1 // This file is Copyright its original authors, visible in version control
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
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.
14 use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn, EcdsaSighashType};
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::sighash;
21 use bitcoin::bech32::u5;
22 use bitcoin::hashes::{Hash, HashEngine};
23 use bitcoin::hashes::sha256::HashEngine as Sha256State;
24 use bitcoin::hashes::sha256::Hash as Sha256;
25 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
26 use bitcoin::hash_types::WPubkeyHash;
28 use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
29 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Signing};
30 use bitcoin::secp256k1::ecdh::SharedSecret;
31 use bitcoin::secp256k1::ecdsa::RecoverableSignature;
32 use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness};
34 use crate::util::transaction_utils;
35 use crate::util::crypto::{hkdf_extract_expand_twice, sign};
36 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
38 use crate::chain::transaction::OutPoint;
39 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
40 use crate::ln::{chan_utils, PaymentPreimage};
41 use crate::ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
42 use crate::ln::msgs::UnsignedChannelAnnouncement;
43 use crate::ln::script::ShutdownScript;
45 use crate::prelude::*;
46 use core::convert::TryInto;
47 use core::sync::atomic::{AtomicUsize, Ordering};
48 use crate::io::{self, Error};
49 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
50 use crate::util::invoice::construct_invoice_preimage;
52 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
53 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
54 /// (C-not exported) as we just use [u8; 32] directly
55 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
56 pub struct KeyMaterial(pub [u8; 32]);
58 /// Information about a spendable output to a P2WSH script. See
59 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
60 #[derive(Clone, Debug, PartialEq, Eq)]
61 pub struct DelayedPaymentOutputDescriptor {
62 /// The outpoint which is spendable
63 pub outpoint: OutPoint,
64 /// Per commitment point to derive delayed_payment_key by key holder
65 pub per_commitment_point: PublicKey,
66 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
67 /// the witness_script.
68 pub to_self_delay: u16,
69 /// The output which is referenced by the given outpoint
71 /// The revocation point specific to the commitment transaction which was broadcast. Used to
72 /// derive the witnessScript for this output.
73 pub revocation_pubkey: PublicKey,
74 /// Arbitrary identification information returned by a call to
75 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
76 /// the channel to spend the output.
77 pub channel_keys_id: [u8; 32],
78 /// The value of the channel which this output originated from, possibly indirectly.
79 pub channel_value_satoshis: u64,
81 impl DelayedPaymentOutputDescriptor {
82 /// The maximum length a well-formed witness spending one of these should have.
83 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
84 // redeemscript push length.
85 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
88 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
89 (0, outpoint, required),
90 (2, per_commitment_point, required),
91 (4, to_self_delay, required),
92 (6, output, required),
93 (8, revocation_pubkey, required),
94 (10, channel_keys_id, required),
95 (12, channel_value_satoshis, required),
98 /// Information about a spendable output to our "payment key". See
99 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
100 #[derive(Clone, Debug, PartialEq, Eq)]
101 pub struct StaticPaymentOutputDescriptor {
102 /// The outpoint which is spendable
103 pub outpoint: OutPoint,
104 /// The output which is referenced by the given outpoint
106 /// Arbitrary identification information returned by a call to
107 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
108 /// the channel to spend the output.
109 pub channel_keys_id: [u8; 32],
110 /// The value of the channel which this transactions spends.
111 pub channel_value_satoshis: u64,
113 impl StaticPaymentOutputDescriptor {
114 /// The maximum length a well-formed witness spending one of these should have.
115 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
116 // redeemscript push length.
117 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
119 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
120 (0, outpoint, required),
121 (2, output, required),
122 (4, channel_keys_id, required),
123 (6, channel_value_satoshis, required),
126 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
127 /// claim at any point in the future) an event is generated which you must track and be able to
128 /// spend on-chain. The information needed to do this is provided in this enum, including the
129 /// outpoint describing which txid and output index is available, the full output which exists at
130 /// that txid/index, and any keys or other information required to sign.
131 #[derive(Clone, Debug, PartialEq, Eq)]
132 pub enum SpendableOutputDescriptor {
133 /// An output to a script which was provided via KeysInterface directly, either from
134 /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
135 /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
136 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
137 /// on-chain using the payment preimage or after it has timed out.
139 /// The outpoint which is spendable
141 /// The output which is referenced by the given outpoint.
144 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
146 /// The witness in the spending input should be:
147 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
149 /// Note that the nSequence field in the spending input must be set to to_self_delay
150 /// (which means the transaction is not broadcastable until at least to_self_delay
151 /// blocks after the outpoint confirms).
153 /// These are generally the result of a "revocable" output to us, spendable only by us unless
154 /// it is an output from an old state which we broadcast (which should never happen).
