1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Provides keys to LDK and defines some useful objects describing spendable on-chain outputs.
12 //! The provided output descriptors follow a custom LDK data format and are currently not fully
13 //! compatible with Bitcoin Core output descriptors.
15 use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn, EcdsaSighashType};
16 use bitcoin::blockdata::script::{Script, Builder};
17 use bitcoin::blockdata::opcodes;
18 use bitcoin::network::constants::Network;
19 use bitcoin::psbt::PartiallySignedTransaction;
20 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
21 use bitcoin::util::sighash;
23 use bitcoin::bech32::u5;
24 use bitcoin::hashes::{Hash, HashEngine};
25 use bitcoin::hashes::sha256::Hash as Sha256;
26 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
27 use bitcoin::hash_types::WPubkeyHash;
29 use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
30 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Signing};
31 use bitcoin::secp256k1::ecdh::SharedSecret;
32 use bitcoin::secp256k1::ecdsa::RecoverableSignature;
33 use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness};
35 use crate::util::transaction_utils;
36 use crate::util::crypto::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
37 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
38 use crate::chain::transaction::OutPoint;
39 use crate::events::bump_transaction::HTLCDescriptor;
40 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
41 use crate::ln::{chan_utils, PaymentPreimage};
42 use crate::ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
43 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
44 use crate::ln::script::ShutdownScript;
46 use crate::prelude::*;
47 use core::convert::TryInto;
49 use core::sync::atomic::{AtomicUsize, Ordering};
50 use crate::io::{self, Error};
51 use crate::ln::features::ChannelTypeFeatures;
52 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
53 use crate::util::atomic_counter::AtomicCounter;
54 use crate::util::chacha20::ChaCha20;
55 use crate::util::invoice::construct_invoice_preimage;
57 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
58 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
60 /// This is not exported to bindings users as we just use `[u8; 32]` directly
61 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
62 pub struct KeyMaterial(pub [u8; 32]);
64 /// Information about a spendable output to a P2WSH script.
66 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
67 #[derive(Clone, Debug, PartialEq, Eq)]
68 pub struct DelayedPaymentOutputDescriptor {
69 /// The outpoint which is spendable.
70 pub outpoint: OutPoint,
71 /// Per commitment point to derive the delayed payment key by key holder.
72 pub per_commitment_point: PublicKey,
73 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
74 /// the witness_script.
75 pub to_self_delay: u16,
76 /// The output which is referenced by the given outpoint.
78 /// The revocation point specific to the commitment transaction which was broadcast. Used to
79 /// derive the witnessScript for this output.
80 pub revocation_pubkey: PublicKey,
81 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
82 /// This may be useful in re-deriving keys used in the channel to spend the output.
83 pub channel_keys_id: [u8; 32],
84 /// The value of the channel which this output originated from, possibly indirectly.
85 pub channel_value_satoshis: u64,
87 impl DelayedPaymentOutputDescriptor {
88 /// The maximum length a well-formed witness spending one of these should have.
89 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
91 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
92 // redeemscript push length.
93 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
96 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
97 (0, outpoint, required),
98 (2, per_commitment_point, required),
99 (4, to_self_delay, required),
100 (6, output, required),
101 (8, revocation_pubkey, required),
102 (10, channel_keys_id, required),
103 (12, channel_value_satoshis, required),
106 /// Information about a spendable output to our "payment key".
108 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
109 #[derive(Clone, Debug, PartialEq, Eq)]
110 pub struct StaticPaymentOutputDescriptor {
111 /// The outpoint which is spendable.
112 pub outpoint: OutPoint,
113 /// The output which is referenced by the given outpoint.
115 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
116 /// This may be useful in re-deriving keys used in the channel to spend the output.
117 pub channel_keys_id: [u8; 32],
118 /// The value of the channel which this transactions spends.
119 pub channel_value_satoshis: u64,
121 impl StaticPaymentOutputDescriptor {
122 /// The maximum length a well-formed witness spending one of these should have.
123 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
125 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
126 // redeemscript push length.
127 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
129 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
130 (0, outpoint, required),
131 (2, output, required),
132 (4, channel_keys_id, required),
133 (6, channel_value_satoshis, required),
136 /// Describes the necessary information to spend a spendable output.
138 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
139 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
140 /// to spend on-chain. The information needed to do this is provided in this enum, including the
141 /// outpoint describing which `txid` and output `index` is available, the full output which exists
142 /// at that `txid`/`index`, and any keys or other information required to sign.
144 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
145 #[derive(Clone, Debug, PartialEq, Eq)]
146 pub enum SpendableOutputDescriptor {
147 /// An output to a script which was provided via [`SignerProvider`] directly, either from
148 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
149 /// know how to spend it. No secret keys are provided as LDK was never given any key.
150 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
151 /// on-chain using the payment preimage or after it has timed out.
153 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
154 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
156 /// The outpoint which is spendable.
158 /// The output which is referenced by the given outpoint.
161 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
164 /// The witness in the spending input should be:
166 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
169 /// Note that the `nSequence` field in the spending input must be set to
170 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
171 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
172 /// the outpoint confirms, see [BIP
173 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
174 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
177 /// These are generally the result of a "revocable" output to us, spendable only by us unless
178 /// it is an output from an old state which we broadcast (which should never happen).
