]> git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/chain/keysinterface.rs
Allow BaseSign validation functions to return an Err
[rust-lightning] / lightning / src / chain / keysinterface.rs
1 // This file is Copyright its original authors, visible in version control
2 // history.
3 //
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
8 // licenses.
9
10 //! keysinterface provides keys into rust-lightning and defines some useful enums which describe
11 //! spendable on-chain outputs which the user owns and is responsible for using just as any other
12 //! on-chain output which is theirs.
13
14 use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn, SigHashType};
15 use bitcoin::blockdata::script::{Script, Builder};
16 use bitcoin::blockdata::opcodes;
17 use bitcoin::network::constants::Network;
18 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
19 use bitcoin::util::bip143;
20
21 use bitcoin::hashes::{Hash, HashEngine};
22 use bitcoin::hashes::sha256::HashEngine as Sha256State;
23 use bitcoin::hashes::sha256::Hash as Sha256;
24 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
25 use bitcoin::hash_types::WPubkeyHash;
26
27 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
28 use bitcoin::secp256k1::{Secp256k1, Signature, Signing};
29 use bitcoin::secp256k1::recovery::RecoverableSignature;
30 use bitcoin::secp256k1;
31
32 use util::{byte_utils, transaction_utils};
33 use util::ser::{Writeable, Writer, Readable};
34
35 use chain::transaction::OutPoint;
36 use ln::chan_utils;
37 use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction};
38 use ln::msgs::UnsignedChannelAnnouncement;
39 use ln::script::ShutdownScript;
40
41 use prelude::*;
42 use core::sync::atomic::{AtomicUsize, Ordering};
43 use io::{self, Error};
44 use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
45
46 /// Information about a spendable output to a P2WSH script. See
47 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
48 #[derive(Clone, Debug, PartialEq)]
49 pub struct DelayedPaymentOutputDescriptor {
50         /// The outpoint which is spendable
51         pub outpoint: OutPoint,
52         /// Per commitment point to derive delayed_payment_key by key holder
53         pub per_commitment_point: PublicKey,
54         /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
55         /// the witness_script.
56         pub to_self_delay: u16,
57         /// The output which is referenced by the given outpoint
58         pub output: TxOut,
59         /// The revocation point specific to the commitment transaction which was broadcast. Used to
60         /// derive the witnessScript for this output.
61         pub revocation_pubkey: PublicKey,
62         /// Arbitrary identification information returned by a call to
63         /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
64         /// the channel to spend the output.
65         pub channel_keys_id: [u8; 32],
66         /// The value of the channel which this output originated from, possibly indirectly.
67         pub channel_value_satoshis: u64,
68 }
69 impl DelayedPaymentOutputDescriptor {
70         /// The maximum length a well-formed witness spending one of these should have.
71         // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
72         // redeemscript push length.
73         pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
74 }
75
76 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
77         (0, outpoint, required),
78         (2, per_commitment_point, required),
79         (4, to_self_delay, required),
80         (6, output, required),
81         (8, revocation_pubkey, required),
82         (10, channel_keys_id, required),
83         (12, channel_value_satoshis, required),
84 });
85
86 /// Information about a spendable output to our "payment key". See
87 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
88 #[derive(Clone, Debug, PartialEq)]
89 pub struct StaticPaymentOutputDescriptor {
90         /// The outpoint which is spendable
91         pub outpoint: OutPoint,
92         /// The output which is referenced by the given outpoint
93         pub output: TxOut,
94         /// Arbitrary identification information returned by a call to
95         /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
96         /// the channel to spend the output.
97         pub channel_keys_id: [u8; 32],
98         /// The value of the channel which this transactions spends.
99         pub channel_value_satoshis: u64,
100 }
101 impl StaticPaymentOutputDescriptor {
102         /// The maximum length a well-formed witness spending one of these should have.
103         // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
104         // redeemscript push length.
105         pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
106 }
107 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
108         (0, outpoint, required),
109         (2, output, required),
110         (4, channel_keys_id, required),
111         (6, channel_value_satoshis, required),
112 });
113
114 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
115 /// claim at any point in the future) an event is generated which you must track and be able to
116 /// spend on-chain. The information needed to do this is provided in this enum, including the
117 /// outpoint describing which txid and output index is available, the full output which exists at
118 /// that txid/index, and any keys or other information required to sign.
119 #[derive(Clone, Debug, PartialEq)]
120 pub enum SpendableOutputDescriptor {
121         /// An output to a script which was provided via KeysInterface directly, either from
122         /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
123         /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
124         /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
125         /// on-chain using the payment preimage or after it has timed out.
126         StaticOutput {
127                 /// The outpoint which is spendable
128                 outpoint: OutPoint,
129                 /// The output which is referenced by the given outpoint.
