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, WriteableEcdsaChannelSigner};
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: WriteableEcdsaChannelSigner, SP: Deref>(
713 &self, signer_provider: &SP,
716 SP::Target: SignerProvider<EcdsaSigner = S>,
718 let mut signer = signer_provider.derive_channel_signer(
719 self.channel_derivation_parameters.value_satoshis,
720 self.channel_derivation_parameters.keys_id,
723 .provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
728 /// A trait to handle Lightning channel key material without concretizing the channel type or
729 /// the signature mechanism.
730 pub trait ChannelSigner {
731 /// Gets the per-commitment point for a specific commitment number
733 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
734 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>)
737 /// Gets the commitment secret for a specific commitment number as part of the revocation process
739 /// An external signer implementation should error here if the commitment was already signed
740 /// and should refuse to sign it in the future.
742 /// May be called more than once for the same index.
744 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
745 // TODO: return a Result so we can signal a validation error
746 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
748 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
750 /// This is required in order for the signer to make sure that releasing a commitment
751 /// secret won't leave us without a broadcastable holder transaction.
752 /// Policy checks should be implemented in this function, including checking the amount
753 /// sent to us and checking the HTLCs.
755 /// The preimages of outbound HTLCs that were fulfilled since the last commitment are provided.
756 /// A validating signer should ensure that an HTLC output is removed only when the matching
757 /// preimage is provided, or when the value to holder is restored.
759 /// Note that all the relevant preimages will be provided, but there may also be additional
760 /// irrelevant or duplicate preimages.
761 fn validate_holder_commitment(
762 &self, holder_tx: &HolderCommitmentTransaction,
763 outbound_htlc_preimages: Vec<PaymentPreimage>,
766 /// Validate the counterparty's revocation.
768 /// This is required in order for the signer to make sure that the state has moved
769 /// forward and it is safe to sign the next counterparty commitment.
770 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
772 /// Returns the holder's channel public keys and basepoints.
773 fn pubkeys(&self) -> &ChannelPublicKeys;
775 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
776 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
777 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
778 fn channel_keys_id(&self) -> [u8; 32];
780 /// Set the counterparty static channel data, including basepoints,
781 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
783 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
784 /// instance, LDK will call this method exactly once - either immediately after construction
785 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
786 /// information has been generated.
788 /// channel_parameters.is_populated() MUST be true.
789 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
792 /// Specifies the recipient of an invoice.
794 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
797 /// The invoice should be signed with the local node secret key.
799 /// The invoice should be signed with the phantom node secret key. This secret key must be the
800 /// same for all nodes participating in the [phantom node payment].
802 /// [phantom node payment]: PhantomKeysManager
806 /// A trait that describes a source of entropy.
807 pub trait EntropySource {
808 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
809 /// different value each time it is called.
810 fn get_secure_random_bytes(&self) -> [u8; 32];
813 /// A trait that can handle cryptographic operations at the scope level of a node.
814 pub trait NodeSigner {
815 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
817 /// If the implementor of this trait supports [phantom node payments], then every node that is
818 /// intended to be included in the phantom invoice route hints must return the same value from
820 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
821 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
822 // nodes, they must share the key that encrypts this payment data.
824 /// This method must return the same value each time it is called.
826 /// [phantom node payments]: PhantomKeysManager
827 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
829 /// Get node id based on the provided [`Recipient`].
831 /// This method must return the same value each time it is called with a given [`Recipient`]
834 /// Errors if the [`Recipient`] variant is not supported by the implementation.
835 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
837 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
838 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
839 /// secret, though this is less efficient.
841 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
842 /// should be resolved to allow LDK to resume forwarding HTLCs.
844 /// Errors if the [`Recipient`] variant is not supported by the implementation.
846 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
847 ) -> Result<SharedSecret, ()>;
851 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
852 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
853 /// blindly signing the hash.
855 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
857 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
859 /// Errors if the [`Recipient`] variant is not supported by the implementation.
861 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
862 ) -> Result<RecoverableSignature, ()>;
864 /// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
866 /// May be called by a function passed to [`UnsignedInvoiceRequest::sign`] where
867 /// `invoice_request` is the callee.
869 /// Implementors may check that the `invoice_request` is expected rather than blindly signing
870 /// the tagged hash. An `Ok` result should sign `invoice_request.tagged_hash().as_digest()` with
871 /// the node's signing key or an ephemeral key to preserve privacy, whichever is associated with
872 /// [`UnsignedInvoiceRequest::payer_id`].
874 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
875 fn sign_bolt12_invoice_request(
876 &self, invoice_request: &UnsignedInvoiceRequest,
877 ) -> Result<schnorr::Signature, ()>;
879 /// Signs the [`TaggedHash`] of a BOLT 12 invoice.
881 /// May be called by a function passed to [`UnsignedBolt12Invoice::sign`] where `invoice` is the
884 /// Implementors may check that the `invoice` is expected rather than blindly signing the tagged
885 /// hash. An `Ok` result should sign `invoice.tagged_hash().as_digest()` with the node's signing
886 /// key or an ephemeral key to preserve privacy, whichever is associated with
887 /// [`UnsignedBolt12Invoice::signing_pubkey`].
889 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
890 fn sign_bolt12_invoice(
891 &self, invoice: &UnsignedBolt12Invoice,
892 ) -> Result<schnorr::Signature, ()>;
894 /// Sign a gossip message.
896 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
897 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
898 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
899 /// corresponding channel.
900 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
903 /// A trait that describes a wallet capable of creating a spending [`Transaction`] from a set of
904 /// [`SpendableOutputDescriptor`]s.
905 pub trait OutputSpender {
906 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
907 /// output to the given change destination (if sufficient change value remains). The
908 /// transaction will have a feerate, at least, of the given value.
910 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
911 /// transaction will have a locktime of 0. It it recommended to set this to the current block
912 /// height to avoid fee sniping, unless you have some specific reason to use a different
915 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
916 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
917 /// does not match the one we can spend.