180 /// To derive the delayed payment key which is used to sign this input, you must pass the
181 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
182 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
183 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The public key can be
184 /// generated without the secret key using [`chan_utils::derive_public_key`] and only the
185 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
187 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
188 /// used in the witness script generation), you must pass the counterparty
189 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
190 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
191 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
192 /// [`chan_utils::derive_public_revocation_key`].
194 /// The witness script which is hashed and included in the output `script_pubkey` may be
195 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
196 /// as explained above), our delayed payment pubkey (derived as explained above), and the
197 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
198 /// [`chan_utils::get_revokeable_redeemscript`].
199 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
200 /// An output to a P2WPKH, spendable exclusively by our payment key (i.e., the private key
201 /// which corresponds to the `payment_point` in [`ChannelSigner::pubkeys`]). The witness
202 /// in the spending input is, thus, simply:
204 /// <BIP 143 signature> <payment key>
207 /// These are generally the result of our counterparty having broadcast the current state,
208 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
209 StaticPaymentOutput(StaticPaymentOutputDescriptor),
212 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
213 (0, StaticOutput) => {
214 (0, outpoint, required),
215 (2, output, required),
218 (1, DelayedPaymentOutput),
219 (2, StaticPaymentOutput),
222 impl SpendableOutputDescriptor {
223 /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
224 /// [`PartiallySignedTransaction`] which spends the given descriptor.
226 /// Note that this does not include any signatures, just the information required to
227 /// construct the transaction and sign it.
228 pub fn to_psbt_input(&self) -> bitcoin::psbt::Input {
230 SpendableOutputDescriptor::StaticOutput { output, .. } => {
231 // Is a standard P2WPKH, no need for witness script
232 bitcoin::psbt::Input {
233 witness_utxo: Some(output.clone()),
237 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
238 // TODO we could add the witness script as well
239 bitcoin::psbt::Input {
240 witness_utxo: Some(descriptor.output.clone()),
244 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
245 // TODO we could add the witness script as well
246 bitcoin::psbt::Input {
247 witness_utxo: Some(descriptor.output.clone()),
254 /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
255 /// the given outputs, plus an output to the given change destination (if sufficient
256 /// change value remains). The PSBT will have a feerate, at least, of the given value.
258 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
259 /// transaction will have a locktime of 0. It it recommended to set this to the current block
260 /// height to avoid fee sniping, unless you have some specific reason to use a different
263 /// Returns the PSBT and expected max transaction weight.
265 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
266 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
267 /// does not match the one we can spend.
269 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
270 pub fn create_spendable_outputs_psbt(descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>) -> Result<(PartiallySignedTransaction, usize), ()> {
271 let mut input = Vec::with_capacity(descriptors.len());
272 let mut input_value = 0;
273 let mut witness_weight = 0;
274 let mut output_set = HashSet::with_capacity(descriptors.len());
275 for outp in descriptors {
277 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
278 if !output_set.insert(descriptor.outpoint) { return Err(()); }
280 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
281 script_sig: Script::new(),
282 sequence: Sequence::ZERO,
283 witness: Witness::new(),
285 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
286 #[cfg(feature = "grind_signatures")]
287 { witness_weight -= 1; } // Guarantees a low R signature
288 input_value += descriptor.output.value;
290 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
291 if !output_set.insert(descriptor.outpoint) { return Err(()); }
293 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
294 script_sig: Script::new(),
295 sequence: Sequence(descriptor.to_self_delay as u32),
296 witness: Witness::new(),
298 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
299 #[cfg(feature = "grind_signatures")]
300 { witness_weight -= 1; } // Guarantees a low R signature
301 input_value += descriptor.output.value;
303 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
304 if !output_set.insert(*outpoint) { return Err(()); }
306 previous_output: outpoint.into_bitcoin_outpoint(),
307 script_sig: Script::new(),
308 sequence: Sequence::ZERO,
309 witness: Witness::new(),
311 witness_weight += 1 + 73 + 34;
312 #[cfg(feature = "grind_signatures")]
313 { witness_weight -= 1; } // Guarantees a low R signature
314 input_value += output.value;
317 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
319 let mut tx = Transaction {
321 lock_time: locktime.unwrap_or(PackedLockTime::ZERO),
325 let expected_max_weight =
326 transaction_utils::maybe_add_change_output(&mut tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
328 let psbt_inputs = descriptors.iter().map(|d| d.to_psbt_input()).collect::<Vec<_>>();
329 let psbt = PartiallySignedTransaction {
331 outputs: vec![Default::default(); tx.output.len()],
333 xpub: Default::default(),
335 proprietary: Default::default(),
336 unknown: Default::default(),
338 Ok((psbt, expected_max_weight))
342 /// A trait to handle Lightning channel key material without concretizing the channel type or
343 /// the signature mechanism.
344 pub trait ChannelSigner {
345 /// Gets the per-commitment point for a specific commitment number
347 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
348 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
350 /// Gets the commitment secret for a specific commitment number as part of the revocation process
352 /// An external signer implementation should error here if the commitment was already signed
353 /// and should refuse to sign it in the future.
355 /// May be called more than once for the same index.
357 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
358 // TODO: return a Result so we can signal a validation error
359 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
361 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
363 /// This is required in order for the signer to make sure that releasing a commitment
364 /// secret won't leave us without a broadcastable holder transaction.
365 /// Policy checks should be implemented in this function, including checking the amount
366 /// sent to us and checking the HTLCs.