130                 output: TxOut,
131         },
132         /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
133         ///
134         /// The witness in the spending input should be:
135         /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
136         ///
137         /// Note that the nSequence field in the spending input must be set to to_self_delay
138         /// (which means the transaction is not broadcastable until at least to_self_delay
139         /// blocks after the outpoint confirms).
140         ///
141         /// These are generally the result of a "revocable" output to us, spendable only by us unless
142         /// it is an output from an old state which we broadcast (which should never happen).
143         ///
144         /// To derive the delayed_payment key which is used to sign for this input, you must pass the
145         /// holder delayed_payment_base_key (ie the private key which corresponds to the pubkey in
146         /// Sign::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
147         /// chan_utils::derive_private_key. The public key can be generated without the secret key
148         /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
149         /// Sign::pubkeys().
150         ///
151         /// To derive the revocation_pubkey provided here (which is used in the witness
152         /// script generation), you must pass the counterparty revocation_basepoint (which appears in the
153         /// call to Sign::ready_channel) and the provided per_commitment point
154         /// to chan_utils::derive_public_revocation_key.
155         ///
156         /// The witness script which is hashed and included in the output script_pubkey may be
157         /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
158         /// (derived as above), and the to_self_delay contained here to
159         /// chan_utils::get_revokeable_redeemscript.
160         DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
161         /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
162         /// corresponds to the public key in Sign::pubkeys().payment_point).
163         /// The witness in the spending input, is, thus, simply:
164         /// <BIP 143 signature> <payment key>
165         ///
166         /// These are generally the result of our counterparty having broadcast the current state,
167         /// allowing us to claim the non-HTLC-encumbered outputs immediately.
168         StaticPaymentOutput(StaticPaymentOutputDescriptor),
169 }
170
171 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
172         (0, StaticOutput) => {
173                 (0, outpoint, required),
174                 (2, output, required),
175         },
176 ;
177         (1, DelayedPaymentOutput),
178         (2, StaticPaymentOutput),
179 );
180
181 /// A trait to sign lightning channel transactions as described in BOLT 3.
182 ///
183 /// Signing services could be implemented on a hardware wallet. In this case,
184 /// the current Sign would be a front-end on top of a communication
185 /// channel connected to your secure device and lightning key material wouldn't
186 /// reside on a hot server. Nevertheless, a this deployment would still need
187 /// to trust the ChannelManager to avoid loss of funds as this latest component
188 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
189 ///
190 /// A more secure iteration would be to use hashlock (or payment points) to pair
191 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
192 /// at the price of more state and computation on the hardware wallet side. In the future,
193 /// we are looking forward to design such interface.
194 ///
195 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
196 /// to act, as liveness and breach reply correctness are always going to be hard requirements
197 /// of LN security model, orthogonal of key management issues.
198 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
199 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
200 pub trait BaseSign {
201         /// Gets the per-commitment point for a specific commitment number
202         ///
203         /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
204         fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
205         /// Gets the commitment secret for a specific commitment number as part of the revocation process
206         ///
207         /// An external signer implementation should error here if the commitment was already signed
208         /// and should refuse to sign it in the future.
209         ///
210         /// May be called more than once for the same index.
211         ///
212         /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
213         // TODO: return a Result so we can signal a validation error
214         fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
215         /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
216         ///
217         /// This is required in order for the signer to make sure that releasing a commitment
218         /// secret won't leave us without a broadcastable holder transaction.
219         /// Policy checks should be implemented in this function, including checking the amount
220         /// sent to us and checking the HTLCs.
221         fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction) -> Result<(), ()>;
222         /// Gets the holder's channel public keys and basepoints
223         fn pubkeys(&self) -> &ChannelPublicKeys;
224         /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
225         /// some SpendableOutputDescriptor types. This should be sufficient to identify this
226         /// Sign object uniquely and lookup or re-derive its keys.
227         fn channel_keys_id(&self) -> [u8; 32];
228
229         /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
230         ///
231         /// Note that if signing fails or is rejected, the channel will be force-closed.
232         ///
233         /// Policy checks should be implemented in this function, including checking the amount
234         /// sent to us and checking the HTLCs.
235         //
236         // TODO: Document the things someone using this interface should enforce before signing.
237         fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
238         /// Validate the counterparty's revocation.
239         ///
240         /// This is required in order for the signer to make sure that the state has moved
241         /// forward and it is safe to sign the next counterparty commitment.
242         fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
243
244         /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
245         /// This will only ever be called with a non-revoked commitment_tx.  This will be called with the
246         /// latest commitment_tx when we initiate a force-close.
247         /// This will be called with the previous latest, just to get claiming HTLC signatures, if we are
248         /// reacting to a ChannelMonitor replica that decided to broadcast before it had been updated to
249         /// the latest.
250         /// This may be called multiple times for the same transaction.
251         ///
252         /// An external signer implementation should check that the commitment has not been revoked.
