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 //! keysinterface provides keys into rust-lightning and defines some useful enums which describe
11 //! spendable on-chain outputs which the user owns and is responsible for using just as any other
12 //! on-chain output which is theirs.
14 use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn, EcdsaSighashType};
15 use bitcoin::blockdata::script::{Script, Builder};
16 use bitcoin::blockdata::opcodes;
17 use bitcoin::network::constants::Network;
18 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
19 use bitcoin::util::sighash;
21 use bitcoin::bech32::u5;
22 use bitcoin::hashes::{Hash, HashEngine};
23 use bitcoin::hashes::sha256::HashEngine as Sha256State;
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};
36 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
38 use crate::util::events::HTLCDescriptor;
39 use crate::chain::transaction::OutPoint;
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;
44 use crate::ln::script::ShutdownScript;
46 use crate::prelude::*;
47 use core::convert::TryInto;
48 use core::sync::atomic::{AtomicUsize, Ordering};
49 use crate::io::{self, Error};
50 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
51 use crate::util::invoice::construct_invoice_preimage;
53 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
54 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
55 /// (C-not exported) as we just use [u8; 32] directly
56 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
57 pub struct KeyMaterial(pub [u8; 32]);
59 /// Information about a spendable output to a P2WSH script. See
60 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
61 #[derive(Clone, Debug, PartialEq, Eq)]
62 pub struct DelayedPaymentOutputDescriptor {
63 /// The outpoint which is spendable
64 pub outpoint: OutPoint,
65 /// Per commitment point to derive delayed_payment_key by key holder
66 pub per_commitment_point: PublicKey,
67 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
68 /// the witness_script.
69 pub to_self_delay: u16,
70 /// The output which is referenced by the given outpoint
72 /// The revocation point specific to the commitment transaction which was broadcast. Used to
73 /// derive the witnessScript for this output.
74 pub revocation_pubkey: PublicKey,
75 /// Arbitrary identification information returned by a call to
76 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
77 /// the channel to spend the output.
78 pub channel_keys_id: [u8; 32],
79 /// The value of the channel which this output originated from, possibly indirectly.
80 pub channel_value_satoshis: u64,
82 impl DelayedPaymentOutputDescriptor {
83 /// The maximum length a well-formed witness spending one of these should have.
84 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
85 // redeemscript push length.
86 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
89 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
90 (0, outpoint, required),
91 (2, per_commitment_point, required),
92 (4, to_self_delay, required),
93 (6, output, required),
94 (8, revocation_pubkey, required),
95 (10, channel_keys_id, required),
96 (12, channel_value_satoshis, required),
99 /// Information about a spendable output to our "payment key". See
100 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
101 #[derive(Clone, Debug, PartialEq, Eq)]
102 pub struct StaticPaymentOutputDescriptor {
103 /// The outpoint which is spendable
104 pub outpoint: OutPoint,
105 /// The output which is referenced by the given outpoint
107 /// Arbitrary identification information returned by a call to
108 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
109 /// the channel to spend the output.
110 pub channel_keys_id: [u8; 32],
111 /// The value of the channel which this transactions spends.
112 pub channel_value_satoshis: u64,
114 impl StaticPaymentOutputDescriptor {
115 /// The maximum length a well-formed witness spending one of these should have.
116 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
117 // redeemscript push length.
118 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
120 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
121 (0, outpoint, required),
122 (2, output, required),
123 (4, channel_keys_id, required),
124 (6, channel_value_satoshis, required),
127 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
128 /// claim at any point in the future) an event is generated which you must track and be able to
129 /// spend on-chain. The information needed to do this is provided in this enum, including the
130 /// outpoint describing which txid and output index is available, the full output which exists at
131 /// that txid/index, and any keys or other information required to sign.
132 #[derive(Clone, Debug, PartialEq, Eq)]
133 pub enum SpendableOutputDescriptor {
134 /// An output to a script which was provided via KeysInterface directly, either from
135 /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
136 /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
137 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
138 /// on-chain using the payment preimage or after it has timed out.
140 /// The outpoint which is spendable
142 /// The output which is referenced by the given outpoint.
145 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
147 /// The witness in the spending input should be:
148 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
150 /// Note that the nSequence field in the spending input must be set to to_self_delay
151 /// (which means the transaction is not broadcastable until at least to_self_delay
152 /// blocks after the outpoint confirms).
154 /// These are generally the result of a "revocable" output to us, spendable only by us unless
155 /// it is an output from an old state which we broadcast (which should never happen).
