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::bip32::{ChildNumber, ExtendedPrivKey, ExtendedPubKey};
16 use bitcoin::blockdata::locktime::absolute::LockTime;
17 use bitcoin::blockdata::opcodes;
18 use bitcoin::blockdata::script::{Builder, Script, ScriptBuf};
19 use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut};
20 use bitcoin::ecdsa::Signature as EcdsaSignature;
21 use bitcoin::network::constants::Network;
22 use bitcoin::psbt::PartiallySignedTransaction;
24 use bitcoin::sighash::EcdsaSighashType;
26 use bitcoin::bech32::u5;
27 use bitcoin::hash_types::WPubkeyHash;
28 use bitcoin::hashes::sha256::Hash as Sha256;
29 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
30 use bitcoin::hashes::{Hash, HashEngine};
32 use bitcoin::secp256k1::ecdh::SharedSecret;
33 use bitcoin::secp256k1::ecdsa::{RecoverableSignature, Signature};
34 use bitcoin::secp256k1::schnorr;
36 use bitcoin::secp256k1::All;
37 use bitcoin::secp256k1::{KeyPair, PublicKey, Scalar, Secp256k1, SecretKey, Signing};
38 use bitcoin::{secp256k1, Sequence, Txid, Witness};
40 use crate::chain::transaction::OutPoint;
41 use crate::crypto::utils::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
42 use crate::ln::chan_utils;
43 use crate::ln::chan_utils::{
44 get_revokeable_redeemscript, make_funding_redeemscript, ChannelPublicKeys,
45 ChannelTransactionParameters, ClosingTransaction, CommitmentTransaction,
46 HTLCOutputInCommitment, HolderCommitmentTransaction,
48 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
49 use crate::ln::channel_keys::{
50 add_public_key_tweak, DelayedPaymentBasepoint, DelayedPaymentKey, HtlcBasepoint, HtlcKey,
51 RevocationBasepoint, RevocationKey,
54 use crate::ln::msgs::PartialSignatureWithNonce;
55 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
56 use crate::ln::script::ShutdownScript;
57 use crate::ln::types::PaymentPreimage;
58 use crate::offers::invoice::UnsignedBolt12Invoice;
59 use crate::offers::invoice_request::UnsignedInvoiceRequest;
60 use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer};
61 use crate::util::transaction_utils;
63 use crate::crypto::chacha20::ChaCha20;
64 use crate::io::{self, Error};
65 use crate::ln::features::ChannelTypeFeatures;
66 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
67 use crate::prelude::*;
68 use crate::sign::ecdsa::EcdsaChannelSigner;
70 use crate::sign::taproot::TaprootChannelSigner;
71 use crate::util::atomic_counter::AtomicCounter;
72 use crate::util::invoice::construct_invoice_preimage;
73 use core::convert::TryInto;
75 use core::sync::atomic::{AtomicUsize, Ordering};
77 use musig2::types::{PartialSignature, PublicNonce};
79 pub(crate) mod type_resolver;
85 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
86 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
88 /// This is not exported to bindings users as we just use `[u8; 32]` directly
89 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
90 pub struct KeyMaterial(pub [u8; 32]);
92 /// Information about a spendable output to a P2WSH script.
94 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
95 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
96 pub struct DelayedPaymentOutputDescriptor {
97 /// The outpoint which is spendable.
98 pub outpoint: OutPoint,
99 /// Per commitment point to derive the delayed payment key by key holder.
100 pub per_commitment_point: PublicKey,
101 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
102 /// the witness_script.
103 pub to_self_delay: u16,
104 /// The output which is referenced by the given outpoint.
106 /// The revocation point specific to the commitment transaction which was broadcast. Used to
107 /// derive the witnessScript for this output.
108 pub revocation_pubkey: RevocationKey,
109 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
110 /// This may be useful in re-deriving keys used in the channel to spend the output.
111 pub channel_keys_id: [u8; 32],
112 /// The value of the channel which this output originated from, possibly indirectly.
113 pub channel_value_satoshis: u64,
114 /// The channel public keys and other parameters needed to generate a spending transaction or
115 /// to provide to a re-derived signer through [`ChannelSigner::provide_channel_parameters`].
117 /// Added as optional, but always `Some` if the descriptor was produced in v0.0.123 or later.
118 pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
121 impl DelayedPaymentOutputDescriptor {
122 /// The maximum length a well-formed witness spending one of these should have.
123 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
125 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
126 // redeemscript push length.
127 pub const MAX_WITNESS_LENGTH: u64 =
128 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH as u64 + 1;
131 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
132 (0, outpoint, required),
133 (2, per_commitment_point, required),
134 (4, to_self_delay, required),
135 (6, output, required),
136 (8, revocation_pubkey, required),
137 (10, channel_keys_id, required),
138 (12, channel_value_satoshis, required),
139 (13, channel_transaction_parameters, option),
142 pub(crate) const P2WPKH_WITNESS_WEIGHT: u64 = 1 /* num stack items */ +
144 73 /* sig including sighash flag */ +
145 1 /* pubkey length */ +
148 /// Witness weight for satisying a P2TR key-path spend.
149 pub(crate) const P2TR_KEY_PATH_WITNESS_WEIGHT: u64 = 1 /* witness items */
150 + 1 /* schnorr sig len */ + 64 /* schnorr sig */;
152 /// Information about a spendable output to our "payment key".
154 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
155 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
156 pub struct StaticPaymentOutputDescriptor {
157 /// The outpoint which is spendable.
158 pub outpoint: OutPoint,
159 /// The output which is referenced by the given outpoint.
161 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
162 /// This may be useful in re-deriving keys used in the channel to spend the output.
163 pub channel_keys_id: [u8; 32],
164 /// The value of the channel which this transactions spends.
165 pub channel_value_satoshis: u64,
166 /// The necessary channel parameters that need to be provided to the re-derived signer through
167 /// [`ChannelSigner::provide_channel_parameters`].
169 /// Added as optional, but always `Some` if the descriptor was produced in v0.0.117 or later.
170 pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
173 impl StaticPaymentOutputDescriptor {
174 /// Returns the `witness_script` of the spendable output.
176 /// Note that this will only return `Some` for [`StaticPaymentOutputDescriptor`]s that
177 /// originated from an anchor outputs channel, as they take the form of a P2WSH script.
178 pub fn witness_script(&self) -> Option<ScriptBuf> {
179 self.channel_transaction_parameters.as_ref().and_then(|channel_params| {
180 if channel_params.supports_anchors() {
181 let payment_point = channel_params.holder_pubkeys.payment_point;
182 Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
189 /// The maximum length a well-formed witness spending one of these should have.
190 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
192 pub fn max_witness_length(&self) -> u64 {
193 if self.channel_transaction_parameters.as_ref().map_or(false, |p| p.supports_anchors()) {
194 let witness_script_weight = 1 /* pubkey push */ + 33 /* pubkey */ +
195 1 /* OP_CHECKSIGVERIFY */ + 1 /* OP_1 */ + 1 /* OP_CHECKSEQUENCEVERIFY */;
196 1 /* num witness items */ + 1 /* sig push */ + 73 /* sig including sighash flag */ +
197 1 /* witness script push */ + witness_script_weight
199 P2WPKH_WITNESS_WEIGHT
203 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
204 (0, outpoint, required),
205 (2, output, required),
206 (4, channel_keys_id, required),
207 (6, channel_value_satoshis, required),
208 (7, channel_transaction_parameters, option),
211 /// Describes the necessary information to spend a spendable output.
213 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
214 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
215 /// to spend on-chain. The information needed to do this is provided in this enum, including the
216 /// outpoint describing which `txid` and output `index` is available, the full output which exists
217 /// at that `txid`/`index`, and any keys or other information required to sign.
219 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
220 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
221 pub enum SpendableOutputDescriptor {
222 /// An output to a script which was provided via [`SignerProvider`] directly, either from
223 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
224 /// know how to spend it. No secret keys are provided as LDK was never given any key.
225 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
226 /// on-chain using the payment preimage or after it has timed out.
228 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
229 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
231 /// The outpoint which is spendable.
233 /// The output which is referenced by the given outpoint.
235 /// The `channel_keys_id` for the channel which this output came from.
237 /// For channels which were generated on LDK 0.0.119 or later, this is the value which was
238 /// passed to the [`SignerProvider::get_destination_script`] call which provided this
241 /// For channels which were generated prior to LDK 0.0.119, no such argument existed,
242 /// however this field may still be filled in if such data is available.
243 channel_keys_id: Option<[u8; 32]>,
245 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
248 /// The witness in the spending input should be:
250 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
253 /// Note that the `nSequence` field in the spending input must be set to
254 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
255 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
256 /// the outpoint confirms, see [BIP
257 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
258 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
261 /// These are generally the result of a "revocable" output to us, spendable only by us unless
262 /// it is an output from an old state which we broadcast (which should never happen).
