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::{KeyPair, PublicKey, Scalar, Secp256k1, SecretKey, Signing};
30 use bitcoin::secp256k1::ecdh::SharedSecret;
31 use bitcoin::secp256k1::ecdsa::{RecoverableSignature, Signature};
32 use bitcoin::secp256k1::schnorr;
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;
45 use crate::offers::invoice::UnsignedBolt12Invoice;
46 use crate::offers::invoice_request::UnsignedInvoiceRequest;
48 use crate::prelude::*;
49 use core::convert::TryInto;
51 use core::sync::atomic::{AtomicUsize, Ordering};
52 use crate::io::{self, Error};
53 use crate::ln::features::ChannelTypeFeatures;
54 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
55 use crate::util::atomic_counter::AtomicCounter;
56 use crate::util::chacha20::ChaCha20;
57 use crate::util::invoice::construct_invoice_preimage;
59 pub(crate) mod type_resolver;
61 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
62 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
64 /// This is not exported to bindings users as we just use `[u8; 32]` directly
65 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
66 pub struct KeyMaterial(pub [u8; 32]);
68 /// Information about a spendable output to a P2WSH script.
70 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
71 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
72 pub struct DelayedPaymentOutputDescriptor {
73 /// The outpoint which is spendable.
74 pub outpoint: OutPoint,
75 /// Per commitment point to derive the delayed payment key by key holder.
76 pub per_commitment_point: PublicKey,
77 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
78 /// the witness_script.
79 pub to_self_delay: u16,
80 /// The output which is referenced by the given outpoint.
82 /// The revocation point specific to the commitment transaction which was broadcast. Used to
83 /// derive the witnessScript for this output.
84 pub revocation_pubkey: PublicKey,
85 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
86 /// This may be useful in re-deriving keys used in the channel to spend the output.
87 pub channel_keys_id: [u8; 32],
88 /// The value of the channel which this output originated from, possibly indirectly.
89 pub channel_value_satoshis: u64,
91 impl DelayedPaymentOutputDescriptor {
92 /// The maximum length a well-formed witness spending one of these should have.
93 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
95 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
96 // redeemscript push length.
97 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
100 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
101 (0, outpoint, required),
102 (2, per_commitment_point, required),
103 (4, to_self_delay, required),
104 (6, output, required),
105 (8, revocation_pubkey, required),
106 (10, channel_keys_id, required),
107 (12, channel_value_satoshis, required),
110 /// Information about a spendable output to our "payment key".
112 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
113 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
114 pub struct StaticPaymentOutputDescriptor {
115 /// The outpoint which is spendable.
116 pub outpoint: OutPoint,
117 /// The output which is referenced by the given outpoint.
119 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
120 /// This may be useful in re-deriving keys used in the channel to spend the output.
121 pub channel_keys_id: [u8; 32],
122 /// The value of the channel which this transactions spends.
123 pub channel_value_satoshis: u64,
125 impl StaticPaymentOutputDescriptor {
126 /// The maximum length a well-formed witness spending one of these should have.
127 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
129 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
130 // redeemscript push length.
131 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
133 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
134 (0, outpoint, required),
135 (2, output, required),
136 (4, channel_keys_id, required),
137 (6, channel_value_satoshis, required),
140 /// Describes the necessary information to spend a spendable output.
142 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
143 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
144 /// to spend on-chain. The information needed to do this is provided in this enum, including the
145 /// outpoint describing which `txid` and output `index` is available, the full output which exists
146 /// at that `txid`/`index`, and any keys or other information required to sign.
148 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
149 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
150 pub enum SpendableOutputDescriptor {
151 /// An output to a script which was provided via [`SignerProvider`] directly, either from
152 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
153 /// know how to spend it. No secret keys are provided as LDK was never given any key.
154 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
155 /// on-chain using the payment preimage or after it has timed out.
157 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
158 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
160 /// The outpoint which is spendable.
162 /// The output which is referenced by the given outpoint.
165 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
168 /// The witness in the spending input should be:
170 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
173 /// Note that the `nSequence` field in the spending input must be set to
174 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
175 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
176 /// the outpoint confirms, see [BIP
177 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
178 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
181 /// These are generally the result of a "revocable" output to us, spendable only by us unless
182 /// it is an output from an old state which we broadcast (which should never happen).
184 /// To derive the delayed payment key which is used to sign this input, you must pass the
185 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
186 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
187 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The public key can be
188 /// generated without the secret key using [`chan_utils::derive_public_key`] and only the
189 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
191 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
192 /// used in the witness script generation), you must pass the counterparty
193 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
194 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
195 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
196 /// [`chan_utils::derive_public_revocation_key`].
198 /// The witness script which is hashed and included in the output `script_pubkey` may be
199 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
200 /// as explained above), our delayed payment pubkey (derived as explained above), and the
201 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
202 /// [`chan_utils::get_revokeable_redeemscript`].
203 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
204 /// An output to a P2WPKH, spendable exclusively by our payment key (i.e., the private key
205 /// which corresponds to the `payment_point` in [`ChannelSigner::pubkeys`]). The witness
206 /// in the spending input is, thus, simply:
208 /// <BIP 143 signature> <payment key>
211 /// These are generally the result of our counterparty having broadcast the current state,
212 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
213 StaticPaymentOutput(StaticPaymentOutputDescriptor),
216 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
217 (0, StaticOutput) => {
218 (0, outpoint, required),
219 (2, output, required),
222 (1, DelayedPaymentOutput),
223 (2, StaticPaymentOutput),
226 impl SpendableOutputDescriptor {
227 /// Turns this into a [`bitcoin::psbt::Input`] which can be used to create a
228 /// [`PartiallySignedTransaction`] which spends the given descriptor.
