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::logger::Logger;
24 use util::ser::{Writeable, Writer, Readable};
27 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction};
31 use std::sync::atomic::{AtomicUsize, Ordering};
33 use ln::msgs::DecodeError;
35 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
36 /// claim at any point in the future) an event is generated which you must track and be able to
37 /// spend on-chain. The information needed to do this is provided in this enum, including the
38 /// outpoint describing which txid and output index is available, the full output which exists at
39 /// that txid/index, and any keys or other information required to sign.
40 #[derive(Clone, PartialEq)]
41 pub enum SpendableOutputDescriptor {
42 /// An output to a script which was provided via KeysInterface, thus you should already know
43 /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the
44 /// script_pubkey as it appears in the output.
45 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
46 /// on-chain using the payment preimage or after it has timed out.
48 /// The outpoint which is spendable
50 /// The output which is referenced by the given outpoint.
53 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
55 /// The witness in the spending input should be:
56 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
58 /// Note that the nSequence field in the spending input must be set to to_self_delay
59 /// (which means the transaction is not broadcastable until at least to_self_delay
60 /// blocks after the outpoint confirms).
62 /// These are generally the result of a "revocable" output to us, spendable only by us unless
63 /// it is an output from an old state which we broadcast (which should never happen).
65 /// To derive the delayed_payment key which is used to sign for this input, you must pass the
66 /// local delayed_payment_base_key (ie the private key which corresponds to the pubkey in
67 /// ChannelKeys::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
68 /// chan_utils::derive_private_key. The public key can be generated without the secret key
69 /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
70 /// ChannelKeys::pubkeys().
72 /// To derive the revocation_pubkey which is used in the witness script generation, you must
73 /// pass the remote revocation_basepoint (which appears in the call to
74 /// ChannelKeys::set_remote_channel_pubkeys) and the provided per_commitment point to
75 /// chan_utils::derive_public_revocation_key.
77 /// The witness script which is hashed and included in the output script_pubkey may be
78 /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
79 /// (derived as above), and the to_self_delay contained here to
80 /// chan_utils::get_revokeable_redeemscript.
82 // TODO: we need to expose utility methods in KeyManager to do all the relevant derivation.
84 /// The outpoint which is spendable
86 /// Per commitment point to derive delayed_payment_key by key holder
87 per_commitment_point: PublicKey,
88 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
89 /// the witness_script.
91 /// The output which is referenced by the given outpoint
93 /// The channel keys state used to proceed to derivation of signing key. Must
94 /// be pass to KeysInterface::derive_channel_keys.
95 key_derivation_params: (u64, u64),
96 /// The remote_revocation_pubkey used to derive witnessScript
97 remote_revocation_pubkey: PublicKey
99 /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
100 /// corresponds to the public key in ChannelKeys::pubkeys().payment_point).
101 /// The witness in the spending input, is, thus, simply:
102 /// <BIP 143 signature> <payment key>
104 /// These are generally the result of our counterparty having broadcast the current state,
105 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
106 StaticOutputRemotePayment {
107 /// The outpoint which is spendable
109 /// The output which is reference by the given outpoint
111 /// The channel keys state used to proceed to derivation of signing key. Must
112 /// be pass to KeysInterface::derive_channel_keys.
113 key_derivation_params: (u64, u64),
117 impl Writeable for SpendableOutputDescriptor {
118 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
120 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
122 outpoint.write(writer)?;
123 output.write(writer)?;
125 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref per_commitment_point, ref to_self_delay, ref output, ref key_derivation_params, ref remote_revocation_pubkey } => {
127 outpoint.write(writer)?;
128 per_commitment_point.write(writer)?;
129 to_self_delay.write(writer)?;
130 output.write(writer)?;
131 key_derivation_params.0.write(writer)?;
132 key_derivation_params.1.write(writer)?;
133 remote_revocation_pubkey.write(writer)?;
135 &SpendableOutputDescriptor::StaticOutputRemotePayment { ref outpoint, ref output, ref key_derivation_params } => {
137 outpoint.write(writer)?;
138 output.write(writer)?;
139 key_derivation_params.0.write(writer)?;
140 key_derivation_params.1.write(writer)?;
147 impl Readable for SpendableOutputDescriptor {
148 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
149 match Readable::read(reader)? {
150 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
151 outpoint: Readable::read(reader)?,
152 output: Readable::read(reader)?,
154 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
155 outpoint: Readable::read(reader)?,
156 per_commitment_point: Readable::read(reader)?,
157 to_self_delay: Readable::read(reader)?,
158 output: Readable::read(reader)?,
159 key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?),
160 remote_revocation_pubkey: Readable::read(reader)?,
162 2u8 => Ok(SpendableOutputDescriptor::StaticOutputRemotePayment {
163 outpoint: Readable::read(reader)?,
164 output: Readable::read(reader)?,
165 key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?),
167 _ => Err(DecodeError::InvalidValue),
172 /// A trait to describe an object which can get user secrets and key material.