264 /// To derive the delayed payment key which is used to sign this input, you must pass the
265 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
266 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
267 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The DelayedPaymentKey can be
268 /// generated without the secret key using [`DelayedPaymentKey::from_basepoint`] and only the
269 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
271 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
272 /// used in the witness script generation), you must pass the counterparty
273 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
274 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
275 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
276 /// [`RevocationKey`].
278 /// The witness script which is hashed and included in the output `script_pubkey` may be
279 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
280 /// as explained above), our delayed payment pubkey (derived as explained above), and the
281 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
282 /// [`chan_utils::get_revokeable_redeemscript`].
283 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
284 /// An output spendable exclusively by our payment key (i.e., the private key that corresponds
285 /// to the `payment_point` in [`ChannelSigner::pubkeys`]). The output type depends on the
286 /// channel type negotiated.
288 /// On an anchor outputs channel, the witness in the spending input is:
290 /// <BIP 143 signature> <witness script>
293 /// Otherwise, it is:
295 /// <BIP 143 signature> <payment key>
298 /// These are generally the result of our counterparty having broadcast the current state,
299 /// allowing us to claim the non-HTLC-encumbered outputs immediately, or after one confirmation
300 /// in the case of anchor outputs channels.
301 StaticPaymentOutput(StaticPaymentOutputDescriptor),
304 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
305 (0, StaticOutput) => {
306 (0, outpoint, required),
307 (1, channel_keys_id, option),
308 (2, output, required),
311 (1, DelayedPaymentOutput),
312 (2, StaticPaymentOutput),
315 impl SpendableOutputDescriptor {
316 /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
317 /// [`PartiallySignedTransaction`] which spends the given descriptor.
319 /// Note that this does not include any signatures, just the information required to
320 /// construct the transaction and sign it.
322 /// This is not exported to bindings users as there is no standard serialization for an input.
323 /// See [`Self::create_spendable_outputs_psbt`] instead.
325 /// The proprietary field is used to store add tweak for the signing key of this transaction.
326 /// See the [`DelayedPaymentBasepoint::derive_add_tweak`] docs for more info on add tweak and how to use it.
328 /// To get the proprietary field use:
330 /// use bitcoin::psbt::{PartiallySignedTransaction};
331 /// use bitcoin::hashes::hex::FromHex;
333 /// # let s = "70736274ff0100520200000001dee978529ab3e61a2987bea5183713d0e6d5ceb5ac81100fdb54a1a2\
334 /// # 69cef505000000000090000000011f26000000000000160014abb3ab63280d4ccc5c11d6b50fd427a8\
335 /// # e19d6470000000000001012b10270000000000002200200afe4736760d814a2651bae63b572d935d9a\
336 /// # b74a1a16c01774e341a32afa763601054d63210394a27a700617f5b7aee72bd4f8076b5770a582b7fb\
337 /// # d1d4ee2ea3802cd3cfbe2067029000b27521034629b1c8fdebfaeb58a74cd181f485e2c462e594cb30\
338 /// # 34dee655875f69f6c7c968ac20fc144c444b5f7370656e6461626c655f6f7574707574006164645f74\
339 /// # 7765616b20a86534f38ad61dc580ef41c3886204adf0911b81619c1ad7a2f5b5de39a2ba600000";
340 /// # let psbt = PartiallySignedTransaction::deserialize(<Vec<u8> as FromHex>::from_hex(s).unwrap().as_slice()).unwrap();
341 /// let key = bitcoin::psbt::raw::ProprietaryKey {
342 /// prefix: "LDK_spendable_output".as_bytes().to_vec(),
344 /// key: "add_tweak".as_bytes().to_vec(),
349 /// .expect("Unable to get add tweak as there are no inputs")
352 /// .map(|x| x.to_owned());
354 pub fn to_psbt_input<T: secp256k1::Signing>(
355 &self, secp_ctx: &Secp256k1<T>,
356 ) -> bitcoin::psbt::Input {
358 SpendableOutputDescriptor::StaticOutput { output, .. } => {
359 // Is a standard P2WPKH, no need for witness script
360 bitcoin::psbt::Input { witness_utxo: Some(output.clone()), ..Default::default() }
362 SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
363 channel_transaction_parameters,
364 per_commitment_point,
370 let delayed_payment_basepoint = channel_transaction_parameters
372 .map(|params| params.holder_pubkeys.delayed_payment_basepoint);
374 let (witness_script, add_tweak) =
375 if let Some(basepoint) = delayed_payment_basepoint.as_ref() {
376 // Required to derive signing key: privkey = basepoint_secret + SHA256(per_commitment_point || basepoint)
377 let add_tweak = basepoint.derive_add_tweak(&per_commitment_point);
378 let payment_key = DelayedPaymentKey(add_public_key_tweak(
380 &basepoint.to_public_key(),
385 Some(get_revokeable_redeemscript(
396 bitcoin::psbt::Input {
397 witness_utxo: Some(output.clone()),
399 proprietary: add_tweak
402 bitcoin::psbt::raw::ProprietaryKey {
403 // A non standard namespace for spendable outputs, used to store the tweak needed
404 // to derive the private key
405 prefix: "LDK_spendable_output".as_bytes().to_vec(),
407 key: "add_tweak".as_bytes().to_vec(),
409 add_tweak.as_byte_array().to_vec(),
414 .unwrap_or_default(),
418 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => bitcoin::psbt::Input {
419 witness_utxo: Some(descriptor.output.clone()),
420 witness_script: descriptor.witness_script(),
426 /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
427 /// the given outputs, plus an output to the given change destination (if sufficient
428 /// change value remains). The PSBT will have a feerate, at least, of the given value.
430 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
431 /// transaction will have a locktime of 0. It it recommended to set this to the current block
432 /// height to avoid fee sniping, unless you have some specific reason to use a different
435 /// Returns the PSBT and expected max transaction weight.
437 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
438 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
439 /// does not match the one we can spend.
441 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
442 pub fn create_spendable_outputs_psbt<T: secp256k1::Signing>(
443 secp_ctx: &Secp256k1<T>, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
444 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
445 locktime: Option<LockTime>,
446 ) -> Result<(PartiallySignedTransaction, u64), ()> {
447 let mut input = Vec::with_capacity(descriptors.len());
448 let mut input_value = 0;
449 let mut witness_weight = 0;
450 let mut output_set = hash_set_with_capacity(descriptors.len());
451 for outp in descriptors {
453 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
454 if !output_set.insert(descriptor.outpoint) {
457 let sequence = if descriptor
458 .channel_transaction_parameters
460 .map_or(false, |p| p.supports_anchors())
462 Sequence::from_consensus(1)
467 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
468 script_sig: ScriptBuf::new(),
470 witness: Witness::new(),
472 witness_weight += descriptor.max_witness_length();
473 #[cfg(feature = "grind_signatures")]
475 // Guarantees a low R signature
478 input_value += descriptor.output.value;
480 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
481 if !output_set.insert(descriptor.outpoint) {
485 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
486 script_sig: ScriptBuf::new(),
487 sequence: Sequence(descriptor.to_self_delay as u32),
488 witness: Witness::new(),
490 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
491 #[cfg(feature = "grind_signatures")]
493 // Guarantees a low R signature
496 input_value += descriptor.output.value;
498 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
499 if !output_set.insert(*outpoint) {
503 previous_output: outpoint.into_bitcoin_outpoint(),
504 script_sig: ScriptBuf::new(),
505 sequence: Sequence::ZERO,
506 witness: Witness::new(),
508 witness_weight += 1 + 73 + 34;
509 #[cfg(feature = "grind_signatures")]
511 // Guarantees a low R signature
514 input_value += output.value;
517 if input_value > MAX_VALUE_MSAT / 1000 {
521 let mut tx = Transaction {
523 lock_time: locktime.unwrap_or(LockTime::ZERO),
527 let expected_max_weight = transaction_utils::maybe_add_change_output(
531 feerate_sat_per_1000_weight,
532 change_destination_script,
536 descriptors.iter().map(|d| d.to_psbt_input(&secp_ctx)).collect::<Vec<_>>();
537 let psbt = PartiallySignedTransaction {
539 outputs: vec![Default::default(); tx.output.len()],
541 xpub: Default::default(),
543 proprietary: Default::default(),
544 unknown: Default::default(),
546 Ok((psbt, expected_max_weight))
550 /// The parameters required to derive a channel signer via [`SignerProvider`].
551 #[derive(Clone, Debug, PartialEq, Eq)]
552 pub struct ChannelDerivationParameters {
553 /// The value in satoshis of the channel we're attempting to spend the anchor output of.