230 /// Note that this does not include any signatures, just the information required to
231 /// construct the transaction and sign it.
232 pub fn to_psbt_input(&self) -> bitcoin::psbt::Input {
234 SpendableOutputDescriptor::StaticOutput { output, .. } => {
235 // Is a standard P2WPKH, no need for witness script
236 bitcoin::psbt::Input {
237 witness_utxo: Some(output.clone()),
241 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
242 // TODO we could add the witness script as well
243 bitcoin::psbt::Input {
244 witness_utxo: Some(descriptor.output.clone()),
248 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
249 // TODO we could add the witness script as well
250 bitcoin::psbt::Input {
251 witness_utxo: Some(descriptor.output.clone()),
258 /// Creates an unsigned [`PartiallySignedTransaction`] which spends the given descriptors to
259 /// the given outputs, plus an output to the given change destination (if sufficient
260 /// change value remains). The PSBT will have a feerate, at least, of the given value.
262 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
263 /// transaction will have a locktime of 0. It it recommended to set this to the current block
264 /// height to avoid fee sniping, unless you have some specific reason to use a different
267 /// Returns the PSBT and expected max transaction weight.
269 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
270 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
271 /// does not match the one we can spend.
273 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
274 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), ()> {
275 let mut input = Vec::with_capacity(descriptors.len());
276 let mut input_value = 0;
277 let mut witness_weight = 0;
278 let mut output_set = HashSet::with_capacity(descriptors.len());
279 for outp in descriptors {
281 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
282 if !output_set.insert(descriptor.outpoint) { return Err(()); }
284 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
285 script_sig: Script::new(),
286 sequence: Sequence::ZERO,
287 witness: Witness::new(),
289 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
290 #[cfg(feature = "grind_signatures")]
291 { witness_weight -= 1; } // Guarantees a low R signature
292 input_value += descriptor.output.value;
294 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
295 if !output_set.insert(descriptor.outpoint) { return Err(()); }
297 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
298 script_sig: Script::new(),
299 sequence: Sequence(descriptor.to_self_delay as u32),
300 witness: Witness::new(),
302 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
303 #[cfg(feature = "grind_signatures")]
304 { witness_weight -= 1; } // Guarantees a low R signature
305 input_value += descriptor.output.value;
307 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
308 if !output_set.insert(*outpoint) { return Err(()); }
310 previous_output: outpoint.into_bitcoin_outpoint(),
311 script_sig: Script::new(),
312 sequence: Sequence::ZERO,
313 witness: Witness::new(),
315 witness_weight += 1 + 73 + 34;
316 #[cfg(feature = "grind_signatures")]
317 { witness_weight -= 1; } // Guarantees a low R signature
318 input_value += output.value;
321 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
323 let mut tx = Transaction {
325 lock_time: locktime.unwrap_or(PackedLockTime::ZERO),
329 let expected_max_weight =
330 transaction_utils::maybe_add_change_output(&mut tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
332 let psbt_inputs = descriptors.iter().map(|d| d.to_psbt_input()).collect::<Vec<_>>();
333 let psbt = PartiallySignedTransaction {
335 outputs: vec![Default::default(); tx.output.len()],
337 xpub: Default::default(),
339 proprietary: Default::default(),
340 unknown: Default::default(),
342 Ok((psbt, expected_max_weight))
346 /// A trait to handle Lightning channel key material without concretizing the channel type or
347 /// the signature mechanism.
348 pub trait ChannelSigner {
349 /// Gets the per-commitment point for a specific commitment number
351 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
352 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
354 /// Gets the commitment secret for a specific commitment number as part of the revocation process
356 /// An external signer implementation should error here if the commitment was already signed
357 /// and should refuse to sign it in the future.
359 /// May be called more than once for the same index.
361 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
362 // TODO: return a Result so we can signal a validation error
363 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
365 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
367 /// This is required in order for the signer to make sure that releasing a commitment
368 /// secret won't leave us without a broadcastable holder transaction.
369 /// Policy checks should be implemented in this function, including checking the amount
370 /// sent to us and checking the HTLCs.
372 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
373 /// A validating signer should ensure that an HTLC output is removed only when the matching
374 /// preimage is provided, or when the value to holder is restored.
376 /// Note that all the relevant preimages will be provided, but there may also be additional
377 /// irrelevant or duplicate preimages.
378 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction,
379 preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
381 /// Returns the holder's channel public keys and basepoints.
382 fn pubkeys(&self) -> &ChannelPublicKeys;
384 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
385 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
386 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
387 fn channel_keys_id(&self) -> [u8; 32];
389 /// Set the counterparty static channel data, including basepoints,
390 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
392 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
393 /// instance, LDK will call this method exactly once - either immediately after construction
394 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
395 /// information has been generated.
397 /// channel_parameters.is_populated() MUST be true.
398 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
401 /// A trait to sign Lightning channel transactions as described in
402 /// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
404 /// Signing services could be implemented on a hardware wallet and should implement signing
405 /// policies in order to be secure. Please refer to the [VLS Policy
406 /// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
407 /// for an example of such policies.
408 pub trait EcdsaChannelSigner: ChannelSigner {
409 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
411 /// Note that if signing fails or is rejected, the channel will be force-closed.
413 /// Policy checks should be implemented in this function, including checking the amount
414 /// sent to us and checking the HTLCs.
416 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
417 /// A validating signer should ensure that an HTLC output is removed only when the matching
418 /// preimage is provided, or when the value to holder is restored.