918 fn spend_spendable_outputs<C: Signing>(
919 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
920 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
921 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
922 ) -> Result<Transaction, ()>;
925 // Primarily needed in doctests because of https://github.com/rust-lang/rust/issues/67295
926 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
928 /// This is not exported to bindings users as it is not intended for public consumption.
931 #[deprecated(note = "Remove once taproot cfg is removed")]
932 pub type DynSignerProvider =
933 dyn SignerProvider<EcdsaSigner = InMemorySigner, TaprootSigner = InMemorySigner>;
935 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
937 /// This is not exported to bindings users as it is not intended for public consumption.
940 #[deprecated(note = "Remove once taproot cfg is removed")]
941 pub type DynSignerProvider = dyn SignerProvider<EcdsaSigner = InMemorySigner>;
943 /// A trait that can return signer instances for individual channels.
944 pub trait SignerProvider {
945 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
946 type EcdsaSigner: WriteableEcdsaChannelSigner;
948 /// A type which implements [`TaprootChannelSigner`]
949 type TaprootSigner: TaprootChannelSigner;
951 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::EcdsaSigner`] through
952 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
953 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
954 /// `channel_keys_id`.
956 /// This method must return a different value each time it is called.
957 fn generate_channel_keys_id(
958 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
961 /// Derives the private key material backing a `Signer`.
963 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
964 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
965 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
966 /// [`ChannelSigner::channel_keys_id`].
967 fn derive_channel_signer(
968 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
969 ) -> Self::EcdsaSigner;
971 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
972 /// This is only called during deserialization of other objects which contain
973 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
974 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
975 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
976 /// you've read all of the provided bytes to ensure no corruption occurred.
978 /// This method is slowly being phased out -- it will only be called when reading objects
979 /// written by LDK versions prior to 0.0.113.
981 /// [`Signer`]: Self::EcdsaSigner
982 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
983 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
984 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError>;
986 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
988 /// If this function returns an error, this will result in a channel failing to open.
990 /// This method should return a different value each time it is called, to avoid linking
991 /// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
992 /// used to derive a unique value for each channel.
993 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
995 /// Get a script pubkey which we will send funds to when closing a channel.
997 /// If this function returns an error, this will result in a channel failing to open or close.
998 /// In the event of a failure when the counterparty is initiating a close, this can result in a
999 /// channel force close.
1001 /// This method should return a different value each time it is called, to avoid linking
1002 /// on-chain funds across channels as controlled to the same user.
1003 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
1006 /// A helper trait that describes an on-chain wallet capable of returning a (change) destination
1008 pub trait ChangeDestinationSource {
1009 /// Returns a script pubkey which can be used as a change destination for
1010 /// [`OutputSpender::spend_spendable_outputs`].
1012 /// This method should return a different value each time it is called, to avoid linking
1013 /// on-chain funds controlled to the same user.
1014 fn get_change_destination_script(&self) -> Result<ScriptBuf, ()>;
1017 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
1019 /// This implementation performs no policy checks and is insufficient by itself as
1020 /// a secure external signer.
1022 pub struct InMemorySigner {
1023 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
1024 /// holder's anchor output in a commitment transaction, if one is present.
1025 pub funding_key: SecretKey,
1026 /// Holder secret key for blinded revocation pubkey.
1027 pub revocation_base_key: SecretKey,
1028 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
1029 pub payment_key: SecretKey,
1030 /// Holder secret key used in an HTLC transaction.
1031 pub delayed_payment_base_key: SecretKey,
1032 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
1033 pub htlc_base_key: SecretKey,
1034 /// Commitment seed.
1035 pub commitment_seed: [u8; 32],
1036 /// Holder public keys and basepoints.
1037 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
1038 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
1039 channel_parameters: Option<ChannelTransactionParameters>,
1040 /// The total value of this channel.
1041 channel_value_satoshis: u64,
1042 /// Key derivation parameters.
1043 channel_keys_id: [u8; 32],
1044 /// A source of random bytes.
1045 entropy_source: RandomBytes,
1048 impl PartialEq for InMemorySigner {
1049 fn eq(&self, other: &Self) -> bool {
1050 self.funding_key == other.funding_key
1051 && self.revocation_base_key == other.revocation_base_key
1052 && self.payment_key == other.payment_key
1053 && self.delayed_payment_base_key == other.delayed_payment_base_key
1054 && self.htlc_base_key == other.htlc_base_key
1055 && self.commitment_seed == other.commitment_seed
1056 && self.holder_channel_pubkeys == other.holder_channel_pubkeys
1057 && self.channel_parameters == other.channel_parameters
1058 && self.channel_value_satoshis == other.channel_value_satoshis
1059 && self.channel_keys_id == other.channel_keys_id
1063 impl Clone for InMemorySigner {
1064 fn clone(&self) -> Self {
1066 funding_key: self.funding_key.clone(),
1067 revocation_base_key: self.revocation_base_key.clone(),
1068 payment_key: self.payment_key.clone(),
1069 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
1070 htlc_base_key: self.htlc_base_key.clone(),
1071 commitment_seed: self.commitment_seed.clone(),
1072 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
1073 channel_parameters: self.channel_parameters.clone(),
1074 channel_value_satoshis: self.channel_value_satoshis,
1075 channel_keys_id: self.channel_keys_id,
1076 entropy_source: RandomBytes::new(self.get_secure_random_bytes()),
1081 impl InMemorySigner {
1082 /// Creates a new [`InMemorySigner`].