554 pub value_satoshis: u64,
555 /// The unique identifier to re-derive the signer for the associated channel.
556 pub keys_id: [u8; 32],
557 /// The necessary channel parameters that need to be provided to the re-derived signer through
558 /// [`ChannelSigner::provide_channel_parameters`].
559 pub transaction_parameters: ChannelTransactionParameters,
562 impl_writeable_tlv_based!(ChannelDerivationParameters, {
563 (0, value_satoshis, required),
564 (2, keys_id, required),
565 (4, transaction_parameters, required),
568 /// A descriptor used to sign for a commitment transaction's HTLC output.
569 #[derive(Clone, Debug, PartialEq, Eq)]
570 pub struct HTLCDescriptor {
571 /// The parameters required to derive the signer for the HTLC input.
572 pub channel_derivation_parameters: ChannelDerivationParameters,
573 /// The txid of the commitment transaction in which the HTLC output lives.
574 pub commitment_txid: Txid,
575 /// The number of the commitment transaction in which the HTLC output lives.
576 pub per_commitment_number: u64,
577 /// The key tweak corresponding to the number of the commitment transaction in which the HTLC
578 /// output lives. This tweak is applied to all the basepoints for both parties in the channel to
579 /// arrive at unique keys per commitment.
581 /// See <https://github.com/lightning/bolts/blob/master/03-transactions.md#keys> for more info.
582 pub per_commitment_point: PublicKey,
583 /// The feerate to use on the HTLC claiming transaction. This is always `0` for HTLCs
584 /// originating from a channel supporting anchor outputs, otherwise it is the channel's
585 /// negotiated feerate at the time the commitment transaction was built.
586 pub feerate_per_kw: u32,
587 /// The details of the HTLC as it appears in the commitment transaction.
588 pub htlc: HTLCOutputInCommitment,
589 /// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
591 pub preimage: Option<PaymentPreimage>,
592 /// The counterparty's signature required to spend the HTLC output.
593 pub counterparty_sig: Signature,
596 impl_writeable_tlv_based!(HTLCDescriptor, {
597 (0, channel_derivation_parameters, required),
598 (1, feerate_per_kw, (default_value, 0)),
599 (2, commitment_txid, required),
600 (4, per_commitment_number, required),
601 (6, per_commitment_point, required),
603 (10, preimage, option),
604 (12, counterparty_sig, required),
607 impl HTLCDescriptor {
608 /// Returns the outpoint of the HTLC output in the commitment transaction. This is the outpoint
609 /// being spent by the HTLC input in the HTLC transaction.
610 pub fn outpoint(&self) -> bitcoin::OutPoint {
612 txid: self.commitment_txid,
613 vout: self.htlc.transaction_output_index.unwrap(),
617 /// Returns the UTXO to be spent by the HTLC input, which can be obtained via
618 /// [`Self::unsigned_tx_input`].
619 pub fn previous_utxo<C: secp256k1::Signing + secp256k1::Verification>(
620 &self, secp: &Secp256k1<C>,
623 script_pubkey: self.witness_script(secp).to_v0_p2wsh(),
624 value: self.htlc.amount_msat / 1000,
628 /// Returns the unsigned transaction input spending the HTLC output in the commitment
630 pub fn unsigned_tx_input(&self) -> TxIn {
631 chan_utils::build_htlc_input(
632 &self.commitment_txid,
634 &self.channel_derivation_parameters.transaction_parameters.channel_type_features,
638 /// Returns the delayed output created as a result of spending the HTLC output in the commitment
640 pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(
641 &self, secp: &Secp256k1<C>,
644 self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
645 let broadcaster_keys = channel_params.broadcaster_pubkeys();
646 let counterparty_keys = channel_params.countersignatory_pubkeys();
647 let broadcaster_delayed_key = DelayedPaymentKey::from_basepoint(
649 &broadcaster_keys.delayed_payment_basepoint,
650 &self.per_commitment_point,
652 let counterparty_revocation_key = &RevocationKey::from_basepoint(
654 &counterparty_keys.revocation_basepoint,
655 &self.per_commitment_point,
657 chan_utils::build_htlc_output(
659 channel_params.contest_delay(),
661 channel_params.channel_type_features(),
662 &broadcaster_delayed_key,
663 &counterparty_revocation_key,
667 /// Returns the witness script of the HTLC output in the commitment transaction.
668 pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(
669 &self, secp: &Secp256k1<C>,
672 self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
673 let broadcaster_keys = channel_params.broadcaster_pubkeys();
674 let counterparty_keys = channel_params.countersignatory_pubkeys();
675 let broadcaster_htlc_key = HtlcKey::from_basepoint(
677 &broadcaster_keys.htlc_basepoint,
678 &self.per_commitment_point,
680 let counterparty_htlc_key = HtlcKey::from_basepoint(
682 &counterparty_keys.htlc_basepoint,
683 &self.per_commitment_point,
685 let counterparty_revocation_key = &RevocationKey::from_basepoint(
687 &counterparty_keys.revocation_basepoint,
688 &self.per_commitment_point,
690 chan_utils::get_htlc_redeemscript_with_explicit_keys(
692 channel_params.channel_type_features(),
693 &broadcaster_htlc_key,
694 &counterparty_htlc_key,
695 &counterparty_revocation_key,
699 /// Returns the fully signed witness required to spend the HTLC output in the commitment
701 pub fn tx_input_witness(&self, signature: &Signature, witness_script: &Script) -> Witness {
702 chan_utils::build_htlc_input_witness(
704 &self.counterparty_sig,
707 &self.channel_derivation_parameters.transaction_parameters.channel_type_features,
711 /// Derives the channel signer required to sign the HTLC input.
712 pub fn derive_channel_signer<S: EcdsaChannelSigner, SP: Deref>(&self, signer_provider: &SP) -> S
714 SP::Target: SignerProvider<EcdsaSigner = S>,
716 let mut signer = signer_provider.derive_channel_signer(
717 self.channel_derivation_parameters.value_satoshis,
718 self.channel_derivation_parameters.keys_id,
721 .provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
726 /// A trait to handle Lightning channel key material without concretizing the channel type or
727 /// the signature mechanism.
728 pub trait ChannelSigner {
729 /// Gets the per-commitment point for a specific commitment number
731 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
732 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>)
735 /// Gets the commitment secret for a specific commitment number as part of the revocation process
737 /// An external signer implementation should error here if the commitment was already signed
738 /// and should refuse to sign it in the future.
740 /// May be called more than once for the same index.
742 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
743 // TODO: return a Result so we can signal a validation error
744 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
746 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
748 /// This is required in order for the signer to make sure that releasing a commitment
749 /// secret won't leave us without a broadcastable holder transaction.
750 /// Policy checks should be implemented in this function, including checking the amount
751 /// sent to us and checking the HTLCs.
753 /// The preimages of outbound HTLCs that were fulfilled since the last commitment are provided.
754 /// A validating signer should ensure that an HTLC output is removed only when the matching
755 /// preimage is provided, or when the value to holder is restored.
757 /// Note that all the relevant preimages will be provided, but there may also be additional
758 /// irrelevant or duplicate preimages.
759 fn validate_holder_commitment(
760 &self, holder_tx: &HolderCommitmentTransaction,
761 outbound_htlc_preimages: Vec<PaymentPreimage>,
764 /// Validate the counterparty's revocation.
766 /// This is required in order for the signer to make sure that the state has moved
767 /// forward and it is safe to sign the next counterparty commitment.
768 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
770 /// Returns the holder's channel public keys and basepoints.
771 fn pubkeys(&self) -> &ChannelPublicKeys;
773 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
774 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
775 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
776 fn channel_keys_id(&self) -> [u8; 32];
778 /// Set the counterparty static channel data, including basepoints,
779 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
781 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
782 /// instance, LDK will call this method exactly once - either immediately after construction
783 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
784 /// information has been generated.
786 /// channel_parameters.is_populated() MUST be true.
787 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
790 /// Specifies the recipient of an invoice.
792 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
795 /// The invoice should be signed with the local node secret key.
797 /// The invoice should be signed with the phantom node secret key. This secret key must be the
798 /// same for all nodes participating in the [phantom node payment].
800 /// [phantom node payment]: PhantomKeysManager
804 /// A trait that describes a source of entropy.
805 pub trait EntropySource {
806 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
807 /// different value each time it is called.
808 fn get_secure_random_bytes(&self) -> [u8; 32];
811 /// A trait that can handle cryptographic operations at the scope level of a node.
812 pub trait NodeSigner {
813 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
815 /// If the implementor of this trait supports [phantom node payments], then every node that is
816 /// intended to be included in the phantom invoice route hints must return the same value from
818 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
819 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
820 // nodes, they must share the key that encrypts this payment data.
822 /// This method must return the same value each time it is called.
