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::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
20 use bitcoin::util::sighash;
22 use bitcoin::bech32::u5;
23 use bitcoin::hashes::{Hash, HashEngine};
24 use bitcoin::hashes::sha256::Hash as Sha256;
25 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
26 use bitcoin::hash_types::WPubkeyHash;
28 use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
29 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Signing};
30 use bitcoin::secp256k1::ecdh::SharedSecret;
31 use bitcoin::secp256k1::ecdsa::RecoverableSignature;
32 use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness};
34 use crate::util::transaction_utils;
35 use crate::util::crypto::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
36 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
37 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::msgs::{DecodeError, MAX_VALUE_MSAT};
52 use crate::util::atomic_counter::AtomicCounter;
53 use crate::util::chacha20::ChaCha20;
54 use crate::util::invoice::construct_invoice_preimage;
56 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
57 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
59 /// This is not exported to bindings users as we just use `[u8; 32]` directly
60 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
61 pub struct KeyMaterial(pub [u8; 32]);
63 /// Information about a spendable output to a P2WSH script.
65 /// See [`SpendableOutputDescriptor::DelayedPaymentOutput`] for more details on how to spend this.
66 #[derive(Clone, Debug, PartialEq, Eq)]
67 pub struct DelayedPaymentOutputDescriptor {
68 /// The outpoint which is spendable.
69 pub outpoint: OutPoint,
70 /// Per commitment point to derive the delayed payment key by key holder.
71 pub per_commitment_point: PublicKey,
72 /// The `nSequence` value which must be set in the spending input to satisfy the `OP_CSV` in
73 /// the witness_script.
74 pub to_self_delay: u16,
75 /// The output which is referenced by the given outpoint.
77 /// The revocation point specific to the commitment transaction which was broadcast. Used to
78 /// derive the witnessScript for this output.
79 pub revocation_pubkey: PublicKey,
80 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
81 /// This may be useful in re-deriving keys used in the channel to spend the output.
82 pub channel_keys_id: [u8; 32],
83 /// The value of the channel which this output originated from, possibly indirectly.
84 pub channel_value_satoshis: u64,
86 impl DelayedPaymentOutputDescriptor {
87 /// The maximum length a well-formed witness spending one of these should have.
88 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
90 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
91 // redeemscript push length.
92 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
95 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
96 (0, outpoint, required),
97 (2, per_commitment_point, required),
98 (4, to_self_delay, required),
99 (6, output, required),
100 (8, revocation_pubkey, required),
101 (10, channel_keys_id, required),
102 (12, channel_value_satoshis, required),
105 /// Information about a spendable output to our "payment key".
107 /// See [`SpendableOutputDescriptor::StaticPaymentOutput`] for more details on how to spend this.
108 #[derive(Clone, Debug, PartialEq, Eq)]
109 pub struct StaticPaymentOutputDescriptor {
110 /// The outpoint which is spendable.
111 pub outpoint: OutPoint,
112 /// The output which is referenced by the given outpoint.
114 /// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
115 /// This may be useful in re-deriving keys used in the channel to spend the output.
116 pub channel_keys_id: [u8; 32],
117 /// The value of the channel which this transactions spends.
118 pub channel_value_satoshis: u64,
120 impl StaticPaymentOutputDescriptor {
121 /// The maximum length a well-formed witness spending one of these should have.
122 /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
124 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
125 // redeemscript push length.
126 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
128 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
129 (0, outpoint, required),
130 (2, output, required),
131 (4, channel_keys_id, required),
132 (6, channel_value_satoshis, required),
135 /// Describes the necessary information to spend a spendable output.
137 /// When on-chain outputs are created by LDK (which our counterparty is not able to claim at any
138 /// point in the future) a [`SpendableOutputs`] event is generated which you must track and be able
139 /// to spend on-chain. The information needed to do this is provided in this enum, including the
140 /// outpoint describing which `txid` and output `index` is available, the full output which exists
141 /// at that `txid`/`index`, and any keys or other information required to sign.
143 /// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
144 #[derive(Clone, Debug, PartialEq, Eq)]
145 pub enum SpendableOutputDescriptor {
146 /// An output to a script which was provided via [`SignerProvider`] directly, either from
147 /// [`get_destination_script`] or [`get_shutdown_scriptpubkey`], thus you should already
148 /// know how to spend it. No secret keys are provided as LDK was never given any key.
149 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
150 /// on-chain using the payment preimage or after it has timed out.
152 /// [`get_shutdown_scriptpubkey`]: SignerProvider::get_shutdown_scriptpubkey
153 /// [`get_destination_script`]: SignerProvider::get_shutdown_scriptpubkey
155 /// The outpoint which is spendable.
157 /// The output which is referenced by the given outpoint.
160 /// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
163 /// The witness in the spending input should be:
165 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
168 /// Note that the `nSequence` field in the spending input must be set to
169 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] (which means the transaction is not
170 /// broadcastable until at least [`DelayedPaymentOutputDescriptor::to_self_delay`] blocks after
171 /// the outpoint confirms, see [BIP
172 /// 68](https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki)). Also note that LDK
173 /// won't generate a [`SpendableOutputDescriptor`] until the corresponding block height
176 /// These are generally the result of a "revocable" output to us, spendable only by us unless
177 /// it is an output from an old state which we broadcast (which should never happen).
