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, SigHashType};
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::logger::Logger;
24 use util::ser::{Writeable, Writer, Readable};
27 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction};
29 use ln::channelmanager::PaymentPreimage;
32 use std::sync::atomic::{AtomicUsize, Ordering};
34 use ln::msgs::DecodeError;
36 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
37 /// claim at any point in the future) an event is generated which you must track and be able to
38 /// spend on-chain. The information needed to do this is provided in this enum, including the
39 /// outpoint describing which txid and output index is available, the full output which exists at
40 /// that txid/index, and any keys or other information required to sign.
41 #[derive(Clone, PartialEq)]
42 pub enum SpendableOutputDescriptor {
43 /// An output to a script which was provided via KeysInterface, thus you should already know
44 /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the
45 /// script_pubkey as it appears in the output.
46 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
47 /// on-chain using the payment preimage or after it has timed out.
49 /// The outpoint which is spendable
51 /// The output which is referenced by the given outpoint.
54 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
56 /// The witness in the spending input should be:
57 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
59 /// Note that the nSequence field in the spending input must be set to to_self_delay
60 /// (which means the transaction not being broadcastable until at least to_self_delay
61 /// blocks after the outpoint confirms).
63 /// These are generally the result of a "revocable" output to us, spendable only by us unless
64 /// it is an output from us having broadcast an old state (which should never happen).
66 /// WitnessScript may be regenerated by passing the revocation_pubkey, to_self_delay and
67 /// delayed_payment_pubkey to chan_utils::get_revokeable_redeemscript.
69 /// To derive the delayed_payment key corresponding to the channel state, you must pass the
70 /// channel's delayed_payment_key and the provided per_commitment_point to
71 /// chan_utils::derive_private_key. The resulting key should be used to sign the spending
74 /// The outpoint which is spendable
76 /// Per commitment point to derive delayed_payment_key by key holder
77 per_commitment_point: PublicKey,
78 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
79 /// the witness_script.
81 /// The output which is referenced by the given outpoint
83 /// The channel keys state used to proceed to derivation of signing key. Must
84 /// be pass to KeysInterface::derive_channel_keys.
85 key_derivation_params: (u64, u64),
86 /// The remote_revocation_pubkey used to derive witnessScript
87 remote_revocation_pubkey: PublicKey
89 // TODO: Note that because key is now static and exactly what is provided by us, we should drop
90 // this in favor of StaticOutput:
91 /// An output to a P2WPKH, spendable exclusively by the given private key.
92 /// The witness in the spending input, is, thus, simply:
93 /// <BIP 143 signature generated with the given key> <public key derived from the given key>
94 /// These are generally the result of our counterparty having broadcast the current state,
95 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
97 /// The outpoint which is spendable
99 /// The secret key which must be used to sign the spending transaction
101 /// The output which is reference by the given outpoint
106 impl Writeable for SpendableOutputDescriptor {
107 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
109 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
111 outpoint.write(writer)?;
112 output.write(writer)?;
114 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref per_commitment_point, ref to_self_delay, ref output, ref key_derivation_params, ref remote_revocation_pubkey } => {
116 outpoint.write(writer)?;
117 per_commitment_point.write(writer)?;
118 to_self_delay.write(writer)?;
119 output.write(writer)?;
120 key_derivation_params.0.write(writer)?;
121 key_derivation_params.1.write(writer)?;
122 remote_revocation_pubkey.write(writer)?;
124 &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref key, ref output } => {
126 outpoint.write(writer)?;
128 output.write(writer)?;
135 impl Readable for SpendableOutputDescriptor {
136 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
137 match Readable::read(reader)? {
138 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
139 outpoint: Readable::read(reader)?,
140 output: Readable::read(reader)?,
142 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
143 outpoint: Readable::read(reader)?,
144 per_commitment_point: Readable::read(reader)?,
145 to_self_delay: Readable::read(reader)?,
146 output: Readable::read(reader)?,
147 key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?),
148 remote_revocation_pubkey: Readable::read(reader)?,
150 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH {
151 outpoint: Readable::read(reader)?,
152 key: Readable::read(reader)?,
153 output: Readable::read(reader)?,
155 _ => Err(DecodeError::InvalidValue),
160 /// A trait to describe an object which can get user secrets and key material.