253         ///
254         /// May return Err if key derivation fails.  Callers, such as ChannelMonitor, will panic in such a case.
255         //
256         // TODO: Document the things someone using this interface should enforce before signing.
257         // TODO: Key derivation failure should panic rather than Err
258         fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
259
260         /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment
261         /// transactions which will be broadcasted later, after the channel has moved on to a newer
262         /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever
263         /// get called once.
264         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
265         fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
266
267         /// Create a signature for the given input in a transaction spending an HTLC transaction output
268         /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
269         ///
270         /// A justice transaction may claim multiple outputs at the same time if timelocks are
271         /// similar, but only a signature for the input at index `input` should be signed for here.
272         /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
273         /// to an upcoming timelock expiration.
274         ///
275         /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
276         ///
277         /// per_commitment_key is revocation secret which was provided by our counterparty when they
278         /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
279         /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
280         /// so).
281         fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
282
283         /// Create a signature for the given input in a transaction spending a commitment transaction
284         /// HTLC output when our counterparty broadcasts an old state.
285         ///
286         /// A justice transaction may claim multiple outputs at the same time if timelocks are
287         /// similar, but only a signature for the input at index `input` should be signed for here.
288         /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
289         /// to an upcoming timelock expiration.
290         ///
291         /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
292         ///
293         /// per_commitment_key is revocation secret which was provided by our counterparty when they
294         /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
295         /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
296         /// so).
297         ///
298         /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
299         /// (which is committed to in the BIP 143 signatures).
300         fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
301
302         /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
303         /// transaction, either offered or received.
304         ///
305         /// Such a transaction may claim multiples offered outputs at same time if we know the
306         /// preimage for each when we create it, but only the input at index `input` should be
307         /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
308         /// needed with regards to an upcoming timelock expiration.
309         ///
310         /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
311         /// outputs.
312         ///
313         /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
314         ///
315         /// Per_commitment_point is the dynamic point corresponding to the channel state
316         /// detected onchain. It has been generated by our counterparty and is used to derive
317         /// channel state keys, which are then included in the witness script and committed to in the
318         /// BIP 143 signature.
319         fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
320
321         /// Create a signature for a (proposed) closing transaction.
322         ///
323         /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
324         /// chosen to forgo their output as dust.
325         fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
326
327         /// Signs a channel announcement message with our funding key, proving it comes from one
328         /// of the channel participants.
329         ///
330         /// Note that if this fails or is rejected, the channel will not be publicly announced and
331         /// our counterparty may (though likely will not) close the channel on us for violating the
332         /// protocol.
333         fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
334
335         /// Set the counterparty static channel data, including basepoints,
336         /// counterparty_selected/holder_selected_contest_delay and funding outpoint.
337         /// This is done as soon as the funding outpoint is known.  Since these are static channel data,
338         /// they MUST NOT be allowed to change to different values once set.
339         ///
340         /// channel_parameters.is_populated() MUST be true.
341         ///
342         /// We bind holder_selected_contest_delay late here for API convenience.
343         ///
344         /// Will be called before any signatures are applied.
345         fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters);
346 }
347
348 /// A cloneable signer.
349 ///
350 /// Although we require signers to be cloneable, it may be useful for developers to be able to use
351 /// signers in an un-sized way, for example as `dyn BaseSign`. Therefore we separate the Clone trait,
352 /// which implies Sized, into this derived trait.
353 pub trait Sign: BaseSign + Writeable + Clone {
354 }
355
356 /// A trait to describe an object which can get user secrets and key material.
357 pub trait KeysInterface {
358         /// A type which implements Sign which will be returned by get_channel_signer.
359         type Signer : Sign;
360
361         /// Get node secret key (aka node_id or network_key).
362         ///
363         /// This method must return the same value each time it is called.
364         fn get_node_secret(&self) -> SecretKey;
365         /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
366         ///
367         /// This method should return a different value each time it is called, to avoid linking
368         /// on-chain funds across channels as controlled to the same user.
369         fn get_destination_script(&self) -> Script;
370         /// Get a script pubkey which we will send funds to when closing a channel.
371         ///
372         /// This method should return a different value each time it is called, to avoid linking
373         /// on-chain funds across channels as controlled to the same user.
374         fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
375         /// Get a new set of Sign for per-channel secrets. These MUST be unique even if you
376         /// restarted with some stale data!
377         ///
378         /// This method must return a different value each time it is called.
379         fn get_channel_signer(&self, inbound: bool, channel_value_satoshis: u64) -> Self::Signer;
380         /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting
381         /// onion packets and for temporary channel IDs. There is no requirement that these be
382         /// persisted anywhere, though they must be unique across restarts.
383         ///
384         /// This method must return a different value each time it is called.
385         fn get_secure_random_bytes(&self) -> [u8; 32];
386
387         /// Reads a `Signer` for this `KeysInterface` from the given input stream.