420 /// Note that all the relevant preimages will be provided, but there may also be additional
421 /// irrelevant or duplicate preimages.
423 // TODO: Document the things someone using this interface should enforce before signing.
424 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction,
425 preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>
426 ) -> Result<(Signature, Vec<Signature>), ()>;
427 /// Validate the counterparty's revocation.
429 /// This is required in order for the signer to make sure that the state has moved
430 /// forward and it is safe to sign the next counterparty commitment.
431 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
432 /// Creates a signature for a holder's commitment transaction and its claiming HTLC transactions.
434 /// This will be called
435 /// - with a non-revoked `commitment_tx`.
436 /// - with the latest `commitment_tx` when we initiate a force-close.
437 /// - with the previous `commitment_tx`, just to get claiming HTLC
438 /// signatures, if we are reacting to a [`ChannelMonitor`]
439 /// [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
440 /// that decided to broadcast before it had been updated to the latest `commitment_tx`.
442 /// This may be called multiple times for the same transaction.
444 /// An external signer implementation should check that the commitment has not been revoked.
446 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
447 // TODO: Document the things someone using this interface should enforce before signing.
448 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
449 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
450 /// Same as [`sign_holder_commitment_and_htlcs`], but exists only for tests to get access to
451 /// holder commitment transactions which will be broadcasted later, after the channel has moved
452 /// on to a newer state. Thus, needs its own method as [`sign_holder_commitment_and_htlcs`] may
453 /// enforce that we only ever get called once.
454 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
455 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
456 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
457 /// Create a signature for the given input in a transaction spending an HTLC transaction output
458 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
460 /// A justice transaction may claim multiple outputs at the same time if timelocks are
461 /// similar, but only a signature for the input at index `input` should be signed for here.
462 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
463 /// to an upcoming timelock expiration.
465 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
467 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
468 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
469 /// not allow the spending of any funds by itself (you need our holder `revocation_secret` to do
471 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64,
472 per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>
473 ) -> Result<Signature, ()>;
474 /// Create a signature for the given input in a transaction spending a commitment transaction
475 /// HTLC output when our counterparty broadcasts an old state.
477 /// A justice transaction may claim multiple outputs at the same time if timelocks are
478 /// similar, but only a signature for the input at index `input` should be signed for here.
479 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
480 /// to an upcoming timelock expiration.
482 /// `amount` is the value of the output spent by this input, committed to in the BIP 143
485 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
486 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
487 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
490 /// `htlc` holds HTLC elements (hash, timelock), thus changing the format of the witness script
491 /// (which is committed to in the BIP 143 signatures).
492 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64,
493 per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment,
494 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
495 /// Computes the signature for a commitment transaction's HTLC output used as an input within
496 /// `htlc_tx`, which spends the commitment transaction at index `input`. The signature returned
497 /// must be be computed using [`EcdsaSighashType::All`]. Note that this should only be used to
498 /// sign HTLC transactions from channels supporting anchor outputs after all additional
499 /// inputs/outputs have been added to the transaction.
501 /// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
502 fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize,
503 htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<secp256k1::All>
504 ) -> Result<Signature, ()>;
505 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
506 /// transaction, either offered or received.
508 /// Such a transaction may claim multiples offered outputs at same time if we know the
509 /// preimage for each when we create it, but only the input at index `input` should be
510 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
511 /// needed with regards to an upcoming timelock expiration.
513 /// `witness_script` is either an offered or received script as defined in BOLT3 for HTLC
516 /// `amount` is value of the output spent by this input, committed to in the BIP 143 signature.
518 /// `per_commitment_point` is the dynamic point corresponding to the channel state
519 /// detected onchain. It has been generated by our counterparty and is used to derive
520 /// channel state keys, which are then included in the witness script and committed to in the
521 /// BIP 143 signature.
522 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64,
523 per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment,
524 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
525 /// Create a signature for a (proposed) closing transaction.
527 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
528 /// chosen to forgo their output as dust.
529 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction,
530 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
531 /// Computes the signature for a commitment transaction's anchor output used as an
532 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
533 fn sign_holder_anchor_input(
534 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
535 ) -> Result<Signature, ()>;
536 /// Signs a channel announcement message with our funding key proving it comes from one of the
537 /// channel participants.
539 /// Channel announcements also require a signature from each node's network key. Our node
540 /// signature is computed through [`NodeSigner::sign_gossip_message`].
542 /// Note that if this fails or is rejected, the channel will not be publicly announced and
543 /// our counterparty may (though likely will not) close the channel on us for violating the
545 fn sign_channel_announcement_with_funding_key(
546 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
547 ) -> Result<Signature, ()>;
550 /// A writeable signer.
552 /// There will always be two instances of a signer per channel, one occupied by the
553 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
555 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
556 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
557 pub trait WriteableEcdsaChannelSigner: EcdsaChannelSigner + Writeable {}
559 /// Specifies the recipient of an invoice.
561 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
564 /// The invoice should be signed with the local node secret key.
566 /// The invoice should be signed with the phantom node secret key. This secret key must be the
567 /// same for all nodes participating in the [phantom node payment].
569 /// [phantom node payment]: PhantomKeysManager
573 /// A trait that describes a source of entropy.
574 pub trait EntropySource {
575 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
576 /// different value each time it is called.
577 fn get_secure_random_bytes(&self) -> [u8; 32];
580 /// A trait that can handle cryptographic operations at the scope level of a node.
581 pub trait NodeSigner {
582 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
584 /// If the implementor of this trait supports [phantom node payments], then every node that is
585 /// intended to be included in the phantom invoice route hints must return the same value from
587 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
588 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
589 // nodes, they must share the key that encrypts this payment data.