824 /// [phantom node payments]: PhantomKeysManager
825 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
827 /// Get node id based on the provided [`Recipient`].
829 /// This method must return the same value each time it is called with a given [`Recipient`]
832 /// Errors if the [`Recipient`] variant is not supported by the implementation.
833 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
835 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
836 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
837 /// secret, though this is less efficient.
839 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
840 /// should be resolved to allow LDK to resume forwarding HTLCs.
842 /// Errors if the [`Recipient`] variant is not supported by the implementation.
844 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
845 ) -> Result<SharedSecret, ()>;
849 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
850 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
851 /// blindly signing the hash.
853 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
855 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
857 /// Errors if the [`Recipient`] variant is not supported by the implementation.
859 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
860 ) -> Result<RecoverableSignature, ()>;
862 /// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
864 /// May be called by a function passed to [`UnsignedInvoiceRequest::sign`] where
865 /// `invoice_request` is the callee.
867 /// Implementors may check that the `invoice_request` is expected rather than blindly signing
868 /// the tagged hash. An `Ok` result should sign `invoice_request.tagged_hash().as_digest()` with
869 /// the node's signing key or an ephemeral key to preserve privacy, whichever is associated with
870 /// [`UnsignedInvoiceRequest::payer_id`].
872 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
873 fn sign_bolt12_invoice_request(
874 &self, invoice_request: &UnsignedInvoiceRequest,
875 ) -> Result<schnorr::Signature, ()>;
877 /// Signs the [`TaggedHash`] of a BOLT 12 invoice.
879 /// May be called by a function passed to [`UnsignedBolt12Invoice::sign`] where `invoice` is the
882 /// Implementors may check that the `invoice` is expected rather than blindly signing the tagged
883 /// hash. An `Ok` result should sign `invoice.tagged_hash().as_digest()` with the node's signing
884 /// key or an ephemeral key to preserve privacy, whichever is associated with
885 /// [`UnsignedBolt12Invoice::signing_pubkey`].
887 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
888 fn sign_bolt12_invoice(
889 &self, invoice: &UnsignedBolt12Invoice,
890 ) -> Result<schnorr::Signature, ()>;
892 /// Sign a gossip message.
894 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
895 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
896 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
897 /// corresponding channel.
898 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
901 /// A trait that describes a wallet capable of creating a spending [`Transaction`] from a set of
902 /// [`SpendableOutputDescriptor`]s.
903 pub trait OutputSpender {
904 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
905 /// output to the given change destination (if sufficient change value remains). The
906 /// transaction will have a feerate, at least, of the given value.
908 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
909 /// transaction will have a locktime of 0. It it recommended to set this to the current block
910 /// height to avoid fee sniping, unless you have some specific reason to use a different
913 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
914 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
915 /// does not match the one we can spend.
916 fn spend_spendable_outputs<C: Signing>(
917 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
918 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
919 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
920 ) -> Result<Transaction, ()>;
923 // Primarily needed in doctests because of https://github.com/rust-lang/rust/issues/67295
924 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
926 /// This is not exported to bindings users as it is not intended for public consumption.
929 #[deprecated(note = "Remove once taproot cfg is removed")]
930 pub type DynSignerProvider =
931 dyn SignerProvider<EcdsaSigner = InMemorySigner, TaprootSigner = InMemorySigner>;
933 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
935 /// This is not exported to bindings users as it is not intended for public consumption.
938 #[deprecated(note = "Remove once taproot cfg is removed")]
939 pub type DynSignerProvider = dyn SignerProvider<EcdsaSigner = InMemorySigner>;
941 /// A trait that can return signer instances for individual channels.
942 pub trait SignerProvider {
943 /// A type which implements [`EcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
944 type EcdsaSigner: EcdsaChannelSigner;
946 /// A type which implements [`TaprootChannelSigner`]
947 type TaprootSigner: TaprootChannelSigner;
949 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::EcdsaSigner`] through
950 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
951 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
952 /// `channel_keys_id`.
954 /// This method must return a different value each time it is called.
955 fn generate_channel_keys_id(
956 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
959 /// Derives the private key material backing a `Signer`.
961 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
962 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
963 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
964 /// [`ChannelSigner::channel_keys_id`].
965 fn derive_channel_signer(
966 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
967 ) -> Self::EcdsaSigner;
969 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
970 /// This is only called during deserialization of other objects which contain
971 /// [`EcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
972 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
973 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
974 /// you've read all of the provided bytes to ensure no corruption occurred.
976 /// This method is slowly being phased out -- it will only be called when reading objects
977 /// written by LDK versions prior to 0.0.113.
979 /// [`Signer`]: Self::EcdsaSigner
980 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
981 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
982 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError>;
984 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
986 /// If this function returns an error, this will result in a channel failing to open.
988 /// This method should return a different value each time it is called, to avoid linking
989 /// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
990 /// used to derive a unique value for each channel.
991 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
993 /// Get a script pubkey which we will send funds to when closing a channel.
995 /// If this function returns an error, this will result in a channel failing to open or close.
996 /// In the event of a failure when the counterparty is initiating a close, this can result in a
997 /// channel force close.
999 /// This method should return a different value each time it is called, to avoid linking
1000 /// on-chain funds across channels as controlled to the same user.
1001 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
1004 /// A helper trait that describes an on-chain wallet capable of returning a (change) destination
1006 pub trait ChangeDestinationSource {
1007 /// Returns a script pubkey which can be used as a change destination for
1008 /// [`OutputSpender::spend_spendable_outputs`].
1010 /// This method should return a different value each time it is called, to avoid linking
1011 /// on-chain funds controlled to the same user.
1012 fn get_change_destination_script(&self) -> Result<ScriptBuf, ()>;
1015 /// A simple implementation of [`EcdsaChannelSigner`] that just keeps the private keys in memory.
1017 /// This implementation performs no policy checks and is insufficient by itself as
1018 /// a secure external signer.
1020 pub struct InMemorySigner {
1021 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
1022 /// holder's anchor output in a commitment transaction, if one is present.
1023 pub funding_key: SecretKey,
1024 /// Holder secret key for blinded revocation pubkey.
1025 pub revocation_base_key: SecretKey,
1026 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
1027 pub payment_key: SecretKey,
1028 /// Holder secret key used in an HTLC transaction.
1029 pub delayed_payment_base_key: SecretKey,
1030 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
1031 pub htlc_base_key: SecretKey,
1032 /// Commitment seed.
1033 pub commitment_seed: [u8; 32],
1034 /// Holder public keys and basepoints.
1035 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
1036 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
1037 channel_parameters: Option<ChannelTransactionParameters>,
1038 /// The total value of this channel.
1039 channel_value_satoshis: u64,
1040 /// Key derivation parameters.
1041 channel_keys_id: [u8; 32],
1042 /// A source of random bytes.
1043 entropy_source: RandomBytes,
1046 impl PartialEq for InMemorySigner {
1047 fn eq(&self, other: &Self) -> bool {
1048 self.funding_key == other.funding_key
1049 && self.revocation_base_key == other.revocation_base_key
1050 && self.payment_key == other.payment_key
1051 && self.delayed_payment_base_key == other.delayed_payment_base_key
1052 && self.htlc_base_key == other.htlc_base_key
1053 && self.commitment_seed == other.commitment_seed
1054 && self.holder_channel_pubkeys == other.holder_channel_pubkeys
1055 && self.channel_parameters == other.channel_parameters
1056 && self.channel_value_satoshis == other.channel_value_satoshis
1057 && self.channel_keys_id == other.channel_keys_id
1061 impl Clone for InMemorySigner {
1062 fn clone(&self) -> Self {
1064 funding_key: self.funding_key.clone(),
1065 revocation_base_key: self.revocation_base_key.clone(),
1066 payment_key: self.payment_key.clone(),
1067 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
1068 htlc_base_key: self.htlc_base_key.clone(),
1069 commitment_seed: self.commitment_seed.clone(),
1070 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
1071 channel_parameters: self.channel_parameters.clone(),
1072 channel_value_satoshis: self.channel_value_satoshis,
1073 channel_keys_id: self.channel_keys_id,
1074 entropy_source: RandomBytes::new(self.get_secure_random_bytes()),
1079 impl InMemorySigner {
1080 /// Creates a new [`InMemorySigner`].
