1 //! keysinterface provides keys into rust-lightning and defines some useful enums which describe
2 //! spendable on-chain outputs which the user owns and is responsible for using just as any other
3 //! on-chain output which is theirs.
5 use bitcoin::blockdata::transaction::{Transaction, OutPoint, TxOut};
6 use bitcoin::blockdata::script::{Script, Builder};
7 use bitcoin::blockdata::opcodes;
8 use bitcoin::network::constants::Network;
9 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
10 use bitcoin::util::bip143;
12 use bitcoin::hashes::{Hash, HashEngine};
13 use bitcoin::hashes::sha256::HashEngine as Sha256State;
14 use bitcoin::hashes::sha256::Hash as Sha256;
15 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
16 use bitcoin::hash_types::WPubkeyHash;
18 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
19 use bitcoin::secp256k1::{Secp256k1, Signature, Signing};
20 use bitcoin::secp256k1;
23 use util::ser::{Writeable, Writer, Readable};
26 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction};
28 use ln::channelmanager::PaymentPreimage;
30 use std::sync::atomic::{AtomicUsize, Ordering};
32 use ln::msgs::DecodeError;
34 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
35 /// claim at any point in the future) an event is generated which you must track and be able to
36 /// spend on-chain. The information needed to do this is provided in this enum, including the
37 /// outpoint describing which txid and output index is available, the full output which exists at
38 /// that txid/index, and any keys or other information required to sign.
39 #[derive(Clone, PartialEq)]
40 pub enum SpendableOutputDescriptor {
41 /// An output to a script which was provided via KeysInterface, thus you should already know
42 /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the
43 /// script_pubkey as it appears in the output.
44 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
45 /// on-chain using the payment preimage or after it has timed out.
47 /// The outpoint which is spendable
49 /// The output which is referenced by the given outpoint.
52 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
54 /// The witness in the spending input should be:
55 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
57 /// Note that the nSequence field in the spending input must be set to to_self_delay
58 /// (which means the transaction not being broadcastable until at least to_self_delay
59 /// blocks after the outpoint confirms).
61 /// These are generally the result of a "revocable" output to us, spendable only by us unless
62 /// it is an output from us having broadcast an old state (which should never happen).
64 /// WitnessScript may be regenerated by passing the revocation_pubkey, to_self_delay and
65 /// delayed_payment_pubkey to chan_utils::get_revokeable_redeemscript.
67 /// To derive the delayed_payment key corresponding to the channel state, you must pass the
68 /// channel's delayed_payment_key and the provided per_commitment_point to
69 /// chan_utils::derive_private_key. The resulting key should be used to sign the spending
72 /// The outpoint which is spendable
74 /// Per commitment point to derive delayed_payment_key by key holder
75 per_commitment_point: PublicKey,
76 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
77 /// the witness_script.
79 /// The output which is referenced by the given outpoint
81 /// The channel keys state used to proceed to derivation of signing key. Must
82 /// be pass to KeysInterface::derive_channel_keys.
83 key_derivation_params: (u64, u64),
84 /// The remote_revocation_pubkey used to derive witnessScript
85 remote_revocation_pubkey: PublicKey
87 // TODO: Note that because key is now static and exactly what is provided by us, we should drop
88 // this in favor of StaticOutput:
89 /// An output to a P2WPKH, spendable exclusively by the given private key.
90 /// The witness in the spending input, is, thus, simply:
91 /// <BIP 143 signature> <payment key>
93 /// These are generally the result of our counterparty having broadcast the current state,
94 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
96 /// To derive the payment key corresponding to the channel state, you must pass the
97 /// channel's payment_base_key and the provided per_commitment_point to
98 /// chan_utils::derive_private_key. The resulting key should be used to sign the spending
100 DynamicOutputP2WPKH {
101 /// The outpoint which is spendable
103 /// The output which is reference by the given outpoint
105 /// The channel keys state used to proceed to derivation of signing key. Must
106 /// be pass to KeysInterface::derive_channel_keys.