368 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
369 /// A validating signer should ensure that an HTLC output is removed only when the matching
370 /// preimage is provided, or when the value to holder is restored.
372 /// Note that all the relevant preimages will be provided, but there may also be additional
373 /// irrelevant or duplicate preimages.
374 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction,
375 preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
377 /// Returns the holder's channel public keys and basepoints.
378 fn pubkeys(&self) -> &ChannelPublicKeys;
380 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
381 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
382 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
383 fn channel_keys_id(&self) -> [u8; 32];
385 /// Set the counterparty static channel data, including basepoints,
386 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
388 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
389 /// instance, LDK will call this method exactly once - either immediately after construction
390 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
391 /// information has been generated.
393 /// channel_parameters.is_populated() MUST be true.
394 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
397 /// A trait to sign Lightning channel transactions as described in
398 /// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
400 /// Signing services could be implemented on a hardware wallet and should implement signing
401 /// policies in order to be secure. Please refer to the [VLS Policy
402 /// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
403 /// for an example of such policies.
404 pub trait EcdsaChannelSigner: ChannelSigner {
405 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
407 /// Note that if signing fails or is rejected, the channel will be force-closed.
409 /// Policy checks should be implemented in this function, including checking the amount
410 /// sent to us and checking the HTLCs.
412 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
413 /// A validating signer should ensure that an HTLC output is removed only when the matching
414 /// preimage is provided, or when the value to holder is restored.
416 /// Note that all the relevant preimages will be provided, but there may also be additional
417 /// irrelevant or duplicate preimages.
419 // TODO: Document the things someone using this interface should enforce before signing.
420 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction,
421 preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>
422 ) -> Result<(Signature, Vec<Signature>), ()>;
423 /// Validate the counterparty's revocation.
425 /// This is required in order for the signer to make sure that the state has moved
426 /// forward and it is safe to sign the next counterparty commitment.
427 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
428 /// Creates a signature for a holder's commitment transaction and its claiming HTLC transactions.
430 /// This will be called
431 /// - with a non-revoked `commitment_tx`.
432 /// - with the latest `commitment_tx` when we initiate a force-close.
433 /// - with the previous `commitment_tx`, just to get claiming HTLC
434 /// signatures, if we are reacting to a [`ChannelMonitor`]
435 /// [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
436 /// that decided to broadcast before it had been updated to the latest `commitment_tx`.
438 /// This may be called multiple times for the same transaction.
440 /// An external signer implementation should check that the commitment has not been revoked.
442 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
443 // TODO: Document the things someone using this interface should enforce before signing.
444 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
445 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
446 /// Same as [`sign_holder_commitment_and_htlcs`], but exists only for tests to get access to
447 /// holder commitment transactions which will be broadcasted later, after the channel has moved
448 /// on to a newer state. Thus, needs its own method as [`sign_holder_commitment_and_htlcs`] may
449 /// enforce that we only ever get called once.
450 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
451 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
452 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
453 /// Create a signature for the given input in a transaction spending an HTLC transaction output
454 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
456 /// A justice transaction may claim multiple outputs at the same time if timelocks are
457 /// similar, but only a signature for the input at index `input` should be signed for here.
458 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
459 /// to an upcoming timelock expiration.
461 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
463 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
464 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
465 /// not allow the spending of any funds by itself (you need our holder `revocation_secret` to do
467 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64,
468 per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>
469 ) -> Result<Signature, ()>;
470 /// Create a signature for the given input in a transaction spending a commitment transaction
471 /// HTLC output when our counterparty broadcasts an old state.
473 /// A justice transaction may claim multiple outputs at the same time if timelocks are
474 /// similar, but only a signature for the input at index `input` should be signed for here.
475 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
476 /// to an upcoming timelock expiration.
478 /// `amount` is the value of the output spent by this input, committed to in the BIP 143
481 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
482 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
483 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
486 /// `htlc` holds HTLC elements (hash, timelock), thus changing the format of the witness script
487 /// (which is committed to in the BIP 143 signatures).
488 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64,
489 per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment,
490 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
491 /// Computes the signature for a commitment transaction's HTLC output used as an input within
492 /// `htlc_tx`, which spends the commitment transaction at index `input`. The signature returned
493 /// must be be computed using [`EcdsaSighashType::All`]. Note that this should only be used to
494 /// sign HTLC transactions from channels supporting anchor outputs after all additional
495 /// inputs/outputs have been added to the transaction.
497 /// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
498 fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize,
499 htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<secp256k1::All>
500 ) -> Result<Signature, ()>;
501 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
502 /// transaction, either offered or received.
504 /// Such a transaction may claim multiples offered outputs at same time if we know the
505 /// preimage for each when we create it, but only the input at index `input` should be
506 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
507 /// needed with regards to an upcoming timelock expiration.
509 /// `witness_script` is either an offered or received script as defined in BOLT3 for HTLC
512 /// `amount` is value of the output spent by this input, committed to in the BIP 143 signature.
514 /// `per_commitment_point` is the dynamic point corresponding to the channel state
515 /// detected onchain. It has been generated by our counterparty and is used to derive
516 /// channel state keys, which are then included in the witness script and committed to in the
517 /// BIP 143 signature.
518 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64,
519 per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment,
520 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
521 /// Create a signature for a (proposed) closing transaction.
523 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
524 /// chosen to forgo their output as dust.
