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 get_revokeable_redeemscript, make_funding_redeemscript, ChannelPublicKeys,
44 ChannelTransactionParameters, ClosingTransaction, CommitmentTransaction,
45 HTLCOutputInCommitment, HolderCommitmentTransaction,
47 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
48 use crate::ln::channel_keys::{
49 add_public_key_tweak, DelayedPaymentBasepoint, DelayedPaymentKey, HtlcBasepoint, HtlcKey,
50 RevocationBasepoint, RevocationKey,
53 use crate::ln::msgs::PartialSignatureWithNonce;
54 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
55 use crate::ln::script::ShutdownScript;
56 use crate::ln::{chan_utils, PaymentPreimage};
57 use crate::offers::invoice::UnsignedBolt12Invoice;
58 use crate::offers::invoice_request::UnsignedInvoiceRequest;
59 use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer};
60 use crate::util::transaction_utils;
62 use crate::crypto::chacha20::ChaCha20;
63 use crate::io::{self, Error};
64 use crate::ln::features::ChannelTypeFeatures;
65 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
66 use crate::prelude::*;
67 use crate::sign::ecdsa::{EcdsaChannelSigner, WriteableEcdsaChannelSigner};
69 use crate::sign::taproot::TaprootChannelSigner;
70 use crate::util::atomic_counter::AtomicCounter;
71 use crate::util::invoice::construct_invoice_preimage;
72 use core::convert::TryInto;
74 use core::sync::atomic::{AtomicUsize, Ordering};
76 use musig2::types::{PartialSignature, PublicNonce};
78 pub(crate) mod type_resolver;
84 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
85 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
87 /// This is not exported to bindings users as we just use `[u8; 32]` directly
88 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
89 pub struct KeyMaterial(pub [u8; 32]);
91 /// Information about a spendable output to a P2WSH script.
93 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
94 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
95 pub struct DelayedPaymentOutputDescriptor {
96 /// The outpoint which is spendable.
97 pub outpoint: OutPoint,
98 /// Per commitment point to derive the delayed payment key by key holder.
99 pub per_commitment_point: PublicKey,
100 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
101 /// the witness_script.
102 pub to_self_delay: u16,
103 /// The output which is referenced by the given outpoint.
105 /// The revocation point specific to the commitment transaction which was broadcast. Used to
106 /// derive the witnessScript for this output.
107 pub revocation_pubkey: RevocationKey,
108 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
109 /// This may be useful in re-deriving keys used in the channel to spend the output.
110 pub channel_keys_id: [u8; 32],
111 /// The value of the channel which this output originated from, possibly indirectly.
112 pub channel_value_satoshis: u64,
113 /// The channel public keys and other parameters needed to generate a spending transaction or
114 /// to provide to a re-derived signer through [`ChannelSigner::provide_channel_parameters`].
116 /// Added as optional, but always `Some` if the descriptor was produced in v0.0.123 or later.
117 pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
120 impl DelayedPaymentOutputDescriptor {
121 /// The maximum length a well-formed witness spending one of these should have.
122 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
124 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
125 // redeemscript push length.
126 pub const MAX_WITNESS_LENGTH: u64 =
127 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH as u64 + 1;
130 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
131 (0, outpoint, required),
132 (2, per_commitment_point, required),
133 (4, to_self_delay, required),
134 (6, output, required),
135 (8, revocation_pubkey, required),
136 (10, channel_keys_id, required),
137 (12, channel_value_satoshis, required),
138 (13, channel_transaction_parameters, option),
141 pub(crate) const P2WPKH_WITNESS_WEIGHT: u64 = 1 /* num stack items */ +
143 73 /* sig including sighash flag */ +
144 1 /* pubkey length */ +
147 /// Information about a spendable output to our "payment key".
149 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
150 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
151 pub struct StaticPaymentOutputDescriptor {
152 /// The outpoint which is spendable.
153 pub outpoint: OutPoint,
154 /// The output which is referenced by the given outpoint.
156 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
157 /// This may be useful in re-deriving keys used in the channel to spend the output.
158 pub channel_keys_id: [u8; 32],
159 /// The value of the channel which this transactions spends.
160 pub channel_value_satoshis: u64,
161 /// The necessary channel parameters that need to be provided to the re-derived signer through
162 /// [`ChannelSigner::provide_channel_parameters`].
164 /// Added as optional, but always `Some` if the descriptor was produced in v0.0.117 or later.
165 pub channel_transaction_parameters: Option<ChannelTransactionParameters>,
168 impl StaticPaymentOutputDescriptor {
169 /// Returns the `witness_script` of the spendable output.
171 /// Note that this will only return `Some` for [`StaticPaymentOutputDescriptor`]s that
172 /// originated from an anchor outputs channel, as they take the form of a P2WSH script.
173 pub fn witness_script(&self) -> Option<ScriptBuf> {
174 self.channel_transaction_parameters.as_ref().and_then(|channel_params| {
175 if channel_params.supports_anchors() {
176 let payment_point = channel_params.holder_pubkeys.payment_point;
177 Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
184 /// The maximum length a well-formed witness spending one of these should have.
185 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
187 pub fn max_witness_length(&self) -> u64 {
188 if self.channel_transaction_parameters.as_ref().map_or(false, |p| p.supports_anchors()) {
189 let witness_script_weight = 1 /* pubkey push */ + 33 /* pubkey */ +
190 1 /* OP_CHECKSIGVERIFY */ + 1 /* OP_1 */ + 1 /* OP_CHECKSEQUENCEVERIFY */;
191 1 /* num witness items */ + 1 /* sig push */ + 73 /* sig including sighash flag */ +
192 1 /* witness script push */ + witness_script_weight
194 P2WPKH_WITNESS_WEIGHT
198 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
199 (0, outpoint, required),
200 (2, output, required),
201 (4, channel_keys_id, required),
202 (6, channel_value_satoshis, required),
203 (7, channel_transaction_parameters, option),
206 /// Describes the necessary information to spend a spendable output.
208 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
209 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
210 /// to spend on-chain. The information needed to do this is provided in this enum, including the
211 /// outpoint describing which `txid` and output `index` is available, the full output which exists
212 /// at that `txid`/`index`, and any keys or other information required to sign.
214 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
215 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
216 pub enum SpendableOutputDescriptor {
217 /// An output to a script which was provided via [`SignerProvider`] directly, either from
218 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
219 /// know how to spend it. No secret keys are provided as LDK was never given any key.
220 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
221 /// on-chain using the payment preimage or after it has timed out.
223 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
224 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
226 /// The outpoint which is spendable.
228 /// The output which is referenced by the given outpoint.
230 /// The `channel_keys_id` for the channel which this output came from.
232 /// For channels which were generated on LDK 0.0.119 or later, this is the value which was
233 /// passed to the [`SignerProvider::get_destination_script`] call which provided this
236 /// For channels which were generated prior to LDK 0.0.119, no such argument existed,
237 /// however this field may still be filled in if such data is available.
238 channel_keys_id: Option<[u8; 32]>,
240 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
243 /// The witness in the spending input should be:
245 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
248 /// Note that the `nSequence` field in the spending input must be set to
249 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
250 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
251 /// the outpoint confirms, see [BIP
252 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
253 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
256 /// These are generally the result of a "revocable" output to us, spendable only by us unless
257 /// it is an output from an old state which we broadcast (which should never happen).
259 /// To derive the delayed payment key which is used to sign this input, you must pass the
260 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
261 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
262 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The DelayedPaymentKey can be
263 /// generated without the secret key using [`DelayedPaymentKey::from_basepoint`] and only the
264 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
266 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
267 /// used in the witness script generation), you must pass the counterparty
268 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
269 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
270 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
271 /// [`RevocationKey`].
273 /// The witness script which is hashed and included in the output `script_pubkey` may be
274 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
275 /// as explained above), our delayed payment pubkey (derived as explained above), and the
276 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
277 /// [`chan_utils::get_revokeable_redeemscript`].
278 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
279 /// An output spendable exclusively by our payment key (i.e., the private key that corresponds
280 /// to the `payment_point` in [`ChannelSigner::pubkeys`]). The output type depends on the
281 /// channel type negotiated.
283 /// On an anchor outputs channel, the witness in the spending input is:
285 /// <BIP 143 signature> <witness script>
288 /// Otherwise, it is:
290 /// <BIP 143 signature> <payment key>
293 /// These are generally the result of our counterparty having broadcast the current state,
294 /// allowing us to claim the non-HTLC-encumbered outputs immediately, or after one confirmation
295 /// in the case of anchor outputs channels.