179 /// To derive the delayed payment key which is used to sign this input, you must pass the
180 /// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
181 /// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
182 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The public key can be
183 /// generated without the secret key using [`chan_utils::derive_public_key`] and only the
184 /// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
186 /// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
187 /// used in the witness script generation), you must pass the counterparty
188 /// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
189 /// [`ChannelSigner::provide_channel_parameters`]) and the provided
190 /// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
191 /// [`chan_utils::derive_public_revocation_key`].
193 /// The witness script which is hashed and included in the output `script_pubkey` may be
194 /// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
195 /// as explained above), our delayed payment pubkey (derived as explained above), and the
196 /// [`DelayedPaymentOutputDescriptor::to_self_delay`] contained here to
197 /// [`chan_utils::get_revokeable_redeemscript`].
198 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
199 /// An output to a P2WPKH, spendable exclusively by our payment key (i.e., the private key
200 /// which corresponds to the `payment_point` in [`ChannelSigner::pubkeys`]). The witness
201 /// in the spending input is, thus, simply:
203 /// <BIP 143 signature> <payment key>
206 /// These are generally the result of our counterparty having broadcast the current state,
207 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
208 StaticPaymentOutput(StaticPaymentOutputDescriptor),
211 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
212 (0, StaticOutput) => {
213 (0, outpoint, required),
214 (2, output, required),
217 (1, DelayedPaymentOutput),
218 (2, StaticPaymentOutput),
221 /// A trait to handle Lightning channel key material without concretizing the channel type or
222 /// the signature mechanism.
223 pub trait ChannelSigner {
224 /// Gets the per-commitment point for a specific commitment number
226 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
227 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
229 /// Gets the commitment secret for a specific commitment number as part of the revocation process
231 /// An external signer implementation should error here if the commitment was already signed
232 /// and should refuse to sign it in the future.
234 /// May be called more than once for the same index.
236 /// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
237 // TODO: return a Result so we can signal a validation error
238 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
240 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
242 /// This is required in order for the signer to make sure that releasing a commitment
243 /// secret won't leave us without a broadcastable holder transaction.
244 /// Policy checks should be implemented in this function, including checking the amount
245 /// sent to us and checking the HTLCs.
247 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
248 /// A validating signer should ensure that an HTLC output is removed only when the matching
249 /// preimage is provided, or when the value to holder is restored.
251 /// Note that all the relevant preimages will be provided, but there may also be additional
252 /// irrelevant or duplicate preimages.
253 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction,
254 preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
256 /// Returns the holder's channel public keys and basepoints.
257 fn pubkeys(&self) -> &ChannelPublicKeys;
259 /// Returns an arbitrary identifier describing the set of keys which are provided back to you in
260 /// some [`SpendableOutputDescriptor`] types. This should be sufficient to identify this
261 /// [`EcdsaChannelSigner`] object uniquely and lookup or re-derive its keys.
262 fn channel_keys_id(&self) -> [u8; 32];
264 /// Set the counterparty static channel data, including basepoints,
265 /// `counterparty_selected`/`holder_selected_contest_delay` and funding outpoint.
267 /// This data is static, and will never change for a channel once set. For a given [`ChannelSigner`]
268 /// instance, LDK will call this method exactly once - either immediately after construction
269 /// (not including if done via [`SignerProvider::read_chan_signer`]) or when the funding
270 /// information has been generated.
272 /// channel_parameters.is_populated() MUST be true.
273 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
276 /// A trait to sign Lightning channel transactions as described in
277 /// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
279 /// Signing services could be implemented on a hardware wallet and should implement signing
280 /// policies in order to be secure. Please refer to the [VLS Policy
281 /// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
282 /// for an example of such policies.
283 pub trait EcdsaChannelSigner: ChannelSigner {
284 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
286 /// Note that if signing fails or is rejected, the channel will be force-closed.
288 /// Policy checks should be implemented in this function, including checking the amount
289 /// sent to us and checking the HTLCs.
291 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
292 /// A validating signer should ensure that an HTLC output is removed only when the matching
293 /// preimage is provided, or when the value to holder is restored.
295 /// Note that all the relevant preimages will be provided, but there may also be additional
296 /// irrelevant or duplicate preimages.
298 // TODO: Document the things someone using this interface should enforce before signing.
299 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction,
300 preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>
301 ) -> Result<(Signature, Vec<Signature>), ()>;
302 /// Validate the counterparty's revocation.
304 /// This is required in order for the signer to make sure that the state has moved
305 /// forward and it is safe to sign the next counterparty commitment.
306 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
307 /// Creates a signature for a holder's commitment transaction and its claiming HTLC transactions.
309 /// This will be called
310 /// - with a non-revoked `commitment_tx`.
311 /// - with the latest `commitment_tx` when we initiate a force-close.
312 /// - with the previous `commitment_tx`, just to get claiming HTLC
313 /// signatures, if we are reacting to a [`ChannelMonitor`]
314 /// [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
315 /// that decided to broadcast before it had been updated to the latest `commitment_tx`.
317 /// This may be called multiple times for the same transaction.
319 /// An external signer implementation should check that the commitment has not been revoked.
321 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
322 // TODO: Document the things someone using this interface should enforce before signing.
323 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
324 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
325 /// Same as [`sign_holder_commitment_and_htlcs`], but exists only for tests to get access to
326 /// holder commitment transactions which will be broadcasted later, after the channel has moved
327 /// on to a newer state. Thus, needs its own method as [`sign_holder_commitment_and_htlcs`] may
328 /// enforce that we only ever get called once.