156 /// To derive the delayed_payment key which is used to sign for this input, you must pass the
157 /// holder delayed_payment_base_key (ie the private key which corresponds to the pubkey in
158 /// Sign::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
159 /// chan_utils::derive_private_key. The public key can be generated without the secret key
160 /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
163 /// To derive the revocation_pubkey provided here (which is used in the witness
164 /// script generation), you must pass the counterparty revocation_basepoint (which appears in the
165 /// call to Sign::provide_channel_parameters) and the provided per_commitment point
166 /// to chan_utils::derive_public_revocation_key.
168 /// The witness script which is hashed and included in the output script_pubkey may be
169 /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
170 /// (derived as above), and the to_self_delay contained here to
171 /// chan_utils::get_revokeable_redeemscript.
172 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
173 /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
174 /// corresponds to the public key in Sign::pubkeys().payment_point).
175 /// The witness in the spending input, is, thus, simply:
176 /// <BIP 143 signature> <payment key>
178 /// These are generally the result of our counterparty having broadcast the current state,
179 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
180 StaticPaymentOutput(StaticPaymentOutputDescriptor),
183 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
184 (0, StaticOutput) => {
185 (0, outpoint, required),
186 (2, output, required),
189 (1, DelayedPaymentOutput),
190 (2, StaticPaymentOutput),
193 /// A trait to sign lightning channel transactions as described in BOLT 3.
195 /// Signing services could be implemented on a hardware wallet. In this case,
196 /// the current Sign would be a front-end on top of a communication
197 /// channel connected to your secure device and lightning key material wouldn't
198 /// reside on a hot server. Nevertheless, a this deployment would still need
199 /// to trust the ChannelManager to avoid loss of funds as this latest component
200 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
202 /// A more secure iteration would be to use hashlock (or payment points) to pair
203 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
204 /// at the price of more state and computation on the hardware wallet side. In the future,
205 /// we are looking forward to design such interface.
207 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
208 /// to act, as liveness and breach reply correctness are always going to be hard requirements
209 /// of LN security model, orthogonal of key management issues.
210 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
211 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
213 /// Gets the per-commitment point for a specific commitment number
215 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
216 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
217 /// Gets the commitment secret for a specific commitment number as part of the revocation process
219 /// An external signer implementation should error here if the commitment was already signed
220 /// and should refuse to sign it in the future.
222 /// May be called more than once for the same index.
224 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
225 // TODO: return a Result so we can signal a validation error
226 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
227 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
229 /// This is required in order for the signer to make sure that releasing a commitment
230 /// secret won't leave us without a broadcastable holder transaction.
231 /// Policy checks should be implemented in this function, including checking the amount
232 /// sent to us and checking the HTLCs.
234 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
235 /// A validating signer should ensure that an HTLC output is removed only when the matching
236 /// preimage is provided, or when the value to holder is restored.
238 /// NOTE: all the relevant preimages will be provided, but there may also be additional
239 /// irrelevant or duplicate preimages.
240 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
241 /// Gets the holder's channel public keys and basepoints
242 fn pubkeys(&self) -> &ChannelPublicKeys;
243 /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
244 /// some SpendableOutputDescriptor types. This should be sufficient to identify this
245 /// Sign object uniquely and lookup or re-derive its keys.
246 fn channel_keys_id(&self) -> [u8; 32];
248 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
250 /// Note that if signing fails or is rejected, the channel will be force-closed.
252 /// Policy checks should be implemented in this function, including checking the amount
253 /// sent to us and checking the HTLCs.
255 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
256 /// A validating signer should ensure that an HTLC output is removed only when the matching
257 /// preimage is provided, or when the value to holder is restored.
259 /// NOTE: all the relevant preimages will be provided, but there may also be additional
260 /// irrelevant or duplicate preimages.
262 // TODO: Document the things someone using this interface should enforce before signing.
263 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
264 /// Validate the counterparty's revocation.
266 /// This is required in order for the signer to make sure that the state has moved
267 /// forward and it is safe to sign the next counterparty commitment.
268 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
270 /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
271 /// This will only ever be called with a non-revoked commitment_tx. This will be called with the
272 /// latest commitment_tx when we initiate a force-close.
273 /// This will be called with the previous latest, just to get claiming HTLC signatures, if we are
274 /// reacting to a ChannelMonitor replica that decided to broadcast before it had been updated to
276 /// This may be called multiple times for the same transaction.
278 /// An external signer implementation should check that the commitment has not been revoked.
280 /// May return Err if key derivation fails. Callers, such as ChannelMonitor, will panic in such a case.
282 // TODO: Document the things someone using this interface should enforce before signing.
283 // TODO: Key derivation failure should panic rather than Err
284 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
286 /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment
287 /// transactions which will be broadcasted later, after the channel has moved on to a newer
288 /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever
290 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
291 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
293 /// Create a signature for the given input in a transaction spending an HTLC transaction output
294 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
296 /// A justice transaction may claim multiple outputs at the same time if timelocks are
297 /// similar, but only a signature for the input at index `input` should be signed for here.
298 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
299 /// to an upcoming timelock expiration.