388         /// This is only called during deserialization of other objects which contain
389         /// `Sign`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s).
390         /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
391         /// contain no versioning scheme. You may wish to include your own version prefix and ensure
392         /// you've read all of the provided bytes to ensure no corruption occurred.
393         fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
394
395         /// Sign an invoice's preimage (note that this is the preimage of the invoice, not the HTLC's
396         /// preimage). By parameterizing by the preimage instead of the hash, we allow implementors of
397         /// this trait to parse the invoice and make sure they're signing what they expect, rather than
398         /// blindly signing the hash.
399         fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()>;
400 }
401
402 #[derive(Clone)]
403 /// A simple implementation of Sign that just keeps the private keys in memory.
404 ///
405 /// This implementation performs no policy checks and is insufficient by itself as
406 /// a secure external signer.
407 pub struct InMemorySigner {
408         /// Private key of anchor tx
409         pub funding_key: SecretKey,
410         /// Holder secret key for blinded revocation pubkey
411         pub revocation_base_key: SecretKey,
412         /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions
413         pub payment_key: SecretKey,
414         /// Holder secret key used in HTLC tx
415         pub delayed_payment_base_key: SecretKey,
416         /// Holder htlc secret key used in commitment tx htlc outputs
417         pub htlc_base_key: SecretKey,
418         /// Commitment seed
419         pub commitment_seed: [u8; 32],
420         /// Holder public keys and basepoints
421         pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
422         /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance
423         channel_parameters: Option<ChannelTransactionParameters>,
424         /// The total value of this channel
425         channel_value_satoshis: u64,
426         /// Key derivation parameters
427         channel_keys_id: [u8; 32],
428 }
429
430 impl InMemorySigner {
431         /// Create a new InMemorySigner
432         pub fn new<C: Signing>(
433                 secp_ctx: &Secp256k1<C>,
434                 funding_key: SecretKey,
435                 revocation_base_key: SecretKey,
436                 payment_key: SecretKey,
437                 delayed_payment_base_key: SecretKey,
438                 htlc_base_key: SecretKey,
439                 commitment_seed: [u8; 32],
440                 channel_value_satoshis: u64,
441                 channel_keys_id: [u8; 32]) -> InMemorySigner {
442                 let holder_channel_pubkeys =
443                         InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
444                                                              &payment_key, &delayed_payment_base_key,
445                                                              &htlc_base_key);
446                 InMemorySigner {
447                         funding_key,
448                         revocation_base_key,
449                         payment_key,
450                         delayed_payment_base_key,
451                         htlc_base_key,
452                         commitment_seed,
453                         channel_value_satoshis,
454                         holder_channel_pubkeys,
455                         channel_parameters: None,
456                         channel_keys_id,
457                 }
458         }
459
460         fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
461                                        funding_key: &SecretKey,
462                                        revocation_base_key: &SecretKey,
463                                        payment_key: &SecretKey,
464                                        delayed_payment_base_key: &SecretKey,
465                                        htlc_base_key: &SecretKey) -> ChannelPublicKeys {
466                 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
467                 ChannelPublicKeys {
468                         funding_pubkey: from_secret(&funding_key),
469                         revocation_basepoint: from_secret(&revocation_base_key),
470                         payment_point: from_secret(&payment_key),
471                         delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
472                         htlc_basepoint: from_secret(&htlc_base_key),
473                 }
474         }
475
476         /// Counterparty pubkeys.
477         /// Will panic if ready_channel wasn't called.
478         pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
479
480         /// The contest_delay value specified by our counterparty and applied on holder-broadcastable
481         /// transactions, ie the amount of time that we have to wait to recover our funds if we
482         /// broadcast a transaction.
483         /// Will panic if ready_channel wasn't called.
484         pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
485
486         /// The contest_delay value specified by us and applied on transactions broadcastable
487         /// by our counterparty, ie the amount of time that they have to wait to recover their funds
488         /// if they broadcast a transaction.
489         /// Will panic if ready_channel wasn't called.
490         pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
491
492         /// Whether the holder is the initiator
493         /// Will panic if ready_channel wasn't called.
494         pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
495
496         /// Funding outpoint
497         /// Will panic if ready_channel wasn't called.
498         pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
499
500         /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or
501         /// building transactions.
502         ///
503         /// Will panic if ready_channel wasn't called.
504         pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
505                 self.channel_parameters.as_ref().unwrap()
506         }
507
508         /// Sign the single input of spend_tx at index `input_idx` which spends the output
509         /// described by descriptor, returning the witness stack for the input.
510         ///
511         /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
512         /// or is not spending the outpoint described by `descriptor.outpoint`.
513         pub fn sign_counterparty_payment_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
514                 // TODO: We really should be taking the SigHashCache as a parameter here instead of
515                 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
516                 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
517                 // bindings updates to support SigHashCache objects).