329 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
330 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
331 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
332 /// Create a signature for the given input in a transaction spending an HTLC transaction output
333 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
335 /// A justice transaction may claim multiple outputs at the same time if timelocks are
336 /// similar, but only a signature for the input at index `input` should be signed for here.
337 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
338 /// to an upcoming timelock expiration.
340 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
342 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
343 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
344 /// not allow the spending of any funds by itself (you need our holder `revocation_secret` to do
346 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64,
347 per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>
348 ) -> Result<Signature, ()>;
349 /// Create a signature for the given input in a transaction spending a commitment transaction
350 /// HTLC output when our counterparty broadcasts an old state.
352 /// A justice transaction may claim multiple outputs at the same time if timelocks are
353 /// similar, but only a signature for the input at index `input` should be signed for here.
354 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
355 /// to an upcoming timelock expiration.
357 /// `amount` is the value of the output spent by this input, committed to in the BIP 143
360 /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
361 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
362 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
365 /// `htlc` holds HTLC elements (hash, timelock), thus changing the format of the witness script
366 /// (which is committed to in the BIP 143 signatures).
367 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64,
368 per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment,
369 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
371 /// Computes the signature for a commitment transaction's HTLC output used as an input within
372 /// `htlc_tx`, which spends the commitment transaction at index `input`. The signature returned
373 /// must be be computed using [`EcdsaSighashType::All`]. Note that this should only be used to
374 /// sign HTLC transactions from channels supporting anchor outputs after all additional
375 /// inputs/outputs have been added to the transaction.
377 /// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
378 fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize,
379 htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<secp256k1::All>
380 ) -> Result<Signature, ()>;
381 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
382 /// transaction, either offered or received.
384 /// Such a transaction may claim multiples offered outputs at same time if we know the
385 /// preimage for each when we create it, but only the input at index `input` should be
386 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
387 /// needed with regards to an upcoming timelock expiration.
389 /// `witness_script` is either an offered or received script as defined in BOLT3 for HTLC
392 /// `amount` is value of the output spent by this input, committed to in the BIP 143 signature.
394 /// `per_commitment_point` is the dynamic point corresponding to the channel state
395 /// detected onchain. It has been generated by our counterparty and is used to derive
396 /// channel state keys, which are then included in the witness script and committed to in the
397 /// BIP 143 signature.
398 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64,
399 per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment,
400 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
401 /// Create a signature for a (proposed) closing transaction.
403 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
404 /// chosen to forgo their output as dust.
405 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction,
406 secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
407 /// Computes the signature for a commitment transaction's anchor output used as an
408 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
409 fn sign_holder_anchor_input(
410 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
411 ) -> Result<Signature, ()>;
412 /// Signs a channel announcement message with our funding key proving it comes from one of the
413 /// channel participants.
415 /// Channel announcements also require a signature from each node's network key. Our node
416 /// signature is computed through [`NodeSigner::sign_gossip_message`].
418 /// Note that if this fails or is rejected, the channel will not be publicly announced and
419 /// our counterparty may (though likely will not) close the channel on us for violating the
421 fn sign_channel_announcement_with_funding_key(
422 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
423 ) -> Result<Signature, ()>;
426 /// A writeable signer.
428 /// There will always be two instances of a signer per channel, one occupied by the
429 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
431 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
432 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
433 pub trait WriteableEcdsaChannelSigner: EcdsaChannelSigner + Writeable {}
435 /// Specifies the recipient of an invoice.
437 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
440 /// The invoice should be signed with the local node secret key.
442 /// The invoice should be signed with the phantom node secret key. This secret key must be the
443 /// same for all nodes participating in the [phantom node payment].
445 /// [phantom node payment]: PhantomKeysManager
449 /// A trait that describes a source of entropy.
450 pub trait EntropySource {
451 /// Gets a unique, cryptographically-secure, random 32-byte value. This method must return a
452 /// different value each time it is called.
453 fn get_secure_random_bytes(&self) -> [u8; 32];
456 /// A trait that can handle cryptographic operations at the scope level of a node.
457 pub trait NodeSigner {
458 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
460 /// If the implementor of this trait supports [phantom node payments], then every node that is
461 /// intended to be included in the phantom invoice route hints must return the same value from
463 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
464 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
465 // nodes, they must share the key that encrypts this payment data.
467 /// This method must return the same value each time it is called.
469 /// [phantom node payments]: PhantomKeysManager
470 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
472 /// Get node id based on the provided [`Recipient`].
474 /// This method must return the same value each time it is called with a given [`Recipient`]
477 /// Errors if the [`Recipient`] variant is not supported by the implementation.
478 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()>;
480 /// Gets the ECDH shared secret of our node secret and `other_key`, multiplying by `tweak` if
481 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
482 /// secret, though this is less efficient.
484 /// Note that if this fails while attempting to forward an HTLC, LDK will panic. The error
485 /// should be resolved to allow LDK to resume forwarding HTLCs.
487 /// Errors if the [`Recipient`] variant is not supported by the implementation.
488 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
492 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
493 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
494 /// blindly signing the hash.
496 /// The `hrp_bytes` are ASCII bytes, while the `invoice_data` is base32.
498 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
500 /// Errors if the [`Recipient`] variant is not supported by the implementation.
501 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()>;
503 /// Sign a gossip message.
505 /// Note that if this fails, LDK may panic and the message will not be broadcast to the network
506 /// or a possible channel counterparty. If LDK panics, the error should be resolved to allow the
507 /// message to be broadcast, as otherwise it may prevent one from receiving funds over the
508 /// corresponding channel.
509 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
512 /// A trait that can return signer instances for individual channels.
