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.
54 /// The private key which should be used to sign the transaction is provided, as well as the
55 /// full witness redeemScript which is hashed in the output script_pubkey.
56 /// The witness in the spending input should be:
57 /// <BIP 143 signature generated with the given key> <empty vector> (MINIMALIF standard rule)
58 /// <witness_script as provided>
59 /// Note that the nSequence field in the input must be set to_self_delay (which corresponds to
60 /// the transaction not being broadcastable until at least to_self_delay blocks after the input
62 /// These are generally the result of a "revocable" output to us, spendable only by us unless
63 /// it is an output from us having broadcast an old state (which should never happen).
65 /// The outpoint which is spendable
67 /// The secret key which must be used to sign the spending transaction
69 /// The witness redeemScript which is hashed to create the script_pubkey in the given output
70 witness_script: Script,
71 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
72 /// the witness_script.
74 /// The output which is referenced by the given outpoint
77 // TODO: Note that because key is now static and exactly what is provided by us, we should drop
78 // this in favor of StaticOutput:
79 /// An output to a P2WPKH, spendable exclusively by the given private key.
80 /// The witness in the spending input, is, thus, simply:
81 /// <BIP 143 signature generated with the given key> <public key derived from the given key>
82 /// These are generally the result of our counterparty having broadcast the current state,
83 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
85 /// The outpoint which is spendable
87 /// The secret key which must be used to sign the spending transaction
89 /// The output which is reference by the given outpoint
94 impl Writeable for SpendableOutputDescriptor {
95 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
97 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
99 outpoint.write(writer)?;
100 output.write(writer)?;
102 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref key, ref witness_script, ref to_self_delay, ref output } => {
104 outpoint.write(writer)?;
106 witness_script.write(writer)?;
107 to_self_delay.write(writer)?;
108 output.write(writer)?;
110 &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref key, ref output } => {
112 outpoint.write(writer)?;
114 output.write(writer)?;
121 impl Readable for SpendableOutputDescriptor {
122 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
123 match Readable::read(reader)? {
124 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
125 outpoint: Readable::read(reader)?,
126 output: Readable::read(reader)?,
128 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
129 outpoint: Readable::read(reader)?,
130 key: Readable::read(reader)?,
131 witness_script: Readable::read(reader)?,
132 to_self_delay: Readable::read(reader)?,
133 output: Readable::read(reader)?,
135 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH {
136 outpoint: Readable::read(reader)?,
137 key: Readable::read(reader)?,
138 output: Readable::read(reader)?,
140 _ => Err(DecodeError::InvalidValue),
145 /// A trait to describe an object which can get user secrets and key material.
146 pub trait KeysInterface: Send + Sync {
147 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
148 type ChanKeySigner : ChannelKeys;
150 /// Get node secret key (aka node_id or network_key)
151 fn get_node_secret(&self) -> SecretKey;
152 /// Get destination redeemScript to encumber static protocol exit points.
153 fn get_destination_script(&self) -> Script;
154 /// Get shutdown_pubkey to use as PublicKey at channel closure
155 fn get_shutdown_pubkey(&self) -> PublicKey;
156 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
157 /// restarted with some stale data!
158 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
159 /// Get a secret and PRNG seed for construting an onion packet
160 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
161 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
162 /// transaction is created, at which point they will use the outpoint in the funding
164 fn get_channel_id(&self) -> [u8; 32];
167 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
169 /// Signing services could be implemented on a hardware wallet. In this case,
170 /// the current ChannelKeys would be a front-end on top of a communication
171 /// channel connected to your secure device and lightning key material wouldn't
172 /// reside on a hot server. Nevertheless, a this deployment would still need
173 /// to trust the ChannelManager to avoid loss of funds as this latest component
174 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
176 /// A more secure iteration would be to use hashlock (or payment points) to pair
177 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
178 /// at the price of more state and computation on the hardware wallet side. In the future,
179 /// we are looking forward to design such interface.
