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_hashes::hash160::Hash as Hash160;
18 use secp256k1::key::{SecretKey, PublicKey};
19 use secp256k1::{Secp256k1, Signature, Signing};
23 use util::logger::Logger;
24 use util::ser::{Writeable, Writer, Readable};
27 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys};
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> <one zero byte aka OP_0>
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 /// 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 /// A trait to describe an object which can get user secrets and key material.
144 pub trait KeysInterface: Send + Sync {
145 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
146 type ChanKeySigner : ChannelKeys;
148 /// Get node secret key (aka node_id or network_key)
149 fn get_node_secret(&self) -> SecretKey;
150 /// Get destination redeemScript to encumber static protocol exit points.
151 fn get_destination_script(&self) -> Script;
152 /// Get shutdown_pubkey to use as PublicKey at channel closure
153 fn get_shutdown_pubkey(&self) -> PublicKey;
154 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
155 /// restarted with some stale data!
156 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
157 /// Get a secret and PRNG seed for construting an onion packet
158 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
159 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
160 /// transaction is created, at which point they will use the outpoint in the funding
162 fn get_channel_id(&self) -> [u8; 32];
165 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
167 /// Signing services could be implemented on a hardware wallet. In this case,
168 /// the current ChannelKeys would be a front-end on top of a communication
169 /// channel connected to your secure device and lightning key material wouldn't
170 /// reside on a hot server. Nevertheless, a this deployment would still need
171 /// to trust the ChannelManager to avoid loss of funds as this latest component
172 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
174 /// A more secure iteration would be to use hashlock (or payment points) to pair
175 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
176 /// at the price of more state and computation on the hardware wallet side. In the future,
177 /// we are looking forward to design such interface.
179 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
180 /// to act, as liveness and breach reply correctness are always going to be hard requirements
181 /// of LN security model, orthogonal of key management issues.
183 /// If you're implementing a custom signer, you almost certainly want to implement
184 /// Readable/Writable to serialize out a unique reference to this set of keys so
185 /// that you can serialize the full ChannelManager object.
187 /// (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
188 /// to the possibility of reentrancy issues by calling the user's code during our deserialization
190 /// TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
191 /// ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
192 pub trait ChannelKeys : Send+Clone {
193 /// Gets the private key for the anchor tx
194 fn funding_key<'a>(&'a self) -> &'a SecretKey;
195 /// Gets the local secret key for blinded revocation pubkey
196 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
197 /// Gets the local secret key used in to_remote output of remote commitment tx
198 /// (and also as part of obscured commitment number)
199 fn payment_base_key<'a>(&'a self) -> &'a SecretKey;
200 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
201 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
202 /// Gets the local htlc secret key used in commitment tx htlc outputs
203 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
204 /// Gets the commitment seed
205 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
206 /// Gets the local channel public keys and basepoints
207 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
209 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
211 /// Note that if signing fails or is rejected, the channel will be force-closed.
213 /// TODO: Document the things someone using this interface should enforce before signing.
214 /// TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
215 /// making the callee generate it via some util function we expose)!
216 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>), ()>;
218 /// Create a signature for a (proposed) closing transaction.
220 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
221 /// chosen to forgo their output as dust.
222 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
224 /// Signs a channel announcement message with our funding key, proving it comes from one
225 /// of the channel participants.
227 /// Note that if this fails or is rejected, the channel will not be publicly announced and
228 /// our counterparty may (though likely will not) close the channel on us for violating the
230 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
232 /// Set the remote channel basepoints. This is done immediately on incoming channels
233 /// and as soon as the channel is accepted on outgoing channels.
235 /// Will be called before any signatures are applied.