513 pub trait SignerProvider {
514 /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
515 type Signer : WriteableEcdsaChannelSigner;
517 /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::Signer`] through
518 /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
519 /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
520 /// `channel_keys_id`.
522 /// This method must return a different value each time it is called.
523 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
525 /// Derives the private key material backing a `Signer`.
527 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
528 /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
529 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
530 /// [`ChannelSigner::channel_keys_id`].
531 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
533 /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
534 /// This is only called during deserialization of other objects which contain
535 /// [`WriteableEcdsaChannelSigner`]-implementing objects (i.e., [`ChannelMonitor`]s and [`ChannelManager`]s).
536 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
537 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
538 /// you've read all of the provided bytes to ensure no corruption occurred.
540 /// This method is slowly being phased out -- it will only be called when reading objects
541 /// written by LDK versions prior to 0.0.113.
543 /// [`Signer`]: Self::Signer
544 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
545 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
546 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
548 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
550 /// If this function returns an error, this will result in a channel failing to open.
552 /// This method should return a different value each time it is called, to avoid linking
553 /// on-chain funds across channels as controlled to the same user.
554 fn get_destination_script(&self) -> Result<Script, ()>;
556 /// Get a script pubkey which we will send funds to when closing a channel.
558 /// If this function returns an error, this will result in a channel failing to open or close.
559 /// In the event of a failure when the counterparty is initiating a close, this can result in a
560 /// channel force close.
562 /// This method should return a different value each time it is called, to avoid linking
563 /// on-chain funds across channels as controlled to the same user.
564 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()>;
567 /// A simple implementation of [`WriteableEcdsaChannelSigner`] that just keeps the private keys in memory.
569 /// This implementation performs no policy checks and is insufficient by itself as
570 /// a secure external signer.
571 pub struct InMemorySigner {
572 /// Holder secret key in the 2-of-2 multisig script of a channel. This key also backs the
573 /// holder's anchor output in a commitment transaction, if one is present.
574 pub funding_key: SecretKey,
575 /// Holder secret key for blinded revocation pubkey.
576 pub revocation_base_key: SecretKey,
577 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions.
578 pub payment_key: SecretKey,
579 /// Holder secret key used in an HTLC transaction.
580 pub delayed_payment_base_key: SecretKey,
581 /// Holder HTLC secret key used in commitment transaction HTLC outputs.
582 pub htlc_base_key: SecretKey,
584 pub commitment_seed: [u8; 32],
585 /// Holder public keys and basepoints.
586 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
587 /// Counterparty public keys and counterparty/holder `selected_contest_delay`, populated on channel acceptance.
588 channel_parameters: Option<ChannelTransactionParameters>,
589 /// The total value of this channel.
590 channel_value_satoshis: u64,
591 /// Key derivation parameters.
592 channel_keys_id: [u8; 32],
593 /// Seed from which all randomness produced is derived from.
594 rand_bytes_unique_start: [u8; 32],
595 /// Tracks the number of times we've produced randomness to ensure we don't return the same
597 rand_bytes_index: AtomicCounter,
600 impl Clone for InMemorySigner {
601 fn clone(&self) -> Self {
603 funding_key: self.funding_key.clone(),
604 revocation_base_key: self.revocation_base_key.clone(),
605 payment_key: self.payment_key.clone(),
606 delayed_payment_base_key: self.delayed_payment_base_key.clone(),
607 htlc_base_key: self.htlc_base_key.clone(),
608 commitment_seed: self.commitment_seed.clone(),
609 holder_channel_pubkeys: self.holder_channel_pubkeys.clone(),
610 channel_parameters: self.channel_parameters.clone(),
611 channel_value_satoshis: self.channel_value_satoshis,
612 channel_keys_id: self.channel_keys_id,
613 rand_bytes_unique_start: self.get_secure_random_bytes(),
614 rand_bytes_index: AtomicCounter::new(),
619 impl InMemorySigner {
620 /// Creates a new [`InMemorySigner`].
621 pub fn new<C: Signing>(
622 secp_ctx: &Secp256k1<C>,
623 funding_key: SecretKey,
624 revocation_base_key: SecretKey,
625 payment_key: SecretKey,
626 delayed_payment_base_key: SecretKey,
627 htlc_base_key: SecretKey,
628 commitment_seed: [u8; 32],
629 channel_value_satoshis: u64,
630 channel_keys_id: [u8; 32],
631 rand_bytes_unique_start: [u8; 32],
632 ) -> InMemorySigner {
633 let holder_channel_pubkeys =
634 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
635 &payment_key, &delayed_payment_base_key,
641 delayed_payment_base_key,
644 channel_value_satoshis,
645 holder_channel_pubkeys,
646 channel_parameters: None,
648 rand_bytes_unique_start,
649 rand_bytes_index: AtomicCounter::new(),
653 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
654 funding_key: &SecretKey,
655 revocation_base_key: &SecretKey,
656 payment_key: &SecretKey,
657 delayed_payment_base_key: &SecretKey,
658 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
659 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
661 funding_pubkey: from_secret(&funding_key),
662 revocation_basepoint: from_secret(&revocation_base_key),
663 payment_point: from_secret(&payment_key),
664 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
665 htlc_basepoint: from_secret(&htlc_base_key),
669 /// Returns the counterparty's pubkeys.
671 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
672 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
673 /// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
674 /// transactions, i.e., the amount of time that we have to wait to recover our funds if we
675 /// broadcast a transaction.
