("Your RNG is busted");
1479 unique_start.input(&child_privkey.private_key[..]);
1481 let seed = Sha256::from_engine(unique_start).to_byte_array();
1483 let commitment_seed = {
1484 let mut sha = Sha256::engine();
1486 sha.input(&b"commitment seed"[..]);
1487 Sha256::from_engine(sha).to_byte_array()
1489 macro_rules! key_step {
1490 ($info: expr, $prev_key: expr) => {{
1491 let mut sha = Sha256::engine();
1493 sha.input(&$prev_key[..]);
1494 sha.input(&$info[..]);
1495 SecretKey::from_slice(&Sha256::from_engine(sha).to_byte_array()).expect("SHA-256 is busted")
1498 let funding_key = key_step!(b"funding key", commitment_seed);
1499 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1500 let payment_key = key_step!(b"payment key", revocation_base_key);
1501 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1502 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1503 let prng_seed = self.get_secure_random_bytes();
1505 InMemorySigner::new(
1508 revocation_base_key,
1510 delayed_payment_base_key,
1513 channel_value_satoshis,
1519 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
1520 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
1521 /// are no other inputs that need signing.
1523 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
1525 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1526 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1527 pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<PartiallySignedTransaction, ()> {
1528 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1529 for outp in descriptors {
1531 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1532 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1533 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1534 let mut signer = self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id);
1535 if let Some(channel_params) = descriptor.channel_transaction_parameters.as_ref() {
1536 signer.provide_channel_parameters(channel_params);
1538 keys_cache = Some((signer, descriptor.channel_keys_id));
1540 let witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?;
1541 psbt.inputs[input_idx].final_script_witness = Some(witness);
1543 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1544 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1545 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1547 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1548 descriptor.channel_keys_id));
1550 let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?;
1551 psbt.inputs[input_idx].final_script_witness = Some(witness);
1553 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
1554 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
1555 let derivation_idx = if output.script_pubkey == self.destination_script {
1561 // Note that when we aren't serializing the key, network doesn't matter
1562 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1564 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1566 Err(_) => panic!("Your RNG is busted"),
1569 Err(_) => panic!("Your rng is busted"),
1572 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1573 if derivation_idx == 2 {
1574 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1576 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1577 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1579 if payment_script != output.script_pubkey { return Err(()); };
1581 let sighash = hash_to_message!(&sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1582 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
1583 let mut sig_ser = sig.serialize_der().to_vec();
1584 sig_ser.push(EcdsaSighashType::All as u8);
1585 let witness = Witness::from_slice(&[&sig_ser, &pubkey.inner.serialize().to_vec()]);
1586 psbt.inputs[input_idx].final_script_witness = Some(witness);
1594 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
1595 /// output to the given change destination (if sufficient change value remains). The
1596 /// transaction will have a feerate, at least, of the given value.
1598 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
1599 /// transaction will have a locktime of 0. It it recommended to set this to the current block
1600 /// height to avoid fee sniping, unless you have some specific reason to use a different
1603 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1604 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1605 /// does not match the one we can spend.
1607 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1609 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1610 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1611 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1612 let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
1613 psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
1615 let spend_tx = psbt.extract_tx();
1617 debug_assert!(expected_max_weight >= spend_tx.weight().to_wu());
1618 // Note that witnesses with a signature vary somewhat in size, so allow
1619 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1620 debug_assert!(expected_max_weight <= spend_tx.weight().to_wu() + descriptors.len() as u64 * 3);
1626 impl EntropySource for KeysManager {
1627 fn get_secure_random_bytes(&self) -> [u8; 32] {
1628 let index = self.rand_bytes_index.get_increment();
1629 let mut nonce = [0u8; 16];
1630 nonce[..8].copy_from_slice(&index.to_be_bytes());
1631 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
1635 impl NodeSigner for KeysManager {
1636 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1638 Recipient::Node => Ok(self.node_id.clone()),
1639 Recipient::PhantomNode => Err(())
1643 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1644 let mut node_secret = match recipient {
1645 Recipient::Node => Ok(self.node_secret.clone()),
1646 Recipient::PhantomNode => Err(())
1648 if let Some(tweak) = tweak {
1649 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1651 Ok(SharedSecret::new(other_key, &node_secret))
1654 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1655 self.inbound_payment_key.clone()
1658 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1659 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1660 let secret = match recipient {
1661 Recipient::Node => Ok(&self.node_secret),
1662 Recipient::PhantomNode => Err(())
1664 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage).to_byte_array()), secret))
1667 fn sign_bolt12_invoice_request(
1668 &self, invoice_request: &UnsignedInvoiceRequest
1669 ) -> Result<schnorr::Signature, ()> {
1670 let message = invoice_request.tagged_hash().as_digest();
1671 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
1672 let aux_rand = self.get_secure_random_bytes();
1673 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
1676 fn sign_bolt12_invoice(
1677 &self, invoice: &UnsignedBolt12Invoice
1678 ) -> Result<schnorr::Signature, ()> {
1679 let message = invoice.tagged_hash().as_digest();
1680 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
1681 let aux_rand = self.get_secure_random_bytes();
1682 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
1685 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1686 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1687 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
1691 impl SignerProvider for KeysManager {
1692 type EcdsaSigner = InMemorySigner;
1694 type TaprootSigner = InMemorySigner;
1696 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1697 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1698 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
1699 // (though `user_channel_id` should help, depending on user behavior). If it manages to
1700 // roll over, we may generate duplicate keys for two different channels, which could result
1701 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
1702 // doesn't reach `u32::MAX`.
