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, SigHashType};
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::bip143;
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::key::{SecretKey, PublicKey};
29 use bitcoin::secp256k1::{Secp256k1, Signature, Signing};
30 use bitcoin::secp256k1::recovery::RecoverableSignature;
31 use bitcoin::secp256k1;
33 use util::{byte_utils, transaction_utils};
34 use util::ser::{Writeable, Writer, Readable, ReadableArgs};
36 use chain::transaction::OutPoint;
37 use ln::{chan_utils, PaymentPreimage};
38 use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
39 use ln::msgs::UnsignedChannelAnnouncement;
40 use ln::script::ShutdownScript;
43 use core::sync::atomic::{AtomicUsize, Ordering};
44 use io::{self, Error};
45 use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
46 use util::invoice::construct_invoice_preimage;
48 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
49 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
50 /// (C-not exported) as we just use [u8; 32] directly
51 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
52 pub struct KeyMaterial(pub [u8; 32]);
54 /// Information about a spendable output to a P2WSH script. See
55 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
56 #[derive(Clone, Debug, PartialEq)]
57 pub struct DelayedPaymentOutputDescriptor {
58 /// The outpoint which is spendable
59 pub outpoint: OutPoint,
60 /// Per commitment point to derive delayed_payment_key by key holder
61 pub per_commitment_point: PublicKey,
62 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
63 /// the witness_script.
64 pub to_self_delay: u16,
65 /// The output which is referenced by the given outpoint
67 /// The revocation point specific to the commitment transaction which was broadcast. Used to
68 /// derive the witnessScript for this output.
69 pub revocation_pubkey: PublicKey,
70 /// Arbitrary identification information returned by a call to
71 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
72 /// the channel to spend the output.
73 pub channel_keys_id: [u8; 32],
74 /// The value of the channel which this output originated from, possibly indirectly.
75 pub channel_value_satoshis: u64,
77 impl DelayedPaymentOutputDescriptor {
78 /// The maximum length a well-formed witness spending one of these should have.
79 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
80 // redeemscript push length.
81 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
84 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
85 (0, outpoint, required),
86 (2, per_commitment_point, required),
87 (4, to_self_delay, required),
88 (6, output, required),
89 (8, revocation_pubkey, required),
90 (10, channel_keys_id, required),
91 (12, channel_value_satoshis, required),
94 /// Information about a spendable output to our "payment key". See
95 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
96 #[derive(Clone, Debug, PartialEq)]
97 pub struct StaticPaymentOutputDescriptor {
98 /// The outpoint which is spendable
99 pub outpoint: OutPoint,
100 /// The output which is referenced by the given outpoint
102 /// Arbitrary identification information returned by a call to
103 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
104 /// the channel to spend the output.
105 pub channel_keys_id: [u8; 32],
106 /// The value of the channel which this transactions spends.
107 pub channel_value_satoshis: u64,
109 impl StaticPaymentOutputDescriptor {
110 /// The maximum length a well-formed witness spending one of these should have.
111 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
112 // redeemscript push length.
113 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
115 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
116 (0, outpoint, required),
117 (2, output, required),
118 (4, channel_keys_id, required),
119 (6, channel_value_satoshis, required),
122 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
123 /// claim at any point in the future) an event is generated which you must track and be able to
124 /// spend on-chain. The information needed to do this is provided in this enum, including the
125 /// outpoint describing which txid and output index is available, the full output which exists at
126 /// that txid/index, and any keys or other information required to sign.
127 #[derive(Clone, Debug, PartialEq)]
128 pub enum SpendableOutputDescriptor {
129 /// An output to a script which was provided via KeysInterface directly, either from
130 /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
131 /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
132 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
133 /// on-chain using the payment preimage or after it has timed out.
135 /// The outpoint which is spendable
137 /// The output which is referenced by the given outpoint.
140 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
142 /// The witness in the spending input should be:
143 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
145 /// Note that the nSequence field in the spending input must be set to to_self_delay
146 /// (which means the transaction is not broadcastable until at least to_self_delay
147 /// blocks after the outpoint confirms).