1081 pub fn new<C: Signing>(
1082 secp_ctx: &Secp256k1<C>, funding_key: SecretKey, revocation_base_key: SecretKey,
1083 payment_key: SecretKey, delayed_payment_base_key: SecretKey, htlc_base_key: SecretKey,
1084 commitment_seed: [u8; 32], channel_value_satoshis: u64, channel_keys_id: [u8; 32],
1085 rand_bytes_unique_start: [u8; 32],
1086 ) -> InMemorySigner {
1087 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1090 &revocation_base_key,
1092 &delayed_payment_base_key,
1097 revocation_base_key,
1099 delayed_payment_base_key,
1102 channel_value_satoshis,
1103 holder_channel_pubkeys,
1104 channel_parameters: None,
1106 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1110 fn make_holder_keys<C: Signing>(
1111 secp_ctx: &Secp256k1<C>, funding_key: &SecretKey, revocation_base_key: &SecretKey,
1112 payment_key: &SecretKey, delayed_payment_base_key: &SecretKey, htlc_base_key: &SecretKey,
1113 ) -> ChannelPublicKeys {
1114 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
1116 funding_pubkey: from_secret(&funding_key),
1117 revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
1118 payment_point: from_secret(&payment_key),
1119 delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(
1120 &delayed_payment_base_key,
1122 htlc_basepoint: HtlcBasepoint::from(from_secret(&htlc_base_key)),
1126 /// Returns the counterparty's pubkeys.
1128 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1129 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1130 pub fn counterparty_pubkeys(&self) -> Option<&ChannelPublicKeys> {
1131 self.get_channel_parameters().and_then(|params| {
1132 params.counterparty_parameters.as_ref().map(|params| ¶ms.pubkeys)
1136 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
1137 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
1138 /// broadcast a transaction.
1140 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1141 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1142 pub fn counterparty_selected_contest_delay(&self) -> Option<u16> {
1143 self.get_channel_parameters().and_then(|params| {
1144 params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay)
1148 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
1149 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
1150 /// if they broadcast a transaction.
1152 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1153 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1154 pub fn holder_selected_contest_delay(&self) -> Option<u16> {
1155 self.get_channel_parameters().map(|params| params.holder_selected_contest_delay)
1158 /// Returns whether the holder is the initiator.
1160 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1161 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1162 pub fn is_outbound(&self) -> Option<bool> {
1163 self.get_channel_parameters().map(|params| params.is_outbound_from_holder)
1166 /// Funding outpoint
1168 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1169 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1170 pub fn funding_outpoint(&self) -> Option<&OutPoint> {
1171 self.get_channel_parameters().map(|params| params.funding_outpoint.as_ref()).flatten()
1174 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
1175 /// building transactions.
1177 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1178 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1179 pub fn get_channel_parameters(&self) -> Option<&ChannelTransactionParameters> {
1180 self.channel_parameters.as_ref()
1183 /// Returns the channel type features of the channel parameters. Should be helpful for
1184 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
1186 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1187 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1188 pub fn channel_type_features(&self) -> Option<&ChannelTypeFeatures> {
1189 self.get_channel_parameters().map(|params| ¶ms.channel_type_features)
1192 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
1193 /// by `descriptor`, returning the witness stack for the input.
1195 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1196 /// is not spending the outpoint described by [`descriptor.outpoint`],
1197 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
1199 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
1200 pub fn sign_counterparty_payment_input<C: Signing>(
1201 &self, spend_tx: &Transaction, input_idx: usize,
1202 descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1203 ) -> Result<Witness, ()> {
1204 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1205 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1206 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1207 // bindings updates to support SigHashCache objects).
1208 if spend_tx.input.len() <= input_idx {
1211 if !spend_tx.input[input_idx].script_sig.is_empty() {
1214 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1219 let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
1220 // We cannot always assume that `channel_parameters` is set, so can't just call
1221 // `self.channel_parameters()` or anything that relies on it
1222 let supports_anchors_zero_fee_htlc_tx = self
1223 .channel_type_features()
1224 .map(|features| features.supports_anchors_zero_fee_htlc_tx())
1227 let witness_script = if supports_anchors_zero_fee_htlc_tx {
1228 chan_utils::get_to_countersignatory_with_anchors_redeemscript(&remotepubkey.inner)
1230 ScriptBuf::new_p2pkh(&remotepubkey.pubkey_hash())
1232 let sighash = hash_to_message!(
1233 &sighash::SighashCache::new(spend_tx)
1234 .segwit_signature_hash(
1237 descriptor.output.value,
1238 EcdsaSighashType::All
1242 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
1243 let payment_script = if supports_anchors_zero_fee_htlc_tx {
1244 witness_script.to_v0_p2wsh()
1246 ScriptBuf::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
1249 if payment_script != descriptor.output.script_pubkey {
1253 let mut witness = Vec::with_capacity(2);
1254 witness.push(remotesig.serialize_der().to_vec());
1255 witness[0].push(EcdsaSighashType::All as u8);
1256 if supports_anchors_zero_fee_htlc_tx {
1257 witness.push(witness_script.to_bytes());
1259 witness.push(remotepubkey.to_bytes());
1264 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
1265 /// described by `descriptor`, returning the witness stack for the input.
1267 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1268 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
1269 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
1270 /// `script_pubkey` does not match the one we can spend.
1272 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
1273 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
1274 pub fn sign_dynamic_p2wsh_input<C: Signing>(
1275 &self, spend_tx: &Transaction, input_idx: usize,
1276 descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1277 ) -> Result<Witness, ()> {
1278 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1279 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1280 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1281 // bindings updates to support SigHashCache objects).
1282 if spend_tx.input.len() <= input_idx {
1285 if !spend_tx.input[input_idx].script_sig.is_empty() {
1288 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1292 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 {
1296 let delayed_payment_key = chan_utils::derive_private_key(
1298 &descriptor.per_commitment_point,
1299 &self.delayed_payment_base_key,
1301 let delayed_payment_pubkey =
1302 DelayedPaymentKey::from_secret_key(&secp_ctx, &delayed_payment_key);
1303 let witness_script = chan_utils::get_revokeable_redeemscript(
1304 &descriptor.revocation_pubkey,
1305 descriptor.to_self_delay,
1306 &delayed_payment_pubkey,
1308 let sighash = hash_to_message!(
1309 &sighash::SighashCache::new(spend_tx)
1310 .segwit_signature_hash(
1313 descriptor.output.value,
1314 EcdsaSighashType::All
1318 let local_delayedsig = EcdsaSignature {
1319 sig: sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self),
1320 hash_ty: EcdsaSighashType::All,
1322 let payment_script =
1323 bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
1325 if descriptor.output.script_pubkey != payment_script {
1329 Ok(Witness::from_slice(&[
1330 &local_delayedsig.serialize()[..],
1332 witness_script.as_bytes(),
1337 impl EntropySource for InMemorySigner {
1338 fn get_secure_random_bytes(&self) -> [u8; 32] {
1339 self.entropy_source.get_secure_random_bytes()
1343 impl ChannelSigner for InMemorySigner {
1344 fn get_per_commitment_point(
1345 &self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>,
1347 let commitment_secret =
1348 SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx))
1350 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
1353 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
1354 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
1357 fn validate_holder_commitment(
1358 &self, _holder_tx: &HolderCommitmentTransaction,
1359 _outbound_htlc_preimages: Vec<PaymentPreimage>,
1360 ) -> Result<(), ()> {
1364 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
1368 fn pubkeys(&self) -> &ChannelPublicKeys {
1369 &self.holder_channel_pubkeys
1372 fn channel_keys_id(&self) -> [u8; 32] {
1373 self.channel_keys_id
1376 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
1378 self.channel_parameters.is_none()
1379 || self.channel_parameters.as_ref().unwrap() == channel_parameters
1381 if self.channel_parameters.is_some() {
1382 // The channel parameters were already set and they match, return early.