525 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction,
526 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
527 /// Computes the signature for a commitment transaction's anchor output used as an
528 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
529 fn sign_holder_anchor_input(
530 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
531 ) -> Result<Signature, ()>;
532 /// Signs a channel announcement message with our funding key proving it comes from one of the
533 /// channel participants.
535 /// Channel announcements also require a signature from each node's network key. Our node
536 /// signature is computed through [`NodeSigner::sign_gossip_message`].
538 /// Note that if this fails or is rejected, the channel will not be publicly announced and
539 /// our counterparty may (though likely will not) close the channel on us for violating the
541 fn sign_channel_announcement_with_funding_key(
542 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
543 ) -> Result<Signature, ()>;
546 /// A writeable signer.
548 /// There will always be two instances of a signer per channel, one occupied by the
549 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
551 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
552 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
553 pub trait WriteableEcdsaChannelSigner: EcdsaChannelSigner + Writeable {}
555 /// Specifies the recipient of an invoice.
557 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
560 /// The invoice should be signed with the local node secret key.
562 /// The invoice should be signed with the phantom node secret key. This secret key must be the
563 /// same for all nodes participating in the [phantom node payment].
565 /// [phantom node payment]: PhantomKeysManager
569 /// A trait that describes a source of entropy.
570 pub trait EntropySource {
571 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
572 /// different value each time it is called.
573 fn get_secure_random_bytes(&self) -> [u8; 32];
576 /// A trait that can handle cryptographic operations at the scope level of a node.
577 pub trait NodeSigner {
578 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
580 /// If the implementor of this trait supports [phantom node payments], then every node that is
581 /// intended to be included in the phantom invoice route hints must return the same value from
583 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
584 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
585 // nodes, they must share the key that encrypts this payment data.
587 /// This method must return the same value each time it is called.
589 /// [phantom node payments]: PhantomKeysManager
590 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
592 /// Get node id based on the provided [`Recipient`].
594 /// This method must return the same value each time it is called with a given [`Recipient`]
597 /// Errors if the [`Recipient`] variant is not supported by the implementation.
598 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
600 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
601 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
602 /// secret, though this is less efficient.
604 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
605 /// should be resolved to allow LDK to resume forwarding HTLCs.
607 /// Errors if the [`Recipient`] variant is not supported by the implementation.
608 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
612 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
613 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
614 /// blindly signing the hash.
616 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
618 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
620 /// Errors if the [`Recipient`] variant is not supported by the implementation.
621 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()>;
623 /// Sign a gossip message.
625 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
626 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
627 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
628 /// corresponding channel.
629 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
632 /// A trait that can return signer instances for individual channels.
633 pub trait SignerProvider {
634 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
635 type Signer : WriteableEcdsaChannelSigner;
637 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::Signer`] through
638 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
639 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
640 /// `channel_keys_id`.
642 /// This method must return a different value each time it is called.
643 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
645 /// Derives the private key material backing a `Signer`.
647 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
648 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
649 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
650 /// [`ChannelSigner::channel_keys_id`].
651 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
653 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
654 /// This is only called during deserialization of other objects which contain
655 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
656 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
657 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
658 /// you've read all of the provided bytes to ensure no corruption occurred.
660 /// This method is slowly being phased out -- it will only be called when reading objects
661 /// written by LDK versions prior to 0.0.113.
663 /// [`Signer`]: Self::Signer
664 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
665 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
666 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
668 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
670 /// If this function returns an error, this will result in a channel failing to open.
672 /// This method should return a different value each time it is called, to avoid linking
673 /// on-chain funds across channels as controlled to the same user.
674 fn get_destination_script(&self) -> Result<Script, ()>;
676 /// Get a script pubkey which we will send funds to when closing a channel.
678 /// If this function returns an error, this will result in a channel failing to open or close.
679 /// In the event of a failure when the counterparty is initiating a close, this can result in a
680 /// channel force close.
682 /// This method should return a different value each time it is called, to avoid linking
683 /// on-chain funds across channels as controlled to the same user.
684 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
687 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
689 /// This implementation performs no policy checks and is insufficient by itself as
690 /// a secure external signer.
692 pub struct InMemorySigner {
693 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
694 /// holder's anchor output in a commitment transaction, if one is present.
695 pub funding_key: SecretKey,
696 /// Holder secret key for blinded revocation pubkey.
697 pub revocation_base_key: SecretKey,
698 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
699 pub payment_key: SecretKey,
700 /// Holder secret key used in an HTLC transaction.
701 pub delayed_payment_base_key: SecretKey,
702 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
703 pub htlc_base_key: SecretKey,
705 pub commitment_seed: [u8; 32],
706 /// Holder public keys and basepoints.
707 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
708 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
709 channel_parameters: Option<ChannelTransactionParameters>,
710 /// The total value of this channel.
711 channel_value_satoshis: u64,
712 /// Key derivation parameters.
713 channel_keys_id: [u8; 32],
714 /// Seed from which all randomness produced is derived from.