173 pub trait KeysInterface: Send + Sync {
174 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
175 type ChanKeySigner : ChannelKeys;
177 /// Get node secret key (aka node_id or network_key)
178 fn get_node_secret(&self) -> SecretKey;
179 /// Get destination redeemScript to encumber static protocol exit points.
180 fn get_destination_script(&self) -> Script;
181 /// Get shutdown_pubkey to use as PublicKey at channel closure
182 fn get_shutdown_pubkey(&self) -> PublicKey;
183 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
184 /// restarted with some stale data!
185 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
186 /// Get a secret and PRNG seed for construting an onion packet
187 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
188 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
189 /// transaction is created, at which point they will use the outpoint in the funding
191 fn get_channel_id(&self) -> [u8; 32];
194 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
196 /// Signing services could be implemented on a hardware wallet. In this case,
197 /// the current ChannelKeys would be a front-end on top of a communication
198 /// channel connected to your secure device and lightning key material wouldn't
199 /// reside on a hot server. Nevertheless, a this deployment would still need
200 /// to trust the ChannelManager to avoid loss of funds as this latest component
201 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
203 /// A more secure iteration would be to use hashlock (or payment points) to pair
204 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
205 /// at the price of more state and computation on the hardware wallet side. In the future,
206 /// we are looking forward to design such interface.
208 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
209 /// to act, as liveness and breach reply correctness are always going to be hard requirements
210 /// of LN security model, orthogonal of key management issues.
212 /// If you're implementing a custom signer, you almost certainly want to implement
213 /// Readable/Writable to serialize out a unique reference to this set of keys so
214 /// that you can serialize the full ChannelManager object.
216 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
217 // to the possibility of reentrancy issues by calling the user's code during our deserialization
219 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
220 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
221 pub trait ChannelKeys : Send+Clone {
222 /// Gets the private key for the anchor tx
223 fn funding_key<'a>(&'a self) -> &'a SecretKey;
224 /// Gets the local secret key for blinded revocation pubkey
225 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
226 /// Gets the local secret key used in the to_remote output of remote commitment tx (ie the
227 /// output to us in transactions our counterparty broadcasts).
228 /// Also as part of obscured commitment number.
229 fn payment_key<'a>(&'a self) -> &'a SecretKey;
230 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
231 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
232 /// Gets the local htlc secret key used in commitment tx htlc outputs
233 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
234 /// Gets the commitment seed
235 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
236 /// Gets the local channel public keys and basepoints
237 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
238 /// Gets the key derivation parameters in case of new derivation.
239 fn key_derivation_params(&self) -> (u64, u64);
241 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
243 /// Note that if signing fails or is rejected, the channel will be force-closed.
245 // TODO: Document the things someone using this interface should enforce before signing.
246 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
247 // making the callee generate it via some util function we expose)!
248 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>), ()>;
250 /// Create a signature for a local commitment transaction. This will only ever be called with
251 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
252 /// that it will not be called multiple times.
254 // TODO: Document the things someone using this interface should enforce before signing.
255 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
256 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
258 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
259 /// transactions which will be broadcasted later, after the channel has moved on to a newer
260 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
263 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
265 /// Create a signature for each HTLC transaction spending a local commitment transaction.
267 /// Unlike sign_local_commitment, this may be called multiple times with *different*
268 /// local_commitment_tx values. While this will never be called with a revoked
269 /// local_commitment_tx, it is possible that it is called with the second-latest
270 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
271 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
273 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
274 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
275 /// (implying they were considered dust at the time the commitment transaction was negotiated),
276 /// a corresponding None should be included in the return value. All other positions in the
277 /// return value must contain a signature.
278 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>>, ()>;
280 /// Create a signature for the given input in a transaction spending an HTLC or commitment
281 /// transaction output when our counterparty broadcast an old state.
283 /// A justice transaction may claim multiples outputs at same time if timelock are similar,
284 /// but only a signature for the input at index `input` should be signed for here.
285 /// It may be called multiples time for same output(s) if a fee-bump is needed with regards
286 /// to an upcoming timelock expiration.