149 /// These are generally the result of a "revocable" output to us, spendable only by us unless
150 /// it is an output from an old state which we broadcast (which should never happen).
152 /// To derive the delayed_payment key which is used to sign for this input, you must pass the
153 /// holder delayed_payment_base_key (ie the private key which corresponds to the pubkey in
154 /// Sign::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
155 /// chan_utils::derive_private_key. The public key can be generated without the secret key
156 /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
159 /// To derive the revocation_pubkey provided here (which is used in the witness
160 /// script generation), you must pass the counterparty revocation_basepoint (which appears in the
161 /// call to Sign::ready_channel) and the provided per_commitment point
162 /// to chan_utils::derive_public_revocation_key.
164 /// The witness script which is hashed and included in the output script_pubkey may be
165 /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
166 /// (derived as above), and the to_self_delay contained here to
167 /// chan_utils::get_revokeable_redeemscript.
168 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
169 /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
170 /// corresponds to the public key in Sign::pubkeys().payment_point).
171 /// The witness in the spending input, is, thus, simply:
172 /// <BIP 143 signature> <payment key>
174 /// These are generally the result of our counterparty having broadcast the current state,
175 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
176 StaticPaymentOutput(StaticPaymentOutputDescriptor),
179 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
180 (0, StaticOutput) => {
181 (0, outpoint, required),
182 (2, output, required),
185 (1, DelayedPaymentOutput),
186 (2, StaticPaymentOutput),
189 /// A trait to sign lightning channel transactions as described in BOLT 3.
191 /// Signing services could be implemented on a hardware wallet. In this case,
192 /// the current Sign would be a front-end on top of a communication
193 /// channel connected to your secure device and lightning key material wouldn't
194 /// reside on a hot server. Nevertheless, a this deployment would still need
195 /// to trust the ChannelManager to avoid loss of funds as this latest component
196 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
198 /// A more secure iteration would be to use hashlock (or payment points) to pair
199 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
200 /// at the price of more state and computation on the hardware wallet side. In the future,
201 /// we are looking forward to design such interface.
203 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
204 /// to act, as liveness and breach reply correctness are always going to be hard requirements
205 /// of LN security model, orthogonal of key management issues.
206 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
207 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
209 /// Gets the per-commitment point for a specific commitment number
211 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
212 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
213 /// Gets the commitment secret for a specific commitment number as part of the revocation process
215 /// An external signer implementation should error here if the commitment was already signed
216 /// and should refuse to sign it in the future.
218 /// May be called more than once for the same index.
220 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
221 // TODO: return a Result so we can signal a validation error
222 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
223 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
225 /// This is required in order for the signer to make sure that releasing a commitment
226 /// secret won't leave us without a broadcastable holder transaction.
227 /// Policy checks should be implemented in this function, including checking the amount
228 /// sent to us and checking the HTLCs.
230 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
231 /// A validating signer should ensure that an HTLC output is removed only when the matching
232 /// preimage is provided, or when the value to holder is restored.
234 /// NOTE: all the relevant preimages will be provided, but there may also be additional
235 /// irrelevant or duplicate preimages.
236 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
237 /// Gets the holder's channel public keys and basepoints
238 fn pubkeys(&self) -> &ChannelPublicKeys;
239 /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
240 /// some SpendableOutputDescriptor types. This should be sufficient to identify this
241 /// Sign object uniquely and lookup or re-derive its keys.
242 fn channel_keys_id(&self) -> [u8; 32];
244 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
246 /// Note that if signing fails or is rejected, the channel will be force-closed.
248 /// Policy checks should be implemented in this function, including checking the amount
249 /// sent to us and checking the HTLCs.
251 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
252 /// A validating signer should ensure that an HTLC output is removed only when the matching
253 /// preimage is provided, or when the value to holder is restored.
255 /// NOTE: all the relevant preimages will be provided, but there may also be additional
256 /// irrelevant or duplicate preimages.
258 // TODO: Document the things someone using this interface should enforce before signing.
259 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
260 /// Validate the counterparty's revocation.
262 /// This is required in order for the signer to make sure that the state has moved
263 /// forward and it is safe to sign the next counterparty commitment.