715 rand_bytes_unique_start: [u8; 32],
716 /// Tracks the number of times we've produced randomness to ensure we don't return the same
718 rand_bytes_index: AtomicCounter,
721 impl PartialEq for InMemorySigner {
722 fn eq(&self, other: &Self) -> bool {
723 self.funding_key == other.funding_key &&
724 self.revocation_base_key == other.revocation_base_key &&
725 self.payment_key == other.payment_key &&
726 self.delayed_payment_base_key == other.delayed_payment_base_key &&
727 self.htlc_base_key == other.htlc_base_key &&
728 self.commitment_seed == other.commitment_seed &&
729 self.holder_channel_pubkeys == other.holder_channel_pubkeys &&
730 self.channel_parameters == other.channel_parameters &&
731 self.channel_value_satoshis == other.channel_value_satoshis &&
732 self.channel_keys_id == other.channel_keys_id
736 impl Clone for InMemorySigner {
737 fn clone(&self) -> Self {
739 funding_key: self.funding_key.clone(),
740 revocation_base_key: self.revocation_base_key.clone(),
741 payment_key: self.payment_key.clone(),
742 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
743 htlc_base_key: self.htlc_base_key.clone(),
744 commitment_seed: self.commitment_seed.clone(),
745 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
746 channel_parameters: self.channel_parameters.clone(),
747 channel_value_satoshis: self.channel_value_satoshis,
748 channel_keys_id: self.channel_keys_id,
749 rand_bytes_unique_start: self.get_secure_random_bytes(),
750 rand_bytes_index: AtomicCounter::new(),
755 impl InMemorySigner {
756 /// Creates a new [`InMemorySigner`].
757 pub fn new<C: Signing>(
758 secp_ctx: &Secp256k1<C>,
759 funding_key: SecretKey,
760 revocation_base_key: SecretKey,
761 payment_key: SecretKey,
762 delayed_payment_base_key: SecretKey,
763 htlc_base_key: SecretKey,
764 commitment_seed: [u8; 32],
765 channel_value_satoshis: u64,
766 channel_keys_id: [u8; 32],
767 rand_bytes_unique_start: [u8; 32],
768 ) -> InMemorySigner {
769 let holder_channel_pubkeys =
770 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
771 &payment_key, &delayed_payment_base_key,
777 delayed_payment_base_key,
780 channel_value_satoshis,
781 holder_channel_pubkeys,
782 channel_parameters: None,
784 rand_bytes_unique_start,
785 rand_bytes_index: AtomicCounter::new(),
789 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
790 funding_key: &SecretKey,
791 revocation_base_key: &SecretKey,
792 payment_key: &SecretKey,
793 delayed_payment_base_key: &SecretKey,
794 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
795 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
797 funding_pubkey: from_secret(&funding_key),
798 revocation_basepoint: from_secret(&revocation_base_key),
799 payment_point: from_secret(&payment_key),
800 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
801 htlc_basepoint: from_secret(&htlc_base_key),
805 /// Returns the counterparty's pubkeys.
807 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
808 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
809 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
810 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
811 /// broadcast a transaction.
813 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
814 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
815 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
816 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
817 /// if they broadcast a transaction.
819 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
820 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
821 /// Returns whether the holder is the initiator.
823 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
824 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
827 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
828 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
829 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
830 /// building transactions.
832 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
833 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
834 self.channel_parameters.as_ref().unwrap()
836 /// Returns the channel type features of the channel parameters. Should be helpful for
837 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
839 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
840 pub fn channel_type_features(&self) -> &ChannelTypeFeatures {
841 &self.get_channel_parameters().channel_type_features
843 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
844 /// by `descriptor`, returning the witness stack for the input.
846 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
847 /// is not spending the outpoint described by [`descriptor.outpoint`],
848 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
850 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
851 pub fn sign_counterparty_payment_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
852 // TODO: We really should be taking the SigHashCache as a parameter here instead of
853 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
854 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
855 // bindings updates to support SigHashCache objects).
856 if spend_tx.input.len() <= input_idx { return Err(()); }
857 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
858 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
860 let remotepubkey = self.pubkeys().payment_point;
861 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
862 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
863 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
864 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
866 if payment_script != descriptor.output.script_pubkey { return Err(()); }
868 let mut witness = Vec::with_capacity(2);
869 witness.push(remotesig.serialize_der().to_vec());
870 witness[0].push(EcdsaSighashType::All as u8);
871 witness.push(remotepubkey.serialize().to_vec());
875 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
876 /// described by `descriptor`, returning the witness stack for the input.
878 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
879 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
880 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
881 /// `script_pubkey` does not match the one we can spend.
883 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
884 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
885 pub fn sign_dynamic_p2wsh_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
886 // TODO: We really should be taking the SigHashCache as a parameter here instead of
887 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
888 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
889 // bindings updates to support SigHashCache objects).
890 if spend_tx.input.len() <= input_idx { return Err(()); }
891 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
892 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
893 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
895 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
896 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
897 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
898 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
899 let local_delayedsig = sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self);
900 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
902 if descriptor.output.script_pubkey != payment_script { return Err(()); }
904 let mut witness = Vec::with_capacity(3);
905 witness.push(local_delayedsig.serialize_der().to_vec());
906 witness[0].push(EcdsaSighashType::All as u8);
907 witness.push(vec!()); //MINIMALIF
908 witness.push(witness_script.clone().into_bytes());
913 impl EntropySource for InMemorySigner {
914 fn get_secure_random_bytes(&self) -> [u8; 32] {
915 let index = self.rand_bytes_index.get_increment();
916 let mut nonce = [0u8; 16];
917 nonce[..8].copy_from_slice(&index.to_be_bytes());
918 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
922 impl ChannelSigner for InMemorySigner {
923 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
924 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
925 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
928 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
929 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
932 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
936 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
938 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
940 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
941 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
942 if self.channel_parameters.is_some() {
943 // The channel parameters were already set and they match, return early.