296 StaticPaymentOutput(StaticPaymentOutputDescriptor),
299 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
300 (0, StaticOutput) => {
301 (0, outpoint, required),
302 (1, channel_keys_id, option),
303 (2, output, required),
306 (1, DelayedPaymentOutput),
307 (2, StaticPaymentOutput),
310 impl SpendableOutputDescriptor {
311 /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
312 /// [`PartiallySignedTransaction`] which spends the given descriptor.
314 /// Note that this does not include any signatures, just the information required to
315 /// construct the transaction and sign it.
317 /// This is not exported to bindings users as there is no standard serialization for an input.
318 /// See [`Self::create_spendable_outputs_psbt`] instead.
320 /// The proprietary field is used to store add tweak for the signing key of this transaction.
321 /// See the [`DelayedPaymentBasepoint::derive_add_tweak`] docs for more info on add tweak and how to use it.
323 /// To get the proprietary field use:
325 /// use bitcoin::psbt::{PartiallySignedTransaction};
326 /// use bitcoin::hashes::hex::FromHex;
328 /// # let s = "70736274ff0100520200000001dee978529ab3e61a2987bea5183713d0e6d5ceb5ac81100fdb54a1a2\
329 /// # 69cef505000000000090000000011f26000000000000160014abb3ab63280d4ccc5c11d6b50fd427a8\
330 /// # e19d6470000000000001012b10270000000000002200200afe4736760d814a2651bae63b572d935d9a\
331 /// # b74a1a16c01774e341a32afa763601054d63210394a27a700617f5b7aee72bd4f8076b5770a582b7fb\
332 /// # d1d4ee2ea3802cd3cfbe2067029000b27521034629b1c8fdebfaeb58a74cd181f485e2c462e594cb30\
333 /// # 34dee655875f69f6c7c968ac20fc144c444b5f7370656e6461626c655f6f7574707574006164645f74\
334 /// # 7765616b20a86534f38ad61dc580ef41c3886204adf0911b81619c1ad7a2f5b5de39a2ba600000";
335 /// # let psbt = PartiallySignedTransaction::deserialize(<Vec<u8> as FromHex>::from_hex(s).unwrap().as_slice()).unwrap();
336 /// let key = bitcoin::psbt::raw::ProprietaryKey {
337 /// prefix: "LDK_spendable_output".as_bytes().to_vec(),
339 /// key: "add_tweak".as_bytes().to_vec(),
344 /// .expect("Unable to get add tweak as there are no inputs")
347 /// .map(|x| x.to_owned());
349 pub fn to_psbt_input<T: secp256k1::Signing>(
350 &self, secp_ctx: &Secp256k1<T>,
351 ) -> bitcoin::psbt::Input {
353 SpendableOutputDescriptor::StaticOutput { output, .. } => {
354 // Is a standard P2WPKH, no need for witness script
355 bitcoin::psbt::Input { witness_utxo: Some(output.clone()), ..Default::default() }
357 SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
358 channel_transaction_parameters,
359 per_commitment_point,
365 let delayed_payment_basepoint = channel_transaction_parameters
367 .map(|params| params.holder_pubkeys.delayed_payment_basepoint);
369 let (witness_script, add_tweak) =
370 if let Some(basepoint) = delayed_payment_basepoint.as_ref() {
371 // Required to derive signing key: privkey = basepoint_secret + SHA256(per_commitment_point || basepoint)
372 let add_tweak = basepoint.derive_add_tweak(&per_commitment_point);
373 let payment_key = DelayedPaymentKey(add_public_key_tweak(
375 &basepoint.to_public_key(),
380 Some(get_revokeable_redeemscript(
391 bitcoin::psbt::Input {
392 witness_utxo: Some(output.clone()),
394 proprietary: add_tweak
397 bitcoin::psbt::raw::ProprietaryKey {
398 // A non standard namespace for spendable outputs, used to store the tweak needed
399 // to derive the private key
400 prefix: "LDK_spendable_output".as_bytes().to_vec(),
402 key: "add_tweak".as_bytes().to_vec(),
404 add_tweak.as_byte_array().to_vec(),
409 .unwrap_or_default(),
413 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => bitcoin::psbt::Input {
414 witness_utxo: Some(descriptor.output.clone()),
415 witness_script: descriptor.witness_script(),
421 /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
422 /// the given outputs, plus an output to the given change destination (if sufficient
423 /// change value remains). The PSBT will have a feerate, at least, of the given value.
425 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
426 /// transaction will have a locktime of 0. It it recommended to set this to the current block
427 /// height to avoid fee sniping, unless you have some specific reason to use a different
430 /// Returns the PSBT and expected max transaction weight.
432 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
433 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
434 /// does not match the one we can spend.
436 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
437 pub fn create_spendable_outputs_psbt<T: secp256k1::Signing>(
438 secp_ctx: &Secp256k1<T>, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
439 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
440 locktime: Option<LockTime>,
441 ) -> Result<(PartiallySignedTransaction, u64), ()> {
442 let mut input = Vec::with_capacity(descriptors.len());
443 let mut input_value = 0;
444 let mut witness_weight = 0;
445 let mut output_set = hash_set_with_capacity(descriptors.len());
446 for outp in descriptors {
448 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
449 if !output_set.insert(descriptor.outpoint) {
452 let sequence = if descriptor
453 .channel_transaction_parameters
455 .map_or(false, |p| p.supports_anchors())
457 Sequence::from_consensus(1)
462 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
463 script_sig: ScriptBuf::new(),
465 witness: Witness::new(),
467 witness_weight += descriptor.max_witness_length();
468 #[cfg(feature = "grind_signatures")]
470 // Guarantees a low R signature
473 input_value += descriptor.output.value;
475 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
476 if !output_set.insert(descriptor.outpoint) {
480 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
481 script_sig: ScriptBuf::new(),
482 sequence: Sequence(descriptor.to_self_delay as u32),
483 witness: Witness::new(),
485 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
486 #[cfg(feature = "grind_signatures")]
488 // Guarantees a low R signature
491 input_value += descriptor.output.value;
493 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
494 if !output_set.insert(*outpoint) {
498 previous_output: outpoint.into_bitcoin_outpoint(),
499 script_sig: ScriptBuf::new(),
500 sequence: Sequence::ZERO,
501 witness: Witness::new(),
503 witness_weight += 1 + 73 + 34;
504 #[cfg(feature = "grind_signatures")]
506 // Guarantees a low R signature
509 input_value += output.value;
512 if input_value > MAX_VALUE_MSAT / 1000 {
516 let mut tx = Transaction {
518 lock_time: locktime.unwrap_or(LockTime::ZERO),
522 let expected_max_weight = transaction_utils::maybe_add_change_output(
526 feerate_sat_per_1000_weight,
527 change_destination_script,
531 descriptors.iter().map(|d| d.to_psbt_input(&secp_ctx)).collect::<Vec<_>>();
532 let psbt = PartiallySignedTransaction {
534 outputs: vec![Default::default(); tx.output.len()],
536 xpub: Default::default(),
538 proprietary: Default::default(),
539 unknown: Default::default(),
541 Ok((psbt, expected_max_weight))
545 /// The parameters required to derive a channel signer via [`SignerProvider`].
546 #[derive(Clone, Debug, PartialEq, Eq)]
547 pub struct ChannelDerivationParameters {
548 /// The value in satoshis of the channel we're attempting to spend the anchor output of.
549 pub value_satoshis: u64,
550 /// The unique identifier to re-derive the signer for the associated channel.
551 pub keys_id: [u8; 32],
552 /// The necessary channel parameters that need to be provided to the re-derived signer through
553 /// [`ChannelSigner::provide_channel_parameters`].
554 pub transaction_parameters: ChannelTransactionParameters,
557 impl_writeable_tlv_based!(ChannelDerivationParameters, {
558 (0, value_satoshis, required),
559 (2, keys_id, required),
560 (4, transaction_parameters, required),
563 /// A descriptor used to sign for a commitment transaction's HTLC output.
564 #[derive(Clone, Debug, PartialEq, Eq)]
565 pub struct HTLCDescriptor {
566 /// The parameters required to derive the signer for the HTLC input.
567 pub channel_derivation_parameters: ChannelDerivationParameters,
568 /// The txid of the commitment transaction in which the HTLC output lives.
569 pub commitment_txid: Txid,
570 /// The number of the commitment transaction in which the HTLC output lives.
571 pub per_commitment_number: u64,
572 /// The key tweak corresponding to the number of the commitment transaction in which the HTLC
573 /// output lives. This tweak is applied to all the basepoints for both parties in the channel to
574 /// arrive at unique keys per commitment.