157 /// To derive the delayed_payment key which is used to sign for this input, you must pass the
158 /// holder delayed_payment_base_key (ie the private key which corresponds to the pubkey in
159 /// Sign::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
160 /// chan_utils::derive_private_key. The public key can be generated without the secret key
161 /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
164 /// To derive the revocation_pubkey provided here (which is used in the witness
165 /// script generation), you must pass the counterparty revocation_basepoint (which appears in the
166 /// call to Sign::provide_channel_parameters) and the provided per_commitment point
167 /// to chan_utils::derive_public_revocation_key.
169 /// The witness script which is hashed and included in the output script_pubkey may be
170 /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
171 /// (derived as above), and the to_self_delay contained here to
172 /// chan_utils::get_revokeable_redeemscript.
173 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
174 /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
175 /// corresponds to the public key in Sign::pubkeys().payment_point).
176 /// The witness in the spending input, is, thus, simply:
177 /// <BIP 143 signature> <payment key>
179 /// These are generally the result of our counterparty having broadcast the current state,
180 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
181 StaticPaymentOutput(StaticPaymentOutputDescriptor),
184 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
185 (0, StaticOutput) => {
186 (0, outpoint, required),
187 (2, output, required),
190 (1, DelayedPaymentOutput),
191 (2, StaticPaymentOutput),
194 /// A trait to sign lightning channel transactions as described in BOLT 3.
196 /// Signing services could be implemented on a hardware wallet. In this case,
197 /// the current Sign would be a front-end on top of a communication
198 /// channel connected to your secure device and lightning key material wouldn't
199 /// reside on a hot server. Nevertheless, a this deployment would still need
200 /// to trust the ChannelManager to avoid loss of funds as this latest component
201 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
203 /// A more secure iteration would be to use hashlock (or payment points) to pair
204 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
205 /// at the price of more state and computation on the hardware wallet side. In the future,
206 /// we are looking forward to design such interface.
208 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
209 /// to act, as liveness and breach reply correctness are always going to be hard requirements
210 /// of LN security model, orthogonal of key management issues.
211 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
212 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
214 /// Gets the per-commitment point for a specific commitment number
216 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
217 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
218 /// Gets the commitment secret for a specific commitment number as part of the revocation process
220 /// An external signer implementation should error here if the commitment was already signed
221 /// and should refuse to sign it in the future.
223 /// May be called more than once for the same index.
225 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
226 // TODO: return a Result so we can signal a validation error
227 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
228 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
230 /// This is required in order for the signer to make sure that releasing a commitment
231 /// secret won't leave us without a broadcastable holder transaction.
232 /// Policy checks should be implemented in this function, including checking the amount
233 /// sent to us and checking the HTLCs.
235 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
236 /// A validating signer should ensure that an HTLC output is removed only when the matching
237 /// preimage is provided, or when the value to holder is restored.
239 /// NOTE: all the relevant preimages will be provided, but there may also be additional
240 /// irrelevant or duplicate preimages.
241 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
242 /// Gets the holder's channel public keys and basepoints
243 fn pubkeys(&self) -> &ChannelPublicKeys;
244 /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
245 /// some SpendableOutputDescriptor types. This should be sufficient to identify this
246 /// Sign object uniquely and lookup or re-derive its keys.
247 fn channel_keys_id(&self) -> [u8; 32];
249 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
251 /// Note that if signing fails or is rejected, the channel will be force-closed.
253 /// Policy checks should be implemented in this function, including checking the amount
254 /// sent to us and checking the HTLCs.
256 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
257 /// A validating signer should ensure that an HTLC output is removed only when the matching
258 /// preimage is provided, or when the value to holder is restored.
260 /// NOTE: all the relevant preimages will be provided, but there may also be additional
261 /// irrelevant or duplicate preimages.
263 // TODO: Document the things someone using this interface should enforce before signing.
264 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
265 /// Validate the counterparty's revocation.
267 /// This is required in order for the signer to make sure that the state has moved
268 /// forward and it is safe to sign the next counterparty commitment.
269 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
271 /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
272 /// This will only ever be called with a non-revoked commitment_tx. This will be called with the
273 /// latest commitment_tx when we initiate a force-close.
274 /// This will be called with the previous latest, just to get claiming HTLC signatures, if we are
275 /// reacting to a ChannelMonitor replica that decided to broadcast before it had been updated to
277 /// This may be called multiple times for the same transaction.
279 /// An external signer implementation should check that the commitment has not been revoked.
281 /// May return Err if key derivation fails. Callers, such as ChannelMonitor, will panic in such a case.
283 // TODO: Document the things someone using this interface should enforce before signing.
284 // TODO: Key derivation failure should panic rather than Err
285 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
287 /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment
288 /// transactions which will be broadcasted later, after the channel has moved on to a newer
289 /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever
291 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
292 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
294 /// Create a signature for the given input in a transaction spending an HTLC transaction output
295 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
297 /// A justice transaction may claim multiple outputs at the same time if timelocks are
298 /// similar, but only a signature for the input at index `input` should be signed for here.