181 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
182 /// to act, as liveness and breach reply correctness are always going to be hard requirements
183 /// of LN security model, orthogonal of key management issues.
185 /// If you're implementing a custom signer, you almost certainly want to implement
186 /// Readable/Writable to serialize out a unique reference to this set of keys so
187 /// that you can serialize the full ChannelManager object.
189 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
190 // to the possibility of reentrancy issues by calling the user's code during our deserialization
192 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
193 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
194 pub trait ChannelKeys : Send+Clone {
195 /// Gets the private key for the anchor tx
196 fn funding_key<'a>(&'a self) -> &'a SecretKey;
197 /// Gets the local secret key for blinded revocation pubkey
198 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
199 /// Gets the local secret key used in to_remote output of remote commitment tx
200 /// (and also as part of obscured commitment number)
201 fn payment_base_key<'a>(&'a self) -> &'a SecretKey;
202 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
203 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
204 /// Gets the local htlc secret key used in commitment tx htlc outputs
205 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
206 /// Gets the commitment seed
207 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
208 /// Gets the local channel public keys and basepoints
209 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
211 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
213 /// Note that if signing fails or is rejected, the channel will be force-closed.
215 // TODO: Document the things someone using this interface should enforce before signing.
216 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
217 // making the callee generate it via some util function we expose)!
218 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>), ()>;
220 /// Create a signature for a local commitment transaction. This will only ever be called with
221 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
222 /// that it will not be called multiple times.
224 // TODO: Document the things someone using this interface should enforce before signing.
225 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
226 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
228 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
229 /// transactions which will be broadcasted later, after the channel has moved on to a newer
230 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
233 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
235 /// Create a signature for each HTLC transaction spending a local commitment transaction.
237 /// Unlike sign_local_commitment, this may be called multiple times with *different*
238 /// local_commitment_tx values. While this will never be called with a revoked
239 /// local_commitment_tx, it is possible that it is called with the second-latest
240 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
241 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
243 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
244 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
245 /// (implying they were considered dust at the time the commitment transaction was negotiated),
246 /// a corresponding None should be included in the return value. All other positions in the
247 /// return value must contain a signature.
248 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>>, ()>;
250 /// Create a signature for a (proposed) closing transaction.
252 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
253 /// chosen to forgo their output as dust.
254 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
256 /// Signs a channel announcement message with our funding key, proving it comes from one
257 /// of the channel participants.
259 /// Note that if this fails or is rejected, the channel will not be publicly announced and
260 /// our counterparty may (though likely will not) close the channel on us for violating the
262 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
264 /// Set the remote channel basepoints. This is done immediately on incoming channels
265 /// and as soon as the channel is accepted on outgoing channels.
267 /// Will be called before any signatures are applied.