1083 pub fn new<C: Signing>(
1084 secp_ctx: &Secp256k1<C>, funding_key: SecretKey, revocation_base_key: SecretKey,
1085 payment_key: SecretKey, delayed_payment_base_key: SecretKey, htlc_base_key: SecretKey,
1086 commitment_seed: [u8; 32], channel_value_satoshis: u64, channel_keys_id: [u8; 32],
1087 rand_bytes_unique_start: [u8; 32],
1088 ) -> InMemorySigner {
1089 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1092 &revocation_base_key,
1094 &delayed_payment_base_key,
1099 revocation_base_key,
1101 delayed_payment_base_key,
1104 channel_value_satoshis,
1105 holder_channel_pubkeys,
1106 channel_parameters: None,
1108 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1112 fn make_holder_keys<C: Signing>(
1113 secp_ctx: &Secp256k1<C>, funding_key: &SecretKey, revocation_base_key: &SecretKey,
1114 payment_key: &SecretKey, delayed_payment_base_key: &SecretKey, htlc_base_key: &SecretKey,
1115 ) -> ChannelPublicKeys {
1116 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
1118 funding_pubkey: from_secret(&funding_key),
1119 revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
1120 payment_point: from_secret(&payment_key),
1121 delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(
1122 &delayed_payment_base_key,
1124 htlc_basepoint: HtlcBasepoint::from(from_secret(&htlc_base_key)),
1128 /// Returns the counterparty's pubkeys.
1130 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1131 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1132 pub fn counterparty_pubkeys(&self) -> Option<&ChannelPublicKeys> {
1133 self.get_channel_parameters().and_then(|params| {
1134 params.counterparty_parameters.as_ref().map(|params| ¶ms.pubkeys)
1138 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
1139 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
1140 /// broadcast a transaction.
1142 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1143 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1144 pub fn counterparty_selected_contest_delay(&self) -> Option<u16> {
1145 self.get_channel_parameters().and_then(|params| {
1146 params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay)
1150 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
1151 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
1152 /// if they broadcast a transaction.
1154 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1155 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1156 pub fn holder_selected_contest_delay(&self) -> Option<u16> {
1157 self.get_channel_parameters().map(|params| params.holder_selected_contest_delay)
1160 /// Returns whether the holder is the initiator.
1162 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1163 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1164 pub fn is_outbound(&self) -> Option<bool> {
1165 self.get_channel_parameters().map(|params| params.is_outbound_from_holder)
1168 /// Funding outpoint
1170 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1171 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1172 pub fn funding_outpoint(&self) -> Option<&OutPoint> {
1173 self.get_channel_parameters().map(|params| params.funding_outpoint.as_ref()).flatten()
1176 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
1177 /// building transactions.
1179 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1180 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1181 pub fn get_channel_parameters(&self) -> Option<&ChannelTransactionParameters> {
1182 self.channel_parameters.as_ref()
1185 /// Returns the channel type features of the channel parameters. Should be helpful for
1186 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
1188 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1189 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1190 pub fn channel_type_features(&self) -> Option<&ChannelTypeFeatures> {
1191 self.get_channel_parameters().map(|params| ¶ms.channel_type_features)
1194 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
1195 /// by `descriptor`, returning the witness stack for the input.
1197 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1198 /// is not spending the outpoint described by [`descriptor.outpoint`],
1199 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
1201 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
1202 pub fn sign_counterparty_payment_input<C: Signing>(
1203 &self, spend_tx: &Transaction, input_idx: usize,
1204 descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1205 ) -> Result<Witness, ()> {
1206 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1207 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1208 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1209 // bindings updates to support SigHashCache objects).
1210 if spend_tx.input.len() <= input_idx {
1213 if !spend_tx.input[input_idx].script_sig.is_empty() {
1216 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1221 let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
1222 // We cannot always assume that `channel_parameters` is set, so can't just call
1223 // `self.channel_parameters()` or anything that relies on it
1224 let supports_anchors_zero_fee_htlc_tx = self
1225 .channel_type_features()
1226 .map(|features| features.supports_anchors_zero_fee_htlc_tx())
1229 let witness_script = if supports_anchors_zero_fee_htlc_tx {
1230 chan_utils::get_to_countersignatory_with_anchors_redeemscript(&remotepubkey.inner)
1232 ScriptBuf::new_p2pkh(&remotepubkey.pubkey_hash())
1234 let sighash = hash_to_message!(
1235 &sighash::SighashCache::new(spend_tx)
1236 .segwit_signature_hash(
1239 descriptor.output.value,
1240 EcdsaSighashType::All
1244 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
1245 let payment_script = if supports_anchors_zero_fee_htlc_tx {
1246 witness_script.to_v0_p2wsh()
1248 ScriptBuf::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
1251 if payment_script != descriptor.output.script_pubkey {
1255 let mut witness = Vec::with_capacity(2);
1256 witness.push(remotesig.serialize_der().to_vec());
1257 witness[0].push(EcdsaSighashType::All as u8);
1258 if supports_anchors_zero_fee_htlc_tx {
1259 witness.push(witness_script.to_bytes());
1261 witness.push(remotepubkey.to_bytes());
1266 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
1267 /// described by `descriptor`, returning the witness stack for the input.
1269 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1270 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
1271 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
1272 /// `script_pubkey` does not match the one we can spend.
1274 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
1275 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
1276 pub fn sign_dynamic_p2wsh_input<C: Signing>(
1277 &self, spend_tx: &Transaction, input_idx: usize,
1278 descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1279 ) -> Result<Witness, ()> {
1280 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1281 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1282 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1283 // bindings updates to support SigHashCache objects).