518                 if spend_tx.input.len() <= input_idx { return Err(()); }
519                 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
520                 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
521
522                 let remotepubkey = self.pubkeys().payment_point;
523                 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, key: remotepubkey}, Network::Testnet).script_pubkey();
524                 let sighash = hash_to_message!(&bip143::SigHashCache::new(spend_tx).signature_hash(input_idx, &witness_script, descriptor.output.value, SigHashType::All)[..]);
525                 let remotesig = secp_ctx.sign(&sighash, &self.payment_key);
526
527                 let mut witness = Vec::with_capacity(2);
528                 witness.push(remotesig.serialize_der().to_vec());
529                 witness[0].push(SigHashType::All as u8);
530                 witness.push(remotepubkey.serialize().to_vec());
531                 Ok(witness)
532         }
533
534         /// Sign the single input of spend_tx at index `input_idx` which spends the output
535         /// described by descriptor, returning the witness stack for the input.
536         ///
537         /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
538         /// is not spending the outpoint described by `descriptor.outpoint`, or does not have a
539         /// sequence set to `descriptor.to_self_delay`.
540         pub fn sign_dynamic_p2wsh_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
541                 // TODO: We really should be taking the SigHashCache as a parameter here instead of
542                 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
543                 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
544                 // bindings updates to support SigHashCache objects).
545                 if spend_tx.input.len() <= input_idx { return Err(()); }
546                 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
547                 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
548                 if spend_tx.input[input_idx].sequence != descriptor.to_self_delay as u32 { return Err(()); }
549
550                 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key)
551                         .expect("We constructed the payment_base_key, so we can only fail here if the RNG is busted.");
552                 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
553                 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
554                 let sighash = hash_to_message!(&bip143::SigHashCache::new(spend_tx).signature_hash(input_idx, &witness_script, descriptor.output.value, SigHashType::All)[..]);
555                 let local_delayedsig = secp_ctx.sign(&sighash, &delayed_payment_key);
556
557                 let mut witness = Vec::with_capacity(3);
558                 witness.push(local_delayedsig.serialize_der().to_vec());
559                 witness[0].push(SigHashType::All as u8);
560                 witness.push(vec!()); //MINIMALIF
561                 witness.push(witness_script.clone().into_bytes());
562                 Ok(witness)
563         }
564 }
565
566 impl BaseSign for InMemorySigner {
567         fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
568                 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
569                 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
570         }
571
572         fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
573                 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
574         }
575
576         fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction) -> Result<(), ()> {
577                 Ok(())
578         }
579
580         fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
581         fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
582
583         fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
584                 let trusted_tx = commitment_tx.trust();
585                 let keys = trusted_tx.keys();
586
587                 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
588                 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
589
590                 let built_tx = trusted_tx.built_transaction();
591                 let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
592                 let commitment_txid = built_tx.txid;
593
594                 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
595                 for htlc in commitment_tx.htlcs() {
596                         let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
597                         let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
598                         let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]);
599                         let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?;
600                         htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &holder_htlc_key));
601                 }
602
603                 Ok((commitment_sig, htlc_sigs))
604         }
605
606         fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
607                 Ok(())
608         }
609
610         fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
611                 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
612                 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
613                 let trusted_tx = commitment_tx.trust();
614                 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
615                 let channel_parameters = self.get_channel_parameters();
616                 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
617                 Ok((sig, htlc_sigs))
618         }
619
620         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
621         fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
622                 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
623                 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
624                 let trusted_tx = commitment_tx.trust();
625                 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
626                 let channel_parameters = self.get_channel_parameters();
627                 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
628                 Ok((sig, htlc_sigs))
629         }
630
631         fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
632                 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
633                 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
634                 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
635                 let witness_script = {
636                         let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?;
637                         chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
638                 };
639                 let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
640                 let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
641                 return Ok(secp_ctx.sign(&sighash, &revocation_key))
642         }
643
644         fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
645                 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
646                 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
647                 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
648                 let witness_script = {
649                         let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?;
650                         let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?;