236 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
240 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
241 pub struct InMemoryChannelKeys {
242 /// Private key of anchor tx
243 funding_key: SecretKey,
244 /// Local secret key for blinded revocation pubkey
245 revocation_base_key: SecretKey,
246 /// Local secret key used in commitment tx htlc outputs
247 payment_base_key: SecretKey,
248 /// Local secret key used in HTLC tx
249 delayed_payment_base_key: SecretKey,
250 /// Local htlc secret key used in commitment tx htlc outputs
251 htlc_base_key: SecretKey,
253 commitment_seed: [u8; 32],
254 /// Local public keys and basepoints
255 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
256 /// Remote public keys and base points
257 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
258 /// The total value of this channel
259 channel_value_satoshis: u64,
262 impl InMemoryChannelKeys {
263 /// Create a new InMemoryChannelKeys
264 pub fn new<C: Signing>(
265 secp_ctx: &Secp256k1<C>,
266 funding_key: SecretKey,
267 revocation_base_key: SecretKey,
268 payment_base_key: SecretKey,
269 delayed_payment_base_key: SecretKey,
270 htlc_base_key: SecretKey,
271 commitment_seed: [u8; 32],
272 channel_value_satoshis: u64) -> InMemoryChannelKeys {
273 let local_channel_pubkeys =
274 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
275 &payment_base_key, &delayed_payment_base_key,
277 InMemoryChannelKeys {
281 delayed_payment_base_key,
284 channel_value_satoshis,
285 local_channel_pubkeys,
286 remote_channel_pubkeys: None,
290 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
291 funding_key: &SecretKey,
292 revocation_base_key: &SecretKey,
293 payment_base_key: &SecretKey,
294 delayed_payment_base_key: &SecretKey,
295 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
296 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
298 funding_pubkey: from_secret(&funding_key),
299 revocation_basepoint: from_secret(&revocation_base_key),
300 payment_basepoint: from_secret(&payment_base_key),
301 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
302 htlc_basepoint: from_secret(&htlc_base_key),
307 impl ChannelKeys for InMemoryChannelKeys {
308 fn funding_key(&self) -> &SecretKey { &self.funding_key }
309 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
310 fn payment_base_key(&self) -> &SecretKey { &self.payment_base_key }
311 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
312 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
313 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
314 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
316 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>), ()> {
317 if commitment_tx.input.len() != 1 { return Err(()); }
319 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
320 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
321 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
323 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
324 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
326 let commitment_txid = commitment_tx.txid();
328 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
329 for ref htlc in htlcs {
330 if let Some(_) = htlc.transaction_output_index {
331 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);
332 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
333 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
334 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
336 Err(_) => return Err(()),
338 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
342 Ok((commitment_sig, htlc_sigs))
345 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
346 if closing_tx.input.len() != 1 { return Err(()); }
347 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
348 if closing_tx.output.len() > 2 { return Err(()); }
350 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
351 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
352 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
354 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
355 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
356 Ok(secp_ctx.sign(&sighash, &self.funding_key))
359 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
360 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
361 Ok(secp_ctx.sign(&msghash, &self.funding_key))
364 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
365 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
366 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
370 impl Writeable for InMemoryChannelKeys {
371 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
372 self.funding_key.write(writer)?;
373 self.revocation_base_key.write(writer)?;
374 self.payment_base_key.write(writer)?;
375 self.delayed_payment_base_key.write(writer)?;
376 self.htlc_base_key.write(writer)?;
377 self.commitment_seed.write(writer)?;
378 self.remote_channel_pubkeys.write(writer)?;
379 self.channel_value_satoshis.write(writer)?;
385 impl Readable for InMemoryChannelKeys {
386 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
387 let funding_key = Readable::read(reader)?;
388 let revocation_base_key = Readable::read(reader)?;
389 let payment_base_key = Readable::read(reader)?;
390 let delayed_payment_base_key = Readable::read(reader)?;
391 let htlc_base_key = Readable::read(reader)?;
392 let commitment_seed = Readable::read(reader)?;
393 let remote_channel_pubkeys = Readable::read(reader)?;
394 let channel_value_satoshis = Readable::read(reader)?;
395 let secp_ctx = Secp256k1::signing_only();
396 let local_channel_pubkeys =
397 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
398 &payment_base_key, &delayed_payment_base_key,
401 Ok(InMemoryChannelKeys {
405 delayed_payment_base_key,
408 channel_value_satoshis,
409 local_channel_pubkeys,
410 remote_channel_pubkeys
415 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
416 /// and derives keys from that.
418 /// Your node_id is seed/0'
419 /// ChannelMonitor closes may use seed/1'
420 /// Cooperative closes may use seed/2'
421 /// The two close keys may be needed to claim on-chain funds!