1284 if spend_tx.input.len() <= input_idx {
1287 if !spend_tx.input[input_idx].script_sig.is_empty() {
1290 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1294 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 {
1298 let delayed_payment_key = chan_utils::derive_private_key(
1300 &descriptor.per_commitment_point,
1301 &self.delayed_payment_base_key,
1303 let delayed_payment_pubkey =
1304 DelayedPaymentKey::from_secret_key(&secp_ctx, &delayed_payment_key);
1305 let witness_script = chan_utils::get_revokeable_redeemscript(
1306 &descriptor.revocation_pubkey,
1307 descriptor.to_self_delay,
1308 &delayed_payment_pubkey,
1310 let sighash = hash_to_message!(
1311 &sighash::SighashCache::new(spend_tx)
1312 .segwit_signature_hash(
1315 descriptor.output.value,
1316 EcdsaSighashType::All
1320 let local_delayedsig = EcdsaSignature {
1321 sig: sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self),
1322 hash_ty: EcdsaSighashType::All,
1324 let payment_script =
1325 bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
1327 if descriptor.output.script_pubkey != payment_script {
1331 Ok(Witness::from_slice(&[
1332 &local_delayedsig.serialize()[..],
1334 witness_script.as_bytes(),
1339 impl EntropySource for InMemorySigner {
1340 fn get_secure_random_bytes(&self) -> [u8; 32] {
1341 self.entropy_source.get_secure_random_bytes()
1345 impl ChannelSigner for InMemorySigner {
1346 fn get_per_commitment_point(
1347 &self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>,
1349 let commitment_secret =
1350 SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx))
1352 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
1355 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
1356 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
1359 fn validate_holder_commitment(
1360 &self, _holder_tx: &HolderCommitmentTransaction,
1361 _outbound_htlc_preimages: Vec<PaymentPreimage>,
1362 ) -> Result<(), ()> {
1366 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
1370 fn pubkeys(&self) -> &ChannelPublicKeys {
1371 &self.holder_channel_pubkeys
1374 fn channel_keys_id(&self) -> [u8; 32] {
1375 self.channel_keys_id
1378 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
1380 self.channel_parameters.is_none()
1381 || self.channel_parameters.as_ref().unwrap() == channel_parameters
1383 if self.channel_parameters.is_some() {
1384 // The channel parameters were already set and they match, return early.
1387 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
1388 self.channel_parameters = Some(channel_parameters.clone());
1392 const MISSING_PARAMS_ERR: &'static str =
1393 "ChannelSigner::provide_channel_parameters must be called before signing operations";
1395 impl EcdsaChannelSigner for InMemorySigner {
1396 fn sign_counterparty_commitment(
1397 &self, commitment_tx: &CommitmentTransaction,
1398 _inbound_htlc_preimages: Vec<PaymentPreimage>,
1399 _outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>,
1400 ) -> Result<(Signature, Vec<Signature>), ()> {
1401 let trusted_tx = commitment_tx.trust();
1402 let keys = trusted_tx.keys();
1404 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1405 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1406 let channel_funding_redeemscript =
1407 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1409 let built_tx = trusted_tx.built_transaction();
1410 let commitment_sig = built_tx.sign_counterparty_commitment(
1412 &channel_funding_redeemscript,
1413 self.channel_value_satoshis,
1416 let commitment_txid = built_tx.txid;
1418 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
1419 for htlc in commitment_tx.htlcs() {
1420 let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
1421 let holder_selected_contest_delay =
1422 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1423 let chan_type = &channel_parameters.channel_type_features;
1424 let htlc_tx = chan_utils::build_htlc_transaction(
1426 commitment_tx.feerate_per_kw(),
1427 holder_selected_contest_delay,
1430 &keys.broadcaster_delayed_payment_key,
1431 &keys.revocation_key,
1433 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, chan_type, &keys);
1434 let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() {
1435 EcdsaSighashType::SinglePlusAnyoneCanPay
1437 EcdsaSighashType::All
1439 let htlc_sighash = hash_to_message!(
1440 &sighash::SighashCache::new(&htlc_tx)
1441 .segwit_signature_hash(
1444 htlc.amount_msat / 1000,
1449 let holder_htlc_key = chan_utils::derive_private_key(
1451 &keys.per_commitment_point,
1452 &self.htlc_base_key,
1454 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
1457 Ok((commitment_sig, htlc_sigs))
1460 fn sign_holder_commitment(
1461 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1462 ) -> Result<Signature, ()> {
1463 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1464 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1465 let funding_redeemscript =
1466 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1467 let trusted_tx = commitment_tx.trust();
1468 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1470 &funding_redeemscript,
1471 self.channel_value_satoshis,
1477 #[cfg(any(test, feature = "unsafe_revoked_tx_signing"))]
1478 fn unsafe_sign_holder_commitment(
1479 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1480 ) -> Result<Signature, ()> {
1481 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1482 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1483 let funding_redeemscript =
1484 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1485 let trusted_tx = commitment_tx.trust();
1486 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1488 &funding_redeemscript,
1489 self.channel_value_satoshis,
1495 fn sign_justice_revoked_output(
1496 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1497 secp_ctx: &Secp256k1<secp256k1::All>,
1498 ) -> Result<Signature, ()> {
1499 let revocation_key = chan_utils::derive_private_revocation_key(
1501 &per_commitment_key,
1502 &self.revocation_base_key,
1504 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1505 let revocation_pubkey = RevocationKey::from_basepoint(
1507 &self.pubkeys().revocation_basepoint,
1508 &per_commitment_point,
1510 let witness_script = {
1511 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1512 let holder_selected_contest_delay =
1513 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1514 let counterparty_delayedpubkey = DelayedPaymentKey::from_basepoint(
1516 &counterparty_keys.delayed_payment_basepoint,
1517 &per_commitment_point,
1519 chan_utils::get_revokeable_redeemscript(
1521 holder_selected_contest_delay,
1522 &counterparty_delayedpubkey,
1525 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1526 let sighash = hash_to_message!(
1528 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1531 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1534 fn sign_justice_revoked_htlc(
1535 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1536 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1537 ) -> Result<Signature, ()> {
1538 let revocation_key = chan_utils::derive_private_revocation_key(
1540 &per_commitment_key,
1541 &self.revocation_base_key,
1543 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1544 let revocation_pubkey = RevocationKey::from_basepoint(
1546 &self.pubkeys().revocation_basepoint,
1547 &per_commitment_point,