161 pub trait KeysInterface: Send + Sync {
162 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
163 type ChanKeySigner : ChannelKeys;
165 /// Get node secret key (aka node_id or network_key)
166 fn get_node_secret(&self) -> SecretKey;
167 /// Get destination redeemScript to encumber static protocol exit points.
168 fn get_destination_script(&self) -> Script;
169 /// Get shutdown_pubkey to use as PublicKey at channel closure
170 fn get_shutdown_pubkey(&self) -> PublicKey;
171 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
172 /// restarted with some stale data!
173 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
174 /// Get a secret and PRNG seed for construting an onion packet
175 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
176 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
177 /// transaction is created, at which point they will use the outpoint in the funding
179 fn get_channel_id(&self) -> [u8; 32];
182 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
184 /// Signing services could be implemented on a hardware wallet. In this case,
185 /// the current ChannelKeys would be a front-end on top of a communication
186 /// channel connected to your secure device and lightning key material wouldn't
187 /// reside on a hot server. Nevertheless, a this deployment would still need
188 /// to trust the ChannelManager to avoid loss of funds as this latest component
189 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
191 /// A more secure iteration would be to use hashlock (or payment points) to pair
192 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
193 /// at the price of more state and computation on the hardware wallet side. In the future,
194 /// we are looking forward to design such interface.
196 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
197 /// to act, as liveness and breach reply correctness are always going to be hard requirements
198 /// of LN security model, orthogonal of key management issues.
200 /// If you're implementing a custom signer, you almost certainly want to implement
201 /// Readable/Writable to serialize out a unique reference to this set of keys so
202 /// that you can serialize the full ChannelManager object.
204 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
205 // to the possibility of reentrancy issues by calling the user's code during our deserialization
207 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
208 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
209 pub trait ChannelKeys : Send+Clone {
210 /// Gets the private key for the anchor tx
211 fn funding_key<'a>(&'a self) -> &'a SecretKey;
212 /// Gets the local secret key for blinded revocation pubkey
213 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
214 /// Gets the local secret key used in the to_remote output of remote commitment tx (ie the
215 /// output to us in transactions our counterparty broadcasts).
216 /// Also as part of obscured commitment number.
217 fn payment_key<'a>(&'a self) -> &'a SecretKey;
218 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
219 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
220 /// Gets the local htlc secret key used in commitment tx htlc outputs
221 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
222 /// Gets the commitment seed
223 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
224 /// Gets the local channel public keys and basepoints
225 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
226 /// Gets the key derivation parameters in case of new derivation.
227 fn key_derivation_params(&self) -> (u64, u64);
229 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
231 /// Note that if signing fails or is rejected, the channel will be force-closed.
233 // TODO: Document the things someone using this interface should enforce before signing.
234 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
235 // making the callee generate it via some util function we expose)!
236 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>), ()>;
238 /// Create a signature for a local commitment transaction. This will only ever be called with
239 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
240 /// that it will not be called multiple times.
242 // TODO: Document the things someone using this interface should enforce before signing.
243 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
244 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
246 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
247 /// transactions which will be broadcasted later, after the channel has moved on to a newer
248 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
251 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
253 /// Create a signature for each HTLC transaction spending a local commitment transaction.
255 /// Unlike sign_local_commitment, this may be called multiple times with *different*
256 /// local_commitment_tx values. While this will never be called with a revoked
257 /// local_commitment_tx, it is possible that it is called with the second-latest
258 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
259 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
261 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
262 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
263 /// (implying they were considered dust at the time the commitment transaction was negotiated),
264 /// a corresponding None should be included in the return value. All other positions in the
265 /// return value must contain a signature.
266 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>>, ()>;
268 /// Create a signature for a transaction spending an HTLC or commitment transaction output
269 /// when our counterparty broadcast an old state.
271 /// Justice transaction may claim multiples outputs at same time if timelock are similar.
272 /// It may be called multiples time for same output(s) if a fee-bump is needed with regards
273 /// to an upcoming timelock expiration.
275 /// Witness_script is a revokable witness script as defined in BOLT3 for `to_local`/HTLC
278 /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143).
280 /// Amount is value of the output spent by this input, committed by sigs (BIP 143).
282 /// Per_commitment key is revocation secret such as provided by remote party while
283 /// revocating detected onchain transaction. It's not a _local_ secret key, therefore
284 /// it may cross interfaces, a node compromise won't allow to spend revoked output without
285 /// also compromissing revocation key.