591 /// This method must return the same value each time it is called.
593 /// [phantom node payments]: PhantomKeysManager
594 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
596 /// Get node id based on the provided [`Recipient`].
598 /// This method must return the same value each time it is called with a given [`Recipient`]
601 /// Errors if the [`Recipient`] variant is not supported by the implementation.
602 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
604 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
605 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
606 /// secret, though this is less efficient.
608 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
609 /// should be resolved to allow LDK to resume forwarding HTLCs.
611 /// Errors if the [`Recipient`] variant is not supported by the implementation.
612 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
616 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
617 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
618 /// blindly signing the hash.
620 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
622 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
624 /// Errors if the [`Recipient`] variant is not supported by the implementation.
625 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()>;
627 /// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
629 /// May be called by a function passed to [`UnsignedInvoiceRequest::sign`] where
630 /// `invoice_request` is the callee.
632 /// Implementors may check that the `invoice_request` is expected rather than blindly signing
633 /// the tagged hash. An `Ok` result should sign `invoice_request.tagged_hash().as_digest()` with
634 /// the node's signing key or an ephemeral key to preserve privacy, whichever is associated with
635 /// [`UnsignedInvoiceRequest::payer_id`].
637 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
638 fn sign_bolt12_invoice_request(
639 &self, invoice_request: &UnsignedInvoiceRequest
640 ) -> Result<schnorr::Signature, ()>;
642 /// Signs the [`TaggedHash`] of a BOLT 12 invoice.
644 /// May be called by a function passed to [`UnsignedBolt12Invoice::sign`] where `invoice` is the
647 /// Implementors may check that the `invoice` is expected rather than blindly signing the tagged
648 /// hash. An `Ok` result should sign `invoice.tagged_hash().as_digest()` with the node's signing
649 /// key or an ephemeral key to preserve privacy, whichever is associated with
650 /// [`UnsignedBolt12Invoice::signing_pubkey`].
652 /// [`TaggedHash`]: crate::offers::merkle::TaggedHash
653 fn sign_bolt12_invoice(
654 &self, invoice: &UnsignedBolt12Invoice
655 ) -> Result<schnorr::Signature, ()>;
657 /// Sign a gossip message.
659 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
660 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
661 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
662 /// corresponding channel.
663 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
666 /// A trait that can return signer instances for individual channels.
667 pub trait SignerProvider {
668 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
669 type Signer : WriteableEcdsaChannelSigner;
671 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::Signer`] through
672 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
673 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
674 /// `channel_keys_id`.
676 /// This method must return a different value each time it is called.
677 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
679 /// Derives the private key material backing a `Signer`.
681 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
682 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
683 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
684 /// [`ChannelSigner::channel_keys_id`].
685 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
687 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
688 /// This is only called during deserialization of other objects which contain
689 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
690 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
691 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
692 /// you've read all of the provided bytes to ensure no corruption occurred.
694 /// This method is slowly being phased out -- it will only be called when reading objects
695 /// written by LDK versions prior to 0.0.113.
697 /// [`Signer`]: Self::Signer
698 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
699 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
700 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
702 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
704 /// If this function returns an error, this will result in a channel failing to open.
706 /// This method should return a different value each time it is called, to avoid linking
707 /// on-chain funds across channels as controlled to the same user.
708 fn get_destination_script(&self) -> Result<Script, ()>;
710 /// Get a script pubkey which we will send funds to when closing a channel.
712 /// If this function returns an error, this will result in a channel failing to open or close.
713 /// In the event of a failure when the counterparty is initiating a close, this can result in a
714 /// channel force close.
716 /// This method should return a different value each time it is called, to avoid linking
717 /// on-chain funds across channels as controlled to the same user.
718 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
721 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
723 /// This implementation performs no policy checks and is insufficient by itself as
724 /// a secure external signer.
726 pub struct InMemorySigner {
727 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
728 /// holder's anchor output in a commitment transaction, if one is present.
729 pub funding_key: SecretKey,
730 /// Holder secret key for blinded revocation pubkey.
731 pub revocation_base_key: SecretKey,
732 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
733 pub payment_key: SecretKey,
734 /// Holder secret key used in an HTLC transaction.
735 pub delayed_payment_base_key: SecretKey,
736 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
737 pub htlc_base_key: SecretKey,
739 pub commitment_seed: [u8; 32],
740 /// Holder public keys and basepoints.
741 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
742 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
743 channel_parameters: Option<ChannelTransactionParameters>,
744 /// The total value of this channel.
745 channel_value_satoshis: u64,
746 /// Key derivation parameters.
747 channel_keys_id: [u8; 32],
748 /// Seed from which all randomness produced is derived from.
749 rand_bytes_unique_start: [u8; 32],
750 /// Tracks the number of times we've produced randomness to ensure we don't return the same
752 rand_bytes_index: AtomicCounter,
755 impl PartialEq for InMemorySigner {
756 fn eq(&self, other: &Self) -> bool {
757 self.funding_key == other.funding_key &&
758 self.revocation_base_key == other.revocation_base_key &&
759 self.payment_key == other.payment_key &&
760 self.delayed_payment_base_key == other.delayed_payment_base_key &&
761 self.htlc_base_key == other.htlc_base_key &&
762 self.commitment_seed == other.commitment_seed &&
763 self.holder_channel_pubkeys == other.holder_channel_pubkeys &&
764 self.channel_parameters == other.channel_parameters &&
765 self.channel_value_satoshis == other.channel_value_satoshis &&
766 self.channel_keys_id == other.channel_keys_id
770 impl Clone for InMemorySigner {
771 fn clone(&self) -> Self {
773 funding_key: self.funding_key.clone(),
774 revocation_base_key: self.revocation_base_key.clone(),
775 payment_key: self.payment_key.clone(),
776 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
777 htlc_base_key: self.htlc_base_key.clone(),
778 commitment_seed: self.commitment_seed.clone(),
779 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
780 channel_parameters: self.channel_parameters.clone(),
781 channel_value_satoshis: self.channel_value_satoshis,
782 channel_keys_id: self.channel_keys_id,
783 rand_bytes_unique_start: self.get_secure_random_bytes(),
784 rand_bytes_index: AtomicCounter::new(),
789 impl InMemorySigner {
790 /// Creates a new [`InMemorySigner`].