1385 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
1386 self.channel_parameters = Some(channel_parameters.clone());
1390 const MISSING_PARAMS_ERR: &'static str =
1391 "ChannelSigner::provide_channel_parameters must be called before signing operations";
1393 impl EcdsaChannelSigner for InMemorySigner {
1394 fn sign_counterparty_commitment(
1395 &self, commitment_tx: &CommitmentTransaction,
1396 _inbound_htlc_preimages: Vec<PaymentPreimage>,
1397 _outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>,
1398 ) -> Result<(Signature, Vec<Signature>), ()> {
1399 let trusted_tx = commitment_tx.trust();
1400 let keys = trusted_tx.keys();
1402 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1403 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1404 let channel_funding_redeemscript =
1405 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1407 let built_tx = trusted_tx.built_transaction();
1408 let commitment_sig = built_tx.sign_counterparty_commitment(
1410 &channel_funding_redeemscript,
1411 self.channel_value_satoshis,
1414 let commitment_txid = built_tx.txid;
1416 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
1417 for htlc in commitment_tx.htlcs() {
1418 let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
1419 let holder_selected_contest_delay =
1420 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1421 let chan_type = &channel_parameters.channel_type_features;
1422 let htlc_tx = chan_utils::build_htlc_transaction(
1424 commitment_tx.feerate_per_kw(),
1425 holder_selected_contest_delay,
1428 &keys.broadcaster_delayed_payment_key,
1429 &keys.revocation_key,
1431 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, chan_type, &keys);
1432 let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() {
1433 EcdsaSighashType::SinglePlusAnyoneCanPay
1435 EcdsaSighashType::All
1437 let htlc_sighash = hash_to_message!(
1438 &sighash::SighashCache::new(&htlc_tx)
1439 .segwit_signature_hash(
1442 htlc.amount_msat / 1000,
1447 let holder_htlc_key = chan_utils::derive_private_key(
1449 &keys.per_commitment_point,
1450 &self.htlc_base_key,
1452 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
1455 Ok((commitment_sig, htlc_sigs))
1458 fn sign_holder_commitment(
1459 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1460 ) -> Result<Signature, ()> {
1461 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1462 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1463 let funding_redeemscript =
1464 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1465 let trusted_tx = commitment_tx.trust();
1466 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1468 &funding_redeemscript,
1469 self.channel_value_satoshis,
1475 #[cfg(any(test, feature = "unsafe_revoked_tx_signing"))]
1476 fn unsafe_sign_holder_commitment(
1477 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1478 ) -> Result<Signature, ()> {
1479 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1480 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1481 let funding_redeemscript =
1482 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1483 let trusted_tx = commitment_tx.trust();
1484 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1486 &funding_redeemscript,
1487 self.channel_value_satoshis,
1493 fn sign_justice_revoked_output(
1494 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1495 secp_ctx: &Secp256k1<secp256k1::All>,
1496 ) -> Result<Signature, ()> {
1497 let revocation_key = chan_utils::derive_private_revocation_key(
1499 &per_commitment_key,
1500 &self.revocation_base_key,
1502 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1503 let revocation_pubkey = RevocationKey::from_basepoint(
1505 &self.pubkeys().revocation_basepoint,
1506 &per_commitment_point,
1508 let witness_script = {
1509 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1510 let holder_selected_contest_delay =
1511 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1512 let counterparty_delayedpubkey = DelayedPaymentKey::from_basepoint(
1514 &counterparty_keys.delayed_payment_basepoint,
1515 &per_commitment_point,
1517 chan_utils::get_revokeable_redeemscript(
1519 holder_selected_contest_delay,
1520 &counterparty_delayedpubkey,
1523 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1524 let sighash = hash_to_message!(
1526 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1529 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1532 fn sign_justice_revoked_htlc(
1533 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1534 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1535 ) -> Result<Signature, ()> {
1536 let revocation_key = chan_utils::derive_private_revocation_key(
1538 &per_commitment_key,
1539 &self.revocation_base_key,
1541 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1542 let revocation_pubkey = RevocationKey::from_basepoint(
1544 &self.pubkeys().revocation_basepoint,
1545 &per_commitment_point,
1547 let witness_script = {
1548 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1549 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1551 &counterparty_keys.htlc_basepoint,
1552 &per_commitment_point,
1554 let holder_htlcpubkey = HtlcKey::from_basepoint(
1556 &self.pubkeys().htlc_basepoint,
1557 &per_commitment_point,
1559 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1560 chan_utils::get_htlc_redeemscript_with_explicit_keys(
1563 &counterparty_htlcpubkey,
1568 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1569 let sighash = hash_to_message!(
1571 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1574 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1577 fn sign_holder_htlc_transaction(
1578 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1579 secp_ctx: &Secp256k1<secp256k1::All>,
1580 ) -> Result<Signature, ()> {
1581 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1582 let sighash = &sighash::SighashCache::new(&*htlc_tx)
1583 .segwit_signature_hash(
1586 htlc_descriptor.htlc.amount_msat / 1000,
1587 EcdsaSighashType::All,
1590 let our_htlc_private_key = chan_utils::derive_private_key(
1592 &htlc_descriptor.per_commitment_point,
1593 &self.htlc_base_key,
1595 let sighash = hash_to_message!(sighash.as_byte_array());
1596 Ok(sign_with_aux_rand(&secp_ctx, &sighash, &our_htlc_private_key, &self))
1599 fn sign_counterparty_htlc_transaction(
1600 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1601 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1602 ) -> Result<Signature, ()> {
1604 chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1605 let revocation_pubkey = RevocationKey::from_basepoint(
1607 &self.pubkeys().revocation_basepoint,
1608 &per_commitment_point,
1610 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1611 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1613 &counterparty_keys.htlc_basepoint,
1614 &per_commitment_point,
1616 let htlc_basepoint = self.pubkeys().htlc_basepoint;
1617 let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &htlc_basepoint, &per_commitment_point);
1618 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1619 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(
1622 &counterparty_htlcpubkey,
1626 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1627 let sighash = hash_to_message!(
1629 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1632 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1635 fn sign_closing_transaction(
1636 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1637 ) -> Result<Signature, ()> {
1638 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1639 let counterparty_funding_key =
1640 &self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
1641 let channel_funding_redeemscript =
1642 make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
1643 Ok(closing_tx.trust().sign(
1645 &channel_funding_redeemscript,
1646 self.channel_value_satoshis,
1651 fn sign_holder_anchor_input(
1652 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1653 ) -> Result<Signature, ()> {
1654 let witness_script =
1655 chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1656 let sighash = sighash::SighashCache::new(&*anchor_tx)
1657 .segwit_signature_hash(
1660 ANCHOR_OUTPUT_VALUE_SATOSHI,
1661 EcdsaSighashType::All,
1664 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1667 fn sign_channel_announcement_with_funding_key(
1668 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>,
1669 ) -> Result<Signature, ()> {
1670 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1671 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1676 impl TaprootChannelSigner for InMemorySigner {
1677 fn generate_local_nonce_pair(
1678 &self, commitment_number: u64, secp_ctx: &Secp256k1<All>,
1683 fn partially_sign_counterparty_commitment(
1684 &self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction,
1685 inbound_htlc_preimages: Vec<PaymentPreimage>,
1686 outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>,
1687 ) -> Result<(PartialSignatureWithNonce, Vec<schnorr::Signature>), ()> {
1691 fn finalize_holder_commitment(
1692 &self, commitment_tx: &HolderCommitmentTransaction,
1693 counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>,
1694 ) -> Result<PartialSignature, ()> {
1698 fn sign_justice_revoked_output(
1699 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1700 secp_ctx: &Secp256k1<All>,
1701 ) -> Result<schnorr::Signature, ()> {
1705 fn sign_justice_revoked_htlc(
1706 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1707 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1708 ) -> Result<schnorr::Signature, ()> {
1712 fn sign_holder_htlc_transaction(
1713 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1714 secp_ctx: &Secp256k1<All>,
1715 ) -> Result<schnorr::Signature, ()> {
1719 fn sign_counterparty_htlc_transaction(
1720 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1721 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1722 ) -> Result<schnorr::Signature, ()> {
1726 fn partially_sign_closing_transaction(
1727 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>,
1728 ) -> Result<PartialSignature, ()> {
1732 fn sign_holder_anchor_input(
1733 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>,
1734 ) -> Result<schnorr::Signature, ()> {
1739 const SERIALIZATION_VERSION: u8 = 1;
1741 const MIN_SERIALIZATION_VERSION: u8 = 1;
1743 impl Writeable for InMemorySigner {
1744 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1745 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1747 self.funding_key.write(writer)?;
1748 self.revocation_base_key.write(writer)?;
1749 self.payment_key.write(writer)?;
1750 self.delayed_payment_base_key.write(writer)?;
1751 self.htlc_base_key.write(writer)?;
1752 self.commitment_seed.write(writer)?;
1753 self.channel_parameters.write(writer)?;
1754 self.channel_value_satoshis.write(writer)?;
1755 self.channel_keys_id.write(writer)?;
1757 write_tlv_fields!(writer, {});
1763 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner
1765 ES::Target: EntropySource,
1767 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1768 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1770 let funding_key = Readable::read(reader)?;
1771 let revocation_base_key = Readable::read(reader)?;
1772 let payment_key = Readable::read(reader)?;
1773 let delayed_payment_base_key = Readable::read(reader)?;
1774 let htlc_base_key = Readable::read(reader)?;
1775 let commitment_seed = Readable::read(reader)?;
1776 let counterparty_channel_data = Readable::read(reader)?;
1777 let channel_value_satoshis = Readable::read(reader)?;
1778 let secp_ctx = Secp256k1::signing_only();
1779 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1782 &revocation_base_key,
1784 &delayed_payment_base_key,
1787 let keys_id = Readable::read(reader)?;
1789 read_tlv_fields!(reader, {});
1793 revocation_base_key,
1795 delayed_payment_base_key,
1798 channel_value_satoshis,
1799 holder_channel_pubkeys,
1800 channel_parameters: counterparty_channel_data,
1801 channel_keys_id: keys_id,
1802 entropy_source: RandomBytes::new(entropy_source.get_secure_random_bytes()),
1807 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1808 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1810 /// Your `node_id` is seed/0'.