264 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
266 /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
267 /// This will only ever be called with a non-revoked commitment_tx. This will be called with the
268 /// latest commitment_tx when we initiate a force-close.
269 /// This will be called with the previous latest, just to get claiming HTLC signatures, if we are
270 /// reacting to a ChannelMonitor replica that decided to broadcast before it had been updated to
272 /// This may be called multiple times for the same transaction.
274 /// An external signer implementation should check that the commitment has not been revoked.
276 /// May return Err if key derivation fails. Callers, such as ChannelMonitor, will panic in such a case.
278 // TODO: Document the things someone using this interface should enforce before signing.
279 // TODO: Key derivation failure should panic rather than Err
280 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
282 /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment
283 /// transactions which will be broadcasted later, after the channel has moved on to a newer
284 /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever
286 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
287 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
289 /// Create a signature for the given input in a transaction spending an HTLC transaction output
290 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
292 /// A justice transaction may claim multiple outputs at the same time if timelocks are
293 /// similar, but only a signature for the input at index `input` should be signed for here.
294 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
295 /// to an upcoming timelock expiration.
297 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
299 /// per_commitment_key is revocation secret which was provided by our counterparty when they
300 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
301 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
303 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
305 /// Create a signature for the given input in a transaction spending a commitment transaction
306 /// HTLC output when our counterparty broadcasts an old state.
308 /// A justice transaction may claim multiple outputs at the same time if timelocks are
309 /// similar, but only a signature for the input at index `input` should be signed for here.
310 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
311 /// to an upcoming timelock expiration.
313 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
315 /// per_commitment_key is revocation secret which was provided by our counterparty when they
316 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
317 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
320 /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
321 /// (which is committed to in the BIP 143 signatures).
322 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, ()>;
324 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
325 /// transaction, either offered or received.
327 /// Such a transaction may claim multiples offered outputs at same time if we know the
328 /// preimage for each when we create it, but only the input at index `input` should be
329 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
330 /// needed with regards to an upcoming timelock expiration.
332 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
335 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
337 /// Per_commitment_point is the dynamic point corresponding to the channel state
338 /// detected onchain. It has been generated by our counterparty and is used to derive
339 /// channel state keys, which are then included in the witness script and committed to in the
340 /// BIP 143 signature.
341 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, ()>;
343 /// Create a signature for a (proposed) closing transaction.
345 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
346 /// chosen to forgo their output as dust.
347 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
349 /// Signs a channel announcement message with our funding key and our node secret key (aka
350 /// node_id or network_key), proving it comes from one of the channel participants.
352 /// The first returned signature should be from our node secret key, the second from our
355 /// Note that if this fails or is rejected, the channel will not be publicly announced and
356 /// our counterparty may (though likely will not) close the channel on us for violating the
358 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
359 -> Result<(Signature, Signature), ()>;
361 /// Set the counterparty static channel data, including basepoints,
362 /// counterparty_selected/holder_selected_contest_delay and funding outpoint.
363 /// This is done as soon as the funding outpoint is known. Since these are static channel data,
364 /// they MUST NOT be allowed to change to different values once set.
366 /// channel_parameters.is_populated() MUST be true.
368 /// We bind holder_selected_contest_delay late here for API convenience.
370 /// Will be called before any signatures are applied.
371 fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters);
374 /// A cloneable signer.
376 /// Although we require signers to be cloneable, it may be useful for developers to be able to use
377 /// signers in an un-sized way, for example as `dyn BaseSign`. Therefore we separate the Clone trait,
378 /// which implies Sized, into this derived trait.
379 pub trait Sign: BaseSign + Writeable + Clone {
382 /// A trait to describe an object which can get user secrets and key material.
383 pub trait KeysInterface {
384 /// A type which implements Sign which will be returned by get_channel_signer.
387 /// Get node secret key (aka node_id or network_key).
389 /// This method must return the same value each time it is called.
390 fn get_node_secret(&self) -> SecretKey;
391 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
393 /// This method should return a different value each time it is called, to avoid linking
394 /// on-chain funds across channels as controlled to the same user.
395 fn get_destination_script(&self) -> Script;
396 /// Get a script pubkey which we will send funds to when closing a channel.
