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};
29 use std::sync::atomic::{AtomicUsize, Ordering};
31 use ln::msgs::DecodeError;
33 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
34 /// claim at any point in the future) an event is generated which you must track and be able to
35 /// spend on-chain. The information needed to do this is provided in this enum, including the
36 /// outpoint describing which txid and output index is available, the full output which exists at
37 /// that txid/index, and any keys or other information required to sign.
38 #[derive(Clone, PartialEq)]
39 pub enum SpendableOutputDescriptor {
40 /// An output to a script which was provided via KeysInterface, thus you should already know
41 /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the
42 /// script_pubkey as it appears in the output.
43 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
44 /// on-chain using the payment preimage or after it has timed out.
46 /// The outpoint which is spendable
48 /// The output which is referenced by the given outpoint.
51 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
52 /// The private key which should be used to sign the transaction is provided, as well as the
53 /// full witness redeemScript which is hashed in the output script_pubkey.
54 /// The witness in the spending input should be:
55 /// <BIP 143 signature generated with the given key> <empty vector> (MINIMALIF standard rule)
56 /// <witness_script as provided>
57 /// Note that the nSequence field in the input must be set to_self_delay (which corresponds to
58 /// the transaction not being broadcastable until at least to_self_delay blocks after the input
60 /// These are generally the result of a "revocable" output to us, spendable only by us unless
61 /// it is an output from us having broadcast an old state (which should never happen).
63 /// The outpoint which is spendable
65 /// The secret key which must be used to sign the spending transaction
67 /// The witness redeemScript which is hashed to create the script_pubkey in the given output
68 witness_script: Script,
69 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
70 /// the witness_script.
72 /// The output which is referenced by the given outpoint
75 // TODO: Note that because key is now static and exactly what is provided by us, we should drop
76 // this in favor of StaticOutput:
77 /// An output to a P2WPKH, spendable exclusively by the given private key.
78 /// The witness in the spending input, is, thus, simply:
79 /// <BIP 143 signature generated with the given key> <public key derived from the given key>
80 /// These are generally the result of our counterparty having broadcast the current state,
81 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
83 /// The outpoint which is spendable
85 /// The secret key which must be used to sign the spending transaction
87 /// The output which is reference by the given outpoint
92 impl Writeable for SpendableOutputDescriptor {
93 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
95 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
97 outpoint.write(writer)?;
98 output.write(writer)?;
100 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref key, ref witness_script, ref to_self_delay, ref output } => {
102 outpoint.write(writer)?;
104 witness_script.write(writer)?;
105 to_self_delay.write(writer)?;
106 output.write(writer)?;
108 &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref key, ref output } => {
110 outpoint.write(writer)?;
112 output.write(writer)?;
119 impl Readable for SpendableOutputDescriptor {
120 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
121 match Readable::read(reader)? {
122 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
123 outpoint: Readable::read(reader)?,
124 output: Readable::read(reader)?,
126 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
127 outpoint: Readable::read(reader)?,
128 key: Readable::read(reader)?,
129 witness_script: Readable::read(reader)?,
130 to_self_delay: Readable::read(reader)?,
131 output: Readable::read(reader)?,
133 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH {
134 outpoint: Readable::read(reader)?,
135 key: Readable::read(reader)?,
136 output: Readable::read(reader)?,
138 _ => Err(DecodeError::InvalidValue),
143 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
145 /// Signing services could be implemented on a hardware wallet. In this case,
146 /// the current ChannelKeys would be a front-end on top of a communication
147 /// channel connected to your secure device and lightning key material wouldn't
148 /// reside on a hot server. Nevertheless, a this deployment would still need
149 /// to trust the ChannelManager to avoid loss of funds as this latest component
150 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
152 /// A more secure iteration would be to use hashlock (or payment points) to pair
153 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
154 /// at the price of more state and computation on the hardware wallet side. In the future,
155 /// we are looking forward to design such interface.
157 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
158 /// to act, as liveness and breach reply correctness are always going to be hard requirements
159 /// of LN security model, orthogonal of key management issues.