946 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
947 self.channel_parameters = Some(channel_parameters.clone());
951 impl EcdsaChannelSigner for InMemorySigner {
952 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
953 let trusted_tx = commitment_tx.trust();
954 let keys = trusted_tx.keys();
956 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
957 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
959 let built_tx = trusted_tx.built_transaction();
960 let commitment_sig = built_tx.sign_counterparty_commitment(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
961 let commitment_txid = built_tx.txid;
963 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
964 for htlc in commitment_tx.htlcs() {
965 let channel_parameters = self.get_channel_parameters();
966 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, &channel_parameters.channel_type_features, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
967 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.channel_type_features(), &keys);
968 let htlc_sighashtype = if self.channel_type_features().supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
969 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
970 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
971 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
974 Ok((commitment_sig, htlc_sigs))
977 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
981 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
982 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
983 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
984 let trusted_tx = commitment_tx.trust();
985 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
986 let channel_parameters = self.get_channel_parameters();
987 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
991 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
992 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
993 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
994 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
995 let trusted_tx = commitment_tx.trust();
996 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
997 let channel_parameters = self.get_channel_parameters();
998 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
1002 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1003 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1004 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1005 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1006 let witness_script = {
1007 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint);
1008 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
1010 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1011 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1012 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1015 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1016 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1017 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1018 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1019 let witness_script = {
1020 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
1021 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
1022 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.channel_type_features(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
1024 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1025 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1026 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1029 fn sign_holder_htlc_transaction(
1030 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1031 secp_ctx: &Secp256k1<secp256k1::All>
1032 ) -> Result<Signature, ()> {
1033 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1034 let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
1035 input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
1037 let our_htlc_private_key = chan_utils::derive_private_key(
1038 &secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_key
1040 Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key, &self))
1043 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1044 let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1045 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1046 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
1047 let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
1048 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.channel_type_features(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
1049 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1050 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1051 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1054 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1055 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1056 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
1057 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
1060 fn sign_holder_anchor_input(
1061 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1062 ) -> Result<Signature, ()> {
1063 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1064 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
1065 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
1067 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1070 fn sign_channel_announcement_with_funding_key(
1071 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
1072 ) -> Result<Signature, ()> {
1073 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1074 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1078 const SERIALIZATION_VERSION: u8 = 1;
1080 const MIN_SERIALIZATION_VERSION: u8 = 1;
1082 impl WriteableEcdsaChannelSigner for InMemorySigner {}
1084 impl Writeable for InMemorySigner {
1085 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1086 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1088 self.funding_key.write(writer)?;
1089 self.revocation_base_key.write(writer)?;
1090 self.payment_key.write(writer)?;
1091 self.delayed_payment_base_key.write(writer)?;
1092 self.htlc_base_key.write(writer)?;
1093 self.commitment_seed.write(writer)?;
1094 self.channel_parameters.write(writer)?;
1095 self.channel_value_satoshis.write(writer)?;
1096 self.channel_keys_id.write(writer)?;
1098 write_tlv_fields!(writer, {});
1104 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySource {
1105 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1106 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1108 let funding_key = Readable::read(reader)?;
1109 let revocation_base_key = Readable::read(reader)?;
1110 let payment_key = Readable::read(reader)?;
1111 let delayed_payment_base_key = Readable::read(reader)?;
1112 let htlc_base_key = Readable::read(reader)?;
1113 let commitment_seed = Readable::read(reader)?;
1114 let counterparty_channel_data = Readable::read(reader)?;
1115 let channel_value_satoshis = Readable::read(reader)?;
1116 let secp_ctx = Secp256k1::signing_only();
1117 let holder_channel_pubkeys =
1118 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
1119 &payment_key, &delayed_payment_base_key, &htlc_base_key);
1120 let keys_id = Readable::read(reader)?;
1122 read_tlv_fields!(reader, {});
1126 revocation_base_key,
1128 delayed_payment_base_key,
1131 channel_value_satoshis,
1132 holder_channel_pubkeys,
1133 channel_parameters: counterparty_channel_data,
1134 channel_keys_id: keys_id,
1135 rand_bytes_unique_start: entropy_source.get_secure_random_bytes(),
1136 rand_bytes_index: AtomicCounter::new(),
1141 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1142 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1144 /// Your `node_id` is seed/0'.
1145 /// Unilateral closes may use seed/1'.
1146 /// Cooperative closes may use seed/2'.
1147 /// The two close keys may be needed to claim on-chain funds!
1149 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1150 /// [`PhantomKeysManager`] must be used instead.
1152 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1153 /// previously issued invoices and attempts to pay previous invoices will fail.
1154 pub struct KeysManager {
1155 secp_ctx: Secp256k1<secp256k1::All>,
1156 node_secret: SecretKey,
1158 inbound_payment_key: KeyMaterial,
1159 destination_script: Script,
1160 shutdown_pubkey: PublicKey,
1161 channel_master_key: ExtendedPrivKey,
1162 channel_child_index: AtomicUsize,
1164 rand_bytes_unique_start: [u8; 32],
1165 rand_bytes_index: AtomicCounter,
1168 starting_time_secs: u64,
1169 starting_time_nanos: u32,
1173 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1174 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1175 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1176 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1177 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1178 /// is to simply use the current time (with very high precision).