1549 let witness_script = {
1550 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1551 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1553 &counterparty_keys.htlc_basepoint,
1554 &per_commitment_point,
1556 let holder_htlcpubkey = HtlcKey::from_basepoint(
1558 &self.pubkeys().htlc_basepoint,
1559 &per_commitment_point,
1561 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1562 chan_utils::get_htlc_redeemscript_with_explicit_keys(
1565 &counterparty_htlcpubkey,
1570 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1571 let sighash = hash_to_message!(
1573 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1576 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1579 fn sign_holder_htlc_transaction(
1580 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1581 secp_ctx: &Secp256k1<secp256k1::All>,
1582 ) -> Result<Signature, ()> {
1583 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1584 let sighash = &sighash::SighashCache::new(&*htlc_tx)
1585 .segwit_signature_hash(
1588 htlc_descriptor.htlc.amount_msat / 1000,
1589 EcdsaSighashType::All,
1592 let our_htlc_private_key = chan_utils::derive_private_key(
1594 &htlc_descriptor.per_commitment_point,
1595 &self.htlc_base_key,
1597 let sighash = hash_to_message!(sighash.as_byte_array());
1598 Ok(sign_with_aux_rand(&secp_ctx, &sighash, &our_htlc_private_key, &self))
1601 fn sign_counterparty_htlc_transaction(
1602 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1603 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1604 ) -> Result<Signature, ()> {
1606 chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1607 let revocation_pubkey = RevocationKey::from_basepoint(
1609 &self.pubkeys().revocation_basepoint,
1610 &per_commitment_point,
1612 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1613 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1615 &counterparty_keys.htlc_basepoint,
1616 &per_commitment_point,
1618 let htlc_basepoint = self.pubkeys().htlc_basepoint;
1619 let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &htlc_basepoint, &per_commitment_point);
1620 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1621 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(
1624 &counterparty_htlcpubkey,
1628 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1629 let sighash = hash_to_message!(
1631 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1634 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1637 fn sign_closing_transaction(
1638 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1639 ) -> Result<Signature, ()> {
1640 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1641 let counterparty_funding_key =
1642 &self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
1643 let channel_funding_redeemscript =
1644 make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
1645 Ok(closing_tx.trust().sign(
1647 &channel_funding_redeemscript,
1648 self.channel_value_satoshis,
1653 fn sign_holder_anchor_input(
1654 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1655 ) -> Result<Signature, ()> {
1656 let witness_script =
1657 chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1658 let sighash = sighash::SighashCache::new(&*anchor_tx)
1659 .segwit_signature_hash(
1662 ANCHOR_OUTPUT_VALUE_SATOSHI,
1663 EcdsaSighashType::All,
1666 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1669 fn sign_channel_announcement_with_funding_key(
1670 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>,
1671 ) -> Result<Signature, ()> {
1672 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1673 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1678 impl TaprootChannelSigner for InMemorySigner {
1679 fn generate_local_nonce_pair(
1680 &self, commitment_number: u64, secp_ctx: &Secp256k1<All>,
1685 fn partially_sign_counterparty_commitment(
1686 &self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction,
1687 inbound_htlc_preimages: Vec<PaymentPreimage>,
1688 outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>,
1689 ) -> Result<(PartialSignatureWithNonce, Vec<schnorr::Signature>), ()> {
1693 fn finalize_holder_commitment(
1694 &self, commitment_tx: &HolderCommitmentTransaction,
1695 counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>,
1696 ) -> Result<PartialSignature, ()> {
1700 fn sign_justice_revoked_output(
1701 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1702 secp_ctx: &Secp256k1<All>,
1703 ) -> Result<schnorr::Signature, ()> {
1707 fn sign_justice_revoked_htlc(
1708 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1709 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1710 ) -> Result<schnorr::Signature, ()> {
1714 fn sign_holder_htlc_transaction(
1715 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1716 secp_ctx: &Secp256k1<All>,
1717 ) -> Result<schnorr::Signature, ()> {
1721 fn sign_counterparty_htlc_transaction(
1722 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1723 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1724 ) -> Result<schnorr::Signature, ()> {
1728 fn partially_sign_closing_transaction(
1729 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>,
1730 ) -> Result<PartialSignature, ()> {
1734 fn sign_holder_anchor_input(
1735 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>,
1736 ) -> Result<schnorr::Signature, ()> {
1741 const SERIALIZATION_VERSION: u8 = 1;
1743 const MIN_SERIALIZATION_VERSION: u8 = 1;
1745 impl WriteableEcdsaChannelSigner for InMemorySigner {}
1747 impl Writeable for InMemorySigner {
1748 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1749 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1751 self.funding_key.write(writer)?;
1752 self.revocation_base_key.write(writer)?;
1753 self.payment_key.write(writer)?;
1754 self.delayed_payment_base_key.write(writer)?;
1755 self.htlc_base_key.write(writer)?;
1756 self.commitment_seed.write(writer)?;
1757 self.channel_parameters.write(writer)?;
1758 self.channel_value_satoshis.write(writer)?;
1759 self.channel_keys_id.write(writer)?;
1761 write_tlv_fields!(writer, {});
1767 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner
1769 ES::Target: EntropySource,
1771 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1772 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1774 let funding_key = Readable::read(reader)?;
1775 let revocation_base_key = Readable::read(reader)?;
1776 let payment_key = Readable::read(reader)?;
1777 let delayed_payment_base_key = Readable::read(reader)?;
1778 let htlc_base_key = Readable::read(reader)?;
1779 let commitment_seed = Readable::read(reader)?;
1780 let counterparty_channel_data = Readable::read(reader)?;
1781 let channel_value_satoshis = Readable::read(reader)?;
1782 let secp_ctx = Secp256k1::signing_only();
1783 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1786 &revocation_base_key,
1788 &delayed_payment_base_key,
1791 let keys_id = Readable::read(reader)?;
1793 read_tlv_fields!(reader, {});
1797 revocation_base_key,
1799 delayed_payment_base_key,
1802 channel_value_satoshis,
1803 holder_channel_pubkeys,
1804 channel_parameters: counterparty_channel_data,
1805 channel_keys_id: keys_id,
1806 entropy_source: RandomBytes::new(entropy_source.get_secure_random_bytes()),
1811 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1812 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1814 /// Your `node_id` is seed/0'.