161 /// If you're implementing a custom signer, you almost certainly want to implement
162 /// Readable/Writable to serialize out a unique reference to this set of keys so
163 /// that you can serialize the full ChannelManager object.
165 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
166 // to the possibility of reentrancy issues by calling the user's code during our deserialization
168 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
169 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
170 pub trait ChannelKeys : Send+Clone {
171 /// Gets the private key for the anchor tx
172 fn funding_key<'a>(&'a self) -> &'a SecretKey;
173 /// Gets the local secret key for blinded revocation pubkey
174 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
175 /// Gets the local secret key used in the to_remote output of remote commitment tx (ie the
176 /// output to us in transactions our counterparty broadcasts).
177 /// Also as part of obscured commitment number.
178 fn payment_key<'a>(&'a self) -> &'a SecretKey;
179 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
180 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
181 /// Gets the local htlc secret key used in commitment tx htlc outputs
182 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
183 /// Gets the commitment seed
184 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
185 /// Gets the local channel public keys and basepoints
186 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
188 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
190 /// Note that if signing fails or is rejected, the channel will be force-closed.
192 // TODO: Document the things someone using this interface should enforce before signing.
193 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
194 // making the callee generate it via some util function we expose)!
195 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>), ()>;
197 /// Create a signature for a local commitment transaction. This will only ever be called with
198 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
199 /// that it will not be called multiple times.
201 // TODO: Document the things someone using this interface should enforce before signing.
202 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
203 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
205 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
206 /// transactions which will be broadcasted later, after the channel has moved on to a newer
207 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
210 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
212 /// Create a signature for each HTLC transaction spending a local commitment transaction.
214 /// Unlike sign_local_commitment, this may be called multiple times with *different*
215 /// local_commitment_tx values. While this will never be called with a revoked
216 /// local_commitment_tx, it is possible that it is called with the second-latest
217 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
218 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
220 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
221 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
222 /// (implying they were considered dust at the time the commitment transaction was negotiated),
223 /// a corresponding None should be included in the return value. All other positions in the
224 /// return value must contain a signature.
225 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>>, ()>;
227 /// Create a signature for a (proposed) closing transaction.
229 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
230 /// chosen to forgo their output as dust.
231 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
233 /// Signs a channel announcement message with our funding key, proving it comes from one
234 /// of the channel participants.
236 /// Note that if this fails or is rejected, the channel will not be publicly announced and
237 /// our counterparty may (though likely will not) close the channel on us for violating the
239 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
241 /// Set the remote channel basepoints. This is done immediately on incoming channels
242 /// and as soon as the channel is accepted on outgoing channels.
244 /// Will be called before any signatures are applied.
245 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
248 /// A trait to describe an object which can get user secrets and key material.
249 pub trait KeysInterface: Send + Sync {
250 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
251 type ChanKeySigner : ChannelKeys;
253 /// Get node secret key (aka node_id or network_key)
254 fn get_node_secret(&self) -> SecretKey;
255 /// Get destination redeemScript to encumber static protocol exit points.
256 fn get_destination_script(&self) -> Script;
257 /// Get shutdown_pubkey to use as PublicKey at channel closure
258 fn get_shutdown_pubkey(&self) -> PublicKey;
259 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
260 /// restarted with some stale data!