268 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
272 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
273 pub struct InMemoryChannelKeys {
274 /// Private key of anchor tx
275 funding_key: SecretKey,
276 /// Local secret key for blinded revocation pubkey
277 revocation_base_key: SecretKey,
278 /// Local secret key used in commitment tx htlc outputs
279 payment_base_key: SecretKey,
280 /// Local secret key used in HTLC tx
281 delayed_payment_base_key: SecretKey,
282 /// Local htlc secret key used in commitment tx htlc outputs
283 htlc_base_key: SecretKey,
285 commitment_seed: [u8; 32],
286 /// Local public keys and basepoints
287 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
288 /// Remote public keys and base points
289 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
290 /// The total value of this channel
291 channel_value_satoshis: u64,
294 impl InMemoryChannelKeys {
295 /// Create a new InMemoryChannelKeys
296 pub fn new<C: Signing>(
297 secp_ctx: &Secp256k1<C>,
298 funding_key: SecretKey,
299 revocation_base_key: SecretKey,
300 payment_base_key: SecretKey,
301 delayed_payment_base_key: SecretKey,
302 htlc_base_key: SecretKey,
303 commitment_seed: [u8; 32],
304 channel_value_satoshis: u64) -> InMemoryChannelKeys {
305 let local_channel_pubkeys =
306 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
307 &payment_base_key, &delayed_payment_base_key,
309 InMemoryChannelKeys {
313 delayed_payment_base_key,
316 channel_value_satoshis,
317 local_channel_pubkeys,
318 remote_channel_pubkeys: None,
322 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
323 funding_key: &SecretKey,
324 revocation_base_key: &SecretKey,
325 payment_base_key: &SecretKey,
326 delayed_payment_base_key: &SecretKey,
327 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
328 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
330 funding_pubkey: from_secret(&funding_key),
331 revocation_basepoint: from_secret(&revocation_base_key),
332 payment_basepoint: from_secret(&payment_base_key),
333 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
334 htlc_basepoint: from_secret(&htlc_base_key),
339 impl ChannelKeys for InMemoryChannelKeys {
340 fn funding_key(&self) -> &SecretKey { &self.funding_key }
341 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
342 fn payment_base_key(&self) -> &SecretKey { &self.payment_base_key }
343 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
344 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
345 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
346 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
348 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>), ()> {
349 if commitment_tx.input.len() != 1 { return Err(()); }
351 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
352 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
353 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
355 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
356 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
358 let commitment_txid = commitment_tx.txid();
360 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
361 for ref htlc in htlcs {
362 if let Some(_) = htlc.transaction_output_index {
363 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);
364 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
365 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
366 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
368 Err(_) => return Err(()),
370 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
374 Ok((commitment_sig, htlc_sigs))
377 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
378 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
379 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
380 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
382 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
386 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
387 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
388 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
389 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
391 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
394 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>>, ()> {
395 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
398 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
399 if closing_tx.input.len() != 1 { return Err(()); }
400 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
401 if closing_tx.output.len() > 2 { return Err(()); }
403 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
404 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
405 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
407 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
408 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
409 Ok(secp_ctx.sign(&sighash, &self.funding_key))
412 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
413 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
414 Ok(secp_ctx.sign(&msghash, &self.funding_key))
417 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
418 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
419 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
423 impl Writeable for InMemoryChannelKeys {
424 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
425 self.funding_key.write(writer)?;
426 self.revocation_base_key.write(writer)?;
427 self.payment_base_key.write(writer)?;
428 self.delayed_payment_base_key.write(writer)?;
429 self.htlc_base_key.write(writer)?;
430 self.commitment_seed.write(writer)?;
431 self.remote_channel_pubkeys.write(writer)?;
432 self.channel_value_satoshis.write(writer)?;
438 impl Readable for InMemoryChannelKeys {
439 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
440 let funding_key = Readable::read(reader)?;
441 let revocation_base_key = Readable::read(reader)?;
442 let payment_base_key = Readable::read(reader)?;
443 let delayed_payment_base_key = Readable::read(reader)?;
444 let htlc_base_key = Readable::read(reader)?;
445 let commitment_seed = Readable::read(reader)?;
446 let remote_channel_pubkeys = Readable::read(reader)?;
447 let channel_value_satoshis = Readable::read(reader)?;
448 let secp_ctx = Secp256k1::signing_only();
449 let local_channel_pubkeys =
450 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
451 &payment_base_key, &delayed_payment_base_key,
454 Ok(InMemoryChannelKeys {
458 delayed_payment_base_key,
461 channel_value_satoshis,
462 local_channel_pubkeys,
463 remote_channel_pubkeys
468 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
469 /// and derives keys from that.
471 /// Your node_id is seed/0'
472 /// ChannelMonitor closes may use seed/1'
473 /// Cooperative closes may use seed/2'
474 /// The two close keys may be needed to claim on-chain funds!