651                         chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
652                 };
653                 let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
654                 let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
655                 return Ok(secp_ctx.sign(&sighash, &revocation_key))
656         }
657
658         fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
659                 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
660                         let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
661                                 if let Ok(counterparty_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) {
662                                         if let Ok(htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
663                                                 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey)
664                                         } else { return Err(()) }
665                                 } else { return Err(()) }
666                         } else { return Err(()) };
667                         let mut sighash_parts = bip143::SigHashCache::new(htlc_tx);
668                         let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
669                         return Ok(secp_ctx.sign(&sighash, &htlc_key))
670                 }
671                 Err(())
672         }
673
674         fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
675                 if closing_tx.input.len() != 1 { return Err(()); }
676                 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
677                 if closing_tx.output.len() > 2 { return Err(()); }
678
679                 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
680                 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
681
682                 let sighash = hash_to_message!(&bip143::SigHashCache::new(closing_tx)
683                         .signature_hash(0, &channel_funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
684                 Ok(secp_ctx.sign(&sighash, &self.funding_key))
685         }
686
687         fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
688                 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
689                 Ok(secp_ctx.sign(&msghash, &self.funding_key))
690         }
691
692         fn ready_channel(&mut self, channel_parameters: &ChannelTransactionParameters) {
693                 assert!(self.channel_parameters.is_none(), "Acceptance already noted");
694                 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
695                 self.channel_parameters = Some(channel_parameters.clone());
696         }
697 }
698
699 const SERIALIZATION_VERSION: u8 = 1;
700 const MIN_SERIALIZATION_VERSION: u8 = 1;
701
702 impl Sign for InMemorySigner {}
703
704 impl Writeable for InMemorySigner {
705         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
706                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
707
708                 self.funding_key.write(writer)?;
709                 self.revocation_base_key.write(writer)?;
710                 self.payment_key.write(writer)?;
711                 self.delayed_payment_base_key.write(writer)?;
712                 self.htlc_base_key.write(writer)?;
713                 self.commitment_seed.write(writer)?;
714                 self.channel_parameters.write(writer)?;
715                 self.channel_value_satoshis.write(writer)?;
716                 self.channel_keys_id.write(writer)?;
717
718                 write_tlv_fields!(writer, {});
719
720                 Ok(())
721         }
722 }
723
724 impl Readable for InMemorySigner {
725         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
726                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
727
728                 let funding_key = Readable::read(reader)?;
729                 let revocation_base_key = Readable::read(reader)?;
730                 let payment_key = Readable::read(reader)?;
731                 let delayed_payment_base_key = Readable::read(reader)?;
732                 let htlc_base_key = Readable::read(reader)?;
733                 let commitment_seed = Readable::read(reader)?;
734                 let counterparty_channel_data = Readable::read(reader)?;
735                 let channel_value_satoshis = Readable::read(reader)?;
736                 let secp_ctx = Secp256k1::signing_only();
737                 let holder_channel_pubkeys =
738                         InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
739                                                              &payment_key, &delayed_payment_base_key,
740                                                              &htlc_base_key);
741                 let keys_id = Readable::read(reader)?;
742
743                 read_tlv_fields!(reader, {});
744
745                 Ok(InMemorySigner {
746                         funding_key,
747                         revocation_base_key,
748                         payment_key,
749                         delayed_payment_base_key,
750                         htlc_base_key,
751                         commitment_seed,
752                         channel_value_satoshis,
753                         holder_channel_pubkeys,
754                         channel_parameters: counterparty_channel_data,
755                         channel_keys_id: keys_id,
756                 })
757         }
758 }
759
760 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
761 /// and derives keys from that.
762 ///
763 /// Your node_id is seed/0'
764 /// ChannelMonitor closes may use seed/1'
765 /// Cooperative closes may use seed/2'
766 /// The two close keys may be needed to claim on-chain funds!
767 pub struct KeysManager {
768         secp_ctx: Secp256k1<secp256k1::All>,
769         node_secret: SecretKey,
770         destination_script: Script,
771         shutdown_pubkey: PublicKey,
772         channel_master_key: ExtendedPrivKey,
773         channel_child_index: AtomicUsize,
774
775         rand_bytes_master_key: ExtendedPrivKey,
776         rand_bytes_child_index: AtomicUsize,
777         rand_bytes_unique_start: Sha256State,
778
779         seed: [u8; 32],
780         starting_time_secs: u64,
781         starting_time_nanos: u32,
782 }
783
784 impl KeysManager {
785         /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
786         /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
787         /// starting_time isn't strictly required to actually be a time, but it must absolutely,
788         /// without a doubt, be unique to this instance. ie if you start multiple times with the same
789         /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
790         /// simply use the current time (with very high precision).
791         ///
792         /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
793         /// obviously, starting_time should be unique every time you reload the library - it is only
794         /// used to generate new ephemeral key data (which will be stored by the individual channel if
795         /// necessary).
796         ///
797         /// Note that the seed is required to recover certain on-chain funds independent of
798         /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
799         /// channel, and some on-chain during-closing funds.
800         ///
801         /// Note that until the 0.1 release there is no guarantee of backward compatibility between
802         /// versions. Once the library is more fully supported, the docs will be updated to include a
803         /// detailed description of the guarantee.