107 key_derivation_params: (u64, u64),
111 impl Writeable for SpendableOutputDescriptor {
112 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
114 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
116 outpoint.write(writer)?;
117 output.write(writer)?;
119 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref per_commitment_point, ref to_self_delay, ref output, ref key_derivation_params, ref remote_revocation_pubkey } => {
121 outpoint.write(writer)?;
122 per_commitment_point.write(writer)?;
123 to_self_delay.write(writer)?;
124 output.write(writer)?;
125 key_derivation_params.0.write(writer)?;
126 key_derivation_params.1.write(writer)?;
127 remote_revocation_pubkey.write(writer)?;
129 &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref output, ref key_derivation_params } => {
131 outpoint.write(writer)?;
132 output.write(writer)?;
133 key_derivation_params.0.write(writer)?;
134 key_derivation_params.1.write(writer)?;
141 impl Readable for SpendableOutputDescriptor {
142 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
143 match Readable::read(reader)? {
144 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
145 outpoint: Readable::read(reader)?,
146 output: Readable::read(reader)?,
148 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
149 outpoint: Readable::read(reader)?,
150 per_commitment_point: Readable::read(reader)?,
151 to_self_delay: Readable::read(reader)?,
152 output: Readable::read(reader)?,
153 key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?),
154 remote_revocation_pubkey: Readable::read(reader)?,
156 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH {
157 outpoint: Readable::read(reader)?,
158 output: Readable::read(reader)?,
159 key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?),
161 _ => Err(DecodeError::InvalidValue),
166 /// A trait to describe an object which can get user secrets and key material.
167 pub trait KeysInterface: Send + Sync {
168 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
169 type ChanKeySigner : ChannelKeys;
171 /// Get node secret key (aka node_id or network_key)
172 fn get_node_secret(&self) -> SecretKey;
173 /// Get destination redeemScript to encumber static protocol exit points.
174 fn get_destination_script(&self) -> Script;
175 /// Get shutdown_pubkey to use as PublicKey at channel closure
176 fn get_shutdown_pubkey(&self) -> PublicKey;
177 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
178 /// restarted with some stale data!
179 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
180 /// Get a secret and PRNG seed for construting an onion packet
181 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
182 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
183 /// transaction is created, at which point they will use the outpoint in the funding
185 fn get_channel_id(&self) -> [u8; 32];
188 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
190 /// Signing services could be implemented on a hardware wallet. In this case,
191 /// the current ChannelKeys would be a front-end on top of a communication
192 /// channel connected to your secure device and lightning key material wouldn't
193 /// reside on a hot server. Nevertheless, a this deployment would still need
194 /// to trust the ChannelManager to avoid loss of funds as this latest component
195 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
197 /// A more secure iteration would be to use hashlock (or payment points) to pair
198 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
199 /// at the price of more state and computation on the hardware wallet side. In the future,
200 /// we are looking forward to design such interface.
202 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
203 /// to act, as liveness and breach reply correctness are always going to be hard requirements
204 /// of LN security model, orthogonal of key management issues.
206 /// If you're implementing a custom signer, you almost certainly want to implement
207 /// Readable/Writable to serialize out a unique reference to this set of keys so
208 /// that you can serialize the full ChannelManager object.
210 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
211 // to the possibility of reentrancy issues by calling the user's code during our deserialization
213 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
214 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
215 pub trait ChannelKeys : Send+Clone {
216 /// Gets the private key for the anchor tx
217 fn funding_key<'a>(&'a self) -> &'a SecretKey;
218 /// Gets the local secret key for blinded revocation pubkey
219 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
220 /// Gets the local secret key used in the to_remote output of remote commitment tx (ie the
221 /// output to us in transactions our counterparty broadcasts).
222 /// Also as part of obscured commitment number.
223 fn payment_key<'a>(&'a self) -> &'a SecretKey;
224 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
225 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
226 /// Gets the local htlc secret key used in commitment tx htlc outputs
227 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
228 /// Gets the commitment seed
229 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
230 /// Gets the local channel public keys and basepoints
231 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
232 /// Gets arbitrary identifiers describing the set of keys which are provided back to you in
233 /// some SpendableOutputDescriptor types. These should be sufficient to identify this
234 /// ChannelKeys object uniquely and lookup or re-derive its keys.