286 //TODO: dry-up witness_script and pass pubkeys
287 fn sign_justice_transaction<T: secp256k1::Signing>(&self, justice_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_key: &SecretKey, revocation_pubkey: &PublicKey, is_htlc: bool, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
289 /// Create a signature for a claiming transaction for a HTLC output on a remote commitment
290 /// transaction, either offered or received.
292 /// HTLC transaction may claim multiples offered outputs at same time if we know preimage
293 /// for each at detection. It may be called multtiples time for same output(s) if a fee-bump
294 /// is needed with regards to an upcoming timelock expiration.
296 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
299 /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143).
301 /// Amount is value of the output spent by this input, committed by sigs (BIP 143).
303 /// Preimage is solution for an offered HTLC haslock. A preimage sets to None hints this
304 /// htlc_tx as timing-out funds back to us on a received output.
305 //TODO: dry-up witness_script and pass pubkeys
306 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, ()>;
308 /// Create a signature for a (proposed) closing transaction.
310 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
311 /// chosen to forgo their output as dust.
312 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
314 /// Signs a channel announcement message with our funding key, proving it comes from one
315 /// of the channel participants.
317 /// Note that if this fails or is rejected, the channel will not be publicly announced and
318 /// our counterparty may (though likely will not) close the channel on us for violating the
320 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
322 /// Set the remote channel basepoints. This is done immediately on incoming channels
323 /// and as soon as the channel is accepted on outgoing channels.
325 /// Will be called before any signatures are applied.
326 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
330 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
331 pub struct InMemoryChannelKeys {
332 /// Private key of anchor tx
333 funding_key: SecretKey,
334 /// Local secret key for blinded revocation pubkey
335 revocation_base_key: SecretKey,
336 /// Local secret key used for our balance in remote-broadcasted commitment transactions
337 payment_key: SecretKey,
338 /// Local secret key used in HTLC tx
339 delayed_payment_base_key: SecretKey,
340 /// Local htlc secret key used in commitment tx htlc outputs
341 htlc_base_key: SecretKey,
343 commitment_seed: [u8; 32],
344 /// Local public keys and basepoints
345 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
346 /// Remote public keys and base points
347 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
348 /// The total value of this channel
349 channel_value_satoshis: u64,
350 /// Key derivation parameters
351 key_derivation_params: (u64, u64),
354 impl InMemoryChannelKeys {
355 /// Create a new InMemoryChannelKeys
356 pub fn new<C: Signing>(
357 secp_ctx: &Secp256k1<C>,
358 funding_key: SecretKey,
359 revocation_base_key: SecretKey,
360 payment_key: SecretKey,
361 delayed_payment_base_key: SecretKey,
362 htlc_base_key: SecretKey,
363 commitment_seed: [u8; 32],
364 channel_value_satoshis: u64,
365 key_derivation_params: (u64, u64)) -> InMemoryChannelKeys {
366 let local_channel_pubkeys =
367 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
368 &payment_key, &delayed_payment_base_key,
370 InMemoryChannelKeys {
374 delayed_payment_base_key,
377 channel_value_satoshis,
378 local_channel_pubkeys,
379 remote_channel_pubkeys: None,
380 key_derivation_params,
384 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
385 funding_key: &SecretKey,
386 revocation_base_key: &SecretKey,
387 payment_key: &SecretKey,
388 delayed_payment_base_key: &SecretKey,
389 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
390 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
392 funding_pubkey: from_secret(&funding_key),
393 revocation_basepoint: from_secret(&revocation_base_key),
394 payment_point: from_secret(&payment_key),
395 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
396 htlc_basepoint: from_secret(&htlc_base_key),
401 impl ChannelKeys for InMemoryChannelKeys {
402 fn funding_key(&self) -> &SecretKey { &self.funding_key }
403 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
404 fn payment_key(&self) -> &SecretKey { &self.payment_key }
405 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
406 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
407 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
408 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
409 fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params }
411 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>), ()> {
412 if commitment_tx.input.len() != 1 { return Err(()); }
414 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
415 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
416 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
418 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
419 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
421 let commitment_txid = commitment_tx.txid();
423 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
424 for ref htlc in htlcs {
425 if let Some(_) = htlc.transaction_output_index {
426 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);
427 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
428 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
429 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
431 Err(_) => return Err(()),