398 /// This method should return a different value each time it is called, to avoid linking
399 /// on-chain funds across channels as controlled to the same user.
400 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
401 /// Get a new set of Sign for per-channel secrets. These MUST be unique even if you
402 /// restarted with some stale data!
404 /// This method must return a different value each time it is called.
405 fn get_channel_signer(&self, inbound: bool, channel_value_satoshis: u64) -> Self::Signer;
406 /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting
407 /// onion packets and for temporary channel IDs. There is no requirement that these be
408 /// persisted anywhere, though they must be unique across restarts.
410 /// This method must return a different value each time it is called.
411 fn get_secure_random_bytes(&self) -> [u8; 32];
413 /// Reads a `Signer` for this `KeysInterface` from the given input stream.
414 /// This is only called during deserialization of other objects which contain
415 /// `Sign`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s).
416 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
417 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
418 /// you've read all of the provided bytes to ensure no corruption occurred.
419 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
422 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
423 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
424 /// blindly signing the hash.
425 /// The hrp is ascii bytes, while the invoice data is base32.
426 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5]) -> Result<RecoverableSignature, ()>;
428 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
430 /// This method must return the same value each time it is called.
431 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
435 /// A simple implementation of Sign that just keeps the private keys in memory.
437 /// This implementation performs no policy checks and is insufficient by itself as
438 /// a secure external signer.
439 pub struct InMemorySigner {
440 /// Private key of anchor tx
441 pub funding_key: SecretKey,
442 /// Holder secret key for blinded revocation pubkey
443 pub revocation_base_key: SecretKey,
444 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions
445 pub payment_key: SecretKey,
446 /// Holder secret key used in HTLC tx
447 pub delayed_payment_base_key: SecretKey,
448 /// Holder htlc secret key used in commitment tx htlc outputs
449 pub htlc_base_key: SecretKey,
451 pub commitment_seed: [u8; 32],
452 /// Holder public keys and basepoints
453 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
454 /// Private key of our node secret, used for signing channel announcements
455 node_secret: SecretKey,
456 /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance
457 channel_parameters: Option<ChannelTransactionParameters>,
458 /// The total value of this channel
459 channel_value_satoshis: u64,
460 /// Key derivation parameters
461 channel_keys_id: [u8; 32],
464 impl InMemorySigner {
465 /// Create a new InMemorySigner
466 pub fn new<C: Signing>(
467 secp_ctx: &Secp256k1<C>,
468 node_secret: SecretKey,
469 funding_key: SecretKey,
470 revocation_base_key: SecretKey,
471 payment_key: SecretKey,
472 delayed_payment_base_key: SecretKey,
473 htlc_base_key: SecretKey,
474 commitment_seed: [u8; 32],
475 channel_value_satoshis: u64,
476 channel_keys_id: [u8; 32]) -> InMemorySigner {
477 let holder_channel_pubkeys =
478 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
479 &payment_key, &delayed_payment_base_key,
485 delayed_payment_base_key,
489 channel_value_satoshis,
490 holder_channel_pubkeys,
491 channel_parameters: None,
496 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
497 funding_key: &SecretKey,
498 revocation_base_key: &SecretKey,
499 payment_key: &SecretKey,
500 delayed_payment_base_key: &SecretKey,
501 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
502 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
504 funding_pubkey: from_secret(&funding_key),
505 revocation_basepoint: from_secret(&revocation_base_key),
506 payment_point: from_secret(&payment_key),
507 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
508 htlc_basepoint: from_secret(&htlc_base_key),
512 /// Counterparty pubkeys.
513 /// Will panic if ready_channel wasn't called.
514 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
516 /// The contest_delay value specified by our counterparty and applied on holder-broadcastable
517 /// transactions, ie the amount of time that we have to wait to recover our funds if we
518 /// broadcast a transaction.
519 /// Will panic if ready_channel wasn't called.
520 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
522 /// The contest_delay value specified by us and applied on transactions broadcastable
523 /// by our counterparty, ie the amount of time that they have to wait to recover their funds
524 /// if they broadcast a transaction.
525 /// Will panic if ready_channel wasn't called.