1815 /// Unilateral closes may use seed/1'.
1816 /// Cooperative closes may use seed/2'.
1817 /// The two close keys may be needed to claim on-chain funds!
1819 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1820 /// [`PhantomKeysManager`] must be used instead.
1822 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1823 /// previously issued invoices and attempts to pay previous invoices will fail.
1824 pub struct KeysManager {
1825 secp_ctx: Secp256k1<secp256k1::All>,
1826 node_secret: SecretKey,
1828 inbound_payment_key: KeyMaterial,
1829 destination_script: ScriptBuf,
1830 shutdown_pubkey: PublicKey,
1831 channel_master_key: ExtendedPrivKey,
1832 channel_child_index: AtomicUsize,
1834 entropy_source: RandomBytes,
1837 starting_time_secs: u64,
1838 starting_time_nanos: u32,
1842 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1843 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1844 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1845 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1846 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1847 /// is to simply use the current time (with very high precision).
1849 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1850 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1851 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1854 /// Note that the seed is required to recover certain on-chain funds independent of
1855 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1856 /// for any channel, and some on-chain during-closing funds.
1858 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1859 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1860 let secp_ctx = Secp256k1::new();
1861 // Note that when we aren't serializing the key, network doesn't matter
1862 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1864 let node_secret = master_key
1865 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap())
1866 .expect("Your RNG is busted")
1868 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1869 let destination_script = match master_key
1870 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap())
1872 Ok(destination_key) => {
1873 let wpubkey_hash = WPubkeyHash::hash(
1874 &ExtendedPubKey::from_priv(&secp_ctx, &destination_key)
1879 .push_opcode(opcodes::all::OP_PUSHBYTES_0)
1880 .push_slice(&wpubkey_hash.to_byte_array())
1883 Err(_) => panic!("Your RNG is busted"),
1885 let shutdown_pubkey = match master_key
1886 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap())
1888 Ok(shutdown_key) => {
1889 ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key
1891 Err(_) => panic!("Your RNG is busted"),
1893 let channel_master_key = master_key
1894 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap())
1895 .expect("Your RNG is busted");
1896 let inbound_payment_key: SecretKey = master_key
1897 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap())
1898 .expect("Your RNG is busted")
1900 let mut inbound_pmt_key_bytes = [0; 32];
1901 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1903 let mut rand_bytes_engine = Sha256::engine();
1904 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1905 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1906 rand_bytes_engine.input(seed);
1907 rand_bytes_engine.input(b"LDK PRNG Seed");
1908 let rand_bytes_unique_start =
1909 Sha256::from_engine(rand_bytes_engine).to_byte_array();
1911 let mut res = KeysManager {
1915 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1921 channel_child_index: AtomicUsize::new(0),
1923 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1927 starting_time_nanos,
1929 let secp_seed = res.get_secure_random_bytes();
1930 res.secp_ctx.seeded_randomize(&secp_seed);
1933 Err(_) => panic!("Your rng is busted"),
1937 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1938 pub fn get_node_secret_key(&self) -> SecretKey {
1942 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1943 pub fn derive_channel_keys(
1944 &self, channel_value_satoshis: u64, params: &[u8; 32],
1945 ) -> InMemorySigner {
1946 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1947 let mut unique_start = Sha256::engine();
1948 unique_start.input(params);
1949 unique_start.input(&self.seed);
1951 // We only seriously intend to rely on the channel_master_key for true secure
1952 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1953 // starting_time provided in the constructor) to be unique.
1954 let child_privkey = self
1958 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31))
1959 .expect("key space exhausted"),
1961 .expect("Your RNG is busted");
1962 unique_start.input(&child_privkey.private_key[..]);
1964 let seed = Sha256::from_engine(unique_start).to_byte_array();
1966 let commitment_seed = {
1967 let mut sha = Sha256::engine();
1969 sha.input(&b"commitment seed"[..]);
1970 Sha256::from_engine(sha).to_byte_array()
1972 macro_rules! key_step {
1973 ($info: expr, $prev_key: expr) => {{
1974 let mut sha = Sha256::engine();
1976 sha.input(&$prev_key[..]);
1977 sha.input(&$info[..]);
1978 SecretKey::from_slice(&Sha256::from_engine(sha).to_byte_array())
1979 .expect("SHA-256 is busted")
1982 let funding_key = key_step!(b"funding key", commitment_seed);
1983 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1984 let payment_key = key_step!(b"payment key", revocation_base_key);
1985 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1986 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1987 let prng_seed = self.get_secure_random_bytes();
1989 InMemorySigner::new(
1992 revocation_base_key,
1994 delayed_payment_base_key,
1997 channel_value_satoshis,
2003 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
2004 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
2005 /// are no other inputs that need signing.