433 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
437 Ok((commitment_sig, htlc_sigs))
440 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
441 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
442 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
443 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
445 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
449 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
450 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
451 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
452 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
454 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
457 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>>, ()> {
458 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
461 fn sign_justice_transaction<T: secp256k1::Signing>(&self, justice_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_key: &SecretKey, revocation_pubkey: &PublicKey, is_htlc: bool, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
462 if let Ok(revocation_key) = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) {
463 let sighash_parts = bip143::SighashComponents::new(&justice_tx);
464 let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]);
465 return Ok(secp_ctx.sign(&sighash, &revocation_key))
470 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, ()> {
471 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
472 let sighash_parts = bip143::SighashComponents::new(&htlc_tx);
473 let sighash = hash_to_message!(&sighash_parts.sighash_all(&htlc_tx.input[input], &witness_script, amount)[..]);
474 return Ok(secp_ctx.sign(&sighash, &htlc_key))
479 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
480 if closing_tx.input.len() != 1 { return Err(()); }
481 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
482 if closing_tx.output.len() > 2 { return Err(()); }
484 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
485 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
486 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
488 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
489 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
490 Ok(secp_ctx.sign(&sighash, &self.funding_key))
493 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
494 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
495 Ok(secp_ctx.sign(&msghash, &self.funding_key))
498 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
499 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
500 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
504 impl Writeable for InMemoryChannelKeys {
505 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
506 self.funding_key.write(writer)?;
507 self.revocation_base_key.write(writer)?;
508 self.payment_key.write(writer)?;
509 self.delayed_payment_base_key.write(writer)?;
510 self.htlc_base_key.write(writer)?;
511 self.commitment_seed.write(writer)?;
512 self.remote_channel_pubkeys.write(writer)?;
513 self.channel_value_satoshis.write(writer)?;
514 self.key_derivation_params.0.write(writer)?;
515 self.key_derivation_params.1.write(writer)?;
521 impl Readable for InMemoryChannelKeys {
522 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
523 let funding_key = Readable::read(reader)?;
524 let revocation_base_key = Readable::read(reader)?;
525 let payment_key = Readable::read(reader)?;
526 let delayed_payment_base_key = Readable::read(reader)?;
527 let htlc_base_key = Readable::read(reader)?;
528 let commitment_seed = Readable::read(reader)?;
529 let remote_channel_pubkeys = Readable::read(reader)?;
530 let channel_value_satoshis = Readable::read(reader)?;
531 let secp_ctx = Secp256k1::signing_only();
532 let local_channel_pubkeys =
533 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
534 &payment_key, &delayed_payment_base_key,
536 let user_id_1 = Readable::read(reader)?;
537 let user_id_2 = Readable::read(reader)?;
539 Ok(InMemoryChannelKeys {
543 delayed_payment_base_key,
546 channel_value_satoshis,
547 local_channel_pubkeys,
548 remote_channel_pubkeys,
549 key_derivation_params: (user_id_1, user_id_2),
554 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
555 /// and derives keys from that.
557 /// Your node_id is seed/0'
558 /// ChannelMonitor closes may use seed/1'
559 /// Cooperative closes may use seed/2'
560 /// The two close keys may be needed to claim on-chain funds!
561 pub struct KeysManager {
562 secp_ctx: Secp256k1<secp256k1::SignOnly>,
563 node_secret: SecretKey,
564 destination_script: Script,
565 shutdown_pubkey: PublicKey,
566 channel_master_key: ExtendedPrivKey,
567 channel_child_index: AtomicUsize,
568 session_master_key: ExtendedPrivKey,
569 session_child_index: AtomicUsize,
570 channel_id_master_key: ExtendedPrivKey,
571 channel_id_child_index: AtomicUsize,
574 starting_time_secs: u64,
575 starting_time_nanos: u32,
580 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
581 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
582 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
583 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
584 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
585 /// simply use the current time (with very high precision).
587 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
588 /// obviously, starting_time should be unique every time you reload the library - it is only
589 /// used to generate new ephemeral key data (which will be stored by the individual channel if
592 /// Note that the seed is required to recover certain on-chain funds independent of
593 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
594 /// channel, and some on-chain during-closing funds.