422 pub struct KeysManager {
423 secp_ctx: Secp256k1<secp256k1::SignOnly>,
424 node_secret: SecretKey,
425 destination_script: Script,
426 shutdown_pubkey: PublicKey,
427 channel_master_key: ExtendedPrivKey,
428 channel_child_index: AtomicUsize,
429 session_master_key: ExtendedPrivKey,
430 session_child_index: AtomicUsize,
431 channel_id_master_key: ExtendedPrivKey,
432 channel_id_child_index: AtomicUsize,
434 unique_start: Sha256State,
439 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
440 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
441 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
442 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
443 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
444 /// simply use the current time (with very high precision).
446 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
447 /// obviously, starting_time should be unique every time you reload the library - it is only
448 /// used to generate new ephemeral key data (which will be stored by the individual channel if
451 /// Note that the seed is required to recover certain on-chain funds independent of
452 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
453 /// channel, and some on-chain during-closing funds.
455 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
456 /// versions. Once the library is more fully supported, the docs will be updated to include a
457 /// detailed description of the guarantee.
458 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
459 let secp_ctx = Secp256k1::signing_only();
460 match ExtendedPrivKey::new_master(network.clone(), seed) {
462 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
463 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
464 Ok(destination_key) => {
465 let pubkey_hash160 = Hash160::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.key.serialize()[..]);
466 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
467 .push_slice(&pubkey_hash160.into_inner())
470 Err(_) => panic!("Your RNG is busted"),
472 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
473 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
474 Err(_) => panic!("Your RNG is busted"),
476 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
477 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
478 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
480 let mut unique_start = Sha256::engine();
481 unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
482 unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
483 unique_start.input(seed);
491 channel_child_index: AtomicUsize::new(0),
493 session_child_index: AtomicUsize::new(0),
494 channel_id_master_key,
495 channel_id_child_index: AtomicUsize::new(0),
501 Err(_) => panic!("Your rng is busted"),
506 impl KeysInterface for KeysManager {
507 type ChanKeySigner = InMemoryChannelKeys;
509 fn get_node_secret(&self) -> SecretKey {
510 self.node_secret.clone()
513 fn get_destination_script(&self) -> Script {
514 self.destination_script.clone()
517 fn get_shutdown_pubkey(&self) -> PublicKey {
518 self.shutdown_pubkey.clone()
521 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
522 // We only seriously intend to rely on the channel_master_key for true secure
523 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
524 // starting_time provided in the constructor) to be unique.
525 let mut sha = self.unique_start.clone();
527 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
528 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");
529 sha.input(&child_privkey.private_key.key[..]);
531 let seed = Sha256::from_engine(sha).into_inner();
533 let commitment_seed = {
534 let mut sha = Sha256::engine();
536 sha.input(&b"commitment seed"[..]);
537 Sha256::from_engine(sha).into_inner()
539 macro_rules! key_step {
540 ($info: expr, $prev_key: expr) => {{
541 let mut sha = Sha256::engine();
543 sha.input(&$prev_key[..]);
544 sha.input(&$info[..]);
545 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
548 let funding_key = key_step!(b"funding key", commitment_seed);
549 let revocation_base_key = key_step!(b"revocation base key", funding_key);
550 let payment_base_key = key_step!(b"payment base key", revocation_base_key);
551 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_base_key);
552 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
554 InMemoryChannelKeys::new(
559 delayed_payment_base_key,
562 channel_value_satoshis
566 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
567 let mut sha = self.unique_start.clone();
569 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
570 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");
571 sha.input(&child_privkey.private_key.key[..]);
573 let mut rng_seed = sha.clone();
574 // Not exactly the most ideal construction, but the second value will get fed into
575 // ChaCha so it is another step harder to break.
576 rng_seed.input(b"RNG Seed Salt");
577 sha.input(b"Session Key Salt");
578 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
579 Sha256::from_engine(rng_seed).into_inner())
582 fn get_channel_id(&self) -> [u8; 32] {
583 let mut sha = self.unique_start.clone();
585 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
586 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");
587 sha.input(&child_privkey.private_key.key[..]);
589 (Sha256::from_engine(sha).into_inner())