791 pub fn new<C: Signing>(
792 secp_ctx: &Secp256k1<C>,
793 funding_key: SecretKey,
794 revocation_base_key: SecretKey,
795 payment_key: SecretKey,
796 delayed_payment_base_key: SecretKey,
797 htlc_base_key: SecretKey,
798 commitment_seed: [u8; 32],
799 channel_value_satoshis: u64,
800 channel_keys_id: [u8; 32],
801 rand_bytes_unique_start: [u8; 32],
802 ) -> InMemorySigner {
803 let holder_channel_pubkeys =
804 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
805 &payment_key, &delayed_payment_base_key,
811 delayed_payment_base_key,
814 channel_value_satoshis,
815 holder_channel_pubkeys,
816 channel_parameters: None,
818 rand_bytes_unique_start,
819 rand_bytes_index: AtomicCounter::new(),
823 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
824 funding_key: &SecretKey,
825 revocation_base_key: &SecretKey,
826 payment_key: &SecretKey,
827 delayed_payment_base_key: &SecretKey,
828 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
829 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
831 funding_pubkey: from_secret(&funding_key),
832 revocation_basepoint: from_secret(&revocation_base_key),
833 payment_point: from_secret(&payment_key),
834 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
835 htlc_basepoint: from_secret(&htlc_base_key),
839 /// Returns the counterparty's pubkeys.
841 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
842 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
843 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
844 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
845 /// broadcast a transaction.
847 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
848 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
849 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
850 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
851 /// if they broadcast a transaction.
853 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
854 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
855 /// Returns whether the holder is the initiator.
857 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
858 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
861 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
862 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
863 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
864 /// building transactions.
866 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
867 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
868 self.channel_parameters.as_ref().unwrap()
870 /// Returns the channel type features of the channel parameters. Should be helpful for
871 /// determining a channel's category, i. e. legacy/anchors/taproot/etc.
873 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
874 pub fn channel_type_features(&self) -> &ChannelTypeFeatures {
875 &self.get_channel_parameters().channel_type_features
877 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
878 /// by `descriptor`, returning the witness stack for the input.
880 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
881 /// is not spending the outpoint described by [`descriptor.outpoint`],
882 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
884 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
885 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>>, ()> {
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(()); }
894 let remotepubkey = self.pubkeys().payment_point;
895 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
896 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
897 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
898 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
900 if payment_script != descriptor.output.script_pubkey { return Err(()); }
902 let mut witness = Vec::with_capacity(2);
903 witness.push(remotesig.serialize_der().to_vec());
904 witness[0].push(EcdsaSighashType::All as u8);
905 witness.push(remotepubkey.serialize().to_vec());
909 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
910 /// described by `descriptor`, returning the witness stack for the input.
912 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
913 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
914 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
915 /// `script_pubkey` does not match the one we can spend.
917 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
918 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
919 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>>, ()> {
920 // TODO: We really should be taking the SigHashCache as a parameter here instead of
921 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
922 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
923 // bindings updates to support SigHashCache objects).
924 if spend_tx.input.len() <= input_idx { return Err(()); }
925 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
926 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
927 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
929 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
930 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
931 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
932 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
933 let local_delayedsig = sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self);
934 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
936 if descriptor.output.script_pubkey != payment_script { return Err(()); }
938 let mut witness = Vec::with_capacity(3);
939 witness.push(local_delayedsig.serialize_der().to_vec());
940 witness[0].push(EcdsaSighashType::All as u8);
941 witness.push(vec!()); //MINIMALIF
942 witness.push(witness_script.clone().into_bytes());
947 impl EntropySource for InMemorySigner {
948 fn get_secure_random_bytes(&self) -> [u8; 32] {
949 let index = self.rand_bytes_index.get_increment();
950 let mut nonce = [0u8; 16];
951 nonce[..8].copy_from_slice(&index.to_be_bytes());
952 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
956 impl ChannelSigner for InMemorySigner {
957 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
958 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
959 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
962 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
963 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
966 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
970 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
972 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
974 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
975 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
976 if self.channel_parameters.is_some() {
977 // The channel parameters were already set and they match, return early.