299 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
300 /// to an upcoming timelock expiration.
302 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
304 /// per_commitment_key is revocation secret which was provided by our counterparty when they
305 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
306 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
308 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
310 /// Create a signature for the given input in a transaction spending a commitment transaction
311 /// HTLC output when our counterparty broadcasts an old state.
313 /// A justice transaction may claim multiple outputs at the same time if timelocks are
314 /// similar, but only a signature for the input at index `input` should be signed for here.
315 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
316 /// to an upcoming timelock expiration.
318 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
320 /// per_commitment_key is revocation secret which was provided by our counterparty when they
321 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
322 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
325 /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
326 /// (which is committed to in the BIP 143 signatures).
327 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, ()>;
330 /// Computes the signature for a commitment transaction's HTLC output used as an input within
331 /// `htlc_tx`, which spends the commitment transaction, at index `input`. The signature returned
332 /// must be be computed using [`EcdsaSighashType::All`]. Note that this should only be used to
333 /// sign HTLC transactions from channels supporting anchor outputs after all additional
334 /// inputs/outputs have been added to the transaction.
336 /// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
337 fn sign_holder_htlc_transaction(
338 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
339 secp_ctx: &Secp256k1<secp256k1::All>
340 ) -> Result<Signature, ()>;
342 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
343 /// transaction, either offered or received.
345 /// Such a transaction may claim multiples offered outputs at same time if we know the
346 /// preimage for each when we create it, but only the input at index `input` should be
347 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
348 /// needed with regards to an upcoming timelock expiration.
350 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
353 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
355 /// Per_commitment_point is the dynamic point corresponding to the channel state
356 /// detected onchain. It has been generated by our counterparty and is used to derive
357 /// channel state keys, which are then included in the witness script and committed to in the
358 /// BIP 143 signature.
359 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, ()>;
361 /// Create a signature for a (proposed) closing transaction.
363 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
364 /// chosen to forgo their output as dust.
365 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
367 /// Computes the signature for a commitment transaction's anchor output used as an
368 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
369 fn sign_holder_anchor_input(
370 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
371 ) -> Result<Signature, ()>;
373 /// Signs a channel announcement message with our funding key and our node secret key (aka
374 /// node_id or network_key), proving it comes from one of the channel participants.
376 /// The first returned signature should be from our node secret key, the second from our
379 /// Note that if this fails or is rejected, the channel will not be publicly announced and
380 /// our counterparty may (though likely will not) close the channel on us for violating the
382 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
383 -> Result<(Signature, Signature), ()>;
385 /// Set the counterparty static channel data, including basepoints,
386 /// counterparty_selected/holder_selected_contest_delay and funding outpoint. Since these are
387 /// static channel data, they MUST NOT be allowed to change to different values once set, as LDK
388 /// may call this method more than once.
390 /// channel_parameters.is_populated() MUST be true.
391 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
394 /// A writeable signer.
396 /// There will always be two instances of a signer per channel, one occupied by the
397 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
399 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
400 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
401 pub trait Sign: BaseSign + Writeable {
404 /// Specifies the recipient of an invoice, to indicate to [`KeysInterface::sign_invoice`] what node
405 /// secret key should be used to sign the invoice.
407 /// The invoice should be signed with the local node secret key.
409 /// The invoice should be signed with the phantom node secret key. This secret key must be the
410 /// same for all nodes participating in the [phantom node payment].
412 /// [phantom node payment]: PhantomKeysManager
416 /// A trait to describe an object which can get user secrets and key material.
417 pub trait KeysInterface {
418 /// A type which implements Sign which will be returned by derive_channel_signer.
421 /// Get node secret key based on the provided [`Recipient`].
423 /// The node_id/network_key is the public key that corresponds to this secret key.
425 /// This method must return the same value each time it is called with a given `Recipient`
428 /// Errors if the `Recipient` variant is not supported by the implementation.
429 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()>;
430 /// Get node id based on the provided [`Recipient`]. This public key corresponds to the secret in
431 /// [`get_node_secret`].
433 /// This method must return the same value each time it is called with a given `Recipient`
436 /// Errors if the `Recipient` variant is not supported by the implementation.
438 /// [`get_node_secret`]: KeysInterface::get_node_secret
439 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
440 let secp_ctx = Secp256k1::signing_only();
441 Ok(PublicKey::from_secret_key(&secp_ctx, &self.get_node_secret(recipient)?))
443 /// Gets the ECDH shared secret of our [`node secret`] and `other_key`, multiplying by `tweak` if
444 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
445 /// secret, though this is less efficient.
447 /// Errors if the `Recipient` variant is not supported by the implementation.