526 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
528 /// Whether the holder is the initiator
529 /// Will panic if ready_channel wasn't called.
530 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
533 /// Will panic if ready_channel wasn't called.
534 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
536 /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or
537 /// building transactions.
539 /// Will panic if ready_channel wasn't called.
540 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
541 self.channel_parameters.as_ref().unwrap()
544 /// Whether anchors should be used.
545 /// Will panic if ready_channel wasn't called.
546 pub fn opt_anchors(&self) -> bool {
547 self.get_channel_parameters().opt_anchors.is_some()
550 /// Sign the single input of spend_tx at index `input_idx` which spends the output
551 /// described by descriptor, returning the witness stack for the input.
553 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
554 /// is not spending the outpoint described by `descriptor.outpoint`,
555 /// or if an output descriptor script_pubkey does not match the one we can spend.
556 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>>, ()> {
557 // TODO: We really should be taking the SigHashCache as a parameter here instead of
558 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
559 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
560 // bindings updates to support SigHashCache objects).
561 if spend_tx.input.len() <= input_idx { return Err(()); }
562 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
563 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
565 let remotepubkey = self.pubkeys().payment_point;
566 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, key: remotepubkey}, Network::Testnet).script_pubkey();
567 let sighash = hash_to_message!(&bip143::SigHashCache::new(spend_tx).signature_hash(input_idx, &witness_script, descriptor.output.value, SigHashType::All)[..]);
568 let remotesig = secp_ctx.sign(&sighash, &self.payment_key);
569 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, key: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
571 if payment_script != descriptor.output.script_pubkey { return Err(()); }
573 let mut witness = Vec::with_capacity(2);
574 witness.push(remotesig.serialize_der().to_vec());
575 witness[0].push(SigHashType::All as u8);
576 witness.push(remotepubkey.serialize().to_vec());
580 /// Sign the single input of spend_tx at index `input_idx` which spends the output
581 /// described by descriptor, returning the witness stack for the input.
583 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
584 /// is not spending the outpoint described by `descriptor.outpoint`, does not have a
585 /// sequence set to `descriptor.to_self_delay`, or if an output descriptor
586 /// script_pubkey does not match the one we can spend.
587 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>>, ()> {
588 // TODO: We really should be taking the SigHashCache as a parameter here instead of
589 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
590 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
591 // bindings updates to support SigHashCache objects).
592 if spend_tx.input.len() <= input_idx { return Err(()); }
593 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
594 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
595 if spend_tx.input[input_idx].sequence != descriptor.to_self_delay as u32 { return Err(()); }
597 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key)
598 .expect("We constructed the payment_base_key, so we can only fail here if the RNG is busted.");
599 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
600 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
601 let sighash = hash_to_message!(&bip143::SigHashCache::new(spend_tx).signature_hash(input_idx, &witness_script, descriptor.output.value, SigHashType::All)[..]);
602 let local_delayedsig = secp_ctx.sign(&sighash, &delayed_payment_key);
603 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
605 if descriptor.output.script_pubkey != payment_script { return Err(()); }
607 let mut witness = Vec::with_capacity(3);
608 witness.push(local_delayedsig.serialize_der().to_vec());
609 witness[0].push(SigHashType::All as u8);
610 witness.push(vec!()); //MINIMALIF
611 witness.push(witness_script.clone().into_bytes());
616 impl BaseSign for InMemorySigner {
617 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
618 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
619 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
622 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
623 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
626 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
630 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
631 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
633 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
634 let trusted_tx = commitment_tx.trust();
635 let keys = trusted_tx.keys();
637 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
638 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
640 let built_tx = trusted_tx.built_transaction();
641 let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
642 let commitment_txid = built_tx.txid;
644 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
645 for htlc in commitment_tx.htlcs() {
646 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, self.opt_anchors(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
647 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
648 let htlc_sighashtype = if self.opt_anchors() { SigHashType::SinglePlusAnyoneCanPay } else { SigHashType::All };
649 let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype)[..]);
650 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?;
651 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &holder_htlc_key));
654 Ok((commitment_sig, htlc_sigs))
657 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
661 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
662 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
663 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