288 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
290 /// per_commitment_key is revocation secret which was provided by our counterparty when they
291 /// revoked the state which they eventually broadcast. It's not a _local_ secret key and does
292 /// not allow the spending of any funds by itself (you need our local revocation_secret to do
295 /// htlc holds HTLC elements (hash, timelock) if the output being spent is a HTLC output, thus
296 /// changing the format of the witness script (which is committed to in the BIP 143
299 /// on_remote_tx_csv is the relative lock-time that that our counterparty would have to set on
300 /// their transaction were they to spend the same output. It is included in the witness script
301 /// and thus committed to in the BIP 143 signature.
302 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, ()>;
304 /// Create a signature for a claiming transaction for a HTLC output on a remote commitment
305 /// transaction, either offered or received.
307 /// Such a transaction may claim multiples offered outputs at same time if we know the preimage
308 /// for each when we create it, but only the input at index `input` should be signed for here.
309 /// It may be called multiple time for same output(s) if a fee-bump is needed with regards to
310 /// an upcoming timelock expiration.
312 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
315 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
317 /// Per_commitment_point is the dynamic point corresponding to the channel state
318 /// detected onchain. It has been generated by our counterparty and is used to derive
319 /// channel state keys, which are then included in the witness script and committed to in the
320 /// BIP 143 signature.
321 fn sign_remote_htlc_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
323 /// Create a signature for a (proposed) closing transaction.
325 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
326 /// chosen to forgo their output as dust.
327 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
329 /// Signs a channel announcement message with our funding key, proving it comes from one
330 /// of the channel participants.
332 /// Note that if this fails or is rejected, the channel will not be publicly announced and
333 /// our counterparty may (though likely will not) close the channel on us for violating the
335 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
337 /// Set the remote channel basepoints. This is done immediately on incoming channels
338 /// and as soon as the channel is accepted on outgoing channels.
340 /// Will be called before any signatures are applied.
341 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
345 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
346 pub struct InMemoryChannelKeys {
347 /// Private key of anchor tx
348 funding_key: SecretKey,
349 /// Local secret key for blinded revocation pubkey
350 revocation_base_key: SecretKey,
351 /// Local secret key used for our balance in remote-broadcasted commitment transactions
352 payment_key: SecretKey,
353 /// Local secret key used in HTLC tx
354 delayed_payment_base_key: SecretKey,
355 /// Local htlc secret key used in commitment tx htlc outputs
356 htlc_base_key: SecretKey,
358 commitment_seed: [u8; 32],
359 /// Local public keys and basepoints
360 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
361 /// Remote public keys and base points
362 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
363 /// The total value of this channel
364 channel_value_satoshis: u64,
365 /// Key derivation parameters
366 key_derivation_params: (u64, u64),
369 impl InMemoryChannelKeys {
370 /// Create a new InMemoryChannelKeys
371 pub fn new<C: Signing>(
372 secp_ctx: &Secp256k1<C>,
373 funding_key: SecretKey,
374 revocation_base_key: SecretKey,
375 payment_key: SecretKey,
376 delayed_payment_base_key: SecretKey,
377 htlc_base_key: SecretKey,
378 commitment_seed: [u8; 32],
379 channel_value_satoshis: u64,
380 key_derivation_params: (u64, u64)) -> InMemoryChannelKeys {
381 let local_channel_pubkeys =
382 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
383 &payment_key, &delayed_payment_base_key,
385 InMemoryChannelKeys {
389 delayed_payment_base_key,
392 channel_value_satoshis,
393 local_channel_pubkeys,
394 remote_channel_pubkeys: None,
395 key_derivation_params,
399 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
400 funding_key: &SecretKey,
401 revocation_base_key: &SecretKey,
402 payment_key: &SecretKey,
403 delayed_payment_base_key: &SecretKey,
404 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
405 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
407 funding_pubkey: from_secret(&funding_key),
408 revocation_basepoint: from_secret(&revocation_base_key),
409 payment_point: from_secret(&payment_key),
410 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
411 htlc_basepoint: from_secret(&htlc_base_key),
415 fn remote_pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.remote_channel_pubkeys.as_ref().unwrap() }
418 impl ChannelKeys for InMemoryChannelKeys {
419 fn funding_key(&self) -> &SecretKey { &self.funding_key }
420 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
421 fn payment_key(&self) -> &SecretKey { &self.payment_key }
422 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
423 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
424 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
425 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
426 fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params }
428 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>), ()> {
429 if commitment_tx.input.len() != 1 { return Err(()); }
431 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
432 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
433 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
435 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
436 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
438 let commitment_txid = commitment_tx.txid();
440 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
441 for ref htlc in htlcs {
442 if let Some(_) = htlc.transaction_output_index {
443 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);
444 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
445 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