677 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
678 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
679 /// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
680 /// by our counterparty, i.e., the amount of time that they have to wait to recover their funds
681 /// if they broadcast a transaction.
683 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
684 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
685 /// Returns whether the holder is the initiator.
687 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
688 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
691 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
692 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
693 /// Returns a [`ChannelTransactionParameters`] for this channel, to be used when verifying or
694 /// building transactions.
696 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
697 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
698 self.channel_parameters.as_ref().unwrap()
700 /// Returns whether anchors should be used.
702 /// Will panic if [`ChannelSigner::provide_channel_parameters`] has not been called before.
703 pub fn opt_anchors(&self) -> bool {
704 self.get_channel_parameters().opt_anchors.is_some()
706 /// Sign the single input of `spend_tx` at index `input_idx`, which spends the output described
707 /// by `descriptor`, returning the witness stack for the input.
709 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
710 /// is not spending the outpoint described by [`descriptor.outpoint`],
711 /// or if an output descriptor `script_pubkey` does not match the one we can spend.
713 /// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
714 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>>, ()> {
715 // TODO: We really should be taking the SigHashCache as a parameter here instead of
716 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
717 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
718 // bindings updates to support SigHashCache objects).
719 if spend_tx.input.len() <= input_idx { return Err(()); }
720 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
721 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
723 let remotepubkey = self.pubkeys().payment_point;
724 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
725 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
726 let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
727 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
729 if payment_script != descriptor.output.script_pubkey { return Err(()); }
731 let mut witness = Vec::with_capacity(2);
732 witness.push(remotesig.serialize_der().to_vec());
733 witness[0].push(EcdsaSighashType::All as u8);
734 witness.push(remotepubkey.serialize().to_vec());
738 /// Sign the single input of `spend_tx` at index `input_idx` which spends the output
739 /// described by `descriptor`, returning the witness stack for the input.
741 /// Returns an error if the input at `input_idx` does not exist, has a non-empty `script_sig`,
742 /// is not spending the outpoint described by [`descriptor.outpoint`], does not have a
743 /// sequence set to [`descriptor.to_self_delay`], or if an output descriptor
744 /// `script_pubkey` does not match the one we can spend.
746 /// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
747 /// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
748 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>>, ()> {
749 // TODO: We really should be taking the SigHashCache as a parameter here instead of
750 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
751 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
752 // bindings updates to support SigHashCache objects).
753 if spend_tx.input.len() <= input_idx { return Err(()); }
754 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
755 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
756 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
758 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
759 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
760 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
761 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
762 let local_delayedsig = sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self);
763 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
765 if descriptor.output.script_pubkey != payment_script { return Err(()); }
767 let mut witness = Vec::with_capacity(3);
768 witness.push(local_delayedsig.serialize_der().to_vec());
769 witness[0].push(EcdsaSighashType::All as u8);
770 witness.push(vec!()); //MINIMALIF
771 witness.push(witness_script.clone().into_bytes());
776 impl EntropySource for InMemorySigner {
777 fn get_secure_random_bytes(&self) -> [u8; 32] {
778 let index = self.rand_bytes_index.get_increment();
779 let mut nonce = [0u8; 16];
780 nonce[..8].copy_from_slice(&index.to_be_bytes());
781 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
785 impl ChannelSigner for InMemorySigner {
786 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
787 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
788 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
791 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
792 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
795 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
799 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
801 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
803 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
804 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
805 if self.channel_parameters.is_some() {
806 // The channel parameters were already set and they match, return early.
809 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
810 self.channel_parameters = Some(channel_parameters.clone());
814 impl EcdsaChannelSigner for InMemorySigner {
815 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
816 let trusted_tx = commitment_tx.trust();
817 let keys = trusted_tx.keys();
819 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
820 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
822 let built_tx = trusted_tx.built_transaction();
823 let commitment_sig = built_tx.sign_counterparty_commitment(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
824 let commitment_txid = built_tx.txid;
826 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
827 for htlc in commitment_tx.htlcs() {
828 let channel_parameters = self.get_channel_parameters();
829 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, self.opt_anchors(), channel_parameters.opt_non_zero_fee_anchors.is_some(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
830 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
831 let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
832 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
833 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
834 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
837 Ok((commitment_sig, htlc_sigs))
840 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
844 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
845 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
846 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
847 let trusted_tx = commitment_tx.trust();
848 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
849 let channel_parameters = self.get_channel_parameters();
850 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
854 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
855 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
856 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
857 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
858 let trusted_tx = commitment_tx.trust();
859 let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
860 let channel_parameters = self.get_channel_parameters();
861 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
865 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
866 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
867 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
868 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
869 let witness_script = {
870 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint);
871 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
873 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
874 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
875 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
878 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, ()> {
879 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
880 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
881 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
882 let witness_script = {
883 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