664 let trusted_tx = commitment_tx.trust();
665 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
666 let channel_parameters = self.get_channel_parameters();
667 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
671 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
672 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
673 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
674 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
675 let trusted_tx = commitment_tx.trust();
676 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
677 let channel_parameters = self.get_channel_parameters();
678 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
682 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
683 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
684 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
685 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
686 let witness_script = {
687 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?;
688 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
690 let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
691 let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
692 return Ok(secp_ctx.sign(&sighash, &revocation_key))
695 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, ()> {
696 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
697 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
698 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
699 let witness_script = {
700 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?;
701 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?;
702 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
704 let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
705 let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
706 return Ok(secp_ctx.sign(&sighash, &revocation_key))
709 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, ()> {
710 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
711 let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
712 if let Ok(counterparty_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) {
713 if let Ok(htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
714 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey)
715 } else { return Err(()) }
716 } else { return Err(()) }
717 } else { return Err(()) };
718 let mut sighash_parts = bip143::SigHashCache::new(htlc_tx);
719 let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
720 return Ok(secp_ctx.sign(&sighash, &htlc_key))
725 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
726 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
727 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
728 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
731 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
732 -> Result<(Signature, Signature), ()> {
733 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
734 Ok((secp_ctx.sign(&msghash, &self.node_secret), secp_ctx.sign(&msghash, &self.funding_key)))
737 fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters) {
738 assert!(self.channel_parameters.is_none(), "Acceptance already noted");
739 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
740 self.channel_parameters = Some(channel_parameters.clone());
744 const SERIALIZATION_VERSION: u8 = 1;
745 const MIN_SERIALIZATION_VERSION: u8 = 1;
747 impl Sign for InMemorySigner {}
749 impl Writeable for InMemorySigner {
750 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
751 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
753 self.funding_key.write(writer)?;
754 self.revocation_base_key.write(writer)?;
755 self.payment_key.write(writer)?;
756 self.delayed_payment_base_key.write(writer)?;
757 self.htlc_base_key.write(writer)?;
758 self.commitment_seed.write(writer)?;
759 self.channel_parameters.write(writer)?;
760 self.channel_value_satoshis.write(writer)?;
761 self.channel_keys_id.write(writer)?;
763 write_tlv_fields!(writer, {});
769 impl ReadableArgs<SecretKey> for InMemorySigner {
770 fn read<R: io::Read>(reader: &mut R, node_secret: SecretKey) -> Result<Self, DecodeError> {
771 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
773 let funding_key = Readable::read(reader)?;
774 let revocation_base_key = Readable::read(reader)?;
775 let payment_key = Readable::read(reader)?;
776 let delayed_payment_base_key = Readable::read(reader)?;
777 let htlc_base_key = Readable::read(reader)?;
778 let commitment_seed = Readable::read(reader)?;
779 let counterparty_channel_data = Readable::read(reader)?;
780 let channel_value_satoshis = Readable::read(reader)?;
781 let secp_ctx = Secp256k1::signing_only();
782 let holder_channel_pubkeys =
783 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
784 &payment_key, &delayed_payment_base_key,
786 let keys_id = Readable::read(reader)?;
788 read_tlv_fields!(reader, {});
794 delayed_payment_base_key,
798 channel_value_satoshis,
799 holder_channel_pubkeys,
800 channel_parameters: counterparty_channel_data,
801 channel_keys_id: keys_id,
806 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
807 /// and derives keys from that.
809 /// Your node_id is seed/0'
810 /// ChannelMonitor closes may use seed/1'
811 /// Cooperative closes may use seed/2'
812 /// The two close keys may be needed to claim on-chain funds!
813 pub struct KeysManager {
814 secp_ctx: Secp256k1<secp256k1::All>,
815 node_secret: SecretKey,
816 inbound_payment_key: KeyMaterial,
817 destination_script: Script,
818 shutdown_pubkey: PublicKey,
819 channel_master_key: ExtendedPrivKey,
820 channel_child_index: AtomicUsize,
822 rand_bytes_master_key: ExtendedPrivKey,
823 rand_bytes_child_index: AtomicUsize,
824 rand_bytes_unique_start: Sha256State,
827 starting_time_secs: u64,
828 starting_time_nanos: u32,
832 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
833 /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
834 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
835 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
836 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
837 /// simply use the current time (with very high precision).