576 /// See <https://github.com/lightning/bolts/blob/master/03-transactions.md#keys> for more info.
577 pub per_commitment_point: PublicKey,
578 /// The feerate to use on the HTLC claiming transaction. This is always `0` for HTLCs
579 /// originating from a channel supporting anchor outputs, otherwise it is the channel's
580 /// negotiated feerate at the time the commitment transaction was built.
581 pub feerate_per_kw: u32,
582 /// The details of the HTLC as it appears in the commitment transaction.
583 pub htlc: HTLCOutputInCommitment,
584 /// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
586 pub preimage: Option<PaymentPreimage>,
587 /// The counterparty's signature required to spend the HTLC output.
588 pub counterparty_sig: Signature,
591 impl_writeable_tlv_based!(HTLCDescriptor, {
592 (0, channel_derivation_parameters, required),
593 (1, feerate_per_kw, (default_value, 0)),
594 (2, commitment_txid, required),
595 (4, per_commitment_number, required),
596 (6, per_commitment_point, required),
598 (10, preimage, option),
599 (12, counterparty_sig, required),
602 impl HTLCDescriptor {
603 /// Returns the outpoint of the HTLC output in the commitment transaction. This is the outpoint
604 /// being spent by the HTLC input in the HTLC transaction.
605 pub fn outpoint(&self) -> bitcoin::OutPoint {
607 txid: self.commitment_txid,
608 vout: self.htlc.transaction_output_index.unwrap(),
612 /// Returns the UTXO to be spent by the HTLC input, which can be obtained via
613 /// [`Self::unsigned_tx_input`].
614 pub fn previous_utxo<C: secp256k1::Signing + secp256k1::Verification>(
615 &self, secp: &Secp256k1<C>,
618 script_pubkey: self.witness_script(secp).to_v0_p2wsh(),
619 value: self.htlc.amount_msat / 1000,
623 /// Returns the unsigned transaction input spending the HTLC output in the commitment
625 pub fn unsigned_tx_input(&self) -> TxIn {
626 chan_utils::build_htlc_input(
627 &self.commitment_txid,
629 &self.channel_derivation_parameters.transaction_parameters.channel_type_features,
633 /// Returns the delayed output created as a result of spending the HTLC output in the commitment
635 pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(
636 &self, secp: &Secp256k1<C>,
639 self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
640 let broadcaster_keys = channel_params.broadcaster_pubkeys();
641 let counterparty_keys = channel_params.countersignatory_pubkeys();
642 let broadcaster_delayed_key = DelayedPaymentKey::from_basepoint(
644 &broadcaster_keys.delayed_payment_basepoint,
645 &self.per_commitment_point,
647 let counterparty_revocation_key = &RevocationKey::from_basepoint(
649 &counterparty_keys.revocation_basepoint,
650 &self.per_commitment_point,
652 chan_utils::build_htlc_output(
654 channel_params.contest_delay(),
656 channel_params.channel_type_features(),
657 &broadcaster_delayed_key,
658 &counterparty_revocation_key,
662 /// Returns the witness script of the HTLC output in the commitment transaction.
663 pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(
664 &self, secp: &Secp256k1<C>,
667 self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
668 let broadcaster_keys = channel_params.broadcaster_pubkeys();
669 let counterparty_keys = channel_params.countersignatory_pubkeys();
670 let broadcaster_htlc_key = HtlcKey::from_basepoint(
672 &broadcaster_keys.htlc_basepoint,
673 &self.per_commitment_point,
675 let counterparty_htlc_key = HtlcKey::from_basepoint(
677 &counterparty_keys.htlc_basepoint,
678 &self.per_commitment_point,
680 let counterparty_revocation_key = &RevocationKey::from_basepoint(
682 &counterparty_keys.revocation_basepoint,
683 &self.per_commitment_point,
685 chan_utils::get_htlc_redeemscript_with_explicit_keys(
687 channel_params.channel_type_features(),
688 &broadcaster_htlc_key,
689 &counterparty_htlc_key,
690 &counterparty_revocation_key,
694 /// Returns the fully signed witness required to spend the HTLC output in the commitment
696 pub fn tx_input_witness(&self, signature: &Signature, witness_script: &Script) -> Witness {
697 chan_utils::build_htlc_input_witness(
699 &self.counterparty_sig,
702 &self.channel_derivation_parameters.transaction_parameters.channel_type_features,
706 /// Derives the channel signer required to sign the HTLC input.
707 pub fn derive_channel_signer<S: WriteableEcdsaChannelSigner, SP: Deref>(
708 &self, signer_provider: &SP,
711 SP::Target: SignerProvider<EcdsaSigner = S>,
713 let mut signer = signer_provider.derive_channel_signer(
714 self.channel_derivation_parameters.value_satoshis,
715 self.channel_derivation_parameters.keys_id,
718 .provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
723 /// A trait to handle Lightning channel key material without concretizing the channel type or
724 /// the signature mechanism.
725 pub trait ChannelSigner {
726 /// Gets the per-commitment point for a specific commitment number
728 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
729 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>)
732 /// Gets the commitment secret for a specific commitment number as part of the revocation process
734 /// An external signer implementation should error here if the commitment was already signed
735 /// and should refuse to sign it in the future.
737 /// May be called more than once for the same index.
739 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
740 // TODO: return a Result so we can signal a validation error
741 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
743 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
745 /// This is required in order for the signer to make sure that releasing a commitment
746 /// secret won't leave us without a broadcastable holder transaction.
747 /// Policy checks should be implemented in this function, including checking the amount
748 /// sent to us and checking the HTLCs.
750 /// The preimages of outbound HTLCs that were fulfilled since the last commitment are provided.
751 /// A validating signer should ensure that an HTLC output is removed only when the matching
752 /// preimage is provided, or when the value to holder is restored.
754 /// Note that all the relevant preimages will be provided, but there may also be additional
755 /// irrelevant or duplicate preimages.
756 fn validate_holder_commitment(
757 &self, holder_tx: &HolderCommitmentTransaction,
758 outbound_htlc_preimages: Vec<PaymentPreimage>,
761 /// Validate the counterparty's revocation.
763 /// This is required in order for the signer to make sure that the state has moved
764 /// forward and it is safe to sign the next counterparty commitment.
765 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
767 /// Returns the holder's channel public keys and basepoints.
768 fn pubkeys(&self) -> &ChannelPublicKeys;
770 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
771 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
772 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
773 fn channel_keys_id(&self) -> [u8; 32];
775 /// Set the counterparty static channel data, including basepoints,
776 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
778 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
779 /// instance, LDK will call this method exactly once - either immediately after construction
780 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
781 /// information has been generated.
783 /// channel_parameters.is_populated() MUST be true.
784 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
787 /// Specifies the recipient of an invoice.
789 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
792 /// The invoice should be signed with the local node secret key.
794 /// The invoice should be signed with the phantom node secret key. This secret key must be the
795 /// same for all nodes participating in the [phantom node payment].
797 /// [phantom node payment]: PhantomKeysManager
801 /// A trait that describes a source of entropy.
802 pub trait EntropySource {
803 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
804 /// different value each time it is called.
805 fn get_secure_random_bytes(&self) -> [u8; 32];
808 /// A trait that can handle cryptographic operations at the scope level of a node.
809 pub trait NodeSigner {
810 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
812 /// If the implementor of this trait supports [phantom node payments], then every node that is
813 /// intended to be included in the phantom invoice route hints must return the same value from
815 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
816 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
817 // nodes, they must share the key that encrypts this payment data.
819 /// This method must return the same value each time it is called.
821 /// [phantom node payments]: PhantomKeysManager
822 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
824 /// Get node id based on the provided [`Recipient`].
826 /// This method must return the same value each time it is called with a given [`Recipient`]
829 /// Errors if the [`Recipient`] variant is not supported by the implementation.
830 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
832 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
833 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
834 /// secret, though this is less efficient.
836 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
837 /// should be resolved to allow LDK to resume forwarding HTLCs.
839 /// Errors if the [`Recipient`] variant is not supported by the implementation.
841 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
842 ) -> Result<SharedSecret, ()>;
846 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
847 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
848 /// blindly signing the hash.
850 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
852 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
854 /// Errors if the [`Recipient`] variant is not supported by the implementation.
856 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
857 ) -> Result<RecoverableSignature, ()>;
859 /// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
861 /// May be called by a function passed to [`UnsignedInvoiceRequest::sign`] where
862 /// `invoice_request` is the callee.
864 /// Implementors may check that the `invoice_request` is expected rather than blindly signing
865 /// the tagged hash. An `Ok` result should sign `invoice_request.tagged_hash().as_digest()` with
866 /// the node's signing key or an ephemeral key to preserve privacy, whichever is associated with
867 /// [`UnsignedInvoiceRequest::payer_id`].