235 fn key_derivation_params(&self) -> (u64, u64);
237 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
239 /// Note that if signing fails or is rejected, the channel will be force-closed.
241 // TODO: Document the things someone using this interface should enforce before signing.
242 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
243 // making the callee generate it via some util function we expose)!
244 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
246 /// Create a signature for a local commitment transaction. This will only ever be called with
247 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
248 /// that it will not be called multiple times.
250 // TODO: Document the things someone using this interface should enforce before signing.
251 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
252 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
254 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
255 /// transactions which will be broadcasted later, after the channel has moved on to a newer
256 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
259 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
261 /// Create a signature for each HTLC transaction spending a local commitment transaction.
263 /// Unlike sign_local_commitment, this may be called multiple times with *different*
264 /// local_commitment_tx values. While this will never be called with a revoked
265 /// local_commitment_tx, it is possible that it is called with the second-latest
266 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
267 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
269 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
270 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
271 /// (implying they were considered dust at the time the commitment transaction was negotiated),
272 /// a corresponding None should be included in the return value. All other positions in the
273 /// return value must contain a signature.
274 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()>;
276 /// Create a signature for a transaction spending an HTLC or commitment transaction output
277 /// when our counterparty broadcast an old state.
279 /// Justice transaction may claim multiples outputs at same time if timelock are similar.
280 /// It may be called multiples time for same output(s) if a fee-bump is needed with regards
281 /// to an upcoming timelock expiration.
283 /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143).
285 /// Amount is value of the output spent by this input, committed by sigs (BIP 143).
287 /// Per_commitment key is revocation secret such as provided by remote party while
288 /// revocating detected onchain transaction. It's not a _local_ secret key, therefore
289 /// it may cross interfaces, a node compromise won't allow to spend revoked output without
290 /// also compromissing revocation key.
292 /// htlc holds HTLC elements (hash, timelock) if output spent is a HTLC one, committed as
293 /// part of witnessScript by sigs (BIP 143).
295 /// on_remote_tx_csv is the relative lock-time challenge if output spent is on remote
296 /// balance or 2nd-stage HTLC transactions, committed as part of witnessScript by sigs
298 fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, on_remote_tx_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
300 /// Create a signature for a claiming transaction for a HTLC output on a remote commitment
301 /// transaction, either offered or received.
303 /// HTLC transaction may claim multiples offered outputs at same time if we know preimage
304 /// for each at detection. It may be called multtiples time for same output(s) if a fee-bump
305 /// is needed with regards to an upcoming timelock expiration.
307 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
310 /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143).
312 /// Amount is value of the output spent by this input, committed by sigs (BIP 143).
314 /// Preimage is solution for an offered HTLC haslock. A preimage sets to None hints this
315 /// htlc_tx as timing-out funds back to us on a received output.
316 //TODO: dry-up witness_script and pass pubkeys
317 fn sign_remote_htlc_transaction<T: secp256k1::Signing>(&self, htlc_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_point: &PublicKey, preimage: &Option<PaymentPreimage>, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
319 /// Create a signature for a (proposed) closing transaction.
321 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
322 /// chosen to forgo their output as dust.
323 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
325 /// Signs a channel announcement message with our funding key, proving it comes from one
326 /// of the channel participants.
328 /// Note that if this fails or is rejected, the channel will not be publicly announced and
329 /// our counterparty may (though likely will not) close the channel on us for violating the
331 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
333 /// Set the remote channel basepoints. This is done immediately on incoming channels
334 /// and as soon as the channel is accepted on outgoing channels.
336 /// Will be called before any signatures are applied.