1811 /// Unilateral closes may use seed/1'.
1812 /// Cooperative closes may use seed/2'.
1813 /// The two close keys may be needed to claim on-chain funds!
1815 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1816 /// [`PhantomKeysManager`] must be used instead.
1818 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1819 /// previously issued invoices and attempts to pay previous invoices will fail.
1820 pub struct KeysManager {
1821 secp_ctx: Secp256k1<secp256k1::All>,
1822 node_secret: SecretKey,
1824 inbound_payment_key: KeyMaterial,
1825 destination_script: ScriptBuf,
1826 shutdown_pubkey: PublicKey,
1827 channel_master_key: ExtendedPrivKey,
1828 channel_child_index: AtomicUsize,
1830 entropy_source: RandomBytes,
1833 starting_time_secs: u64,
1834 starting_time_nanos: u32,
1838 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1839 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1840 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1841 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1842 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1843 /// is to simply use the current time (with very high precision).
1845 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1846 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1847 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1850 /// Note that the seed is required to recover certain on-chain funds independent of
1851 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1852 /// for any channel, and some on-chain during-closing funds.
1854 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1855 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1856 let secp_ctx = Secp256k1::new();
1857 // Note that when we aren't serializing the key, network doesn't matter
1858 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1860 let node_secret = master_key
1861 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap())
1862 .expect("Your RNG is busted")
1864 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1865 let destination_script = match master_key
1866 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap())
1868 Ok(destination_key) => {
1869 let wpubkey_hash = WPubkeyHash::hash(
1870 &ExtendedPubKey::from_priv(&secp_ctx, &destination_key)
1875 .push_opcode(opcodes::all::OP_PUSHBYTES_0)
1876 .push_slice(&wpubkey_hash.to_byte_array())
1879 Err(_) => panic!("Your RNG is busted"),
1881 let shutdown_pubkey = match master_key
1882 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap())
1884 Ok(shutdown_key) => {
1885 ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key
1887 Err(_) => panic!("Your RNG is busted"),
1889 let channel_master_key = master_key
1890 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap())
1891 .expect("Your RNG is busted");
1892 let inbound_payment_key: SecretKey = master_key
1893 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap())
1894 .expect("Your RNG is busted")
1896 let mut inbound_pmt_key_bytes = [0; 32];
1897 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1899 let mut rand_bytes_engine = Sha256::engine();
1900 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1901 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1902 rand_bytes_engine.input(seed);
1903 rand_bytes_engine.input(b"LDK PRNG Seed");
1904 let rand_bytes_unique_start =
1905 Sha256::from_engine(rand_bytes_engine).to_byte_array();
1907 let mut res = KeysManager {
1911 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1917 channel_child_index: AtomicUsize::new(0),
1919 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1923 starting_time_nanos,
1925 let secp_seed = res.get_secure_random_bytes();
1926 res.secp_ctx.seeded_randomize(&secp_seed);
1929 Err(_) => panic!("Your rng is busted"),
1933 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1934 pub fn get_node_secret_key(&self) -> SecretKey {
1938 /// Derive an old [`EcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1939 pub fn derive_channel_keys(
1940 &self, channel_value_satoshis: u64, params: &[u8; 32],
1941 ) -> InMemorySigner {
1942 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1943 let mut unique_start = Sha256::engine();
1944 unique_start.input(params);
1945 unique_start.input(&self.seed);
1947 // We only seriously intend to rely on the channel_master_key for true secure
1948 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1949 // starting_time provided in the constructor) to be unique.
1950 let child_privkey = self
1954 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31))
1955 .expect("key space exhausted"),
1957 .expect("Your RNG is busted");
1958 unique_start.input(&child_privkey.private_key[..]);
1960 let seed = Sha256::from_engine(unique_start).to_byte_array();
1962 let commitment_seed = {
1963 let mut sha = Sha256::engine();
1965 sha.input(&b"commitment seed"[..]);
1966 Sha256::from_engine(sha).to_byte_array()
1968 macro_rules! key_step {
1969 ($info: expr, $prev_key: expr) => {{
1970 let mut sha = Sha256::engine();
1972 sha.input(&$prev_key[..]);
1973 sha.input(&$info[..]);
1974 SecretKey::from_slice(&Sha256::from_engine(sha).to_byte_array())
1975 .expect("SHA-256 is busted")
1978 let funding_key = key_step!(b"funding key", commitment_seed);
1979 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1980 let payment_key = key_step!(b"payment key", revocation_base_key);
1981 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1982 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1983 let prng_seed = self.get_secure_random_bytes();
1985 InMemorySigner::new(
1988 revocation_base_key,
1990 delayed_payment_base_key,
1993 channel_value_satoshis,
1999 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
2000 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
2001 /// are no other inputs that need signing.
2003 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
2005 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2006 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2007 pub fn sign_spendable_outputs_psbt<C: Signing>(
2008 &self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction,
2009 secp_ctx: &Secp256k1<C>,
2010 ) -> Result<PartiallySignedTransaction, ()> {
2011 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
2012 for outp in descriptors {
2013 let get_input_idx = |outpoint: &OutPoint| {
2017 .position(|i| i.previous_output == outpoint.into_bitcoin_outpoint())
2021 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
2022 let input_idx = get_input_idx(&descriptor.outpoint)?;
2023 if keys_cache.is_none()
2024 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2026 let mut signer = self.derive_channel_keys(
2027 descriptor.channel_value_satoshis,
2028 &descriptor.channel_keys_id,
2030 if let Some(channel_params) =
2031 descriptor.channel_transaction_parameters.as_ref()
2033 signer.provide_channel_parameters(channel_params);
2035 keys_cache = Some((signer, descriptor.channel_keys_id));
2037 let witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(
2043 psbt.inputs[input_idx].final_script_witness = Some(witness);
2045 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
2046 let input_idx = get_input_idx(&descriptor.outpoint)?;
2047 if keys_cache.is_none()
2048 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2051 self.derive_channel_keys(
2052 descriptor.channel_value_satoshis,
2053 &descriptor.channel_keys_id,
2055 descriptor.channel_keys_id,
2058 let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(
2064 psbt.inputs[input_idx].final_script_witness = Some(witness);
2066 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
2067 let input_idx = get_input_idx(outpoint)?;
2068 let derivation_idx =
2069 if output.script_pubkey == self.destination_script { 1 } else { 2 };
2071 // Note that when we aren't serializing the key, network doesn't matter
2072 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
2074 match master_key.ckd_priv(
2076 ChildNumber::from_hardened_idx(derivation_idx)
2077 .expect("key space exhausted"),
2080 Err(_) => panic!("Your RNG is busted"),
2083 Err(_) => panic!("Your rng is busted"),
2086 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
2087 if derivation_idx == 2 {
2088 assert_eq!(pubkey.inner, self.shutdown_pubkey);
2090 let witness_script =
2091 bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
2092 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet)
2093 .expect("uncompressed key found")
2096 if payment_script != output.script_pubkey {
2100 let sighash = hash_to_message!(
2101 &sighash::SighashCache::new(&psbt.unsigned_tx)
2102 .segwit_signature_hash(
2106 EcdsaSighashType::All
2110 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
2111 let mut sig_ser = sig.serialize_der().to_vec();
2112 sig_ser.push(EcdsaSighashType::All as u8);
2114 Witness::from_slice(&[&sig_ser, &pubkey.inner.serialize().to_vec()]);
2115 psbt.inputs[input_idx].final_script_witness = Some(witness);
2124 impl EntropySource for KeysManager {
2125 fn get_secure_random_bytes(&self) -> [u8; 32] {
2126 self.entropy_source.get_secure_random_bytes()
2130 impl NodeSigner for KeysManager {
2131 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2133 Recipient::Node => Ok(self.node_id.clone()),
2134 Recipient::PhantomNode => Err(()),
2139 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2140 ) -> Result<SharedSecret, ()> {
2141 let mut node_secret = match recipient {
2142 Recipient::Node => Ok(self.node_secret.clone()),
2143 Recipient::PhantomNode => Err(()),
2145 if let Some(tweak) = tweak {
2146 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2148 Ok(SharedSecret::new(other_key, &node_secret))
2151 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2152 self.inbound_payment_key.clone()
2156 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2157 ) -> Result<RecoverableSignature, ()> {
2158 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2159 let secret = match recipient {
2160 Recipient::Node => Ok(&self.node_secret),
2161 Recipient::PhantomNode => Err(()),
2163 Ok(self.secp_ctx.sign_ecdsa_recoverable(
2164 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2169 fn sign_bolt12_invoice_request(
2170 &self, invoice_request: &UnsignedInvoiceRequest,
2171 ) -> Result<schnorr::Signature, ()> {
2172 let message = invoice_request.tagged_hash().as_digest();
2173 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
2174 let aux_rand = self.get_secure_random_bytes();
2175 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
2178 fn sign_bolt12_invoice(
2179 &self, invoice: &UnsignedBolt12Invoice,
2180 ) -> Result<schnorr::Signature, ()> {
2181 let message = invoice.tagged_hash().as_digest();
2182 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
2183 let aux_rand = self.get_secure_random_bytes();
2184 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
2187 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2188 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
2189 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
2193 impl OutputSpender for KeysManager {
2194 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
2195 /// output to the given change destination (if sufficient change value remains).