839 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
840 /// obviously, starting_time should be unique every time you reload the library - it is only
841 /// used to generate new ephemeral key data (which will be stored by the individual channel if
844 /// Note that the seed is required to recover certain on-chain funds independent of
845 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
846 /// channel, and some on-chain during-closing funds.
848 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
849 /// versions. Once the library is more fully supported, the docs will be updated to include a
850 /// detailed description of the guarantee.
851 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
852 let secp_ctx = Secp256k1::new();
853 // Note that when we aren't serializing the key, network doesn't matter
854 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
856 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
857 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
858 Ok(destination_key) => {
859 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
860 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
861 .push_slice(&wpubkey_hash.into_inner())
864 Err(_) => panic!("Your RNG is busted"),
866 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
867 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
868 Err(_) => panic!("Your RNG is busted"),
870 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
871 let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
872 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key.key;
873 let mut inbound_pmt_key_bytes = [0; 32];
874 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
876 let mut rand_bytes_unique_start = Sha256::engine();
877 rand_bytes_unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
878 rand_bytes_unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
879 rand_bytes_unique_start.input(seed);
881 let mut res = KeysManager {
884 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
890 channel_child_index: AtomicUsize::new(0),
892 rand_bytes_master_key,
893 rand_bytes_child_index: AtomicUsize::new(0),
894 rand_bytes_unique_start,
900 let secp_seed = res.get_secure_random_bytes();
901 res.secp_ctx.seeded_randomize(&secp_seed);
904 Err(_) => panic!("Your rng is busted"),
907 /// Derive an old Sign containing per-channel secrets based on a key derivation parameters.
909 /// Key derivation parameters are accessible through a per-channel secrets
910 /// Sign::channel_keys_id and is provided inside DynamicOuputP2WSH in case of
911 /// onchain output detection for which a corresponding delayed_payment_key must be derived.
912 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
913 let chan_id = byte_utils::slice_to_be64(¶ms[0..8]);
914 assert!(chan_id <= core::u32::MAX as u64); // Otherwise the params field wasn't created by us
915 let mut unique_start = Sha256::engine();
916 unique_start.input(params);
917 unique_start.input(&self.seed);
919 // We only seriously intend to rely on the channel_master_key for true secure
920 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
921 // starting_time provided in the constructor) to be unique.
922 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");
923 unique_start.input(&child_privkey.private_key.key[..]);
925 let seed = Sha256::from_engine(unique_start).into_inner();
927 let commitment_seed = {
928 let mut sha = Sha256::engine();
930 sha.input(&b"commitment seed"[..]);
931 Sha256::from_engine(sha).into_inner()
933 macro_rules! key_step {
934 ($info: expr, $prev_key: expr) => {{
935 let mut sha = Sha256::engine();
937 sha.input(&$prev_key[..]);
938 sha.input(&$info[..]);
939 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
942 let funding_key = key_step!(b"funding key", commitment_seed);
943 let revocation_base_key = key_step!(b"revocation base key", funding_key);
944 let payment_key = key_step!(b"payment key", revocation_base_key);
945 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
946 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
954 delayed_payment_base_key,
957 channel_value_satoshis,
962 /// Creates a Transaction which spends the given descriptors to the given outputs, plus an
963 /// output to the given change destination (if sufficient change value remains). The
964 /// transaction will have a feerate, at least, of the given value.
966 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
967 /// if a descriptor was duplicated, or if an output descriptor script_pubkey
968 /// does not match the one we can spend.
970 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
972 /// May panic if the `SpendableOutputDescriptor`s were not generated by Channels which used
973 /// this KeysManager or one of the `InMemorySigner` created by this KeysManager.