884 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
885 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
887 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
888 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
889 return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
893 fn sign_holder_htlc_transaction(
894 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
895 secp_ctx: &Secp256k1<secp256k1::All>
896 ) -> Result<Signature, ()> {
897 let per_commitment_point = self.get_per_commitment_point(
898 htlc_descriptor.per_commitment_number, &secp_ctx
900 let witness_script = htlc_descriptor.witness_script(&per_commitment_point, secp_ctx);
901 let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
902 input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
904 let our_htlc_private_key = chan_utils::derive_private_key(
905 &secp_ctx, &per_commitment_point, &self.htlc_base_key
907 Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key, &self))
910 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, ()> {
911 let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
912 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
913 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
914 let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
915 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
916 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
917 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
918 Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
921 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
922 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
923 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
924 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
927 fn sign_holder_anchor_input(
928 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
929 ) -> Result<Signature, ()> {
930 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
931 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
932 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
934 Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
937 fn sign_channel_announcement_with_funding_key(
938 &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
939 ) -> Result<Signature, ()> {
940 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
941 Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
945 const SERIALIZATION_VERSION: u8 = 1;
947 const MIN_SERIALIZATION_VERSION: u8 = 1;
949 impl WriteableEcdsaChannelSigner for InMemorySigner {}
951 impl Writeable for InMemorySigner {
952 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
953 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
955 self.funding_key.write(writer)?;
956 self.revocation_base_key.write(writer)?;
957 self.payment_key.write(writer)?;
958 self.delayed_payment_base_key.write(writer)?;
959 self.htlc_base_key.write(writer)?;
960 self.commitment_seed.write(writer)?;
961 self.channel_parameters.write(writer)?;
962 self.channel_value_satoshis.write(writer)?;
963 self.channel_keys_id.write(writer)?;
965 write_tlv_fields!(writer, {});
971 impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySource {
972 fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
973 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
975 let funding_key = Readable::read(reader)?;
976 let revocation_base_key = Readable::read(reader)?;
977 let payment_key = Readable::read(reader)?;
978 let delayed_payment_base_key = Readable::read(reader)?;
979 let htlc_base_key = Readable::read(reader)?;
980 let commitment_seed = Readable::read(reader)?;
981 let counterparty_channel_data = Readable::read(reader)?;
982 let channel_value_satoshis = Readable::read(reader)?;
983 let secp_ctx = Secp256k1::signing_only();
984 let holder_channel_pubkeys =
985 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
986 &payment_key, &delayed_payment_base_key, &htlc_base_key);
987 let keys_id = Readable::read(reader)?;
989 read_tlv_fields!(reader, {});
995 delayed_payment_base_key,
998 channel_value_satoshis,
999 holder_channel_pubkeys,
1000 channel_parameters: counterparty_channel_data,
1001 channel_keys_id: keys_id,
1002 rand_bytes_unique_start: entropy_source.get_secure_random_bytes(),
1003 rand_bytes_index: AtomicCounter::new(),
1008 /// Simple implementation of [`EntropySource`], [`NodeSigner`], and [`SignerProvider`] that takes a
1009 /// 32-byte seed for use as a BIP 32 extended key and derives keys from that.
1011 /// Your `node_id` is seed/0'.
1012 /// Unilateral closes may use seed/1'.
1013 /// Cooperative closes may use seed/2'.
1014 /// The two close keys may be needed to claim on-chain funds!
1016 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
1017 /// [`PhantomKeysManager`] must be used instead.
1019 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
1020 /// previously issued invoices and attempts to pay previous invoices will fail.
1021 pub struct KeysManager {
1022 secp_ctx: Secp256k1<secp256k1::All>,
1023 node_secret: SecretKey,
1025 inbound_payment_key: KeyMaterial,
1026 destination_script: Script,
1027 shutdown_pubkey: PublicKey,
1028 channel_master_key: ExtendedPrivKey,
1029 channel_child_index: AtomicUsize,
1031 rand_bytes_unique_start: [u8; 32],
1032 rand_bytes_index: AtomicCounter,
1035 starting_time_secs: u64,
1036 starting_time_nanos: u32,
1040 /// Constructs a [`KeysManager`] from a 32-byte seed. If the seed is in some way biased (e.g.,
1041 /// your CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
1042 /// `starting_time` isn't strictly required to actually be a time, but it must absolutely,
1043 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
1044 /// `seed`, `starting_time` must be unique to each run. Thus, the easiest way to achieve this
1045 /// is to simply use the current time (with very high precision).
1047 /// The `seed` MUST be backed up safely prior to use so that the keys can be re-created, however,
1048 /// obviously, `starting_time` should be unique every time you reload the library - it is only
1049 /// used to generate new ephemeral key data (which will be stored by the individual channel if
1052 /// Note that the seed is required to recover certain on-chain funds independent of
1053 /// [`ChannelMonitor`] data, though a current copy of [`ChannelMonitor`] data is also required
1054 /// for any channel, and some on-chain during-closing funds.
1056 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
1057 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
1058 let secp_ctx = Secp256k1::new();
1059 // Note that when we aren't serializing the key, network doesn't matter
1060 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
1062 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
1063 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
1064 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
1065 Ok(destination_key) => {
1066 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
1067 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
1068 .push_slice(&wpubkey_hash.into_inner())
1071 Err(_) => panic!("Your RNG is busted"),
1073 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
1074 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
1075 Err(_) => panic!("Your RNG is busted"),
1077 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
1078 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
1079 let mut inbound_pmt_key_bytes = [0; 32];
1080 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
1082 let mut rand_bytes_engine = Sha256::engine();
1083 rand_bytes_engine.input(&starting_time_secs.to_be_bytes());
1084 rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
1085 rand_bytes_engine.input(seed);
1086 rand_bytes_engine.input(b"LDK PRNG Seed");
1087 let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).into_inner();
1089 let mut res = KeysManager {
1093 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1099 channel_child_index: AtomicUsize::new(0),
1101 rand_bytes_unique_start,
1102 rand_bytes_index: AtomicCounter::new(),
1106 starting_time_nanos,
1108 let secp_seed = res.get_secure_random_bytes();
1109 res.secp_ctx.seeded_randomize(&secp_seed);
1112 Err(_) => panic!("Your rng is busted"),
1116 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1117 pub fn get_node_secret_key(&self) -> SecretKey {
1121 /// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
1122 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1123 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1124 let mut unique_start = Sha256::engine();
1125 unique_start.input(params);
1126 unique_start.input(&self.seed);
1128 // We only seriously intend to rely on the channel_master_key for true secure
1129 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1130 // starting_time provided in the constructor) to be unique.