2197 /// See [`OutputSpender::spend_spendable_outputs`] documentation for more information.
2199 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
2201 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2202 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2203 fn spend_spendable_outputs<C: Signing>(
2204 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2205 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2206 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2207 ) -> Result<Transaction, ()> {
2208 let (mut psbt, expected_max_weight) =
2209 SpendableOutputDescriptor::create_spendable_outputs_psbt(
2213 change_destination_script,
2214 feerate_sat_per_1000_weight,
2217 psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
2219 let spend_tx = psbt.extract_tx();
2221 debug_assert!(expected_max_weight >= spend_tx.weight().to_wu());
2222 // Note that witnesses with a signature vary somewhat in size, so allow
2223 // `expected_max_weight` to overshoot by up to 3 bytes per input.
2225 expected_max_weight <= spend_tx.weight().to_wu() + descriptors.len() as u64 * 3
2232 impl SignerProvider for KeysManager {
2233 type EcdsaSigner = InMemorySigner;
2235 type TaprootSigner = InMemorySigner;
2237 fn generate_channel_keys_id(
2238 &self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128,
2240 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
2241 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
2242 // (though `user_channel_id` should help, depending on user behavior). If it manages to
2243 // roll over, we may generate duplicate keys for two different channels, which could result
2244 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
2245 // doesn't reach `u32::MAX`.
2246 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
2247 let mut id = [0; 32];
2248 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
2249 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
2250 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
2251 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
2255 fn derive_channel_signer(
2256 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2257 ) -> Self::EcdsaSigner {
2258 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
2261 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2262 InMemorySigner::read(&mut io::Cursor::new(reader), self)
2265 fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2266 Ok(self.destination_script.clone())
2269 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2270 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
2274 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
2277 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
2278 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
2279 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
2280 /// itself without ever needing to forward to this fake node.
2282 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
2283 /// provide some fault tolerance, because payers will automatically retry paying other provided
2284 /// nodes in the case that one node goes down.
2286 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
2287 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
2288 // nodes to know when the full payment has been received (and the preimage can be released) without
2289 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
2290 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
2291 // is released too early.
2293 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
2294 /// invoices and attempts to pay previous invoices will fail.
2295 pub struct PhantomKeysManager {
2297 inbound_payment_key: KeyMaterial,
2298 phantom_secret: SecretKey,
2299 phantom_node_id: PublicKey,
2302 impl EntropySource for PhantomKeysManager {
2303 fn get_secure_random_bytes(&self) -> [u8; 32] {
2304 self.inner.get_secure_random_bytes()
2308 impl NodeSigner for PhantomKeysManager {
2309 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2311 Recipient::Node => self.inner.get_node_id(Recipient::Node),
2312 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
2317 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2318 ) -> Result<SharedSecret, ()> {
2319 let mut node_secret = match recipient {
2320 Recipient::Node => self.inner.node_secret.clone(),
2321 Recipient::PhantomNode => self.phantom_secret.clone(),
2323 if let Some(tweak) = tweak {
2324 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2326 Ok(SharedSecret::new(other_key, &node_secret))
2329 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2330 self.inbound_payment_key.clone()
2334 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2335 ) -> Result<RecoverableSignature, ()> {
2336 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2337 let secret = match recipient {
2338 Recipient::Node => &self.inner.node_secret,
2339 Recipient::PhantomNode => &self.phantom_secret,
2341 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(
2342 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2347 fn sign_bolt12_invoice_request(
2348 &self, invoice_request: &UnsignedInvoiceRequest,
2349 ) -> Result<schnorr::Signature, ()> {
2350 self.inner.sign_bolt12_invoice_request(invoice_request)
2353 fn sign_bolt12_invoice(
2354 &self, invoice: &UnsignedBolt12Invoice,
2355 ) -> Result<schnorr::Signature, ()> {
2356 self.inner.sign_bolt12_invoice(invoice)
2359 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2360 self.inner.sign_gossip_message(msg)
2364 impl OutputSpender for PhantomKeysManager {
2365 /// See [`OutputSpender::spend_spendable_outputs`] and [`KeysManager::spend_spendable_outputs`]
2366 /// for documentation on this method.
2367 fn spend_spendable_outputs<C: Signing>(
2368 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2369 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2370 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2371 ) -> Result<Transaction, ()> {
2372 self.inner.spend_spendable_outputs(
2375 change_destination_script,
2376 feerate_sat_per_1000_weight,
2383 impl SignerProvider for PhantomKeysManager {
2384 type EcdsaSigner = InMemorySigner;
2386 type TaprootSigner = InMemorySigner;
2388 fn generate_channel_keys_id(
2389 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
2391 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
2394 fn derive_channel_signer(
2395 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2396 ) -> Self::EcdsaSigner {
2397 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
2400 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2401 self.inner.read_chan_signer(reader)
2404 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2405 self.inner.get_destination_script(channel_keys_id)
2408 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2409 self.inner.get_shutdown_scriptpubkey()
2413 impl PhantomKeysManager {
2414 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
2415 /// that is shared across all nodes that intend to participate in [phantom node payments]
2418 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
2419 /// `starting_time_nanos`.
2421 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
2422 /// same across restarts, or else inbound payments may fail.
2424 /// [phantom node payments]: PhantomKeysManager
2426 seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32,
2427 cross_node_seed: &[u8; 32],
2429 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
2430 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(
2431 b"LDK Inbound and Phantom Payment Key Expansion",
2434 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
2435 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
2438 inbound_payment_key: KeyMaterial(inbound_key),
2444 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
2445 pub fn derive_channel_keys(
2446 &self, channel_value_satoshis: u64, params: &[u8; 32],
2447 ) -> InMemorySigner {
2448 self.inner.derive_channel_keys(channel_value_satoshis, params)
2451 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
2452 pub fn get_node_secret_key(&self) -> SecretKey {
2453 self.inner.get_node_secret_key()
2456 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
2457 /// last-hop onion data, etc.
2458 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
2463 /// An implementation of [`EntropySource`] using ChaCha20.
2465 pub struct RandomBytes {
2466 /// Seed from which all randomness produced is derived from.
2468 /// Tracks the number of times we've produced randomness to ensure we don't return the same
2470 index: AtomicCounter,
2474 /// Creates a new instance using the given seed.
2475 pub fn new(seed: [u8; 32]) -> Self {
2476 Self { seed, index: AtomicCounter::new() }
2480 impl EntropySource for RandomBytes {
2481 fn get_secure_random_bytes(&self) -> [u8; 32] {
2482 let index = self.index.get_increment();
2483 let mut nonce = [0u8; 16];
2484 nonce[..8].copy_from_slice(&index.to_be_bytes());
2485 ChaCha20::get_single_block(&self.seed, &nonce)
2489 // Ensure that EcdsaChannelSigner can have a vtable
2492 let _signer: Box<dyn EcdsaChannelSigner>;
2497 use crate::sign::{EntropySource, KeysManager};
2498 use bitcoin::blockdata::constants::genesis_block;
2499 use bitcoin::Network;
2500 use std::sync::mpsc::TryRecvError;
2501 use std::sync::{mpsc, Arc};
2503 use std::time::Duration;
2505 use criterion::Criterion;
2507 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
2508 let seed = [0u8; 32];
2509 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
2510 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
2512 let mut handles = Vec::new();
2513 let mut stops = Vec::new();
2515 let keys_manager_clone = Arc::clone(&keys_manager);
2516 let (stop_sender, stop_receiver) = mpsc::channel();
2517 let handle = thread::spawn(move || loop {
2518 keys_manager_clone.get_secure_random_bytes();
2519 match stop_receiver.try_recv() {
2520 Ok(_) | Err(TryRecvError::Disconnected) => {
2521 println!("Terminating.");
2524 Err(TryRecvError::Empty) => {},
2527 handles.push(handle);
2528 stops.push(stop_sender);
2531 bench.bench_function("get_secure_random_bytes", |b| {
2532 b.iter(|| keys_manager.get_secure_random_bytes())
2536 let _ = stop.send(());
2538 for handle in handles {
2539 handle.join().unwrap();