974 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, ()> {
975 let mut input = Vec::new();
976 let mut input_value = 0;
977 let mut witness_weight = 0;
978 let mut output_set = HashSet::with_capacity(descriptors.len());
979 for outp in descriptors {
981 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
983 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
984 script_sig: Script::new(),
988 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
989 input_value += descriptor.output.value;
990 if !output_set.insert(descriptor.outpoint) { return Err(()); }
992 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
994 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
995 script_sig: Script::new(),
996 sequence: descriptor.to_self_delay as u32,
999 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1000 input_value += descriptor.output.value;
1001 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1003 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1005 previous_output: outpoint.into_bitcoin_outpoint(),
1006 script_sig: Script::new(),
1008 witness: Vec::new(),
1010 witness_weight += 1 + 73 + 34;
1011 input_value += output.value;
1012 if !output_set.insert(*outpoint) { return Err(()); }
1015 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
1017 let mut spend_tx = Transaction {
1023 let expected_max_weight =
1024 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
1026 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1027 let mut input_idx = 0;
1028 for outp in descriptors {
1030 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1031 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1033 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1034 descriptor.channel_keys_id));
1036 spend_tx.input[input_idx].witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?;
1038 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1039 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1041 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1042 descriptor.channel_keys_id));
1044 spend_tx.input[input_idx].witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?;
1046 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
1047 let derivation_idx = if output.script_pubkey == self.destination_script {
1053 // Note that when we aren't serializing the key, network doesn't matter
1054 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1056 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1058 Err(_) => panic!("Your RNG is busted"),
1061 Err(_) => panic!("Your rng is busted"),
1064 let pubkey = ExtendedPubKey::from_private(&secp_ctx, &secret).public_key;
1065 if derivation_idx == 2 {
1066 assert_eq!(pubkey.key, self.shutdown_pubkey);
1068 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1069 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1071 if payment_script != output.script_pubkey { return Err(()); };
1073 let sighash = hash_to_message!(&bip143::SigHashCache::new(&spend_tx).signature_hash(input_idx, &witness_script, output.value, SigHashType::All)[..]);
1074 let sig = secp_ctx.sign(&sighash, &secret.private_key.key);
1075 spend_tx.input[input_idx].witness.push(sig.serialize_der().to_vec());
1076 spend_tx.input[input_idx].witness[0].push(SigHashType::All as u8);
1077 spend_tx.input[input_idx].witness.push(pubkey.key.serialize().to_vec());
1083 debug_assert!(expected_max_weight >= spend_tx.get_weight());
1084 // Note that witnesses with a signature vary somewhat in size, so allow
1085 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1086 debug_assert!(expected_max_weight <= spend_tx.get_weight() + descriptors.len() * 3);
1092 impl KeysInterface for KeysManager {
1093 type Signer = InMemorySigner;
1095 fn get_node_secret(&self) -> SecretKey {
1096 self.node_secret.clone()
1099 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1100 self.inbound_payment_key.clone()
1103 fn get_destination_script(&self) -> Script {
1104 self.destination_script.clone()
1107 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1108 ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
1111 fn get_channel_signer(&self, _inbound: bool, channel_value_satoshis: u64) -> Self::Signer {
1112 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1113 assert!(child_ix <= core::u32::MAX as usize);
1114 let mut id = [0; 32];
1115 id[0..8].copy_from_slice(&byte_utils::be64_to_array(child_ix as u64));
1116 id[8..16].copy_from_slice(&byte_utils::be64_to_array(self.starting_time_nanos as u64));
1117 id[16..24].copy_from_slice(&byte_utils::be64_to_array(self.starting_time_secs));
1118 self.derive_channel_keys(channel_value_satoshis, &id)
1121 fn get_secure_random_bytes(&self) -> [u8; 32] {
1122 let mut sha = self.rand_bytes_unique_start.clone();
1124 let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel);
1125 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");
1126 sha.input(&child_privkey.private_key.key[..]);
1128 sha.input(b"Unique Secure Random Bytes Salt");
1129 Sha256::from_engine(sha).into_inner()
1132 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1133 InMemorySigner::read(&mut io::Cursor::new(reader), self.get_node_secret())
1136 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5]) -> Result<RecoverableSignature, ()> {
1137 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1138 Ok(self.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &self.get_node_secret()))
1142 // Ensure that BaseSign can have a vtable
1145 let _signer: Box<dyn BaseSign>;