869 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
870 fn sign_bolt12_invoice_request(
871 &self, invoice_request: &UnsignedInvoiceRequest,
872 ) -> Result<schnorr::Signature, ()>;
874 /// Signs the [`TaggedHash`] of a BOLT 12 invoice.
876 /// May be called by a function passed to [`UnsignedBolt12Invoice::sign`] where `invoice` is the
879 /// Implementors may check that the `invoice` is expected rather than blindly signing the tagged
880 /// hash. An `Ok` result should sign `invoice.tagged_hash().as_digest()` with the node's signing
881 /// key or an ephemeral key to preserve privacy, whichever is associated with
882 /// [`UnsignedBolt12Invoice::signing_pubkey`].
884 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
885 fn sign_bolt12_invoice(
886 &self, invoice: &UnsignedBolt12Invoice,
887 ) -> Result<schnorr::Signature, ()>;
889 /// Sign a gossip message.
891 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
892 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
893 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
894 /// corresponding channel.
895 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
898 /// A trait that describes a wallet capable of creating a spending [`Transaction`] from a set of
899 /// [`SpendableOutputDescriptor`]s.
900 pub trait OutputSpender {
901 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
902 /// output to the given change destination (if sufficient change value remains). The
903 /// transaction will have a feerate, at least, of the given value.
905 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
906 /// transaction will have a locktime of 0. It it recommended to set this to the current block
907 /// height to avoid fee sniping, unless you have some specific reason to use a different
910 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
911 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
912 /// does not match the one we can spend.
913 fn spend_spendable_outputs<C: Signing>(
914 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
915 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
916 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
917 ) -> Result<Transaction, ()>;
920 // Primarily needed in doctests because of https://github.com/rust-lang/rust/issues/67295
921 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
924 #[deprecated(note = "Remove once taproot cfg is removed")]
925 pub type DynSignerProvider =
926 dyn SignerProvider<EcdsaSigner = InMemorySigner, TaprootSigner = InMemorySigner>;
928 /// A dynamic [`SignerProvider`] temporarily needed for doc tests.
931 #[deprecated(note = "Remove once taproot cfg is removed")]
932 pub type DynSignerProvider = dyn SignerProvider<EcdsaSigner = InMemorySigner>;
934 /// A trait that can return signer instances for individual channels.
935 pub trait SignerProvider {
936 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
937 type EcdsaSigner: WriteableEcdsaChannelSigner;
939 /// A type which implements [`TaprootChannelSigner`]
940 type TaprootSigner: TaprootChannelSigner;
942 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::EcdsaSigner`] through
943 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
944 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
945 /// `channel_keys_id`.
947 /// This method must return a different value each time it is called.
948 fn generate_channel_keys_id(
949 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
952 /// Derives the private key material backing a `Signer`.
954 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
955 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
956 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
957 /// [`ChannelSigner::channel_keys_id`].
958 fn derive_channel_signer(
959 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
960 ) -> Self::EcdsaSigner;
962 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
963 /// This is only called during deserialization of other objects which contain
964 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
965 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
966 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
967 /// you've read all of the provided bytes to ensure no corruption occurred.
969 /// This method is slowly being phased out -- it will only be called when reading objects
970 /// written by LDK versions prior to 0.0.113.
972 /// [`Signer`]: Self::EcdsaSigner
973 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
974 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
975 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError>;
977 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
979 /// If this function returns an error, this will result in a channel failing to open.
981 /// This method should return a different value each time it is called, to avoid linking
982 /// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
983 /// used to derive a unique value for each channel.
984 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
986 /// Get a script pubkey which we will send funds to when closing a channel.
988 /// If this function returns an error, this will result in a channel failing to open or close.
989 /// In the event of a failure when the counterparty is initiating a close, this can result in a
990 /// channel force close.
992 /// This method should return a different value each time it is called, to avoid linking
993 /// on-chain funds across channels as controlled to the same user.
994 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
997 /// A helper trait that describes an on-chain wallet capable of returning a (change) destination
999 pub trait ChangeDestinationSource {
1000 /// Returns a script pubkey which can be used as a change destination for
1001 /// [`OutputSpender::spend_spendable_outputs`].
1003 /// This method should return a different value each time it is called, to avoid linking
1004 /// on-chain funds controlled to the same user.
1005 fn get_change_destination_script(&self) -> Result<ScriptBuf, ()>;
1008 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
1010 /// This implementation performs no policy checks and is insufficient by itself as
1011 /// a secure external signer.
1013 pub struct InMemorySigner {
1014 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
1015 /// holder's anchor output in a commitment transaction, if one is present.
1016 pub funding_key: SecretKey,
1017 /// Holder secret key for blinded revocation pubkey.
1018 pub revocation_base_key: SecretKey,
1019 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
1020 pub payment_key: SecretKey,
1021 /// Holder secret key used in an HTLC transaction.
1022 pub delayed_payment_base_key: SecretKey,
1023 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
1024 pub htlc_base_key: SecretKey,
1025 /// Commitment seed.
1026 pub commitment_seed: [u8; 32],
1027 /// Holder public keys and basepoints.
1028 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
1029 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
1030 channel_parameters: Option<ChannelTransactionParameters>,
1031 /// The total value of this channel.
1032 channel_value_satoshis: u64,
1033 /// Key derivation parameters.
1034 channel_keys_id: [u8; 32],
1035 /// A source of random bytes.
1036 entropy_source: RandomBytes,
1039 impl PartialEq for InMemorySigner {
1040 fn eq(&self, other: &Self) -> bool {
1041 self.funding_key == other.funding_key
1042 && self.revocation_base_key == other.revocation_base_key
1043 && self.payment_key == other.payment_key
1044 && self.delayed_payment_base_key == other.delayed_payment_base_key
1045 && self.htlc_base_key == other.htlc_base_key
1046 && self.commitment_seed == other.commitment_seed
1047 && self.holder_channel_pubkeys == other.holder_channel_pubkeys
1048 && self.channel_parameters == other.channel_parameters
1049 && self.channel_value_satoshis == other.channel_value_satoshis
1050 && self.channel_keys_id == other.channel_keys_id
1054 impl Clone for InMemorySigner {
1055 fn clone(&self) -> Self {
1057 funding_key: self.funding_key.clone(),
1058 revocation_base_key: self.revocation_base_key.clone(),
1059 payment_key: self.payment_key.clone(),
1060 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
1061 htlc_base_key: self.htlc_base_key.clone(),
1062 commitment_seed: self.commitment_seed.clone(),
1063 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
1064 channel_parameters: self.channel_parameters.clone(),
1065 channel_value_satoshis: self.channel_value_satoshis,
1066 channel_keys_id: self.channel_keys_id,
1067 entropy_source: RandomBytes::new(self.get_secure_random_bytes()),
1072 impl InMemorySigner {
1073 /// Creates a new [`InMemorySigner`].
1074 pub fn new<C: Signing>(
1075 secp_ctx: &Secp256k1<C>, funding_key: SecretKey, revocation_base_key: SecretKey,
1076 payment_key: SecretKey, delayed_payment_base_key: SecretKey, htlc_base_key: SecretKey,
1077 commitment_seed: [u8; 32], channel_value_satoshis: u64, channel_keys_id: [u8; 32],
1078 rand_bytes_unique_start: [u8; 32],
1079 ) -> InMemorySigner {
1080 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1083 &revocation_base_key,
1085 &delayed_payment_base_key,
1090 revocation_base_key,
1092 delayed_payment_base_key,
1095 channel_value_satoshis,
1096 holder_channel_pubkeys,
1097 channel_parameters: None,
1099 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1103 fn make_holder_keys<C: Signing>(
1104 secp_ctx: &Secp256k1<C>, funding_key: &SecretKey, revocation_base_key: &SecretKey,
1105 payment_key: &SecretKey, delayed_payment_base_key: &SecretKey, htlc_base_key: &SecretKey,
1106 ) -> ChannelPublicKeys {
1107 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
1109 funding_pubkey: from_secret(&funding_key),
1110 revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
1111 payment_point: from_secret(&payment_key),
1112 delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(
1113 &delayed_payment_base_key,
1115 htlc_basepoint: HtlcBasepoint::from(from_secret(&htlc_base_key)),
1119 /// Returns the counterparty's pubkeys.
1121 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1122 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1123 pub fn counterparty_pubkeys(&self) -> Option<&ChannelPublicKeys> {
1124 self.get_channel_parameters().and_then(|params| {
1125 params.counterparty_parameters.as_ref().map(|params| ¶ms.pubkeys)
1129 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
1130 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
1131 /// broadcast a transaction.