1703 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
1704 let mut id = [0; 32];
1705 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1706 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1707 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1708 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1712 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner {
1713 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1716 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
1717 InMemorySigner::read(&mut io::Cursor::new(reader), self)
1720 fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
1721 Ok(self.destination_script.clone())
1724 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1725 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
1729 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1732 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1733 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1734 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1735 /// itself without ever needing to forward to this fake node.
1737 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1738 /// provide some fault tolerance, because payers will automatically retry paying other provided
1739 /// nodes in the case that one node goes down.
1741 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1742 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1743 // nodes to know when the full payment has been received (and the preimage can be released) without
1744 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1745 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1746 // is released too early.
1748 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1749 /// invoices and attempts to pay previous invoices will fail.
1750 pub struct PhantomKeysManager {
1752 inbound_payment_key: KeyMaterial,
1753 phantom_secret: SecretKey,
1754 phantom_node_id: PublicKey,
1757 impl EntropySource for PhantomKeysManager {
1758 fn get_secure_random_bytes(&self) -> [u8; 32] {
1759 self.inner.get_secure_random_bytes()
1763 impl NodeSigner for PhantomKeysManager {
1764 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1766 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1767 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1771 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1772 let mut node_secret = match recipient {
1773 Recipient::Node => self.inner.node_secret.clone(),
1774 Recipient::PhantomNode => self.phantom_secret.clone(),
1776 if let Some(tweak) = tweak {
1777 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1779 Ok(SharedSecret::new(other_key, &node_secret))
1782 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1783 self.inbound_payment_key.clone()
1786 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1787 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1788 let secret = match recipient {
1789 Recipient::Node => &self.inner.node_secret,
1790 Recipient::PhantomNode => &self.phantom_secret,
1792 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage).to_byte_array()), secret))
1795 fn sign_bolt12_invoice_request(
1796 &self, invoice_request: &UnsignedInvoiceRequest
1797 ) -> Result<schnorr::Signature, ()> {
1798 self.inner.sign_bolt12_invoice_request(invoice_request)
1801 fn sign_bolt12_invoice(
1802 &self, invoice: &UnsignedBolt12Invoice
1803 ) -> Result<schnorr::Signature, ()> {
1804 self.inner.sign_bolt12_invoice(invoice)
1807 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1808 self.inner.sign_gossip_message(msg)
1812 impl SignerProvider for PhantomKeysManager {
1813 type EcdsaSigner = InMemorySigner;
1815 type TaprootSigner = InMemorySigner;
1817 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1818 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1821 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner {
1822 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1825 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
1826 self.inner.read_chan_signer(reader)
1829 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
1830 self.inner.get_destination_script(channel_keys_id)
1833 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1834 self.inner.get_shutdown_scriptpubkey()
1838 impl PhantomKeysManager {
1839 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
1840 /// that is shared across all nodes that intend to participate in [phantom node payments]
1843 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1844 /// `starting_time_nanos`.
1846 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1847 /// same across restarts, or else inbound payments may fail.
1849 /// [phantom node payments]: PhantomKeysManager
1850 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1851 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1852 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1853 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1854 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1857 inbound_payment_key: KeyMaterial(inbound_key),
1863 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1864 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1865 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
1868 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1869 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1870 self.inner.derive_channel_keys(channel_value_satoshis, params)
1873 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1874 pub fn get_node_secret_key(&self) -> SecretKey {
1875 self.inner.get_node_secret_key()
1878 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
1879 /// last-hop onion data, etc.
1880 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
1885 // Ensure that EcdsaChannelSigner can have a vtable
1888 let _signer: Box<dyn EcdsaChannelSigner>;
1893 use std::sync::{Arc, mpsc};
1894 use std::sync::mpsc::TryRecvError;
1896 use std::time::Duration;
1897 use bitcoin::blockdata::constants::genesis_block;
1898 use bitcoin::Network;
1899 use crate::sign::{EntropySource, KeysManager};
1901 use criterion::Criterion;
1903 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
1904 let seed = [0u8; 32];
1905 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
1906 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
1908 let mut handles = Vec::new();
1909 let mut stops = Vec::new();
1911 let keys_manager_clone = Arc::clone(&keys_manager);
1912 let (stop_sender, stop_receiver) = mpsc::channel();
1913 let handle = thread::spawn(move || {
1915 keys_manager_clone.get_secure_random_bytes();
1916 match stop_receiver.try_recv() {
1917 Ok(_) | Err(TryRecvError::Disconnected) => {
1918 println!("Terminating.");
1921 Err(TryRecvError::Empty) => {}
1925 handles.push(handle);
1926 stops.push(stop_sender);
1929 bench.bench_function("get_secure_random_bytes", |b| b.iter(||
1930 keys_manager.get_secure_random_bytes()));
1933 let _ = stop.send(());
1935 for handle in handles {
1936 handle.join().unwrap();