446 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
448 Err(_) => return Err(()),
450 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
454 Ok((commitment_sig, htlc_sigs))
457 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
458 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
459 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
460 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
462 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
466 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
467 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
468 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
469 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
471 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
474 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>>, ()> {
475 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
478 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, ()> {
479 if let Ok(revocation_key) = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) {
480 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
481 let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
482 if let &Some(ref htlc) = htlc {
483 if let Ok(remote_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().htlc_basepoint) {
484 if let Ok(local_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
485 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &remote_htlcpubkey, &local_htlcpubkey, &revocation_pubkey)
486 } else { return Err(()) }
487 } else { return Err(()) }
489 if let Ok(remote_delayedpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().delayed_payment_basepoint) {
490 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, on_remote_tx_csv, &remote_delayedpubkey)
491 } else { return Err(()) }
493 } else { return Err(()) };
494 let sighash_parts = bip143::SighashComponents::new(&justice_tx);
495 let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]);
496 return Ok(secp_ctx.sign(&sighash, &revocation_key))
501 fn sign_remote_htlc_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
502 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
503 let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
504 if let Ok(remote_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().htlc_basepoint) {
505 if let Ok(local_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
506 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &remote_htlcpubkey, &local_htlcpubkey, &revocation_pubkey)
507 } else { return Err(()) }
508 } else { return Err(()) }
509 } else { return Err(()) };
510 let sighash_parts = bip143::SighashComponents::new(&htlc_tx);
511 let sighash = hash_to_message!(&sighash_parts.sighash_all(&htlc_tx.input[input], &witness_script, amount)[..]);
512 return Ok(secp_ctx.sign(&sighash, &htlc_key))
517 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
518 if closing_tx.input.len() != 1 { return Err(()); }
519 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
520 if closing_tx.output.len() > 2 { return Err(()); }
522 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
523 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
524 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
526 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
527 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
528 Ok(secp_ctx.sign(&sighash, &self.funding_key))
531 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
532 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
533 Ok(secp_ctx.sign(&msghash, &self.funding_key))
536 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
537 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
538 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
542 impl Writeable for InMemoryChannelKeys {
543 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
544 self.funding_key.write(writer)?;
545 self.revocation_base_key.write(writer)?;
546 self.payment_key.write(writer)?;
547 self.delayed_payment_base_key.write(writer)?;
548 self.htlc_base_key.write(writer)?;
549 self.commitment_seed.write(writer)?;
550 self.remote_channel_pubkeys.write(writer)?;
551 self.channel_value_satoshis.write(writer)?;
552 self.key_derivation_params.0.write(writer)?;
553 self.key_derivation_params.1.write(writer)?;
559 impl Readable for InMemoryChannelKeys {
560 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
561 let funding_key = Readable::read(reader)?;
562 let revocation_base_key = Readable::read(reader)?;
563 let payment_key = Readable::read(reader)?;
564 let delayed_payment_base_key = Readable::read(reader)?;
565 let htlc_base_key = Readable::read(reader)?;
566 let commitment_seed = Readable::read(reader)?;
567 let remote_channel_pubkeys = Readable::read(reader)?;
568 let channel_value_satoshis = Readable::read(reader)?;
569 let secp_ctx = Secp256k1::signing_only();
570 let local_channel_pubkeys =
571 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
572 &payment_key, &delayed_payment_base_key,
574 let user_id_1 = Readable::read(reader)?;
575 let user_id_2 = Readable::read(reader)?;
577 Ok(InMemoryChannelKeys {
581 delayed_payment_base_key,
584 channel_value_satoshis,
585 local_channel_pubkeys,
586 remote_channel_pubkeys,
587 key_derivation_params: (user_id_1, user_id_2),
592 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
593 /// and derives keys from that.
595 /// Your node_id is seed/0'
596 /// ChannelMonitor closes may use seed/1'
597 /// Cooperative closes may use seed/2'
598 /// The two close keys may be needed to claim on-chain funds!
599 pub struct KeysManager {
600 secp_ctx: Secp256k1<secp256k1::SignOnly>,
601 node_secret: SecretKey,
602 destination_script: Script,
603 shutdown_pubkey: PublicKey,
604 channel_master_key: ExtendedPrivKey,
605 channel_child_index: AtomicUsize,
606 session_master_key: ExtendedPrivKey,
607 session_child_index: AtomicUsize,
608 channel_id_master_key: ExtendedPrivKey,
609 channel_id_child_index: AtomicUsize,
612 starting_time_secs: u64,
613 starting_time_nanos: u32,
618 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
619 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
620 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
621 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
622 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
623 /// simply use the current time (with very high precision).