1131 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
1132 ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
1133 ).expect("Your RNG is busted");
1134 unique_start.input(&child_privkey.private_key[..]);
1136 let seed = Sha256::from_engine(unique_start).into_inner();
1138 let commitment_seed = {
1139 let mut sha = Sha256::engine();
1141 sha.input(&b"commitment seed"[..]);
1142 Sha256::from_engine(sha).into_inner()
1144 macro_rules! key_step {
1145 ($info: expr, $prev_key: expr) => {{
1146 let mut sha = Sha256::engine();
1148 sha.input(&$prev_key[..]);
1149 sha.input(&$info[..]);
1150 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1153 let funding_key = key_step!(b"funding key", commitment_seed);
1154 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1155 let payment_key = key_step!(b"payment key", revocation_base_key);
1156 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1157 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1158 let prng_seed = self.get_secure_random_bytes();
1160 InMemorySigner::new(
1163 revocation_base_key,
1165 delayed_payment_base_key,
1168 channel_value_satoshis,
1174 /// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
1175 /// output to the given change destination (if sufficient change value remains). The
1176 /// transaction will have a feerate, at least, of the given value.
1178 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1179 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1180 /// does not match the one we can spend.
1182 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1184 /// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
1185 /// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
1186 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1187 let mut input = Vec::new();
1188 let mut input_value = 0;
1189 let mut witness_weight = 0;
1190 let mut output_set = HashSet::with_capacity(descriptors.len());
1191 for outp in descriptors {
1193 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1195 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1196 script_sig: Script::new(),
1197 sequence: Sequence::ZERO,
1198 witness: Witness::new(),
1200 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1201 #[cfg(feature = "grind_signatures")]
1202 { witness_weight -= 1; } // Guarantees a low R signature
1203 input_value += descriptor.output.value;
1204 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1206 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1208 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1209 script_sig: Script::new(),
1210 sequence: Sequence(descriptor.to_self_delay as u32),
1211 witness: Witness::new(),
1213 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1214 #[cfg(feature = "grind_signatures")]
1215 { witness_weight -= 1; } // Guarantees a low R signature
1216 input_value += descriptor.output.value;
1217 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1219 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1221 previous_output: outpoint.into_bitcoin_outpoint(),
1222 script_sig: Script::new(),
1223 sequence: Sequence::ZERO,
1224 witness: Witness::new(),
1226 witness_weight += 1 + 73 + 34;
1227 #[cfg(feature = "grind_signatures")]
1228 { witness_weight -= 1; } // Guarantees a low R signature
1229 input_value += output.value;
1230 if !output_set.insert(*outpoint) { return Err(()); }
1233 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
1235 let mut spend_tx = Transaction {
1237 lock_time: PackedLockTime(0),
1241 let expected_max_weight =
1242 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
1244 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1245 let mut input_idx = 0;
1246 for outp in descriptors {
1248 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1249 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1251 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1252 descriptor.channel_keys_id));
1254 spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
1256 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1257 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1259 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1260 descriptor.channel_keys_id));
1262 spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
1264 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
1265 let derivation_idx = if output.script_pubkey == self.destination_script {
1271 // Note that when we aren't serializing the key, network doesn't matter
1272 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1274 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1276 Err(_) => panic!("Your RNG is busted"),
1279 Err(_) => panic!("Your rng is busted"),
1282 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1283 if derivation_idx == 2 {
1284 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1286 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1287 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1289 if payment_script != output.script_pubkey { return Err(()); };
1291 let sighash = hash_to_message!(&sighash::SighashCache::new(&spend_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1292 let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
1293 let mut sig_ser = sig.serialize_der().to_vec();
1294 sig_ser.push(EcdsaSighashType::All as u8);
1295 spend_tx.input[input_idx].witness.push(sig_ser);
1296 spend_tx.input[input_idx].witness.push(pubkey.inner.serialize().to_vec());
1302 debug_assert!(expected_max_weight >= spend_tx.weight());
1303 // Note that witnesses with a signature vary somewhat in size, so allow
1304 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1305 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1311 impl EntropySource for KeysManager {
1312 fn get_secure_random_bytes(&self) -> [u8; 32] {
1313 let index = self.rand_bytes_index.get_increment();
1314 let mut nonce = [0u8; 16];
1315 nonce[..8].copy_from_slice(&index.to_be_bytes());
1316 ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
1320 impl NodeSigner for KeysManager {
1321 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1323 Recipient::Node => Ok(self.node_id.clone()),
1324 Recipient::PhantomNode => Err(())
1328 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1329 let mut node_secret = match recipient {
1330 Recipient::Node => Ok(self.node_secret.clone()),
1331 Recipient::PhantomNode => Err(())
1333 if let Some(tweak) = tweak {
1334 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1336 Ok(SharedSecret::new(other_key, &node_secret))
1339 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1340 self.inbound_payment_key.clone()
1343 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1344 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1345 let secret = match recipient {
1346 Recipient::Node => Ok(&self.node_secret),
1347 Recipient::PhantomNode => Err(())
1349 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1352 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1353 let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
1354 Ok(self.secp_ctx.sign_ecdsa(&msg_hash, &self.node_secret))
1358 impl SignerProvider for KeysManager {
1359 type Signer = InMemorySigner;
1361 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1362 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1363 // `child_idx` is the only thing guaranteed to make each channel unique without a restart
1364 // (though `user_channel_id` should help, depending on user behavior). If it manages to
1365 // roll over, we may generate duplicate keys for two different channels, which could result
1366 // in loss of funds. Because we only support 32-bit+ systems, assert that our `AtomicUsize`
1367 // doesn't reach `u32::MAX`.