449 /// [`node secret`]: Self::get_node_secret
450 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
451 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
453 /// This method should return a different value each time it is called, to avoid linking
454 /// on-chain funds across channels as controlled to the same user.
455 fn get_destination_script(&self) -> Script;
456 /// Get a script pubkey which we will send funds to when closing a channel.
458 /// This method should return a different value each time it is called, to avoid linking
459 /// on-chain funds across channels as controlled to the same user.
460 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
461 /// Generates a unique `channel_keys_id` that can be used to obtain a `Signer` through
462 /// [`KeysInterface::derive_channel_signer`]. The `user_channel_id` is provided to allow
463 /// implementations of `KeysInterface` to maintain a mapping between it and the generated
464 /// `channel_keys_id`.
466 /// This method must return a different value each time it is called.
467 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
468 /// Derives the private key material backing a `Signer`.
470 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
471 /// [`KeysInterface::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
472 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
473 /// [`BaseSign::channel_keys_id`].
474 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
475 /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting
476 /// onion packets and for temporary channel IDs. There is no requirement that these be
477 /// persisted anywhere, though they must be unique across restarts.
479 /// This method must return a different value each time it is called.
480 fn get_secure_random_bytes(&self) -> [u8; 32];
482 /// Reads a `Signer` for this `KeysInterface` from the given input stream.
483 /// This is only called during deserialization of other objects which contain
484 /// `Sign`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s).
485 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
486 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
487 /// you've read all of the provided bytes to ensure no corruption occurred.
489 /// This method is slowly being phased out -- it will only be called when reading objects
490 /// written by LDK versions prior to 0.0.113.
491 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
494 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
495 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
496 /// blindly signing the hash.
497 /// The hrp is ascii bytes, while the invoice data is base32.
499 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
501 /// Errors if the `Recipient` variant is not supported by the implementation.
502 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], receipient: Recipient) -> Result<RecoverableSignature, ()>;
504 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
506 /// If the implementor of this trait supports [phantom node payments], then every node that is
507 /// intended to be included in the phantom invoice route hints must return the same value from
509 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
510 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
511 // nodes, they must share the key that encrypts this payment data.
513 /// This method must return the same value each time it is called.
515 /// [phantom node payments]: PhantomKeysManager
516 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
520 /// A simple implementation of Sign that just keeps the private keys in memory.
522 /// This implementation performs no policy checks and is insufficient by itself as
523 /// a secure external signer.
524 pub struct InMemorySigner {
525 /// Private key of anchor tx
526 pub funding_key: SecretKey,
527 /// Holder secret key for blinded revocation pubkey
528 pub revocation_base_key: SecretKey,
529 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions
530 pub payment_key: SecretKey,
531 /// Holder secret key used in HTLC tx
532 pub delayed_payment_base_key: SecretKey,
533 /// Holder htlc secret key used in commitment tx htlc outputs
534 pub htlc_base_key: SecretKey,
536 pub commitment_seed: [u8; 32],
537 /// Holder public keys and basepoints
538 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
539 /// Private key of our node secret, used for signing channel announcements
540 node_secret: SecretKey,
541 /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance
542 channel_parameters: Option<ChannelTransactionParameters>,
543 /// The total value of this channel
544 channel_value_satoshis: u64,
545 /// Key derivation parameters
546 channel_keys_id: [u8; 32],
549 impl InMemorySigner {
550 /// Create a new InMemorySigner
551 pub fn new<C: Signing>(
552 secp_ctx: &Secp256k1<C>,
553 node_secret: SecretKey,
554 funding_key: SecretKey,
555 revocation_base_key: SecretKey,
556 payment_key: SecretKey,
557 delayed_payment_base_key: SecretKey,
558 htlc_base_key: SecretKey,
559 commitment_seed: [u8; 32],
560 channel_value_satoshis: u64,
561 channel_keys_id: [u8; 32],
562 ) -> InMemorySigner {
563 let holder_channel_pubkeys =
564 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
565 &payment_key, &delayed_payment_base_key,
571 delayed_payment_base_key,
575 channel_value_satoshis,
576 holder_channel_pubkeys,
577 channel_parameters: None,
582 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
583 funding_key: &SecretKey,
584 revocation_base_key: &SecretKey,
585 payment_key: &SecretKey,
586 delayed_payment_base_key: &SecretKey,
587 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
588 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
590 funding_pubkey: from_secret(&funding_key),
591 revocation_basepoint: from_secret(&revocation_base_key),
592 payment_point: from_secret(&payment_key),
593 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
594 htlc_basepoint: from_secret(&htlc_base_key),
598 /// Counterparty pubkeys.
599 /// Will panic if provide_channel_parameters wasn't called.