1133 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1134 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1135 pub fn counterparty_selected_contest_delay(&self) -> Option<u16> {
1136 self.get_channel_parameters().and_then(|params| {
1137 params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay)
1141 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
1142 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
1143 /// if they broadcast a transaction.
1145 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1146 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1147 pub fn holder_selected_contest_delay(&self) -> Option<u16> {
1148 self.get_channel_parameters().map(|params| params.holder_selected_contest_delay)
1151 /// Returns whether the holder is the initiator.
1153 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1154 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1155 pub fn is_outbound(&self) -> Option<bool> {
1156 self.get_channel_parameters().map(|params| params.is_outbound_from_holder)
1159 /// Funding outpoint
1161 /// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
1162 /// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
1163 pub fn funding_outpoint(&self) -> Option<&OutPoint> {
1164 self.get_channel_parameters().map(|params| params.funding_outpoint.as_ref()).flatten()
1167 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
1168 /// building transactions.
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 get_channel_parameters(&self) -> Option<&ChannelTransactionParameters> {
1173 self.channel_parameters.as_ref()
1176 /// Returns the channel type features of the channel parameters. Should be helpful for
1177 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
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 channel_type_features(&self) -> Option<&ChannelTypeFeatures> {
1182 self.get_channel_parameters().map(|params| ¶ms.channel_type_features)
1185 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
1186 /// by `descriptor`, returning the witness stack for the input.
1188 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1189 /// is not spending the outpoint described by [`descriptor.outpoint`],
1190 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
1192 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
1193 pub fn sign_counterparty_payment_input<C: Signing>(
1194 &self, spend_tx: &Transaction, input_idx: usize,
1195 descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1196 ) -> Result<Witness, ()> {
1197 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1198 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1199 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1200 // bindings updates to support SigHashCache objects).
1201 if spend_tx.input.len() <= input_idx {
1204 if !spend_tx.input[input_idx].script_sig.is_empty() {
1207 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1212 let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
1213 // We cannot always assume that `channel_parameters` is set, so can't just call
1214 // `self.channel_parameters()` or anything that relies on it
1215 let supports_anchors_zero_fee_htlc_tx = self
1216 .channel_type_features()
1217 .map(|features| features.supports_anchors_zero_fee_htlc_tx())
1220 let witness_script = if supports_anchors_zero_fee_htlc_tx {
1221 chan_utils::get_to_countersignatory_with_anchors_redeemscript(&remotepubkey.inner)
1223 ScriptBuf::new_p2pkh(&remotepubkey.pubkey_hash())
1225 let sighash = hash_to_message!(
1226 &sighash::SighashCache::new(spend_tx)
1227 .segwit_signature_hash(
1230 descriptor.output.value,
1231 EcdsaSighashType::All
1235 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
1236 let payment_script = if supports_anchors_zero_fee_htlc_tx {
1237 witness_script.to_v0_p2wsh()
1239 ScriptBuf::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
1242 if payment_script != descriptor.output.script_pubkey {
1246 let mut witness = Vec::with_capacity(2);
1247 witness.push(remotesig.serialize_der().to_vec());
1248 witness[0].push(EcdsaSighashType::All as u8);
1249 if supports_anchors_zero_fee_htlc_tx {
1250 witness.push(witness_script.to_bytes());
1252 witness.push(remotepubkey.to_bytes());
1257 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
1258 /// described by `descriptor`, returning the witness stack for the input.
1260 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
1261 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
1262 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
1263 /// `script_pubkey` does not match the one we can spend.
1265 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
1266 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
1267 pub fn sign_dynamic_p2wsh_input<C: Signing>(
1268 &self, spend_tx: &Transaction, input_idx: usize,
1269 descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>,
1270 ) -> Result<Witness, ()> {
1271 // TODO: We really should be taking the SigHashCache as a parameter here instead of
1272 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
1273 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
1274 // bindings updates to support SigHashCache objects).
1275 if spend_tx.input.len() <= input_idx {
1278 if !spend_tx.input[input_idx].script_sig.is_empty() {
1281 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
1285 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 {
1289 let delayed_payment_key = chan_utils::derive_private_key(
1291 &descriptor.per_commitment_point,
1292 &self.delayed_payment_base_key,
1294 let delayed_payment_pubkey =
1295 DelayedPaymentKey::from_secret_key(&secp_ctx, &delayed_payment_key);
1296 let witness_script = chan_utils::get_revokeable_redeemscript(
1297 &descriptor.revocation_pubkey,
1298 descriptor.to_self_delay,
1299 &delayed_payment_pubkey,
1301 let sighash = hash_to_message!(
1302 &sighash::SighashCache::new(spend_tx)
1303 .segwit_signature_hash(
1306 descriptor.output.value,
1307 EcdsaSighashType::All
1311 let local_delayedsig = EcdsaSignature {
1312 sig: sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self),
1313 hash_ty: EcdsaSighashType::All,
1315 let payment_script =
1316 bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
1318 if descriptor.output.script_pubkey != payment_script {
1322 Ok(Witness::from_slice(&[
1323 &local_delayedsig.serialize()[..],
1325 witness_script.as_bytes(),
1330 impl EntropySource for InMemorySigner {
1331 fn get_secure_random_bytes(&self) -> [u8; 32] {
1332 self.entropy_source.get_secure_random_bytes()
1336 impl ChannelSigner for InMemorySigner {
1337 fn get_per_commitment_point(
1338 &self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>,
1340 let commitment_secret =
1341 SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx))
1343 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
1346 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
1347 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
1350 fn validate_holder_commitment(
1351 &self, _holder_tx: &HolderCommitmentTransaction,
1352 _outbound_htlc_preimages: Vec<PaymentPreimage>,
1353 ) -> Result<(), ()> {
1357 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
1361 fn pubkeys(&self) -> &ChannelPublicKeys {
1362 &self.holder_channel_pubkeys
1365 fn channel_keys_id(&self) -> [u8; 32] {
1366 self.channel_keys_id
1369 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
1371 self.channel_parameters.is_none()
1372 || self.channel_parameters.as_ref().unwrap() == channel_parameters
1374 if self.channel_parameters.is_some() {
1375 // The channel parameters were already set and they match, return early.