337 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
341 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
342 pub struct InMemoryChannelKeys {
343 /// Private key of anchor tx
344 funding_key: SecretKey,
345 /// Local secret key for blinded revocation pubkey
346 revocation_base_key: SecretKey,
347 /// Local secret key used for our balance in remote-broadcasted commitment transactions
348 payment_key: SecretKey,
349 /// Local secret key used in HTLC tx
350 delayed_payment_base_key: SecretKey,
351 /// Local htlc secret key used in commitment tx htlc outputs
352 htlc_base_key: SecretKey,
354 commitment_seed: [u8; 32],
355 /// Local public keys and basepoints
356 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
357 /// Remote public keys and base points
358 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
359 /// The total value of this channel
360 channel_value_satoshis: u64,
361 /// Key derivation parameters
362 key_derivation_params: (u64, u64),
365 impl InMemoryChannelKeys {
366 /// Create a new InMemoryChannelKeys
367 pub fn new<C: Signing>(
368 secp_ctx: &Secp256k1<C>,
369 funding_key: SecretKey,
370 revocation_base_key: SecretKey,
371 payment_key: SecretKey,
372 delayed_payment_base_key: SecretKey,
373 htlc_base_key: SecretKey,
374 commitment_seed: [u8; 32],
375 channel_value_satoshis: u64,
376 key_derivation_params: (u64, u64)) -> InMemoryChannelKeys {
377 let local_channel_pubkeys =
378 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
379 &payment_key, &delayed_payment_base_key,
381 InMemoryChannelKeys {
385 delayed_payment_base_key,
388 channel_value_satoshis,
389 local_channel_pubkeys,
390 remote_channel_pubkeys: None,
391 key_derivation_params,
395 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
396 funding_key: &SecretKey,
397 revocation_base_key: &SecretKey,
398 payment_key: &SecretKey,
399 delayed_payment_base_key: &SecretKey,
400 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
401 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
403 funding_pubkey: from_secret(&funding_key),
404 revocation_basepoint: from_secret(&revocation_base_key),
405 payment_point: from_secret(&payment_key),
406 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
407 htlc_basepoint: from_secret(&htlc_base_key),
411 fn remote_pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.remote_channel_pubkeys.as_ref().unwrap() }
414 impl ChannelKeys for InMemoryChannelKeys {
415 fn funding_key(&self) -> &SecretKey { &self.funding_key }
416 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
417 fn payment_key(&self) -> &SecretKey { &self.payment_key }
418 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
419 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
420 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
421 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
422 fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params }
424 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
425 if commitment_tx.input.len() != 1 { return Err(()); }
427 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
428 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
429 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
431 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
432 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
434 let commitment_txid = commitment_tx.txid();
436 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
437 for ref htlc in htlcs {
438 if let Some(_) = htlc.transaction_output_index {
439 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key);
440 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
441 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
442 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
444 Err(_) => return Err(()),
446 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
450 Ok((commitment_sig, htlc_sigs))
453 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
454 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
455 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
456 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
458 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
462 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
463 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
464 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
465 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
467 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
470 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
471 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
474 fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, on_remote_tx_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
475 let revocation_key = match chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) {
476 Ok(revocation_key) => revocation_key,
477 Err(_) => return Err(())
479 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
480 let revocation_pubkey = match chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
481 Ok(revocation_pubkey) => revocation_pubkey,
482 Err(_) => return Err(())
484 let witness_script = if let &Some(ref htlc) = htlc {
485 let remote_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().htlc_basepoint) {
486 Ok(remote_htlcpubkey) => remote_htlcpubkey,
487 Err(_) => return Err(())
489 let local_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