804         pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
805                 let secp_ctx = Secp256k1::new();
806                 // Note that when we aren't serializing the key, network doesn't matter
807                 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
808                         Ok(master_key) => {
809                                 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
810                                 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
811                                         Ok(destination_key) => {
812                                                 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes());
813                                                 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
814                                                               .push_slice(&wpubkey_hash.into_inner())
815                                                               .into_script()
816                                         },
817                                         Err(_) => panic!("Your RNG is busted"),
818                                 };
819                                 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
820                                         Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
821                                         Err(_) => panic!("Your RNG is busted"),
822                                 };
823                                 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
824                                 let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
825
826                                 let mut rand_bytes_unique_start = Sha256::engine();
827                                 rand_bytes_unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
828                                 rand_bytes_unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
829                                 rand_bytes_unique_start.input(seed);
830
831                                 let mut res = KeysManager {
832                                         secp_ctx,
833                                         node_secret,
834
835                                         destination_script,
836                                         shutdown_pubkey,
837
838                                         channel_master_key,
839                                         channel_child_index: AtomicUsize::new(0),
840
841                                         rand_bytes_master_key,
842                                         rand_bytes_child_index: AtomicUsize::new(0),
843                                         rand_bytes_unique_start,
844
845                                         seed: *seed,
846                                         starting_time_secs,
847                                         starting_time_nanos,
848                                 };
849                                 let secp_seed = res.get_secure_random_bytes();
850                                 res.secp_ctx.seeded_randomize(&secp_seed);
851                                 res
852                         },
853                         Err(_) => panic!("Your rng is busted"),
854                 }
855         }
856         /// Derive an old Sign containing per-channel secrets based on a key derivation parameters.
857         ///
858         /// Key derivation parameters are accessible through a per-channel secrets
859         /// Sign::channel_keys_id and is provided inside DynamicOuputP2WSH in case of
860         /// onchain output detection for which a corresponding delayed_payment_key must be derived.
861         pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
862                 let chan_id = byte_utils::slice_to_be64(&params[0..8]);
863                 assert!(chan_id <= core::u32::MAX as u64); // Otherwise the params field wasn't created by us
864                 let mut unique_start = Sha256::engine();
865                 unique_start.input(params);
866                 unique_start.input(&self.seed);
867
868                 // We only seriously intend to rely on the channel_master_key for true secure
869                 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
870                 // starting_time provided in the constructor) to be unique.
871                 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(chan_id as u32).expect("key space exhausted")).expect("Your RNG is busted");
872                 unique_start.input(&child_privkey.private_key.key[..]);
873
874                 let seed = Sha256::from_engine(unique_start).into_inner();
875
876                 let commitment_seed = {
877                         let mut sha = Sha256::engine();
878                         sha.input(&seed);
879                         sha.input(&b"commitment seed"[..]);
880                         Sha256::from_engine(sha).into_inner()
881                 };
882                 macro_rules! key_step {
883                         ($info: expr, $prev_key: expr) => {{
884                                 let mut sha = Sha256::engine();
885                                 sha.input(&seed);
886                                 sha.input(&$prev_key[..]);
887                                 sha.input(&$info[..]);
888                                 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
889                         }}
890                 }
891                 let funding_key = key_step!(b"funding key", commitment_seed);
892                 let revocation_base_key = key_step!(b"revocation base key", funding_key);
893                 let payment_key = key_step!(b"payment key", revocation_base_key);
894                 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
895                 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
896
897                 InMemorySigner::new(
898                         &self.secp_ctx,
899                         funding_key,
900                         revocation_base_key,
901                         payment_key,
902                         delayed_payment_base_key,
903                         htlc_base_key,
904                         commitment_seed,
905                         channel_value_satoshis,
906                         params.clone()
907                 )
908         }
909
910         /// Creates a Transaction which spends the given descriptors to the given outputs, plus an
911         /// output to the given change destination (if sufficient change value remains). The
912         /// transaction will have a feerate, at least, of the given value.
913         ///
914         /// Returns `Err(())` if the output value is greater than the input value minus required fee or
915         /// if a descriptor was duplicated.
916         ///
917         /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
918         ///
919         /// May panic if the `SpendableOutputDescriptor`s were not generated by Channels which used
920         /// this KeysManager or one of the `InMemorySigner` created by this KeysManager.