980 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
981 self.channel_parameters = Some(channel_parameters.clone());
985 impl EcdsaChannelSigner for InMemorySigner {
986 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
987 let trusted_tx = commitment_tx.trust();
988 let keys = trusted_tx.keys();
990 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
991 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
993 let built_tx = trusted_tx.built_transaction();
994 let commitment_sig = built_tx.sign_counterparty_commitment(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
995 let commitment_txid = built_tx.txid;
997 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
998 for htlc in commitment_tx.htlcs() {
999 let channel_parameters = self.get_channel_parameters();
1000 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);
1001 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.channel_type_features(), &keys);
1002 let htlc_sighashtype = if self.channel_type_features().supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
1003 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
1004 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
1005 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
1008 Ok((commitment_sig, htlc_sigs))
1011 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
1015 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
1016 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1017 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
1018 let trusted_tx = commitment_tx.trust();
1019 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
1020 let channel_parameters = self.get_channel_parameters();
1021 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
1022 Ok((sig, htlc_sigs))
1025 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
1026 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
1027 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1028 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
1029 let trusted_tx = commitment_tx.trust();
1030 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
1031 let channel_parameters = self.get_channel_parameters();
1032 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
1033 Ok((sig, htlc_sigs))
1036 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1037 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1038 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1039 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1040 let witness_script = {
1041 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint);
1042 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
1044 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1045 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1046 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1049 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, ()> {
1050 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
1051 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
1052 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1053 let witness_script = {
1054 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
1055 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
1056 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.channel_type_features(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
1058 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
1059 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1060 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
1063 fn sign_holder_htlc_transaction(
1064 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
1065 secp_ctx: &Secp256k1<secp256k1::All>
1066 ) -> Result<Signature, ()> {
1067 let witness_script = htlc_descriptor.witness_script(secp_ctx);
1068 let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
1069 input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
1071 let our_htlc_private_key = chan_utils::derive_private_key(
1072 &secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_key
1074 Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key, &self))
1077 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, ()> {
1078 let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
1079 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
1080 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
1081 let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
1082 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.channel_type_features(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
1083 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
1084 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
1085 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
1088 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
1089 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
1090 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
1091 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
1094 fn sign_holder_anchor_input(
1095 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
1096 ) -> Result<Signature, ()> {
1097 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
1098 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
1099 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
1101 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
1104 fn sign_channel_announcement_with_funding_key(
1105 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
1106 ) -> Result<Signature, ()> {
1107 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1108 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
1112 const SERIALIZATION_VERSION: u8 = 1;
1114 const MIN_SERIALIZATION_VERSION: u8 = 1;
1116 impl WriteableEcdsaChannelSigner for InMemorySigner {}
1118 impl Writeable for InMemorySigner {
1119 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
1120 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
1122 self.funding_key.write(writer)?;
1123 self.revocation_base_key.write(writer)?;
1124 self.payment_key.write(writer)?;
1125 self.delayed_payment_base_key.write(writer)?;
1126 self.htlc_base_key.write(writer)?;
1127 self.commitment_seed.write(writer)?;
1128 self.channel_parameters.write(writer)?;
1129 self.channel_value_satoshis.write(writer)?;
1130 self.channel_keys_id.write(writer)?;
1132 write_tlv_fields!(writer, {});
1138 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySource {
1139 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
1140 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
1142 let funding_key = Readable::read(reader)?;
1143 let revocation_base_key = Readable::read(reader)?;
1144 let payment_key = Readable::read(reader)?;
1145 let delayed_payment_base_key = Readable::read(reader)?;
1146 let htlc_base_key = Readable::read(reader)?;
1147 let commitment_seed = Readable::read(reader)?;
1148 let counterparty_channel_data = Readable::read(reader)?;
1149 let channel_value_satoshis = Readable::read(reader)?;
1150 let secp_ctx = Secp256k1::signing_only();
1151 let holder_channel_pubkeys =
1152 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
1153 &payment_key, &delayed_payment_base_key, &htlc_base_key);
1154 let keys_id = Readable::read(reader)?;
1156 read_tlv_fields!(reader, {});
1160 revocation_base_key,
1162 delayed_payment_base_key,
1165 channel_value_satoshis,
1166 holder_channel_pubkeys,
1167 channel_parameters: counterparty_channel_data,
1168 channel_keys_id: keys_id,
1169 rand_bytes_unique_start: entropy_source.get_secure_random_bytes(),
1170 rand_bytes_index: AtomicCounter::new(),
1175 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1176 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1178 /// Your `node_id` is seed/0'.
1179 /// Unilateral closes may use seed/1'.
1180 /// Cooperative closes may use seed/2'.
1181 /// The two close keys may be needed to claim on-chain funds!
1183 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1184 /// [`PhantomKeysManager`] must be used instead.
1186 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1187 /// previously issued invoices and attempts to pay previous invoices will fail.
1188 pub struct KeysManager {
1189 secp_ctx: Secp256k1<secp256k1::All>,
1190 node_secret: SecretKey,
1192 inbound_payment_key: KeyMaterial,
1193 destination_script: Script,
1194 shutdown_pubkey: PublicKey,
1195 channel_master_key: ExtendedPrivKey,
1196 channel_child_index: AtomicUsize,
1198 rand_bytes_unique_start: [u8; 32],
1199 rand_bytes_index: AtomicCounter,
1202 starting_time_secs: u64,
1203 starting_time_nanos: u32,
1207 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1208 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1209 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1210 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1211 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1212 /// is to simply use the current time (with very high precision).
1214 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1215 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1216 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1219 /// Note that the seed is required to recover certain on-chain funds independent of
1220 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1221 /// for any channel, and some on-chain during-closing funds.