2007 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
2009 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2010 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2011 pub fn sign_spendable_outputs_psbt<C: Signing>(
2012 &self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction,
2013 secp_ctx: &Secp256k1<C>,
2014 ) -> Result<PartiallySignedTransaction, ()> {
2015 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
2016 for outp in descriptors {
2017 let get_input_idx = |outpoint: &OutPoint| {
2021 .position(|i| i.previous_output == outpoint.into_bitcoin_outpoint())
2025 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
2026 let input_idx = get_input_idx(&descriptor.outpoint)?;
2027 if keys_cache.is_none()
2028 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2030 let mut signer = self.derive_channel_keys(
2031 descriptor.channel_value_satoshis,
2032 &descriptor.channel_keys_id,
2034 if let Some(channel_params) =
2035 descriptor.channel_transaction_parameters.as_ref()
2037 signer.provide_channel_parameters(channel_params);
2039 keys_cache = Some((signer, descriptor.channel_keys_id));
2041 let witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(
2047 psbt.inputs[input_idx].final_script_witness = Some(witness);
2049 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
2050 let input_idx = get_input_idx(&descriptor.outpoint)?;
2051 if keys_cache.is_none()
2052 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2055 self.derive_channel_keys(
2056 descriptor.channel_value_satoshis,
2057 &descriptor.channel_keys_id,
2059 descriptor.channel_keys_id,
2062 let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(
2068 psbt.inputs[input_idx].final_script_witness = Some(witness);
2070 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
2071 let input_idx = get_input_idx(outpoint)?;
2072 let derivation_idx =
2073 if output.script_pubkey == self.destination_script { 1 } else { 2 };
2075 // Note that when we aren't serializing the key, network doesn't matter
2076 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
2078 match master_key.ckd_priv(
2080 ChildNumber::from_hardened_idx(derivation_idx)
2081 .expect("key space exhausted"),
2084 Err(_) => panic!("Your RNG is busted"),
2087 Err(_) => panic!("Your rng is busted"),
2090 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
2091 if derivation_idx == 2 {
2092 assert_eq!(pubkey.inner, self.shutdown_pubkey);
2094 let witness_script =
2095 bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
2096 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet)
2097 .expect("uncompressed key found")
2100 if payment_script != output.script_pubkey {
2104 let sighash = hash_to_message!(
2105 &sighash::SighashCache::new(&psbt.unsigned_tx)
2106 .segwit_signature_hash(
2110 EcdsaSighashType::All
2114 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
2115 let mut sig_ser = sig.serialize_der().to_vec();
2116 sig_ser.push(EcdsaSighashType::All as u8);
2118 Witness::from_slice(&[&sig_ser, &pubkey.inner.serialize().to_vec()]);
2119 psbt.inputs[input_idx].final_script_witness = Some(witness);
2128 impl EntropySource for KeysManager {
2129 fn get_secure_random_bytes(&self) -> [u8; 32] {
2130 self.entropy_source.get_secure_random_bytes()
2134 impl NodeSigner for KeysManager {
2135 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2137 Recipient::Node => Ok(self.node_id.clone()),
2138 Recipient::PhantomNode => Err(()),
2143 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2144 ) -> Result<SharedSecret, ()> {
2145 let mut node_secret = match recipient {
2146 Recipient::Node => Ok(self.node_secret.clone()),
2147 Recipient::PhantomNode => Err(()),
2149 if let Some(tweak) = tweak {
2150 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2152 Ok(SharedSecret::new(other_key, &node_secret))
2155 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2156 self.inbound_payment_key.clone()
2160 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2161 ) -> Result<RecoverableSignature, ()> {
2162 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2163 let secret = match recipient {
2164 Recipient::Node => Ok(&self.node_secret),
2165 Recipient::PhantomNode => Err(()),
2167 Ok(self.secp_ctx.sign_ecdsa_recoverable(
2168 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2173 fn sign_bolt12_invoice_request(
2174 &self, invoice_request: &UnsignedInvoiceRequest,
2175 ) -> Result<schnorr::Signature, ()> {
2176 let message = invoice_request.tagged_hash().as_digest();
2177 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
2178 let aux_rand = self.get_secure_random_bytes();
2179 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
2182 fn sign_bolt12_invoice(
2183 &self, invoice: &UnsignedBolt12Invoice,
2184 ) -> Result<schnorr::Signature, ()> {
2185 let message = invoice.tagged_hash().as_digest();
2186 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
2187 let aux_rand = self.get_secure_random_bytes();
2188 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
2191 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2192 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
2193 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
2197 impl OutputSpender for KeysManager {
2198 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
2199 /// output to the given change destination (if sufficient change value remains).
2201 /// See [`OutputSpender::spend_spendable_outputs`] documentation for more information.
2203 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
2205 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2206 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2207 fn spend_spendable_outputs<C: Signing>(
2208 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2209 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2210 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2211 ) -> Result<Transaction, ()> {
2212 let (mut psbt, expected_max_weight) =
2213 SpendableOutputDescriptor::create_spendable_outputs_psbt(
2217 change_destination_script,
2218 feerate_sat_per_1000_weight,
2221 psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
2223 let spend_tx = psbt.extract_tx();
2225 debug_assert!(expected_max_weight >= spend_tx.weight().to_wu());
2226 // Note that witnesses with a signature vary somewhat in size, so allow
2227 // `expected_max_weight` to overshoot by up to 3 bytes per input.
2229 expected_max_weight <= spend_tx.weight().to_wu() + descriptors.len() as u64 * 3
2236 impl SignerProvider for KeysManager {
2237 type EcdsaSigner = InMemorySigner;
2239 type TaprootSigner = InMemorySigner;
2241 fn generate_channel_keys_id(
2242 &self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128,
2244 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
2245 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
2246 // (though `user_channel_id` should help, depending on user behavior). If it manages to
2247 // roll over, we may generate duplicate keys for two different channels, which could result
2248 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
2249 // doesn't reach `u32::MAX`.
2250 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
2251 let mut id = [0; 32];
2252 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
2253 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
2254 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
2255 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
2259 fn derive_channel_signer(
2260 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2261 ) -> Self::EcdsaSigner {
2262 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
2265 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2266 InMemorySigner::read(&mut io::Cursor::new(reader), self)
2269 fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2270 Ok(self.destination_script.clone())
2273 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2274 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
2278 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
2281 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
2282 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
2283 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
2284 /// itself without ever needing to forward to this fake node.
2286 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
2287 /// provide some fault tolerance, because payers will automatically retry paying other provided
2288 /// nodes in the case that one node goes down.
2290 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
2291 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
2292 // nodes to know when the full payment has been received (and the preimage can be released) without
2293 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
2294 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
2295 // is released too early.
2297 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
2298 /// invoices and attempts to pay previous invoices will fail.