921         pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
922                 let mut input = Vec::new();
923                 let mut input_value = 0;
924                 let mut witness_weight = 0;
925                 let mut output_set = HashSet::with_capacity(descriptors.len());
926                 for outp in descriptors {
927                         match outp {
928                                 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
929                                         input.push(TxIn {
930                                                 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
931                                                 script_sig: Script::new(),
932                                                 sequence: 0,
933                                                 witness: Vec::new(),
934                                         });
935                                         witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
936                                         input_value += descriptor.output.value;
937                                         if !output_set.insert(descriptor.outpoint) { return Err(()); }
938                                 },
939                                 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
940                                         input.push(TxIn {
941                                                 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
942                                                 script_sig: Script::new(),
943                                                 sequence: descriptor.to_self_delay as u32,
944                                                 witness: Vec::new(),
945                                         });
946                                         witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
947                                         input_value += descriptor.output.value;
948                                         if !output_set.insert(descriptor.outpoint) { return Err(()); }
949                                 },
950                                 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
951                                         input.push(TxIn {
952                                                 previous_output: outpoint.into_bitcoin_outpoint(),
953                                                 script_sig: Script::new(),
954                                                 sequence: 0,
955                                                 witness: Vec::new(),
956                                         });
957                                         witness_weight += 1 + 73 + 34;
958                                         input_value += output.value;
959                                         if !output_set.insert(*outpoint) { return Err(()); }
960                                 }
961                         }
962                         if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
963                 }
964                 let mut spend_tx = Transaction {
965                         version: 2,
966                         lock_time: 0,
967                         input,
968                         output: outputs,
969                 };
970                 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
971
972                 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
973                 let mut input_idx = 0;
974                 for outp in descriptors {
975                         match outp {
976                                 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
977                                         if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
978                                                 keys_cache = Some((
979                                                         self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
980                                                         descriptor.channel_keys_id));
981                                         }
982                                         spend_tx.input[input_idx].witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&spend_tx, input_idx, &descriptor, &secp_ctx).unwrap();
983                                 },
984                                 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
985                                         if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
986                                                 keys_cache = Some((
987                                                         self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
988                                                         descriptor.channel_keys_id));
989                                         }
990                                         spend_tx.input[input_idx].witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&spend_tx, input_idx, &descriptor, &secp_ctx).unwrap();
991                                 },
992                                 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
993                                         let derivation_idx = if output.script_pubkey == self.destination_script {
994                                                 1
995                                         } else {
996                                                 2
997                                         };
998                                         let secret = {
999                                                 // Note that when we aren't serializing the key, network doesn't matter
1000                                                 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1001                                                         Ok(master_key) => {
1002                                                                 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1003                                                                         Ok(key) => key,
1004                                                                         Err(_) => panic!("Your RNG is busted"),
1005                                                                 }
1006                                                         }
1007                                                         Err(_) => panic!("Your rng is busted"),
1008                                                 }
1009                                         };
1010                                         let pubkey = ExtendedPubKey::from_private(&secp_ctx, &secret).public_key;
1011                                         if derivation_idx == 2 {
1012                                                 assert_eq!(pubkey.key, self.shutdown_pubkey);
1013                                         }
1014                                         let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1015                                         let sighash = hash_to_message!(&bip143::SigHashCache::new(&spend_tx).signature_hash(input_idx, &witness_script, output.value, SigHashType::All)[..]);
1016                                         let sig = secp_ctx.sign(&sighash, &secret.private_key.key);
1017                                         spend_tx.input[input_idx].witness.push(sig.serialize_der().to_vec());
1018                                         spend_tx.input[input_idx].witness[0].push(SigHashType::All as u8);
1019                                         spend_tx.input[input_idx].witness.push(pubkey.key.serialize().to_vec());
1020                                 },
1021                         }
1022                         input_idx += 1;
1023                 }
1024                 Ok(spend_tx)
1025         }
1026 }
1027
1028 impl KeysInterface for KeysManager {
1029         type Signer = InMemorySigner;
1030
1031         fn get_node_secret(&self) -> SecretKey {
1032                 self.node_secret.clone()
1033         }
1034
1035         fn get_destination_script(&self) -> Script {
1036                 self.destination_script.clone()
1037         }
1038
1039         fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1040                 ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
1041         }
1042
1043         fn get_channel_signer(&self, _inbound: bool, channel_value_satoshis: u64) -> Self::Signer {
1044                 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1045                 assert!(child_ix <= core::u32::MAX as usize);
1046                 let mut id = [0; 32];
1047                 id[0..8].copy_from_slice(&byte_utils::be64_to_array(child_ix as u64));
1048                 id[8..16].copy_from_slice(&byte_utils::be64_to_array(self.starting_time_nanos as u64));
1049                 id[16..24].copy_from_slice(&byte_utils::be64_to_array(self.starting_time_secs));
1050                 self.derive_channel_keys(channel_value_satoshis, &id)
1051         }
1052
1053         fn get_secure_random_bytes(&self) -> [u8; 32] {
1054                 let mut sha = self.rand_bytes_unique_start.clone();
1055
1056                 let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel);
1057                 let child_privkey = self.rand_bytes_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
1058                 sha.input(&child_privkey.private_key.key[..]);
1059
1060                 sha.input(b"Unique Secure Random Bytes Salt");
1061                 Sha256::from_engine(sha).into_inner()
1062         }
1063
1064         fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1065                 InMemorySigner::read(&mut io::Cursor::new(reader))
1066         }
1067
1068         fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()> {
1069                 Ok(self.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&invoice_preimage)), &self.get_node_secret()))
1070         }
1071 }
1072
1073 // Ensure that BaseSign can have a vtable
1074 #[test]
1075 pub fn dyn_sign() {
1076         let _signer: Box<dyn BaseSign>;
1077 }