261 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
262 /// Get a secret and PRNG seed for constructing an onion packet
263 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
264 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
265 /// transaction is created, at which point they will use the outpoint in the funding
267 fn get_channel_id(&self) -> [u8; 32];
271 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
272 pub struct InMemoryChannelKeys {
273 /// Private key of anchor tx
274 funding_key: SecretKey,
275 /// Local secret key for blinded revocation pubkey
276 revocation_base_key: SecretKey,
277 /// Local secret key used for our balance in remote-broadcasted commitment transactions
278 payment_key: SecretKey,
279 /// Local secret key used in HTLC tx
280 delayed_payment_base_key: SecretKey,
281 /// Local htlc secret key used in commitment tx htlc outputs
282 htlc_base_key: SecretKey,
284 commitment_seed: [u8; 32],
285 /// Local public keys and basepoints
286 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
287 /// Remote public keys and base points
288 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
289 /// The total value of this channel
290 channel_value_satoshis: u64,
293 impl InMemoryChannelKeys {
294 /// Create a new InMemoryChannelKeys
295 pub fn new<C: Signing>(
296 secp_ctx: &Secp256k1<C>,
297 funding_key: SecretKey,
298 revocation_base_key: SecretKey,
299 payment_key: SecretKey,
300 delayed_payment_base_key: SecretKey,
301 htlc_base_key: SecretKey,
302 commitment_seed: [u8; 32],
303 channel_value_satoshis: u64) -> InMemoryChannelKeys {
304 let local_channel_pubkeys =
305 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
306 &payment_key, &delayed_payment_base_key,
308 InMemoryChannelKeys {
312 delayed_payment_base_key,
315 channel_value_satoshis,
316 local_channel_pubkeys,
317 remote_channel_pubkeys: None,
321 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
322 funding_key: &SecretKey,
323 revocation_base_key: &SecretKey,
324 payment_key: &SecretKey,
325 delayed_payment_base_key: &SecretKey,
326 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
327 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
329 funding_pubkey: from_secret(&funding_key),
330 revocation_basepoint: from_secret(&revocation_base_key),
331 payment_point: from_secret(&payment_key),
332 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
333 htlc_basepoint: from_secret(&htlc_base_key),
338 impl ChannelKeys for InMemoryChannelKeys {
339 fn funding_key(&self) -> &SecretKey { &self.funding_key }
340 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
341 fn payment_key(&self) -> &SecretKey { &self.payment_key }
342 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
343 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
344 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
345 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
347 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>), ()> {
348 if commitment_tx.input.len() != 1 { return Err(()); }
350 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
351 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
352 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
354 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
355 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
357 let commitment_txid = commitment_tx.txid();
359 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
360 for ref htlc in htlcs {
361 if let Some(_) = htlc.transaction_output_index {
362 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);
363 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
364 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
365 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
367 Err(_) => return Err(()),
369 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
373 Ok((commitment_sig, htlc_sigs))
376 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
377 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
378 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
379 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
381 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
385 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
386 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
387 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
388 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
390 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
393 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>>, ()> {
394 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
397 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
398 if closing_tx.input.len() != 1 { return Err(()); }
399 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
400 if closing_tx.output.len() > 2 { return Err(()); }
402 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
403 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
404 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
406 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
407 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
408 Ok(secp_ctx.sign(&sighash, &self.funding_key))
411 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
412 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
413 Ok(secp_ctx.sign(&msghash, &self.funding_key))
416 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
417 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
418 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
422 impl Writeable for InMemoryChannelKeys {
423 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
424 self.funding_key.write(writer)?;
425 self.revocation_base_key.write(writer)?;
426 self.payment_key.write(writer)?;
427 self.delayed_payment_base_key.write(writer)?;
428 self.htlc_base_key.write(writer)?;
429 self.commitment_seed.write(writer)?;
430 self.remote_channel_pubkeys.write(writer)?;
431 self.channel_value_satoshis.write(writer)?;
437 impl Readable for InMemoryChannelKeys {
438 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
439 let funding_key = Readable::read(reader)?;
440 let revocation_base_key = Readable::read(reader)?;
441 let payment_key = Readable::read(reader)?;
442 let delayed_payment_base_key = Readable::read(reader)?;
443 let htlc_base_key = Readable::read(reader)?;
444 let commitment_seed = Readable::read(reader)?;
445 let remote_channel_pubkeys = Readable::read(reader)?;
446 let channel_value_satoshis = Readable::read(reader)?;
447 let secp_ctx = Secp256k1::signing_only();
448 let local_channel_pubkeys =
449 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
450 &payment_key, &delayed_payment_base_key,
453 Ok(InMemoryChannelKeys {
457 delayed_payment_base_key,
460 channel_value_satoshis,
461 local_channel_pubkeys,
462 remote_channel_pubkeys
467 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
468 /// and derives keys from that.
470 /// Your node_id is seed/0'
471 /// ChannelMonitor closes may use seed/1'
472 /// Cooperative closes may use seed/2'
473 /// The two close keys may be needed to claim on-chain funds!