600 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
602 /// The contest_delay value specified by our counterparty and applied on holder-broadcastable
603 /// transactions, ie the amount of time that we have to wait to recover our funds if we
604 /// broadcast a transaction.
605 /// Will panic if provide_channel_parameters wasn't called.
606 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
608 /// The contest_delay value specified by us and applied on transactions broadcastable
609 /// by our counterparty, ie the amount of time that they have to wait to recover their funds
610 /// if they broadcast a transaction.
611 /// Will panic if provide_channel_parameters wasn't called.
612 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
614 /// Whether the holder is the initiator
615 /// Will panic if provide_channel_parameters wasn't called.
616 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
619 /// Will panic if provide_channel_parameters wasn't called.
620 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
622 /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or
623 /// building transactions.
625 /// Will panic if provide_channel_parameters wasn't called.
626 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
627 self.channel_parameters.as_ref().unwrap()
630 /// Whether anchors should be used.
631 /// Will panic if provide_channel_parameters wasn't called.
632 pub fn opt_anchors(&self) -> bool {
633 self.get_channel_parameters().opt_anchors.is_some()
636 /// Sign the single input of spend_tx at index `input_idx` which spends the output
637 /// described by descriptor, returning the witness stack for the input.
639 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
640 /// is not spending the outpoint described by `descriptor.outpoint`,
641 /// or if an output descriptor script_pubkey does not match the one we can spend.
642 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>>, ()> {
643 // TODO: We really should be taking the SigHashCache as a parameter here instead of
644 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
645 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
646 // bindings updates to support SigHashCache objects).
647 if spend_tx.input.len() <= input_idx { return Err(()); }
648 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
649 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
651 let remotepubkey = self.pubkeys().payment_point;
652 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
653 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
654 let remotesig = sign(secp_ctx, &sighash, &self.payment_key);
655 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
657 if payment_script != descriptor.output.script_pubkey { return Err(()); }
659 let mut witness = Vec::with_capacity(2);
660 witness.push(remotesig.serialize_der().to_vec());
661 witness[0].push(EcdsaSighashType::All as u8);
662 witness.push(remotepubkey.serialize().to_vec());
666 /// Sign the single input of spend_tx at index `input_idx` which spends the output
667 /// described by descriptor, returning the witness stack for the input.
669 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
670 /// is not spending the outpoint described by `descriptor.outpoint`, does not have a
671 /// sequence set to `descriptor.to_self_delay`, or if an output descriptor
672 /// script_pubkey does not match the one we can spend.
673 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>>, ()> {
674 // TODO: We really should be taking the SigHashCache as a parameter here instead of
675 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
676 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
677 // bindings updates to support SigHashCache objects).
678 if spend_tx.input.len() <= input_idx { return Err(()); }
679 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
680 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
681 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
683 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
684 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
685 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
686 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
687 let local_delayedsig = sign(secp_ctx, &sighash, &delayed_payment_key);
688 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
690 if descriptor.output.script_pubkey != payment_script { return Err(()); }
692 let mut witness = Vec::with_capacity(3);
693 witness.push(local_delayedsig.serialize_der().to_vec());
694 witness[0].push(EcdsaSighashType::All as u8);
695 witness.push(vec!()); //MINIMALIF
696 witness.push(witness_script.clone().into_bytes());
701 impl BaseSign for InMemorySigner {
702 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
703 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
704 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
707 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
708 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
711 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
715 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
716 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
718 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
719 let trusted_tx = commitment_tx.trust();
720 let keys = trusted_tx.keys();
722 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
723 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
725 let built_tx = trusted_tx.built_transaction();
726 let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
727 let commitment_txid = built_tx.txid;
729 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
730 for htlc in commitment_tx.htlcs() {
731 let channel_parameters = self.get_channel_parameters();
732 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);
733 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
734 let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
735 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
736 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
737 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
740 Ok((commitment_sig, htlc_sigs))
743 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
747 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
748 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
749 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
750 let trusted_tx = commitment_tx.trust();
751 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
752 let channel_parameters = self.get_channel_parameters();
753 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
757 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
758 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
759 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
760 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
761 let trusted_tx = commitment_tx.trust();
762 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
763 let channel_parameters = self.get_channel_parameters();
764 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
768 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
769 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
770 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
771 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
772 let witness_script = {
773 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint);
774 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
776 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
777 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
778 return Ok(sign(secp_ctx, &sighash, &revocation_key))
781 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, ()> {
782 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key);
783 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
784 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
785 let witness_script = {
786 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
787 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
788 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
790 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
791 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
792 return Ok(sign(secp_ctx, &sighash, &revocation_key))
796 fn sign_holder_htlc_transaction(
797 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
798 secp_ctx: &Secp256k1<secp256k1::All>
799 ) -> Result<Signature, ()> {
800 let per_commitment_point = self.get_per_commitment_point(
801 htlc_descriptor.per_commitment_number, &secp_ctx
803 let witness_script = htlc_descriptor.witness_script(&per_commitment_point, secp_ctx);
804 let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
805 input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
807 let our_htlc_private_key = chan_utils::derive_private_key(
808 &secp_ctx, &per_commitment_point, &self.htlc_base_key
810 Ok(sign(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key))
813 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, ()> {
814 let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
815 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
816 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint);
817 let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
818 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
819 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
820 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
821 Ok(sign(secp_ctx, &sighash, &htlc_key))
824 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
825 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
826 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
827 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
830 fn sign_holder_anchor_input(
831 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
832 ) -> Result<Signature, ()> {
833 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
834 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
835 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
837 Ok(sign(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key))
840 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
841 -> Result<(Signature, Signature), ()> {
842 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
843 Ok((sign(secp_ctx, &msghash, &self.node_secret), sign(secp_ctx, &msghash, &self.funding_key)))
846 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
847 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
848 if self.channel_parameters.is_some() {
849 // The channel parameters were already set and they match, return early.