2299 pub struct PhantomKeysManager {
2301 inbound_payment_key: KeyMaterial,
2302 phantom_secret: SecretKey,
2303 phantom_node_id: PublicKey,
2306 impl EntropySource for PhantomKeysManager {
2307 fn get_secure_random_bytes(&self) -> [u8; 32] {
2308 self.inner.get_secure_random_bytes()
2312 impl NodeSigner for PhantomKeysManager {
2313 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2315 Recipient::Node => self.inner.get_node_id(Recipient::Node),
2316 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
2321 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2322 ) -> Result<SharedSecret, ()> {
2323 let mut node_secret = match recipient {
2324 Recipient::Node => self.inner.node_secret.clone(),
2325 Recipient::PhantomNode => self.phantom_secret.clone(),
2327 if let Some(tweak) = tweak {
2328 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2330 Ok(SharedSecret::new(other_key, &node_secret))
2333 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2334 self.inbound_payment_key.clone()
2338 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2339 ) -> Result<RecoverableSignature, ()> {
2340 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2341 let secret = match recipient {
2342 Recipient::Node => &self.inner.node_secret,
2343 Recipient::PhantomNode => &self.phantom_secret,
2345 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(
2346 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2351 fn sign_bolt12_invoice_request(
2352 &self, invoice_request: &UnsignedInvoiceRequest,
2353 ) -> Result<schnorr::Signature, ()> {
2354 self.inner.sign_bolt12_invoice_request(invoice_request)
2357 fn sign_bolt12_invoice(
2358 &self, invoice: &UnsignedBolt12Invoice,
2359 ) -> Result<schnorr::Signature, ()> {
2360 self.inner.sign_bolt12_invoice(invoice)
2363 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2364 self.inner.sign_gossip_message(msg)
2368 impl OutputSpender for PhantomKeysManager {
2369 /// See [`OutputSpender::spend_spendable_outputs`] and [`KeysManager::spend_spendable_outputs`]
2370 /// for documentation on this method.
2371 fn spend_spendable_outputs<C: Signing>(
2372 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2373 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2374 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2375 ) -> Result<Transaction, ()> {
2376 self.inner.spend_spendable_outputs(
2379 change_destination_script,
2380 feerate_sat_per_1000_weight,
2387 impl SignerProvider for PhantomKeysManager {
2388 type EcdsaSigner = InMemorySigner;
2390 type TaprootSigner = InMemorySigner;
2392 fn generate_channel_keys_id(
2393 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
2395 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
2398 fn derive_channel_signer(
2399 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2400 ) -> Self::EcdsaSigner {
2401 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
2404 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2405 self.inner.read_chan_signer(reader)
2408 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2409 self.inner.get_destination_script(channel_keys_id)
2412 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2413 self.inner.get_shutdown_scriptpubkey()
2417 impl PhantomKeysManager {
2418 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
2419 /// that is shared across all nodes that intend to participate in [phantom node payments]
2422 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
2423 /// `starting_time_nanos`.
2425 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
2426 /// same across restarts, or else inbound payments may fail.
2428 /// [phantom node payments]: PhantomKeysManager
2430 seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32,
2431 cross_node_seed: &[u8; 32],
2433 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
2434 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(
2435 b"LDK Inbound and Phantom Payment Key Expansion",
2438 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
2439 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
2442 inbound_payment_key: KeyMaterial(inbound_key),
2448 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
2449 pub fn derive_channel_keys(
2450 &self, channel_value_satoshis: u64, params: &[u8; 32],
2451 ) -> InMemorySigner {
2452 self.inner.derive_channel_keys(channel_value_satoshis, params)
2455 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
2456 pub fn get_node_secret_key(&self) -> SecretKey {
2457 self.inner.get_node_secret_key()
2460 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
2461 /// last-hop onion data, etc.
2462 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
2467 /// An implementation of [`EntropySource`] using ChaCha20.
2469 pub struct RandomBytes {
2470 /// Seed from which all randomness produced is derived from.
2472 /// Tracks the number of times we've produced randomness to ensure we don't return the same
2474 index: AtomicCounter,
2478 /// Creates a new instance using the given seed.
2479 pub fn new(seed: [u8; 32]) -> Self {
2480 Self { seed, index: AtomicCounter::new() }
2484 impl EntropySource for RandomBytes {
2485 fn get_secure_random_bytes(&self) -> [u8; 32] {
2486 let index = self.index.get_increment();
2487 let mut nonce = [0u8; 16];
2488 nonce[..8].copy_from_slice(&index.to_be_bytes());
2489 ChaCha20::get_single_block(&self.seed, &nonce)
2493 // Ensure that EcdsaChannelSigner can have a vtable
2496 let _signer: Box<dyn EcdsaChannelSigner>;
2501 use crate::sign::{EntropySource, KeysManager};
2502 use bitcoin::blockdata::constants::genesis_block;
2503 use bitcoin::Network;
2504 use std::sync::mpsc::TryRecvError;
2505 use std::sync::{mpsc, Arc};
2507 use std::time::Duration;
2509 use criterion::Criterion;
2511 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
2512 let seed = [0u8; 32];
2513 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
2514 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
2516 let mut handles = Vec::new();
2517 let mut stops = Vec::new();
2519 let keys_manager_clone = Arc::clone(&keys_manager);
2520 let (stop_sender, stop_receiver) = mpsc::channel();
2521 let handle = thread::spawn(move || loop {
2522 keys_manager_clone.get_secure_random_bytes();
2523 match stop_receiver.try_recv() {
2524 Ok(_) | Err(TryRecvError::Disconnected) => {
2525 println!("Terminating.");
2528 Err(TryRecvError::Empty) => {},
2531 handles.push(handle);
2532 stops.push(stop_sender);
2535 bench.bench_function("get_secure_random_bytes", |b| {
2536 b.iter(|| keys_manager.get_secure_random_bytes())
2540 let _ = stop.send(());
2542 for handle in handles {
2543 handle.join().unwrap();