475 pub struct KeysManager {
476 secp_ctx: Secp256k1<secp256k1::SignOnly>,
477 node_secret: SecretKey,
478 destination_script: Script,
479 shutdown_pubkey: PublicKey,
480 channel_master_key: ExtendedPrivKey,
481 channel_child_index: AtomicUsize,
482 session_master_key: ExtendedPrivKey,
483 session_child_index: AtomicUsize,
484 channel_id_master_key: ExtendedPrivKey,
485 channel_id_child_index: AtomicUsize,
487 unique_start: Sha256State,
492 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
493 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
494 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
495 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
496 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
497 /// simply use the current time (with very high precision).
499 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
500 /// obviously, starting_time should be unique every time you reload the library - it is only
501 /// used to generate new ephemeral key data (which will be stored by the individual channel if
504 /// Note that the seed is required to recover certain on-chain funds independent of
505 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
506 /// channel, and some on-chain during-closing funds.
508 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
509 /// versions. Once the library is more fully supported, the docs will be updated to include a
510 /// detailed description of the guarantee.
511 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
512 let secp_ctx = Secp256k1::signing_only();
513 match ExtendedPrivKey::new_master(network.clone(), seed) {
515 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
516 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
517 Ok(destination_key) => {
518 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
519 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
520 .push_slice(&wpubkey_hash.into_inner())
523 Err(_) => panic!("Your RNG is busted"),
525 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
526 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
527 Err(_) => panic!("Your RNG is busted"),
529 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
530 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
531 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
533 let mut unique_start = Sha256::engine();
534 unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
535 unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
536 unique_start.input(seed);
544 channel_child_index: AtomicUsize::new(0),
546 session_child_index: AtomicUsize::new(0),
547 channel_id_master_key,
548 channel_id_child_index: AtomicUsize::new(0),
554 Err(_) => panic!("Your rng is busted"),
559 impl KeysInterface for KeysManager {
560 type ChanKeySigner = InMemoryChannelKeys;
562 fn get_node_secret(&self) -> SecretKey {
563 self.node_secret.clone()
566 fn get_destination_script(&self) -> Script {
567 self.destination_script.clone()
570 fn get_shutdown_pubkey(&self) -> PublicKey {
571 self.shutdown_pubkey.clone()
574 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
575 // We only seriously intend to rely on the channel_master_key for true secure
576 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
577 // starting_time provided in the constructor) to be unique.
578 let mut sha = self.unique_start.clone();
580 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
581 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");
582 sha.input(&child_privkey.private_key.key[..]);
584 let seed = Sha256::from_engine(sha).into_inner();
586 let commitment_seed = {
587 let mut sha = Sha256::engine();
589 sha.input(&b"commitment seed"[..]);
590 Sha256::from_engine(sha).into_inner()
592 macro_rules! key_step {
593 ($info: expr, $prev_key: expr) => {{
594 let mut sha = Sha256::engine();
596 sha.input(&$prev_key[..]);
597 sha.input(&$info[..]);
598 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
601 let funding_key = key_step!(b"funding key", commitment_seed);
602 let revocation_base_key = key_step!(b"revocation base key", funding_key);
603 let payment_base_key = key_step!(b"payment base key", revocation_base_key);
604 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_base_key);
605 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
607 InMemoryChannelKeys::new(
612 delayed_payment_base_key,
615 channel_value_satoshis
619 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
620 let mut sha = self.unique_start.clone();
622 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
623 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");
624 sha.input(&child_privkey.private_key.key[..]);
626 let mut rng_seed = sha.clone();
627 // Not exactly the most ideal construction, but the second value will get fed into
628 // ChaCha so it is another step harder to break.
629 rng_seed.input(b"RNG Seed Salt");
630 sha.input(b"Session Key Salt");
631 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
632 Sha256::from_engine(rng_seed).into_inner())
635 fn get_channel_id(&self) -> [u8; 32] {
636 let mut sha = self.unique_start.clone();
638 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
639 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");
640 sha.input(&child_privkey.private_key.key[..]);
642 Sha256::from_engine(sha).into_inner()