1378 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
1379 self.channel_parameters = Some(channel_parameters.clone());
1383 const MISSING_PARAMS_ERR: &'static str =
1384 "ChannelSigner::provide_channel_parameters must be called before signing operations";
1386 impl EcdsaChannelSigner for InMemorySigner {
1387 fn sign_counterparty_commitment(
1388 &self, commitment_tx: &CommitmentTransaction,
1389 _inbound_htlc_preimages: Vec<PaymentPreimage>,
1390 _outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>,
1391 ) -> Result<(Signature, Vec<Signature>), ()> {
1392 let trusted_tx = commitment_tx.trust();
1393 let keys = trusted_tx.keys();
1395 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1396 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1397 let channel_funding_redeemscript =
1398 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1400 let built_tx = trusted_tx.built_transaction();
1401 let commitment_sig = built_tx.sign_counterparty_commitment(
1403 &channel_funding_redeemscript,
1404 self.channel_value_satoshis,
1407 let commitment_txid = built_tx.txid;
1409 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
1410 for htlc in commitment_tx.htlcs() {
1411 let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
1412 let holder_selected_contest_delay =
1413 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1414 let chan_type = &channel_parameters.channel_type_features;
1415 let htlc_tx = chan_utils::build_htlc_transaction(
1417 commitment_tx.feerate_per_kw(),
1418 holder_selected_contest_delay,
1421 &keys.broadcaster_delayed_payment_key,
1422 &keys.revocation_key,
1424 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, chan_type, &keys);
1425 let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() {
1426 EcdsaSighashType::SinglePlusAnyoneCanPay
1428 EcdsaSighashType::All
1430 let htlc_sighash = hash_to_message!(
1431 &sighash::SighashCache::new(&htlc_tx)
1432 .segwit_signature_hash(
1435 htlc.amount_msat / 1000,
1440 let holder_htlc_key = chan_utils::derive_private_key(
1442 &keys.per_commitment_point,
1443 &self.htlc_base_key,
1445 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
1448 Ok((commitment_sig, htlc_sigs))
1451 fn sign_holder_commitment(
1452 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1453 ) -> Result<Signature, ()> {
1454 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1455 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1456 let funding_redeemscript =
1457 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1458 let trusted_tx = commitment_tx.trust();
1459 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1461 &funding_redeemscript,
1462 self.channel_value_satoshis,
1468 #[cfg(any(test, feature = "unsafe_revoked_tx_signing"))]
1469 fn unsafe_sign_holder_commitment(
1470 &self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1471 ) -> Result<Signature, ()> {
1472 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1473 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1474 let funding_redeemscript =
1475 make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
1476 let trusted_tx = commitment_tx.trust();
1477 Ok(trusted_tx.built_transaction().sign_holder_commitment(
1479 &funding_redeemscript,
1480 self.channel_value_satoshis,
1486 fn sign_justice_revoked_output(
1487 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1488 secp_ctx: &Secp256k1<secp256k1::All>,
1489 ) -> Result<Signature, ()> {
1490 let revocation_key = chan_utils::derive_private_revocation_key(
1492 &per_commitment_key,
1493 &self.revocation_base_key,
1495 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1496 let revocation_pubkey = RevocationKey::from_basepoint(
1498 &self.pubkeys().revocation_basepoint,
1499 &per_commitment_point,
1501 let witness_script = {
1502 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1503 let holder_selected_contest_delay =
1504 self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
1505 let counterparty_delayedpubkey = DelayedPaymentKey::from_basepoint(
1507 &counterparty_keys.delayed_payment_basepoint,
1508 &per_commitment_point,
1510 chan_utils::get_revokeable_redeemscript(
1512 holder_selected_contest_delay,
1513 &counterparty_delayedpubkey,
1516 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1517 let sighash = hash_to_message!(
1519 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1522 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1525 fn sign_justice_revoked_htlc(
1526 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1527 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1528 ) -> Result<Signature, ()> {
1529 let revocation_key = chan_utils::derive_private_revocation_key(
1531 &per_commitment_key,
1532 &self.revocation_base_key,
1534 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1535 let revocation_pubkey = RevocationKey::from_basepoint(
1537 &self.pubkeys().revocation_basepoint,
1538 &per_commitment_point,
1540 let witness_script = {
1541 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1542 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1544 &counterparty_keys.htlc_basepoint,
1545 &per_commitment_point,
1547 let holder_htlcpubkey = HtlcKey::from_basepoint(
1549 &self.pubkeys().htlc_basepoint,
1550 &per_commitment_point,
1552 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1553 chan_utils::get_htlc_redeemscript_with_explicit_keys(
1556 &counterparty_htlcpubkey,
1561 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1562 let sighash = hash_to_message!(
1564 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1567 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
1570 fn sign_holder_htlc_transaction(
1571 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1572 secp_ctx: &Secp256k1<secp256k1::All>,
1573 ) -> Result<Signature, ()> {
1574 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1575 let sighash = &sighash::SighashCache::new(&*htlc_tx)
1576 .segwit_signature_hash(
1579 htlc_descriptor.htlc.amount_msat / 1000,
1580 EcdsaSighashType::All,
1583 let our_htlc_private_key = chan_utils::derive_private_key(
1585 &htlc_descriptor.per_commitment_point,
1586 &self.htlc_base_key,
1588 let sighash = hash_to_message!(sighash.as_byte_array());
1589 Ok(sign_with_aux_rand(&secp_ctx, &sighash, &our_htlc_private_key, &self))
1592 fn sign_counterparty_htlc_transaction(
1593 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1594 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>,
1595 ) -> Result<Signature, ()> {
1597 chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1598 let revocation_pubkey = RevocationKey::from_basepoint(
1600 &self.pubkeys().revocation_basepoint,
1601 &per_commitment_point,
1603 let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
1604 let counterparty_htlcpubkey = HtlcKey::from_basepoint(
1606 &counterparty_keys.htlc_basepoint,
1607 &per_commitment_point,
1609 let htlc_basepoint = self.pubkeys().htlc_basepoint;
1610 let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &htlc_basepoint, &per_commitment_point);
1611 let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
1612 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(
1615 &counterparty_htlcpubkey,
1619 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1620 let sighash = hash_to_message!(
1622 .segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
1625 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1628 fn sign_closing_transaction(
1629 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
1630 ) -> Result<Signature, ()> {
1631 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1632 let counterparty_funding_key =
1633 &self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
1634 let channel_funding_redeemscript =
1635 make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
1636 Ok(closing_tx.trust().sign(
1638 &channel_funding_redeemscript,
1639 self.channel_value_satoshis,
1644 fn sign_holder_anchor_input(
1645 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1646 ) -> Result<Signature, ()> {
1647 let witness_script =
1648 chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1649 let sighash = sighash::SighashCache::new(&*anchor_tx)
1650 .segwit_signature_hash(
1653 ANCHOR_OUTPUT_VALUE_SATOSHI,
1654 EcdsaSighashType::All,
1657 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1660 fn sign_channel_announcement_with_funding_key(
1661 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>,
1662 ) -> Result<Signature, ()> {
1663 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1664 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1669 impl TaprootChannelSigner for InMemorySigner {
1670 fn generate_local_nonce_pair(
1671 &self, commitment_number: u64, secp_ctx: &Secp256k1<All>,
1676 fn partially_sign_counterparty_commitment(
1677 &self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction,
1678 inbound_htlc_preimages: Vec<PaymentPreimage>,
1679 outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>,
1680 ) -> Result<(PartialSignatureWithNonce, Vec<schnorr::Signature>), ()> {
1684 fn finalize_holder_commitment(
1685 &self, commitment_tx: &HolderCommitmentTransaction,
1686 counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>,
1687 ) -> Result<PartialSignature, ()> {
1691 fn sign_justice_revoked_output(
1692 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1693 secp_ctx: &Secp256k1<All>,
1694 ) -> Result<schnorr::Signature, ()> {
1698 fn sign_justice_revoked_htlc(
1699 &self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey,
1700 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1701 ) -> Result<schnorr::Signature, ()> {
1705 fn sign_holder_htlc_transaction(
1706 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1707 secp_ctx: &Secp256k1<All>,
1708 ) -> Result<schnorr::Signature, ()> {
1712 fn sign_counterparty_htlc_transaction(
1713 &self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey,
1714 htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>,
1715 ) -> Result<schnorr::Signature, ()> {
1719 fn partially_sign_closing_transaction(
1720 &self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>,
1721 ) -> Result<PartialSignature, ()> {
1725 fn sign_holder_anchor_input(
1726 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>,
1727 ) -> Result<schnorr::Signature, ()> {
1732 const SERIALIZATION_VERSION: u8 = 1;
1734 const MIN_SERIALIZATION_VERSION: u8 = 1;
1736 impl WriteableEcdsaChannelSigner for InMemorySigner {}
1738 impl Writeable for InMemorySigner {
1739 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1740 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1742 self.funding_key.write(writer)?;
1743 self.revocation_base_key.write(writer)?;
1744 self.payment_key.write(writer)?;
1745 self.delayed_payment_base_key.write(writer)?;
1746 self.htlc_base_key.write(writer)?;
1747 self.commitment_seed.write(writer)?;
1748 self.channel_parameters.write(writer)?;
1749 self.channel_value_satoshis.write(writer)?;
1750 self.channel_keys_id.write(writer)?;
1752 write_tlv_fields!(writer, {});
1758 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner
1760 ES::Target: EntropySource,
1762 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1763 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1765 let funding_key = Readable::read(reader)?;
1766 let revocation_base_key = Readable::read(reader)?;
1767 let payment_key = Readable::read(reader)?;
1768 let delayed_payment_base_key = Readable::read(reader)?;
1769 let htlc_base_key = Readable::read(reader)?;
1770 let commitment_seed = Readable::read(reader)?;
1771 let counterparty_channel_data = Readable::read(reader)?;
1772 let channel_value_satoshis = Readable::read(reader)?;
1773 let secp_ctx = Secp256k1::signing_only();
1774 let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
1777 &revocation_base_key,
1779 &delayed_payment_base_key,
1782 let keys_id = Readable::read(reader)?;
1784 read_tlv_fields!(reader, {});
1788 revocation_base_key,
1790 delayed_payment_base_key,
1793 channel_value_satoshis,
1794 holder_channel_pubkeys,
1795 channel_parameters: counterparty_channel_data,
1796 channel_keys_id: keys_id,
1797 entropy_source: RandomBytes::new(entropy_source.get_secure_random_bytes()),
1802 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1803 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1805 /// Your `node_id` is seed/0'.
1806 /// Unilateral closes may use seed/1'.
1807 /// Cooperative closes may use seed/2'.
1808 /// The two close keys may be needed to claim on-chain funds!
1810 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1811 /// [`PhantomKeysManager`] must be used instead.
1813 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1814 /// previously issued invoices and attempts to pay previous invoices will fail.