625 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
626 /// obviously, starting_time should be unique every time you reload the library - it is only
627 /// used to generate new ephemeral key data (which will be stored by the individual channel if
630 /// Note that the seed is required to recover certain on-chain funds independent of
631 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
632 /// channel, and some on-chain during-closing funds.
634 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
635 /// versions. Once the library is more fully supported, the docs will be updated to include a
636 /// detailed description of the guarantee.
637 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
638 let secp_ctx = Secp256k1::signing_only();
639 match ExtendedPrivKey::new_master(network.clone(), seed) {
641 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
642 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
643 Ok(destination_key) => {
644 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
645 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
646 .push_slice(&wpubkey_hash.into_inner())
649 Err(_) => panic!("Your RNG is busted"),
651 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
652 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
653 Err(_) => panic!("Your RNG is busted"),
655 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
656 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
657 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
665 channel_child_index: AtomicUsize::new(0),
667 session_child_index: AtomicUsize::new(0),
668 channel_id_master_key,
669 channel_id_child_index: AtomicUsize::new(0),
677 Err(_) => panic!("Your rng is busted"),
680 fn derive_unique_start(&self) -> Sha256State {
681 let mut unique_start = Sha256::engine();
682 unique_start.input(&byte_utils::be64_to_array(self.starting_time_secs));
683 unique_start.input(&byte_utils::be32_to_array(self.starting_time_nanos));
684 unique_start.input(&self.seed);
687 /// Derive an old set of ChannelKeys for per-channel secrets based on a key derivation
689 /// Key derivation parameters are accessible through a per-channel secrets
690 /// ChannelKeys::key_derivation_params and is provided inside DynamicOuputP2WSH in case of
691 /// onchain output detection for which a corresponding delayed_payment_key must be derived.
692 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, user_id_1: u64, user_id_2: u64) -> InMemoryChannelKeys {
693 let chan_id = ((user_id_1 & 0xFFFF0000) >> 32) as u32;
694 let mut unique_start = Sha256::engine();
695 unique_start.input(&byte_utils::be64_to_array(user_id_2));
696 unique_start.input(&byte_utils::be32_to_array(user_id_1 as u32));
697 unique_start.input(&self.seed);
699 // We only seriously intend to rely on the channel_master_key for true secure
700 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
701 // starting_time provided in the constructor) to be unique.
702 let mut sha = self.derive_unique_start();
704 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");
705 sha.input(&child_privkey.private_key.key[..]);
707 let seed = Sha256::from_engine(sha).into_inner();
709 let commitment_seed = {
710 let mut sha = Sha256::engine();
712 sha.input(&b"commitment seed"[..]);
713 Sha256::from_engine(sha).into_inner()
715 macro_rules! key_step {
716 ($info: expr, $prev_key: expr) => {{
717 let mut sha = Sha256::engine();
719 sha.input(&$prev_key[..]);
720 sha.input(&$info[..]);
721 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
724 let funding_key = key_step!(b"funding key", commitment_seed);
725 let revocation_base_key = key_step!(b"revocation base key", funding_key);
726 let payment_key = key_step!(b"payment key", revocation_base_key);
727 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
728 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
730 InMemoryChannelKeys::new(
735 delayed_payment_base_key,
738 channel_value_satoshis,
739 (user_id_1, user_id_2),
744 impl KeysInterface for KeysManager {
745 type ChanKeySigner = InMemoryChannelKeys;
747 fn get_node_secret(&self) -> SecretKey {
748 self.node_secret.clone()
751 fn get_destination_script(&self) -> Script {
752 self.destination_script.clone()
755 fn get_shutdown_pubkey(&self) -> PublicKey {
756 self.shutdown_pubkey.clone()
759 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
760 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
761 let ix_and_nanos: u64 = (child_ix as u64) << 32 | (self.starting_time_nanos as u64);
762 self.derive_channel_keys(channel_value_satoshis, ix_and_nanos, self.starting_time_secs)
765 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
766 let mut sha = self.derive_unique_start();
768 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
769 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");
770 sha.input(&child_privkey.private_key.key[..]);
772 let mut rng_seed = sha.clone();
773 // Not exactly the most ideal construction, but the second value will get fed into
774 // ChaCha so it is another step harder to break.
775 rng_seed.input(b"RNG Seed Salt");
776 sha.input(b"Session Key Salt");
777 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
778 Sha256::from_engine(rng_seed).into_inner())
781 fn get_channel_id(&self) -> [u8; 32] {
782 let mut sha = self.derive_unique_start();
784 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
785 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");
786 sha.input(&child_privkey.private_key.key[..]);
788 Sha256::from_engine(sha).into_inner()