852 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
853 self.channel_parameters = Some(channel_parameters.clone());
857 const SERIALIZATION_VERSION: u8 = 1;
858 const MIN_SERIALIZATION_VERSION: u8 = 1;
860 impl Sign for InMemorySigner {}
862 impl Writeable for InMemorySigner {
863 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
864 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
866 self.funding_key.write(writer)?;
867 self.revocation_base_key.write(writer)?;
868 self.payment_key.write(writer)?;
869 self.delayed_payment_base_key.write(writer)?;
870 self.htlc_base_key.write(writer)?;
871 self.commitment_seed.write(writer)?;
872 self.channel_parameters.write(writer)?;
873 self.channel_value_satoshis.write(writer)?;
874 self.channel_keys_id.write(writer)?;
876 write_tlv_fields!(writer, {});
882 impl ReadableArgs<SecretKey> for InMemorySigner {
883 fn read<R: io::Read>(reader: &mut R, node_secret: SecretKey) -> Result<Self, DecodeError> {
884 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
886 let funding_key = Readable::read(reader)?;
887 let revocation_base_key = Readable::read(reader)?;
888 let payment_key = Readable::read(reader)?;
889 let delayed_payment_base_key = Readable::read(reader)?;
890 let htlc_base_key = Readable::read(reader)?;
891 let commitment_seed = Readable::read(reader)?;
892 let counterparty_channel_data = Readable::read(reader)?;
893 let channel_value_satoshis = Readable::read(reader)?;
894 let secp_ctx = Secp256k1::signing_only();
895 let holder_channel_pubkeys =
896 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
897 &payment_key, &delayed_payment_base_key,
899 let keys_id = Readable::read(reader)?;
901 read_tlv_fields!(reader, {});
907 delayed_payment_base_key,
911 channel_value_satoshis,
912 holder_channel_pubkeys,
913 channel_parameters: counterparty_channel_data,
914 channel_keys_id: keys_id,
919 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
920 /// and derives keys from that.
922 /// Your node_id is seed/0'
923 /// ChannelMonitor closes may use seed/1'
924 /// Cooperative closes may use seed/2'
925 /// The two close keys may be needed to claim on-chain funds!
927 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
928 /// [`PhantomKeysManager`] must be used instead.
930 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
931 /// previously issued invoices and attempts to pay previous invoices will fail.
932 pub struct KeysManager {
933 secp_ctx: Secp256k1<secp256k1::All>,
934 node_secret: SecretKey,
936 inbound_payment_key: KeyMaterial,
937 destination_script: Script,
938 shutdown_pubkey: PublicKey,
939 channel_master_key: ExtendedPrivKey,
940 channel_child_index: AtomicUsize,
942 rand_bytes_master_key: ExtendedPrivKey,
943 rand_bytes_child_index: AtomicUsize,
944 rand_bytes_unique_start: Sha256State,
947 starting_time_secs: u64,
948 starting_time_nanos: u32,
952 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
953 /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
954 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
955 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
956 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
957 /// simply use the current time (with very high precision).
959 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
960 /// obviously, starting_time should be unique every time you reload the library - it is only
961 /// used to generate new ephemeral key data (which will be stored by the individual channel if
964 /// Note that the seed is required to recover certain on-chain funds independent of
965 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
966 /// channel, and some on-chain during-closing funds.
968 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
969 /// versions. Once the library is more fully supported, the docs will be updated to include a
970 /// detailed description of the guarantee.