1815 pub struct KeysManager {
1816 secp_ctx: Secp256k1<secp256k1::All>,
1817 node_secret: SecretKey,
1819 inbound_payment_key: KeyMaterial,
1820 destination_script: ScriptBuf,
1821 shutdown_pubkey: PublicKey,
1822 channel_master_key: ExtendedPrivKey,
1823 channel_child_index: AtomicUsize,
1825 entropy_source: RandomBytes,
1828 starting_time_secs: u64,
1829 starting_time_nanos: u32,
1833 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1834 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1835 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1836 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1837 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1838 /// is to simply use the current time (with very high precision).
1840 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1841 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1842 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1845 /// Note that the seed is required to recover certain on-chain funds independent of
1846 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1847 /// for any channel, and some on-chain during-closing funds.
1849 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1850 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1851 let secp_ctx = Secp256k1::new();
1852 // Note that when we aren't serializing the key, network doesn't matter
1853 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1855 let node_secret = master_key
1856 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap())
1857 .expect("Your RNG is busted")
1859 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1860 let destination_script = match master_key
1861 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap())
1863 Ok(destination_key) => {
1864 let wpubkey_hash = WPubkeyHash::hash(
1865 &ExtendedPubKey::from_priv(&secp_ctx, &destination_key)
1870 .push_opcode(opcodes::all::OP_PUSHBYTES_0)
1871 .push_slice(&wpubkey_hash.to_byte_array())
1874 Err(_) => panic!("Your RNG is busted"),
1876 let shutdown_pubkey = match master_key
1877 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap())
1879 Ok(shutdown_key) => {
1880 ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key
1882 Err(_) => panic!("Your RNG is busted"),
1884 let channel_master_key = master_key
1885 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap())
1886 .expect("Your RNG is busted");
1887 let inbound_payment_key: SecretKey = master_key
1888 .ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap())
1889 .expect("Your RNG is busted")
1891 let mut inbound_pmt_key_bytes = [0; 32];
1892 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1894 let mut rand_bytes_engine = Sha256::engine();
1895 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1896 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1897 rand_bytes_engine.input(seed);
1898 rand_bytes_engine.input(b"LDK PRNG Seed");
1899 let rand_bytes_unique_start =
1900 Sha256::from_engine(rand_bytes_engine).to_byte_array();
1902 let mut res = KeysManager {
1906 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1912 channel_child_index: AtomicUsize::new(0),
1914 entropy_source: RandomBytes::new(rand_bytes_unique_start),
1918 starting_time_nanos,
1920 let secp_seed = res.get_secure_random_bytes();
1921 res.secp_ctx.seeded_randomize(&secp_seed);
1924 Err(_) => panic!("Your rng is busted"),
1928 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1929 pub fn get_node_secret_key(&self) -> SecretKey {
1933 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1934 pub fn derive_channel_keys(
1935 &self, channel_value_satoshis: u64, params: &[u8; 32],
1936 ) -> InMemorySigner {
1937 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1938 let mut unique_start = Sha256::engine();
1939 unique_start.input(params);
1940 unique_start.input(&self.seed);
1942 // We only seriously intend to rely on the channel_master_key for true secure
1943 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1944 // starting_time provided in the constructor) to be unique.
1945 let child_privkey = self
1949 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31))
1950 .expect("key space exhausted"),
1952 .expect("Your RNG is busted");
1953 unique_start.input(&child_privkey.private_key[..]);
1955 let seed = Sha256::from_engine(unique_start).to_byte_array();
1957 let commitment_seed = {
1958 let mut sha = Sha256::engine();
1960 sha.input(&b"commitment seed"[..]);
1961 Sha256::from_engine(sha).to_byte_array()
1963 macro_rules! key_step {
1964 ($info: expr, $prev_key: expr) => {{
1965 let mut sha = Sha256::engine();
1967 sha.input(&$prev_key[..]);
1968 sha.input(&$info[..]);
1969 SecretKey::from_slice(&Sha256::from_engine(sha).to_byte_array())
1970 .expect("SHA-256 is busted")
1973 let funding_key = key_step!(b"funding key", commitment_seed);
1974 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1975 let payment_key = key_step!(b"payment key", revocation_base_key);
1976 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1977 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1978 let prng_seed = self.get_secure_random_bytes();
1980 InMemorySigner::new(
1983 revocation_base_key,
1985 delayed_payment_base_key,
1988 channel_value_satoshis,
1994 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
1995 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
1996 /// are no other inputs that need signing.
1998 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
2000 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2001 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2002 pub fn sign_spendable_outputs_psbt<C: Signing>(
2003 &self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction,
2004 secp_ctx: &Secp256k1<C>,
2005 ) -> Result<PartiallySignedTransaction, ()> {
2006 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
2007 for outp in descriptors {
2008 let get_input_idx = |outpoint: &OutPoint| {
2012 .position(|i| i.previous_output == outpoint.into_bitcoin_outpoint())
2016 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
2017 let input_idx = get_input_idx(&descriptor.outpoint)?;
2018 if keys_cache.is_none()
2019 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2021 let mut signer = self.derive_channel_keys(
2022 descriptor.channel_value_satoshis,
2023 &descriptor.channel_keys_id,
2025 if let Some(channel_params) =
2026 descriptor.channel_transaction_parameters.as_ref()
2028 signer.provide_channel_parameters(channel_params);
2030 keys_cache = Some((signer, descriptor.channel_keys_id));
2032 let witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(
2038 psbt.inputs[input_idx].final_script_witness = Some(witness);
2040 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
2041 let input_idx = get_input_idx(&descriptor.outpoint)?;
2042 if keys_cache.is_none()
2043 || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
2046 self.derive_channel_keys(
2047 descriptor.channel_value_satoshis,
2048 &descriptor.channel_keys_id,
2050 descriptor.channel_keys_id,
2053 let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(
2059 psbt.inputs[input_idx].final_script_witness = Some(witness);
2061 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
2062 let input_idx = get_input_idx(outpoint)?;
2063 let derivation_idx =
2064 if output.script_pubkey == self.destination_script { 1 } else { 2 };
2066 // Note that when we aren't serializing the key, network doesn't matter
2067 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
2069 match master_key.ckd_priv(
2071 ChildNumber::from_hardened_idx(derivation_idx)
2072 .expect("key space exhausted"),
2075 Err(_) => panic!("Your RNG is busted"),
2078 Err(_) => panic!("Your rng is busted"),
2081 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
2082 if derivation_idx == 2 {
2083 assert_eq!(pubkey.inner, self.shutdown_pubkey);
2085 let witness_script =
2086 bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
2087 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet)
2088 .expect("uncompressed key found")
2091 if payment_script != output.script_pubkey {
2095 let sighash = hash_to_message!(
2096 &sighash::SighashCache::new(&psbt.unsigned_tx)
2097 .segwit_signature_hash(
2101 EcdsaSighashType::All
2105 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
2106 let mut sig_ser = sig.serialize_der().to_vec();
2107 sig_ser.push(EcdsaSighashType::All as u8);
2109 Witness::from_slice(&[&sig_ser, &pubkey.inner.serialize().to_vec()]);
2110 psbt.inputs[input_idx].final_script_witness = Some(witness);
2119 impl EntropySource for KeysManager {
2120 fn get_secure_random_bytes(&self) -> [u8; 32] {
2121 self.entropy_source.get_secure_random_bytes()
2125 impl NodeSigner for KeysManager {
2126 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2128 Recipient::Node => Ok(self.node_id.clone()),
2129 Recipient::PhantomNode => Err(()),
2134 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2135 ) -> Result<SharedSecret, ()> {
2136 let mut node_secret = match recipient {
2137 Recipient::Node => Ok(self.node_secret.clone()),
2138 Recipient::PhantomNode => Err(()),
2140 if let Some(tweak) = tweak {
2141 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2143 Ok(SharedSecret::new(other_key, &node_secret))
2146 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2147 self.inbound_payment_key.clone()
2151 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2152 ) -> Result<RecoverableSignature, ()> {
2153 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2154 let secret = match recipient {
2155 Recipient::Node => Ok(&self.node_secret),
2156 Recipient::PhantomNode => Err(()),
2158 Ok(self.secp_ctx.sign_ecdsa_recoverable(
2159 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2164 fn sign_bolt12_invoice_request(
2165 &self, invoice_request: &UnsignedInvoiceRequest,
2166 ) -> Result<schnorr::Signature, ()> {
2167 let message = invoice_request.tagged_hash().as_digest();
2168 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
2169 let aux_rand = self.get_secure_random_bytes();
2170 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
2173 fn sign_bolt12_invoice(
2174 &self, invoice: &UnsignedBolt12Invoice,
2175 ) -> Result<schnorr::Signature, ()> {
2176 let message = invoice.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_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2183 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
2184 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
2188 impl OutputSpender for KeysManager {
2189 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
2190 /// output to the given change destination (if sufficient change value remains).