490 Ok(local_htlcpubkey) => local_htlcpubkey,
491 Err(_) => return Err(())
493 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &remote_htlcpubkey, &local_htlcpubkey, &revocation_pubkey)
495 let remote_delayedpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().delayed_payment_basepoint) {
496 Ok(remote_delayedpubkey) => remote_delayedpubkey,
497 Err(_) => return Err(())
499 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, on_remote_tx_csv, &remote_delayedpubkey)
501 let sighash_parts = bip143::SighashComponents::new(&justice_tx);
502 let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]);
503 return Ok(secp_ctx.sign(&sighash, &revocation_key))
506 fn sign_remote_htlc_transaction<T: secp256k1::Signing>(&self, htlc_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_point: &PublicKey, preimage: &Option<PaymentPreimage>, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
507 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
508 let sighash_parts = bip143::SighashComponents::new(&htlc_tx);
509 let sighash = hash_to_message!(&sighash_parts.sighash_all(&htlc_tx.input[input], &witness_script, amount)[..]);
510 return Ok(secp_ctx.sign(&sighash, &htlc_key))
515 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
516 if closing_tx.input.len() != 1 { return Err(()); }
517 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
518 if closing_tx.output.len() > 2 { return Err(()); }
520 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
521 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
522 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
524 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
525 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
526 Ok(secp_ctx.sign(&sighash, &self.funding_key))
529 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
530 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
531 Ok(secp_ctx.sign(&msghash, &self.funding_key))
534 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
535 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
536 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
540 impl Writeable for InMemoryChannelKeys {
541 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
542 self.funding_key.write(writer)?;
543 self.revocation_base_key.write(writer)?;
544 self.payment_key.write(writer)?;
545 self.delayed_payment_base_key.write(writer)?;
546 self.htlc_base_key.write(writer)?;
547 self.commitment_seed.write(writer)?;
548 self.remote_channel_pubkeys.write(writer)?;
549 self.channel_value_satoshis.write(writer)?;
550 self.key_derivation_params.0.write(writer)?;
551 self.key_derivation_params.1.write(writer)?;
557 impl Readable for InMemoryChannelKeys {
558 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
559 let funding_key = Readable::read(reader)?;
560 let revocation_base_key = Readable::read(reader)?;
561 let payment_key = Readable::read(reader)?;
562 let delayed_payment_base_key = Readable::read(reader)?;
563 let htlc_base_key = Readable::read(reader)?;
564 let commitment_seed = Readable::read(reader)?;
565 let remote_channel_pubkeys = Readable::read(reader)?;
566 let channel_value_satoshis = Readable::read(reader)?;
567 let secp_ctx = Secp256k1::signing_only();
568 let local_channel_pubkeys =
569 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
570 &payment_key, &delayed_payment_base_key,
572 let params_1 = Readable::read(reader)?;
573 let params_2 = Readable::read(reader)?;
575 Ok(InMemoryChannelKeys {
579 delayed_payment_base_key,
582 channel_value_satoshis,
583 local_channel_pubkeys,
584 remote_channel_pubkeys,
585 key_derivation_params: (params_1, params_2),
590 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
591 /// and derives keys from that.
593 /// Your node_id is seed/0'
594 /// ChannelMonitor closes may use seed/1'
595 /// Cooperative closes may use seed/2'
596 /// The two close keys may be needed to claim on-chain funds!
597 pub struct KeysManager {
598 secp_ctx: Secp256k1<secp256k1::SignOnly>,
599 node_secret: SecretKey,
600 destination_script: Script,
601 shutdown_pubkey: PublicKey,
602 channel_master_key: ExtendedPrivKey,
603 channel_child_index: AtomicUsize,
604 session_master_key: ExtendedPrivKey,
605 session_child_index: AtomicUsize,
606 channel_id_master_key: ExtendedPrivKey,
607 channel_id_child_index: AtomicUsize,
610 starting_time_secs: u64,
611 starting_time_nanos: u32,
615 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
616 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
617 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
618 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
619 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
620 /// simply use the current time (with very high precision).
622 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
623 /// obviously, starting_time should be unique every time you reload the library - it is only
624 /// used to generate new ephemeral key data (which will be stored by the individual channel if
627 /// Note that the seed is required to recover certain on-chain funds independent of
628 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
629 /// channel, and some on-chain during-closing funds.
631 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
632 /// versions. Once the library is more fully supported, the docs will be updated to include a
633 /// detailed description of the guarantee.