971 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
972 let secp_ctx = Secp256k1::new();
973 // Note that when we aren't serializing the key, network doesn't matter
974 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
976 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
977 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
978 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
979 Ok(destination_key) => {
980 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
981 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
982 .push_slice(&wpubkey_hash.into_inner())
985 Err(_) => panic!("Your RNG is busted"),
987 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
988 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
989 Err(_) => panic!("Your RNG is busted"),
991 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
992 let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
993 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
994 let mut inbound_pmt_key_bytes = [0; 32];
995 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
997 let mut rand_bytes_unique_start = Sha256::engine();
998 rand_bytes_unique_start.input(&starting_time_secs.to_be_bytes());
999 rand_bytes_unique_start.input(&starting_time_nanos.to_be_bytes());
1000 rand_bytes_unique_start.input(seed);
1002 let mut res = KeysManager {
1006 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
1012 channel_child_index: AtomicUsize::new(0),
1014 rand_bytes_master_key,
1015 rand_bytes_child_index: AtomicUsize::new(0),
1016 rand_bytes_unique_start,
1020 starting_time_nanos,
1022 let secp_seed = res.get_secure_random_bytes();
1023 res.secp_ctx.seeded_randomize(&secp_seed);
1026 Err(_) => panic!("Your rng is busted"),
1029 /// Derive an old Sign containing per-channel secrets based on a key derivation parameters.
1030 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1031 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1032 let mut unique_start = Sha256::engine();
1033 unique_start.input(params);
1034 unique_start.input(&self.seed);
1036 // We only seriously intend to rely on the channel_master_key for true secure
1037 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1038 // starting_time provided in the constructor) to be unique.
1039 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(chan_id as u32).expect("key space exhausted")).expect("Your RNG is busted");
1040 unique_start.input(&child_privkey.private_key[..]);
1042 let seed = Sha256::from_engine(unique_start).into_inner();
1044 let commitment_seed = {
1045 let mut sha = Sha256::engine();
1047 sha.input(&b"commitment seed"[..]);
1048 Sha256::from_engine(sha).into_inner()
1050 macro_rules! key_step {
1051 ($info: expr, $prev_key: expr) => {{
1052 let mut sha = Sha256::engine();
1054 sha.input(&$prev_key[..]);
1055 sha.input(&$info[..]);
1056 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1059 let funding_key = key_step!(b"funding key", commitment_seed);
1060 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1061 let payment_key = key_step!(b"payment key", revocation_base_key);
1062 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1063 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1065 InMemorySigner::new(
1069 revocation_base_key,
1071 delayed_payment_base_key,
1074 channel_value_satoshis,
1079 /// Creates a Transaction which spends the given descriptors to the given outputs, plus an
1080 /// output to the given change destination (if sufficient change value remains). The
1081 /// transaction will have a feerate, at least, of the given value.
1083 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1084 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1085 /// does not match the one we can spend.
1087 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1089 /// May panic if the `SpendableOutputDescriptor`s were not generated by Channels which used
1090 /// this KeysManager or one of the `InMemorySigner` created by this KeysManager.
1091 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, ()> {
1092 let mut input = Vec::new();
1093 let mut input_value = 0;
1094 let mut witness_weight = 0;
1095 let mut output_set = HashSet::with_capacity(descriptors.len());
1096 for outp in descriptors {
1098 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1100 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1101 script_sig: Script::new(),
1102 sequence: Sequence::ZERO,
1103 witness: Witness::new(),
1105 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1106 input_value += descriptor.output.value;
1107 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1109 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1111 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1112 script_sig: Script::new(),
1113 sequence: Sequence(descriptor.to_self_delay as u32),
1114 witness: Witness::new(),
1116 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1117 input_value += descriptor.output.value;
1118 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1120 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1122 previous_output: outpoint.into_bitcoin_outpoint(),
1123 script_sig: Script::new(),
1124 sequence: Sequence::ZERO,
1125 witness: Witness::new(),
1127 witness_weight += 1 + 73 + 34;
1128 input_value += output.value;
1129 if !output_set.insert(*outpoint) { return Err(()); }
1132 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
1134 let mut spend_tx = Transaction {
1136 lock_time: PackedLockTime(0),
1140 let expected_max_weight =
1141 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
1143 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1144 let mut input_idx = 0;
1145 for outp in descriptors {
1147 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1148 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1150 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1151 descriptor.channel_keys_id));
1153 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)?);
1155 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1156 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1158 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1159 descriptor.channel_keys_id));
1161 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)?);
1163 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
1164 let derivation_idx = if output.script_pubkey == self.destination_script {
1170 // Note that when we aren't serializing the key, network doesn't matter
1171 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1173 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1175 Err(_) => panic!("Your RNG is busted"),
1178 Err(_) => panic!("Your rng is busted"),
1181 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1182 if derivation_idx == 2 {
1183 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1185 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1186 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1188 if payment_script != output.script_pubkey { return Err(()); };