596 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
597 /// versions. Once the library is more fully supported, the docs will be updated to include a
598 /// detailed description of the guarantee.
599 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
600 let secp_ctx = Secp256k1::signing_only();
601 match ExtendedPrivKey::new_master(network.clone(), seed) {
603 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
604 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
605 Ok(destination_key) => {
606 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
607 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
608 .push_slice(&wpubkey_hash.into_inner())
611 Err(_) => panic!("Your RNG is busted"),
613 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
614 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
615 Err(_) => panic!("Your RNG is busted"),
617 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
618 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
619 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
627 channel_child_index: AtomicUsize::new(0),
629 session_child_index: AtomicUsize::new(0),
630 channel_id_master_key,
631 channel_id_child_index: AtomicUsize::new(0),
639 Err(_) => panic!("Your rng is busted"),
642 fn derive_unique_start(&self) -> Sha256State {
643 let mut unique_start = Sha256::engine();
644 unique_start.input(&byte_utils::be64_to_array(self.starting_time_secs));
645 unique_start.input(&byte_utils::be32_to_array(self.starting_time_nanos));
646 unique_start.input(&self.seed);
649 /// Derive an old set of ChannelKeys for per-channel secrets based on a key derivation
651 /// Key derivation parameters are accessible through a per-channel secrets
652 /// ChannelKeys::key_derivation_params and is provided inside DynamicOuputP2WSH in case of
653 /// onchain output detection for which a corresponding delayed_payment_key must be derived.
654 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, user_id_1: u64, user_id_2: u64) -> InMemoryChannelKeys {
655 let chan_id = ((user_id_1 & 0xFFFF0000) >> 32) as u32;
656 let mut unique_start = Sha256::engine();
657 unique_start.input(&byte_utils::be64_to_array(user_id_2));
658 unique_start.input(&byte_utils::be32_to_array(user_id_1 as u32));
659 unique_start.input(&self.seed);
661 // We only seriously intend to rely on the channel_master_key for true secure
662 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
663 // starting_time provided in the constructor) to be unique.
664 let mut sha = self.derive_unique_start();
666 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");
667 sha.input(&child_privkey.private_key.key[..]);
669 let seed = Sha256::from_engine(sha).into_inner();
671 let commitment_seed = {
672 let mut sha = Sha256::engine();
674 sha.input(&b"commitment seed"[..]);
675 Sha256::from_engine(sha).into_inner()
677 macro_rules! key_step {
678 ($info: expr, $prev_key: expr) => {{
679 let mut sha = Sha256::engine();
681 sha.input(&$prev_key[..]);
682 sha.input(&$info[..]);
683 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
686 let funding_key = key_step!(b"funding key", commitment_seed);
687 let revocation_base_key = key_step!(b"revocation base key", funding_key);
688 let payment_key = key_step!(b"payment key", revocation_base_key);
689 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
690 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
692 InMemoryChannelKeys::new(
697 delayed_payment_base_key,
700 channel_value_satoshis,
701 (user_id_1, user_id_2),
706 impl KeysInterface for KeysManager {
707 type ChanKeySigner = InMemoryChannelKeys;
709 fn get_node_secret(&self) -> SecretKey {
710 self.node_secret.clone()
713 fn get_destination_script(&self) -> Script {
714 self.destination_script.clone()
717 fn get_shutdown_pubkey(&self) -> PublicKey {
718 self.shutdown_pubkey.clone()
721 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
722 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
723 let ix_and_nanos: u64 = (child_ix as u64) << 32 | (self.starting_time_nanos as u64);
724 self.derive_channel_keys(channel_value_satoshis, ix_and_nanos, self.starting_time_secs)
727 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
728 let mut sha = self.derive_unique_start();
730 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
731 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");
732 sha.input(&child_privkey.private_key.key[..]);
734 let mut rng_seed = sha.clone();
735 // Not exactly the most ideal construction, but the second value will get fed into
736 // ChaCha so it is another step harder to break.
737 rng_seed.input(b"RNG Seed Salt");
738 sha.input(b"Session Key Salt");
739 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
740 Sha256::from_engine(rng_seed).into_inner())
743 fn get_channel_id(&self) -> [u8; 32] {
744 let mut sha = self.derive_unique_start();
746 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
747 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");
748 sha.input(&child_privkey.private_key.key[..]);
750 Sha256::from_engine(sha).into_inner()