2192 /// See [`OutputSpender::spend_spendable_outputs`] documentation for more information.
2194 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
2196 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
2197 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
2198 fn spend_spendable_outputs<C: Signing>(
2199 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2200 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2201 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2202 ) -> Result<Transaction, ()> {
2203 let (mut psbt, expected_max_weight) =
2204 SpendableOutputDescriptor::create_spendable_outputs_psbt(
2208 change_destination_script,
2209 feerate_sat_per_1000_weight,
2212 psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
2214 let spend_tx = psbt.extract_tx();
2216 debug_assert!(expected_max_weight >= spend_tx.weight().to_wu());
2217 // Note that witnesses with a signature vary somewhat in size, so allow
2218 // `expected_max_weight` to overshoot by up to 3 bytes per input.
2220 expected_max_weight <= spend_tx.weight().to_wu() + descriptors.len() as u64 * 3
2227 impl SignerProvider for KeysManager {
2228 type EcdsaSigner = InMemorySigner;
2230 type TaprootSigner = InMemorySigner;
2232 fn generate_channel_keys_id(
2233 &self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128,
2235 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
2236 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
2237 // (though `user_channel_id` should help, depending on user behavior). If it manages to
2238 // roll over, we may generate duplicate keys for two different channels, which could result
2239 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
2240 // doesn't reach `u32::MAX`.
2241 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
2242 let mut id = [0; 32];
2243 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
2244 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
2245 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
2246 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
2250 fn derive_channel_signer(
2251 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2252 ) -> Self::EcdsaSigner {
2253 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
2256 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2257 InMemorySigner::read(&mut io::Cursor::new(reader), self)
2260 fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2261 Ok(self.destination_script.clone())
2264 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2265 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
2269 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
2272 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
2273 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
2274 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
2275 /// itself without ever needing to forward to this fake node.
2277 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
2278 /// provide some fault tolerance, because payers will automatically retry paying other provided
2279 /// nodes in the case that one node goes down.
2281 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
2282 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
2283 // nodes to know when the full payment has been received (and the preimage can be released) without
2284 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
2285 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
2286 // is released too early.
2288 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
2289 /// invoices and attempts to pay previous invoices will fail.
2290 pub struct PhantomKeysManager {
2292 inbound_payment_key: KeyMaterial,
2293 phantom_secret: SecretKey,
2294 phantom_node_id: PublicKey,
2297 impl EntropySource for PhantomKeysManager {
2298 fn get_secure_random_bytes(&self) -> [u8; 32] {
2299 self.inner.get_secure_random_bytes()
2303 impl NodeSigner for PhantomKeysManager {
2304 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
2306 Recipient::Node => self.inner.get_node_id(Recipient::Node),
2307 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
2312 &self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
2313 ) -> Result<SharedSecret, ()> {
2314 let mut node_secret = match recipient {
2315 Recipient::Node => self.inner.node_secret.clone(),
2316 Recipient::PhantomNode => self.phantom_secret.clone(),
2318 if let Some(tweak) = tweak {
2319 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
2321 Ok(SharedSecret::new(other_key, &node_secret))
2324 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
2325 self.inbound_payment_key.clone()
2329 &self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
2330 ) -> Result<RecoverableSignature, ()> {
2331 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
2332 let secret = match recipient {
2333 Recipient::Node => &self.inner.node_secret,
2334 Recipient::PhantomNode => &self.phantom_secret,
2336 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(
2337 &hash_to_message!(&Sha256::hash(&preimage).to_byte_array()),
2342 fn sign_bolt12_invoice_request(
2343 &self, invoice_request: &UnsignedInvoiceRequest,
2344 ) -> Result<schnorr::Signature, ()> {
2345 self.inner.sign_bolt12_invoice_request(invoice_request)
2348 fn sign_bolt12_invoice(
2349 &self, invoice: &UnsignedBolt12Invoice,
2350 ) -> Result<schnorr::Signature, ()> {
2351 self.inner.sign_bolt12_invoice(invoice)
2354 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
2355 self.inner.sign_gossip_message(msg)
2359 impl OutputSpender for PhantomKeysManager {
2360 /// See [`OutputSpender::spend_spendable_outputs`] and [`KeysManager::spend_spendable_outputs`]
2361 /// for documentation on this method.
2362 fn spend_spendable_outputs<C: Signing>(
2363 &self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>,
2364 change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32,
2365 locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>,
2366 ) -> Result<Transaction, ()> {
2367 self.inner.spend_spendable_outputs(
2370 change_destination_script,
2371 feerate_sat_per_1000_weight,
2378 impl SignerProvider for PhantomKeysManager {
2379 type EcdsaSigner = InMemorySigner;
2381 type TaprootSigner = InMemorySigner;
2383 fn generate_channel_keys_id(
2384 &self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
2386 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
2389 fn derive_channel_signer(
2390 &self, channel_value_satoshis: u64, channel_keys_id: [u8; 32],
2391 ) -> Self::EcdsaSigner {
2392 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
2395 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
2396 self.inner.read_chan_signer(reader)
2399 fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
2400 self.inner.get_destination_script(channel_keys_id)
2403 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
2404 self.inner.get_shutdown_scriptpubkey()
2408 impl PhantomKeysManager {
2409 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
2410 /// that is shared across all nodes that intend to participate in [phantom node payments]
2413 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
2414 /// `starting_time_nanos`.
2416 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
2417 /// same across restarts, or else inbound payments may fail.
2419 /// [phantom node payments]: PhantomKeysManager
2421 seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32,
2422 cross_node_seed: &[u8; 32],
2424 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
2425 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(
2426 b"LDK Inbound and Phantom Payment Key Expansion",
2429 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
2430 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
2433 inbound_payment_key: KeyMaterial(inbound_key),
2439 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
2440 pub fn derive_channel_keys(
2441 &self, channel_value_satoshis: u64, params: &[u8; 32],
2442 ) -> InMemorySigner {
2443 self.inner.derive_channel_keys(channel_value_satoshis, params)
2446 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
2447 pub fn get_node_secret_key(&self) -> SecretKey {
2448 self.inner.get_node_secret_key()
2451 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
2452 /// last-hop onion data, etc.
2453 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
2458 /// An implementation of [`EntropySource`] using ChaCha20.
2460 pub struct RandomBytes {
2461 /// Seed from which all randomness produced is derived from.
2463 /// Tracks the number of times we've produced randomness to ensure we don't return the same
2465 index: AtomicCounter,
2469 /// Creates a new instance using the given seed.
2470 pub fn new(seed: [u8; 32]) -> Self {
2471 Self { seed, index: AtomicCounter::new() }
2475 impl EntropySource for RandomBytes {
2476 fn get_secure_random_bytes(&self) -> [u8; 32] {
2477 let index = self.index.get_increment();
2478 let mut nonce = [0u8; 16];
2479 nonce[..8].copy_from_slice(&index.to_be_bytes());
2480 ChaCha20::get_single_block(&self.seed, &nonce)
2484 // Ensure that EcdsaChannelSigner can have a vtable
2487 let _signer: Box<dyn EcdsaChannelSigner>;
2492 use crate::sign::{EntropySource, KeysManager};
2493 use bitcoin::blockdata::constants::genesis_block;
2494 use bitcoin::Network;
2495 use std::sync::mpsc::TryRecvError;
2496 use std::sync::{mpsc, Arc};
2498 use std::time::Duration;
2500 use criterion::Criterion;
2502 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
2503 let seed = [0u8; 32];
2504 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
2505 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
2507 let mut handles = Vec::new();
2508 let mut stops = Vec::new();
2510 let keys_manager_clone = Arc::clone(&keys_manager);
2511 let (stop_sender, stop_receiver) = mpsc::channel();
2512 let handle = thread::spawn(move || loop {
2513 keys_manager_clone.get_secure_random_bytes();
2514 match stop_receiver.try_recv() {
2515 Ok(_) | Err(TryRecvError::Disconnected) => {
2516 println!("Terminating.");
2519 Err(TryRecvError::Empty) => {},
2522 handles.push(handle);
2523 stops.push(stop_sender);
2526 bench.bench_function("get_secure_random_bytes", |b| {
2527 b.iter(|| keys_manager.get_secure_random_bytes())
2531 let _ = stop.send(());
2533 for handle in handles {
2534 handle.join().unwrap();