1190 let sighash = hash_to_message!(&sighash::SighashCache::new(&spend_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1191 let sig = sign(secp_ctx, &sighash, &secret.private_key);
1192 let mut sig_ser = sig.serialize_der().to_vec();
1193 sig_ser.push(EcdsaSighashType::All as u8);
1194 spend_tx.input[input_idx].witness.push(sig_ser);
1195 spend_tx.input[input_idx].witness.push(pubkey.inner.serialize().to_vec());
1201 debug_assert!(expected_max_weight >= spend_tx.weight());
1202 // Note that witnesses with a signature vary somewhat in size, so allow
1203 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1204 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1210 impl KeysInterface for KeysManager {
1211 type Signer = InMemorySigner;
1213 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1215 Recipient::Node => Ok(self.node_secret.clone()),
1216 Recipient::PhantomNode => Err(())
1220 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1222 Recipient::Node => Ok(self.node_id.clone()),
1223 Recipient::PhantomNode => Err(())
1227 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1228 let mut node_secret = self.get_node_secret(recipient)?;
1229 if let Some(tweak) = tweak {
1230 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1232 Ok(SharedSecret::new(other_key, &node_secret))
1235 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1236 self.inbound_payment_key.clone()
1239 fn get_destination_script(&self) -> Script {
1240 self.destination_script.clone()
1243 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1244 ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
1247 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1248 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1249 assert!(child_idx <= core::u32::MAX as usize);
1250 let mut id = [0; 32];
1251 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1252 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1253 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1254 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1258 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1259 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1262 fn get_secure_random_bytes(&self) -> [u8; 32] {
1263 let mut sha = self.rand_bytes_unique_start.clone();
1265 let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel);
1266 let child_privkey = self.rand_bytes_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
1267 sha.input(&child_privkey.private_key[..]);
1269 sha.input(b"Unique Secure Random Bytes Salt");
1270 Sha256::from_engine(sha).into_inner()
1273 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1274 InMemorySigner::read(&mut io::Cursor::new(reader), self.node_secret.clone())
1277 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1278 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1279 let secret = match recipient {
1280 Recipient::Node => self.get_node_secret(Recipient::Node)?,
1281 Recipient::PhantomNode => return Err(()),
1283 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1287 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1290 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1291 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1292 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1293 /// itself without ever needing to forward to this fake node.
1295 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1296 /// provide some fault tolerance, because payers will automatically retry paying other provided
1297 /// nodes in the case that one node goes down.
1299 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1300 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1301 // nodes to know when the full payment has been received (and the preimage can be released) without
1302 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1303 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1304 // is released too early.
1306 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1307 /// invoices and attempts to pay previous invoices will fail.
1308 pub struct PhantomKeysManager {
1310 inbound_payment_key: KeyMaterial,
1311 phantom_secret: SecretKey,
1312 phantom_node_id: PublicKey,
1315 impl KeysInterface for PhantomKeysManager {
1316 type Signer = InMemorySigner;
1318 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1320 Recipient::Node => self.inner.get_node_secret(Recipient::Node),
1321 Recipient::PhantomNode => Ok(self.phantom_secret.clone()),
1325 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1327 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1328 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1332 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1333 let mut node_secret = self.get_node_secret(recipient)?;
1334 if let Some(tweak) = tweak {
1335 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1337 Ok(SharedSecret::new(other_key, &node_secret))
1340 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1341 self.inbound_payment_key.clone()
1344 fn get_destination_script(&self) -> Script {
1345 self.inner.get_destination_script()
1348 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1349 self.inner.get_shutdown_scriptpubkey()
1352 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1353 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1356 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1357 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1360 fn get_secure_random_bytes(&self) -> [u8; 32] {
1361 self.inner.get_secure_random_bytes()
1364 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1365 self.inner.read_chan_signer(reader)
1368 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1369 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1370 let secret = self.get_node_secret(recipient)?;
1371 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1375 impl PhantomKeysManager {
1376 /// Constructs a `PhantomKeysManager` given a 32-byte seed and an additional `cross_node_seed`
1377 /// that is shared across all nodes that intend to participate in [phantom node payments] together.
1379 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1380 /// `starting_time_nanos`.
1382 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1383 /// same across restarts, or else inbound payments may fail.
1385 /// [phantom node payments]: PhantomKeysManager
1386 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1387 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1388 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1389 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1390 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1393 inbound_payment_key: KeyMaterial(inbound_key),
1399 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1400 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, ()> {
1401 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
1404 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1405 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1406 self.inner.derive_channel_keys(channel_value_satoshis, params)
1410 // Ensure that BaseSign can have a vtable
1413 let _signer: Box<dyn BaseSign>;