1180 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1181 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1182 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1185 /// Note that the seed is required to recover certain on-chain funds independent of
1186 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1187 /// for any channel, and some on-chain during-closing funds.
1189 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1190 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1191 let secp_ctx = Secp256k1::new();
1192 // Note that when we aren't serializing the key, network doesn't matter
1193 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1195 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
1196 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1197 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
1198 Ok(destination_key) => {
1199 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
1200 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1201 .push_slice(&wpubkey_hash.into_inner())
1204 Err(_) => panic!("Your RNG is busted"),
1206 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
1207 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
1208 Err(_) => panic!("Your RNG is busted"),
1210 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
1211 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
1212 let mut inbound_pmt_key_bytes = [0; 32];
1213 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1215 let mut rand_bytes_engine = Sha256::engine();
1216 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1217 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1218 rand_bytes_engine.input(seed);
1219 rand_bytes_engine.input(b"LDK PRNG Seed");
1220 let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).into_inner();
1222 let mut res = KeysManager {
1226 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1232 channel_child_index: AtomicUsize::new(0),
1234 rand_bytes_unique_start,
1235 rand_bytes_index: AtomicCounter::new(),
1239 starting_time_nanos,
1241 let secp_seed = res.get_secure_random_bytes();
1242 res.secp_ctx.seeded_randomize(&secp_seed);
1245 Err(_) => panic!("Your rng is busted"),
1249 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1250 pub fn get_node_secret_key(&self) -> SecretKey {
1254 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1255 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1256 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1257 let mut unique_start = Sha256::engine();
1258 unique_start.input(params);
1259 unique_start.input(&self.seed);
1261 // We only seriously intend to rely on the channel_master_key for true secure
1262 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1263 // starting_time provided in the constructor) to be unique.
1264 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
1265 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
1266 ).expect("Your RNG is busted");
1267 unique_start.input(&child_privkey.private_key[..]);
1269 let seed = Sha256::from_engine(unique_start).into_inner();
1271 let commitment_seed = {
1272 let mut sha = Sha256::engine();
1274 sha.input(&b"commitment seed"[..]);
1275 Sha256::from_engine(sha).into_inner()
1277 macro_rules! key_step {
1278 ($info: expr, $prev_key: expr) => {{
1279 let mut sha = Sha256::engine();
1281 sha.input(&$prev_key[..]);
1282 sha.input(&$info[..]);
1283 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1286 let funding_key = key_step!(b"funding key", commitment_seed);
1287 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1288 let payment_key = key_step!(b"payment key", revocation_base_key);
1289 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1290 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1291 let prng_seed = self.get_secure_random_bytes();
1293 InMemorySigner::new(
1296 revocation_base_key,
1298 delayed_payment_base_key,
1301 channel_value_satoshis,
1307 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
1308 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
1309 /// are no other inputs that need signing.
1311 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
1313 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1314 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1315 pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], psbt: &mut PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<(), ()> {
1316 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1317 for outp in descriptors {
1319 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1320 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1321 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1323 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1324 descriptor.channel_keys_id));
1326 let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
1327 psbt.inputs[input_idx].final_script_witness = Some(witness);
1329 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1330 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1331 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1333 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1334 descriptor.channel_keys_id));
1336 let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
1337 psbt.inputs[input_idx].final_script_witness = Some(witness);
1339 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1340 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
1341 let derivation_idx = if output.script_pubkey == self.destination_script {
1347 // Note that when we aren't serializing the key, network doesn't matter
1348 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1350 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1352 Err(_) => panic!("Your RNG is busted"),
1355 Err(_) => panic!("Your rng is busted"),
1358 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1359 if derivation_idx == 2 {
1360 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1362 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1363 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1365 if payment_script != output.script_pubkey { return Err(()); };
1367 let sighash = hash_to_message!(&sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1368 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
1369 let mut sig_ser = sig.serialize_der().to_vec();
1370 sig_ser.push(EcdsaSighashType::All as u8);
1371 let witness = Witness::from_vec(vec![sig_ser, pubkey.inner.serialize().to_vec()]);
1372 psbt.inputs[input_idx].final_script_witness = Some(witness);
1380 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
1381 /// output to the given change destination (if sufficient change value remains). The
1382 /// transaction will have a feerate, at least, of the given value.
1384 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
1385 /// transaction will have a locktime of 0. It it recommended to set this to the current block
1386 /// height to avoid fee sniping, unless you have some specific reason to use a different
1389 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1390 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1391 /// does not match the one we can spend.