634 pub fn new(seed: &[u8; 32], network: Network, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
635 let secp_ctx = Secp256k1::signing_only();
636 match ExtendedPrivKey::new_master(network.clone(), seed) {
638 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
639 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
640 Ok(destination_key) => {
641 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
642 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
643 .push_slice(&wpubkey_hash.into_inner())
646 Err(_) => panic!("Your RNG is busted"),
648 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
649 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
650 Err(_) => panic!("Your RNG is busted"),
652 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
653 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
654 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
662 channel_child_index: AtomicUsize::new(0),
664 session_child_index: AtomicUsize::new(0),
665 channel_id_master_key,
666 channel_id_child_index: AtomicUsize::new(0),
673 Err(_) => panic!("Your rng is busted"),
676 fn derive_unique_start(&self) -> Sha256State {
677 let mut unique_start = Sha256::engine();
678 unique_start.input(&byte_utils::be64_to_array(self.starting_time_secs));
679 unique_start.input(&byte_utils::be32_to_array(self.starting_time_nanos));
680 unique_start.input(&self.seed);
683 /// Derive an old set of ChannelKeys for per-channel secrets based on a key derivation
685 /// Key derivation parameters are accessible through a per-channel secrets
686 /// ChannelKeys::key_derivation_params and is provided inside DynamicOuputP2WSH in case of
687 /// onchain output detection for which a corresponding delayed_payment_key must be derived.
688 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params_1: u64, params_2: u64) -> InMemoryChannelKeys {
689 let chan_id = ((params_1 & 0xFFFF_FFFF_0000_0000) >> 32) as u32;
690 let mut unique_start = Sha256::engine();
691 unique_start.input(&byte_utils::be64_to_array(params_2));
692 unique_start.input(&byte_utils::be32_to_array(params_1 as u32));
693 unique_start.input(&self.seed);
695 // We only seriously intend to rely on the channel_master_key for true secure
696 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
697 // starting_time provided in the constructor) to be unique.
698 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(chan_id).expect("key space exhausted")).expect("Your RNG is busted");
699 unique_start.input(&child_privkey.private_key.key[..]);
701 let seed = Sha256::from_engine(unique_start).into_inner();
703 let commitment_seed = {
704 let mut sha = Sha256::engine();
706 sha.input(&b"commitment seed"[..]);
707 Sha256::from_engine(sha).into_inner()
709 macro_rules! key_step {
710 ($info: expr, $prev_key: expr) => {{
711 let mut sha = Sha256::engine();
713 sha.input(&$prev_key[..]);
714 sha.input(&$info[..]);
715 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
718 let funding_key = key_step!(b"funding key", commitment_seed);
719 let revocation_base_key = key_step!(b"revocation base key", funding_key);
720 let payment_key = key_step!(b"payment key", revocation_base_key);
721 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
722 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
724 InMemoryChannelKeys::new(
729 delayed_payment_base_key,
732 channel_value_satoshis,
733 (params_1, params_2),
738 impl KeysInterface for KeysManager {
739 type ChanKeySigner = InMemoryChannelKeys;
741 fn get_node_secret(&self) -> SecretKey {
742 self.node_secret.clone()
745 fn get_destination_script(&self) -> Script {
746 self.destination_script.clone()
749 fn get_shutdown_pubkey(&self) -> PublicKey {
750 self.shutdown_pubkey.clone()
753 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
754 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
755 let ix_and_nanos: u64 = (child_ix as u64) << 32 | (self.starting_time_nanos as u64);
756 self.derive_channel_keys(channel_value_satoshis, ix_and_nanos, self.starting_time_secs)
759 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
760 let mut sha = self.derive_unique_start();
762 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
763 let child_privkey = self.session_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
764 sha.input(&child_privkey.private_key.key[..]);
766 let mut rng_seed = sha.clone();
767 // Not exactly the most ideal construction, but the second value will get fed into
768 // ChaCha so it is another step harder to break.
769 rng_seed.input(b"RNG Seed Salt");
770 sha.input(b"Session Key Salt");
771 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
772 Sha256::from_engine(rng_seed).into_inner())
775 fn get_channel_id(&self) -> [u8; 32] {
776 let mut sha = self.derive_unique_start();
778 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
779 let child_privkey = self.channel_id_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
780 sha.input(&child_privkey.private_key.key[..]);
782 Sha256::from_engine(sha).into_inner()