1223 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1224 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1225 let secp_ctx = Secp256k1::new();
1226 // Note that when we aren't serializing the key, network doesn't matter
1227 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1229 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
1230 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1231 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
1232 Ok(destination_key) => {
1233 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
1234 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1235 .push_slice(&wpubkey_hash.into_inner())
1238 Err(_) => panic!("Your RNG is busted"),
1240 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
1241 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
1242 Err(_) => panic!("Your RNG is busted"),
1244 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
1245 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
1246 let mut inbound_pmt_key_bytes = [0; 32];
1247 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1249 let mut rand_bytes_engine = Sha256::engine();
1250 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1251 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1252 rand_bytes_engine.input(seed);
1253 rand_bytes_engine.input(b"LDK PRNG Seed");
1254 let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).into_inner();
1256 let mut res = KeysManager {
1260 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1266 channel_child_index: AtomicUsize::new(0),
1268 rand_bytes_unique_start,
1269 rand_bytes_index: AtomicCounter::new(),
1273 starting_time_nanos,
1275 let secp_seed = res.get_secure_random_bytes();
1276 res.secp_ctx.seeded_randomize(&secp_seed);
1279 Err(_) => panic!("Your rng is busted"),
1283 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1284 pub fn get_node_secret_key(&self) -> SecretKey {
1288 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1289 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1290 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1291 let mut unique_start = Sha256::engine();
1292 unique_start.input(params);
1293 unique_start.input(&self.seed);
1295 // We only seriously intend to rely on the channel_master_key for true secure
1296 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1297 // starting_time provided in the constructor) to be unique.
1298 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
1299 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
1300 ).expect("Your RNG is busted");
1301 unique_start.input(&child_privkey.private_key[..]);
1303 let seed = Sha256::from_engine(unique_start).into_inner();
1305 let commitment_seed = {
1306 let mut sha = Sha256::engine();
1308 sha.input(&b"commitment seed"[..]);
1309 Sha256::from_engine(sha).into_inner()
1311 macro_rules! key_step {
1312 ($info: expr, $prev_key: expr) => {{
1313 let mut sha = Sha256::engine();
1315 sha.input(&$prev_key[..]);
1316 sha.input(&$info[..]);
1317 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1320 let funding_key = key_step!(b"funding key", commitment_seed);
1321 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1322 let payment_key = key_step!(b"payment key", revocation_base_key);
1323 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1324 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1325 let prng_seed = self.get_secure_random_bytes();
1327 InMemorySigner::new(
1330 revocation_base_key,
1332 delayed_payment_base_key,
1335 channel_value_satoshis,
1341 /// Signs the given [`PartiallySignedTransaction`] which spends the given [`SpendableOutputDescriptor`]s.
1342 /// The resulting inputs will be finalized and the PSBT will be ready for broadcast if there
1343 /// are no other inputs that need signing.
1345 /// Returns `Err(())` if the PSBT is missing a descriptor or if we fail to sign.
1347 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1348 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1349 pub fn sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<PartiallySignedTransaction, ()> {
1350 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1351 for outp in descriptors {
1353 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1354 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1355 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1357 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1358 descriptor.channel_keys_id));
1360 let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
1361 psbt.inputs[input_idx].final_script_witness = Some(witness);
1363 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1364 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
1365 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1367 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1368 descriptor.channel_keys_id));
1370 let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
1371 psbt.inputs[input_idx].final_script_witness = Some(witness);
1373 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1374 let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
1375 let derivation_idx = if output.script_pubkey == self.destination_script {
1381 // Note that when we aren't serializing the key, network doesn't matter
1382 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1384 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1386 Err(_) => panic!("Your RNG is busted"),
1389 Err(_) => panic!("Your rng is busted"),
1392 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1393 if derivation_idx == 2 {
1394 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1396 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1397 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1399 if payment_script != output.script_pubkey { return Err(()); };
1401 let sighash = hash_to_message!(&sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1402 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
1403 let mut sig_ser = sig.serialize_der().to_vec();
1404 sig_ser.push(EcdsaSighashType::All as u8);
1405 let witness = Witness::from_vec(vec![sig_ser, pubkey.inner.serialize().to_vec()]);
1406 psbt.inputs[input_idx].final_script_witness = Some(witness);
1414 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
1415 /// output to the given change destination (if sufficient change value remains). The
1416 /// transaction will have a feerate, at least, of the given value.
1418 /// The `locktime` argument is used to set the transaction's locktime. If `None`, the
1419 /// transaction will have a locktime of 0. It it recommended to set this to the current block
1420 /// height to avoid fee sniping, unless you have some specific reason to use a different
1423 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1424 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1425 /// does not match the one we can spend.
1427 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1429 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1430 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1431 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, ()> {
1432 let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
1433 psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
1435 let spend_tx = psbt.extract_tx();
1437 debug_assert!(expected_max_weight >= spend_tx.weight());
1438 // Note that witnesses with a signature vary somewhat in size, so allow
1439 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1440 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1446 impl EntropySource for KeysManager {
1447 fn get_secure_random_bytes(&self) -> [u8; 32] {
1448 let index = self.rand_bytes_index.get_increment();
1449 let mut nonce = [0u8; 16];
1450 nonce[..8].copy_from_slice(&index.to_be_bytes());
1451 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
1455 impl NodeSigner for KeysManager {
1456 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1458 Recipient::Node => Ok(self.node_id.clone()),
1459 Recipient::PhantomNode => Err(())
1463 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1464 let mut node_secret = match recipient {
1465 Recipient::Node => Ok(self.node_secret.clone()),
1466 Recipient::PhantomNode => Err(())
1468 if let Some(tweak) = tweak {
1469 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1471 Ok(SharedSecret::new(other_key, &node_secret))
1474 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1475 self.inbound_payment_key.clone()
1478 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1479 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1480 let secret = match recipient {
1481 Recipient::Node => Ok(&self.node_secret),
1482 Recipient::PhantomNode => Err(())
1484 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1487 fn sign_bolt12_invoice_request(
1488 &self, invoice_request: &UnsignedInvoiceRequest
1489 ) -> Result<schnorr::Signature, ()> {
1490 let message = invoice_request.tagged_hash().as_digest();
1491 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
1492 let aux_rand = self.get_secure_random_bytes();
1493 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
1496 fn sign_bolt12_invoice(
1497 &self, invoice: &UnsignedBolt12Invoice
1498 ) -> Result<schnorr::Signature, ()> {
1499 let message = invoice.tagged_hash().as_digest();
1500 let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
1501 let aux_rand = self.get_secure_random_bytes();
1502 Ok(self.secp_ctx.sign_schnorr_with_aux_rand(message, &keys, &aux_rand))
1505 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1506 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1507 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
1511 impl SignerProvider for KeysManager {
1512 type Signer = InMemorySigner;
1514 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1515 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1516 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
1517 // (though `user_channel_id` should help, depending on user behavior). If it manages to
1518 // roll over, we may generate duplicate keys for two different channels, which could result
1519 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
1520 // doesn't reach `u32::MAX`.