1393 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1395 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1396 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1397 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1398 let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
1399 self.sign_spendable_outputs_psbt(descriptors, &mut psbt, secp_ctx)?;
1401 let spend_tx = psbt.extract_tx();
1403 debug_assert!(expected_max_weight >= spend_tx.weight());
1404 // Note that witnesses with a signature vary somewhat in size, so allow
1405 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1406 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1412 impl EntropySource for KeysManager {
1413 fn get_secure_random_bytes(&self) -> [u8; 32] {
1414 let index = self.rand_bytes_index.get_increment();
1415 let mut nonce = [0u8; 16];
1416 nonce[..8].copy_from_slice(&index.to_be_bytes());
1417 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
1421 impl NodeSigner for KeysManager {
1422 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1424 Recipient::Node => Ok(self.node_id.clone()),
1425 Recipient::PhantomNode => Err(())
1429 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1430 let mut node_secret = match recipient {
1431 Recipient::Node => Ok(self.node_secret.clone()),
1432 Recipient::PhantomNode => Err(())
1434 if let Some(tweak) = tweak {
1435 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1437 Ok(SharedSecret::new(other_key, &node_secret))
1440 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1441 self.inbound_payment_key.clone()
1444 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1445 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1446 let secret = match recipient {
1447 Recipient::Node => Ok(&self.node_secret),
1448 Recipient::PhantomNode => Err(())
1450 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1453 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1454 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1455 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
1459 impl SignerProvider for KeysManager {
1460 type Signer = InMemorySigner;
1462 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1463 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1464 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
1465 // (though `user_channel_id` should help, depending on user behavior). If it manages to
1466 // roll over, we may generate duplicate keys for two different channels, which could result
1467 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
1468 // doesn't reach `u32::MAX`.
1469 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
1470 let mut id = [0; 32];
1471 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1472 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1473 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1474 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1478 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1479 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1482 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1483 InMemorySigner::read(&mut io::Cursor::new(reader), self)
1486 fn get_destination_script(&self) -> Result<Script, ()> {
1487 Ok(self.destination_script.clone())
1490 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1491 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
1495 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1498 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1499 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1500 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1501 /// itself without ever needing to forward to this fake node.
1503 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1504 /// provide some fault tolerance, because payers will automatically retry paying other provided
1505 /// nodes in the case that one node goes down.
1507 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1508 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1509 // nodes to know when the full payment has been received (and the preimage can be released) without
1510 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1511 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1512 // is released too early.
1514 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1515 /// invoices and attempts to pay previous invoices will fail.
1516 pub struct PhantomKeysManager {
1518 inbound_payment_key: KeyMaterial,
1519 phantom_secret: SecretKey,
1520 phantom_node_id: PublicKey,
1523 impl EntropySource for PhantomKeysManager {
1524 fn get_secure_random_bytes(&self) -> [u8; 32] {
1525 self.inner.get_secure_random_bytes()
1529 impl NodeSigner for PhantomKeysManager {
1530 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1532 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1533 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1537 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1538 let mut node_secret = match recipient {
1539 Recipient::Node => self.inner.node_secret.clone(),
1540 Recipient::PhantomNode => self.phantom_secret.clone(),
1542 if let Some(tweak) = tweak {
1543 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1545 Ok(SharedSecret::new(other_key, &node_secret))
1548 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1549 self.inbound_payment_key.clone()
1552 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1553 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1554 let secret = match recipient {
1555 Recipient::Node => &self.inner.node_secret,
1556 Recipient::PhantomNode => &self.phantom_secret,
1558 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1561 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1562 self.inner.sign_gossip_message(msg)
1566 impl SignerProvider for PhantomKeysManager {
1567 type Signer = InMemorySigner;
1569 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1570 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1573 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1574 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1577 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1578 self.inner.read_chan_signer(reader)
1581 fn get_destination_script(&self) -> Result<Script, ()> {
1582 self.inner.get_destination_script()
1585 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1586 self.inner.get_shutdown_scriptpubkey()
1590 impl PhantomKeysManager {
1591 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
1592 /// that is shared across all nodes that intend to participate in [phantom node payments]
1595 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1596 /// `starting_time_nanos`.
1598 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1599 /// same across restarts, or else inbound payments may fail.
1601 /// [phantom node payments]: PhantomKeysManager
1602 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1603 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1604 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1605 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1606 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1609 inbound_payment_key: KeyMaterial(inbound_key),
1615 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1616 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1617 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
1620 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1621 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1622 self.inner.derive_channel_keys(channel_value_satoshis, params)
1625 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1626 pub fn get_node_secret_key(&self) -> SecretKey {
1627 self.inner.get_node_secret_key()
1630 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
1631 /// last-hop onion data, etc.
1632 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
1637 // Ensure that EcdsaChannelSigner can have a vtable
1640 let _signer: Box<dyn EcdsaChannelSigner>;
1645 use std::sync::{Arc, mpsc};
1646 use std::sync::mpsc::TryRecvError;
1648 use std::time::Duration;
1649 use bitcoin::blockdata::constants::genesis_block;
1650 use bitcoin::Network;
1651 use crate::sign::{EntropySource, KeysManager};
1653 use criterion::Criterion;
1655 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
1656 let seed = [0u8; 32];
1657 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
1658 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
1660 let mut handles = Vec::new();
1661 let mut stops = Vec::new();
1663 let keys_manager_clone = Arc::clone(&keys_manager);
1664 let (stop_sender, stop_receiver) = mpsc::channel();
1665 let handle = thread::spawn(move || {
1667 keys_manager_clone.get_secure_random_bytes();
1668 match stop_receiver.try_recv() {
1669 Ok(_) | Err(TryRecvError::Disconnected) => {
1670 println!("Terminating.");
1673 Err(TryRecvError::Empty) => {}
1677 handles.push(handle);
1678 stops.push(stop_sender);
1681 bench.bench_function("get_secure_random_bytes", |b| b.iter(||
1682 keys_manager.get_secure_random_bytes()));
1685 let _ = stop.send(());
1687 for handle in handles {
1688 handle.join().unwrap();