1368 assert!(child_idx < core::u32::MAX as usize, "2^32 channels opened without restart");
1369 let mut id = [0; 32];
1370 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1371 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1372 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1373 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1377 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1378 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1381 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1382 InMemorySigner::read(&mut io::Cursor::new(reader), self)
1385 fn get_destination_script(&self) -> Result<Script, ()> {
1386 Ok(self.destination_script.clone())
1389 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1390 Ok(ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone()))
1394 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1397 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1398 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1399 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1400 /// itself without ever needing to forward to this fake node.
1402 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1403 /// provide some fault tolerance, because payers will automatically retry paying other provided
1404 /// nodes in the case that one node goes down.
1406 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1407 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1408 // nodes to know when the full payment has been received (and the preimage can be released) without
1409 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1410 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1411 // is released too early.
1413 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1414 /// invoices and attempts to pay previous invoices will fail.
1415 pub struct PhantomKeysManager {
1417 inbound_payment_key: KeyMaterial,
1418 phantom_secret: SecretKey,
1419 phantom_node_id: PublicKey,
1422 impl EntropySource for PhantomKeysManager {
1423 fn get_secure_random_bytes(&self) -> [u8; 32] {
1424 self.inner.get_secure_random_bytes()
1428 impl NodeSigner for PhantomKeysManager {
1429 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1431 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1432 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1436 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1437 let mut node_secret = match recipient {
1438 Recipient::Node => self.inner.node_secret.clone(),
1439 Recipient::PhantomNode => self.phantom_secret.clone(),
1441 if let Some(tweak) = tweak {
1442 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1444 Ok(SharedSecret::new(other_key, &node_secret))
1447 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1448 self.inbound_payment_key.clone()
1451 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1452 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1453 let secret = match recipient {
1454 Recipient::Node => &self.inner.node_secret,
1455 Recipient::PhantomNode => &self.phantom_secret,
1457 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
1460 fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()> {
1461 self.inner.sign_gossip_message(msg)
1465 impl SignerProvider for PhantomKeysManager {
1466 type Signer = InMemorySigner;
1468 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1469 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1472 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1473 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1476 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1477 self.inner.read_chan_signer(reader)
1480 fn get_destination_script(&self) -> Result<Script, ()> {
1481 self.inner.get_destination_script()
1484 fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
1485 self.inner.get_shutdown_scriptpubkey()
1489 impl PhantomKeysManager {
1490 /// Constructs a [`PhantomKeysManager`] given a 32-byte seed and an additional `cross_node_seed`
1491 /// that is shared across all nodes that intend to participate in [phantom node payments]
1494 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1495 /// `starting_time_nanos`.
1497 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1498 /// same across restarts, or else inbound payments may fail.
1500 /// [phantom node payments]: PhantomKeysManager
1501 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1502 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1503 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1504 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1505 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1508 inbound_payment_key: KeyMaterial(inbound_key),
1514 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1515 pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
1516 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
1519 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1520 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1521 self.inner.derive_channel_keys(channel_value_satoshis, params)
1524 /// Gets the "node_id" secret key used to sign gossip announcements, decode onion data, etc.
1525 pub fn get_node_secret_key(&self) -> SecretKey {
1526 self.inner.get_node_secret_key()
1529 /// Gets the "node_id" secret key of the phantom node used to sign invoices, decode the
1530 /// last-hop onion data, etc.
1531 pub fn get_phantom_node_secret_key(&self) -> SecretKey {
1536 // Ensure that EcdsaChannelSigner can have a vtable
1539 let _signer: Box<dyn EcdsaChannelSigner>;
1542 #[cfg(all(test, feature = "_bench_unstable", not(feature = "no-std")))]
1544 use std::sync::{Arc, mpsc};
1545 use std::sync::mpsc::TryRecvError;
1547 use std::time::Duration;
1548 use bitcoin::blockdata::constants::genesis_block;
1549 use bitcoin::Network;
1550 use crate::chain::keysinterface::{EntropySource, KeysManager};
1555 fn bench_get_secure_random_bytes(bench: &mut Bencher) {
1556 let seed = [0u8; 32];
1557 let now = Duration::from_secs(genesis_block(Network::Testnet).header.time as u64);
1558 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_micros()));
1560 let mut handles = Vec::new();
1561 let mut stops = Vec::new();
1563 let keys_manager_clone = Arc::clone(&keys_manager);
1564 let (stop_sender, stop_receiver) = mpsc::channel();
1565 let handle = thread::spawn(move || {
1567 keys_manager_clone.get_secure_random_bytes();
1568 match stop_receiver.try_recv() {
1569 Ok(_) | Err(TryRecvError::Disconnected) => {
1570 println!("Terminating.");
1573 Err(TryRecvError::Empty) => {}
1577 handles.push(handle);
1578 stops.push(stop_sender);
1583 keys_manager.get_secure_random_bytes();
1588 let _ = stop.send(());
1590 for handle in handles {
1591 handle.join().unwrap();