1521 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
1522 let mut id = [0; 32];
1523 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1524 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1525 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1526 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1530 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1531 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1534 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1535 InMemorySigner::read(&mut io::Cursor::new(reader), self)
1538 fn get_destination_script(&self) -> Result<Script, ()> {
1539 Ok(self.destination_script.clone())
1542 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1543 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
1547 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1550 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1551 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1552 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1553 /// itself without ever needing to forward to this fake node.
1555 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1556 /// provide some fault tolerance, because payers will automatically retry paying other provided
1557 /// nodes in the case that one node goes down.
1559 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1560 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1561 // nodes to know when the full payment has been received (and the preimage can be released) without
1562 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1563 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1564 // is released too early.
1566 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1567 /// invoices and attempts to pay previous invoices will fail.
1568 pub struct PhantomKeysManager {
1570 inbound_payment_key: KeyMaterial,
1571 phantom_secret: SecretKey,
1572 phantom_node_id: PublicKey,
1575 impl EntropySource for PhantomKeysManager {
1576 fn get_secure_random_bytes(&self) -> [u8; 32] {
1577 self.inner.get_secure_random_bytes()
1581 impl NodeSigner for PhantomKeysManager {
1582 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1584 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1585 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1589 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1590 let mut node_secret = match recipient {
1591 Recipient::Node => self.inner.node_secret.clone(),
1592 Recipient::PhantomNode => self.phantom_secret.clone(),
1594 if let Some(tweak) = tweak {
1595 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1597 Ok(SharedSecret::new(other_key, &node_secret))
1600 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1601 self.inbound_payment_key.clone()
1604 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1605 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1606 let secret = match recipient {
1607 Recipient::Node => &self.inner.node_secret,
1608 Recipient::PhantomNode => &self.phantom_secret,
1610 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1613 fn sign_bolt12_invoice_request(
1614 &self, invoice_request: &UnsignedInvoiceRequest
1615 ) -> Result<schnorr::Signature, ()> {
1616 self.inner.sign_bolt12_invoice_request(invoice_request)
1619 fn sign_bolt12_invoice(
1620 &self, invoice: &UnsignedBolt12Invoice
1621 ) -> Result<schnorr::Signature, ()> {
1622 self.inner.sign_bolt12_invoice(invoice)
1625 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1626 self.inner.sign_gossip_message(msg)
1630 impl SignerProvider for PhantomKeysManager {
1631 type Signer = InMemorySigner;
1633 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1634 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1637 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1638 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1641 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1642 self.inner.read_chan_signer(reader)
1645 fn get_destination_script(&self) -> Result<Script, ()> {
1646 self.inner.get_destination_script()
1649 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1650 self.inner.get_shutdown_scriptpubkey()
1654 impl PhantomKeysManager {
1655 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
1656 /// that is shared across all nodes that intend to participate in [phantom node payments]
1659 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1660 /// `starting_time_nanos`.
1662 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1663 /// same across restarts, or else inbound payments may fail.
1665 /// [phantom node payments]: PhantomKeysManager
1666 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1667 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1668 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1669 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1670 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1673 inbound_payment_key: KeyMaterial(inbound_key),
1679 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1680 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, ()> {
1681 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
1684 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1685 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1686 self.inner.derive_channel_keys(channel_value_satoshis, params)
1689 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1690 pub fn get_node_secret_key(&self) -> SecretKey {
1691 self.inner.get_node_secret_key()
1694 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
1695 /// last-hop onion data, etc.
1696 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
1701 // Ensure that EcdsaChannelSigner can have a vtable
1704 let _signer: Box<dyn EcdsaChannelSigner>;
1709 use std::sync::{Arc, mpsc};
1710 use std::sync::mpsc::TryRecvError;
1712 use std::time::Duration;
1713 use bitcoin::blockdata::constants::genesis_block;
1714 use bitcoin::Network;
1715 use crate::sign::{EntropySource, KeysManager};
1717 use criterion::Criterion;
1719 pub fn bench_get_secure_random_bytes(bench: &mut Criterion) {
1720 let seed = [0u8; 32];
1721 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
1722 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
1724 let mut handles = Vec::new();
1725 let mut stops = Vec::new();
1727 let keys_manager_clone = Arc::clone(&keys_manager);
1728 let (stop_sender, stop_receiver) = mpsc::channel();
1729 let handle = thread::spawn(move || {
1731 keys_manager_clone.get_secure_random_bytes();
1732 match stop_receiver.try_recv() {
1733 Ok(_) | Err(TryRecvError::Disconnected) => {
1734 println!("Terminating.");
1737 Err(TryRecvError::Empty) => {}
1741 handles.push(handle);
1742 stops.push(stop_sender);
1745 bench.bench_function("get_secure_random_bytes", |b| b.iter(||
1746 keys_manager.get_secure_random_bytes()));
1749 let _ = stop.send(());
1751 for handle in handles {
1752 handle.join().unwrap();