474 pub struct KeysManager {
475 secp_ctx: Secp256k1<secp256k1::SignOnly>,
476 node_secret: SecretKey,
477 destination_script: Script,
478 shutdown_pubkey: PublicKey,
479 channel_master_key: ExtendedPrivKey,
480 channel_child_index: AtomicUsize,
481 session_master_key: ExtendedPrivKey,
482 session_child_index: AtomicUsize,
483 channel_id_master_key: ExtendedPrivKey,
484 channel_id_child_index: AtomicUsize,
486 unique_start: Sha256State,
490 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
491 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
492 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
493 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
494 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
495 /// simply use the current time (with very high precision).
497 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
498 /// obviously, starting_time should be unique every time you reload the library - it is only
499 /// used to generate new ephemeral key data (which will be stored by the individual channel if
502 /// Note that the seed is required to recover certain on-chain funds independent of
503 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
504 /// channel, and some on-chain during-closing funds.
506 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
507 /// versions. Once the library is more fully supported, the docs will be updated to include a
508 /// detailed description of the guarantee.
509 pub fn new(seed: &[u8; 32], network: Network, starting_time_secs: u64, starting_time_nanos: u32) -> Self {
510 let secp_ctx = Secp256k1::signing_only();
511 match ExtendedPrivKey::new_master(network.clone(), seed) {
513 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
514 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
515 Ok(destination_key) => {
516 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
517 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
518 .push_slice(&wpubkey_hash.into_inner())
521 Err(_) => panic!("Your RNG is busted"),
523 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
524 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
525 Err(_) => panic!("Your RNG is busted"),
527 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
528 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
529 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
531 let mut unique_start = Sha256::engine();
532 unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
533 unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
534 unique_start.input(seed);
542 channel_child_index: AtomicUsize::new(0),
544 session_child_index: AtomicUsize::new(0),
545 channel_id_master_key,
546 channel_id_child_index: AtomicUsize::new(0),
551 Err(_) => panic!("Your rng is busted"),
556 impl KeysInterface for KeysManager {
557 type ChanKeySigner = InMemoryChannelKeys;
559 fn get_node_secret(&self) -> SecretKey {
560 self.node_secret.clone()
563 fn get_destination_script(&self) -> Script {
564 self.destination_script.clone()
567 fn get_shutdown_pubkey(&self) -> PublicKey {
568 self.shutdown_pubkey.clone()
571 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
572 // We only seriously intend to rely on the channel_master_key for true secure
573 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
574 // starting_time provided in the constructor) to be unique.
575 let mut sha = self.unique_start.clone();
577 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
578 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
579 sha.input(&child_privkey.private_key.key[..]);
581 let seed = Sha256::from_engine(sha).into_inner();
583 let commitment_seed = {
584 let mut sha = Sha256::engine();
586 sha.input(&b"commitment seed"[..]);
587 Sha256::from_engine(sha).into_inner()
589 macro_rules! key_step {
590 ($info: expr, $prev_key: expr) => {{
591 let mut sha = Sha256::engine();
593 sha.input(&$prev_key[..]);
594 sha.input(&$info[..]);
595 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
598 let funding_key = key_step!(b"funding key", commitment_seed);
599 let revocation_base_key = key_step!(b"revocation base key", funding_key);
600 let payment_key = key_step!(b"payment key", revocation_base_key);
601 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
602 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
604 InMemoryChannelKeys::new(
609 delayed_payment_base_key,
612 channel_value_satoshis
616 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
617 let mut sha = self.unique_start.clone();
619 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
620 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");
621 sha.input(&child_privkey.private_key.key[..]);
623 let mut rng_seed = sha.clone();
624 // Not exactly the most ideal construction, but the second value will get fed into
625 // ChaCha so it is another step harder to break.
626 rng_seed.input(b"RNG Seed Salt");
627 sha.input(b"Session Key Salt");
628 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
629 Sha256::from_engine(rng_seed).into_inner())
632 fn get_channel_id(&self) -> [u8; 32] {
633 let mut sha = self.unique_start.clone();
635 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
636 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");
637 sha.input(&child_privkey.private_key.key[..]);
639 Sha256::from_engine(sha).into_inner()