301 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
303 /// per_commitment_key is revocation secret which was provided by our counterparty when they
304 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
305 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
307 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
309 /// Create a signature for the given input in a transaction spending a commitment transaction
310 /// HTLC output when our counterparty broadcasts an old state.
312 /// A justice transaction may claim multiple outputs at the same time if timelocks are
313 /// similar, but only a signature for the input at index `input` should be signed for here.
314 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
315 /// to an upcoming timelock expiration.
317 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
319 /// per_commitment_key is revocation secret which was provided by our counterparty when they
320 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
321 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
324 /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
325 /// (which is committed to in the BIP 143 signatures).
326 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, ()>;
328 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
329 /// transaction, either offered or received.
331 /// Such a transaction may claim multiples offered outputs at same time if we know the
332 /// preimage for each when we create it, but only the input at index `input` should be
333 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
334 /// needed with regards to an upcoming timelock expiration.
336 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
339 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
341 /// Per_commitment_point is the dynamic point corresponding to the channel state
342 /// detected onchain. It has been generated by our counterparty and is used to derive
343 /// channel state keys, which are then included in the witness script and committed to in the
344 /// BIP 143 signature.
345 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, ()>;
347 /// Create a signature for a (proposed) closing transaction.
349 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
350 /// chosen to forgo their output as dust.
351 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
353 /// Computes the signature for a commitment transaction's anchor output used as an
354 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
355 fn sign_holder_anchor_input(
356 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
357 ) -> Result<Signature, ()>;
359 /// Signs a channel announcement message with our funding key and our node secret key (aka
360 /// node_id or network_key), proving it comes from one of the channel participants.
362 /// The first returned signature should be from our node secret key, the second from our
365 /// Note that if this fails or is rejected, the channel will not be publicly announced and
366 /// our counterparty may (though likely will not) close the channel on us for violating the
368 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
369 -> Result<(Signature, Signature), ()>;
371 /// Set the counterparty static channel data, including basepoints,
372 /// counterparty_selected/holder_selected_contest_delay and funding outpoint. Since these are
373 /// static channel data, they MUST NOT be allowed to change to different values once set, as LDK
374 /// may call this method more than once.
376 /// channel_parameters.is_populated() MUST be true.
377 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
380 /// A writeable signer.
382 /// There will always be two instances of a signer per channel, one occupied by the
383 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
385 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
386 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
387 pub trait Sign: BaseSign + Writeable {
390 /// Specifies the recipient of an invoice, to indicate to [`KeysInterface::sign_invoice`] what node
391 /// secret key should be used to sign the invoice.
393 /// The invoice should be signed with the local node secret key.
395 /// The invoice should be signed with the phantom node secret key. This secret key must be the
396 /// same for all nodes participating in the [phantom node payment].
398 /// [phantom node payment]: PhantomKeysManager
402 /// A trait to describe an object which can get user secrets and key material.
403 pub trait KeysInterface {
404 /// A type which implements Sign which will be returned by derive_channel_signer.
407 /// Get node secret key based on the provided [`Recipient`].
409 /// The node_id/network_key is the public key that corresponds to this secret key.
411 /// This method must return the same value each time it is called with a given `Recipient`
414 /// Errors if the `Recipient` variant is not supported by the implementation.
415 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()>;
416 /// Get node id based on the provided [`Recipient`]. This public key corresponds to the secret in
417 /// [`get_node_secret`].
419 /// This method must return the same value each time it is called with a given `Recipient`
422 /// Errors if the `Recipient` variant is not supported by the implementation.
424 /// [`get_node_secret`]: KeysInterface::get_node_secret
425 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
426 let secp_ctx = Secp256k1::signing_only();
427 Ok(PublicKey::from_secret_key(&secp_ctx, &self.get_node_secret(recipient)?))
429 /// Gets the ECDH shared secret of our [`node secret`] and `other_key`, multiplying by `tweak` if
430 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
431 /// secret, though this is less efficient.
433 /// Errors if the `Recipient` variant is not supported by the implementation.
435 /// [`node secret`]: Self::get_node_secret
436 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
437 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
439 /// This method should return a different value each time it is called, to avoid linking
440 /// on-chain funds across channels as controlled to the same user.
441 fn get_destination_script(&self) -> Script;
442 /// Get a script pubkey which we will send funds to when closing a channel.
444 /// This method should return a different value each time it is called, to avoid linking
445 /// on-chain funds across channels as controlled to the same user.
446 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
447 /// Generates a unique `channel_keys_id` that can be used to obtain a `Signer` through
448 /// [`KeysInterface::derive_channel_signer`]. The `user_channel_id` is provided to allow
449 /// implementations of `KeysInterface` to maintain a mapping between it and the generated
450 /// `channel_keys_id`.
452 /// This method must return a different value each time it is called.
453 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
454 /// Derives the private key material backing a `Signer`.
456 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
457 /// [`KeysInterface::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
458 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
459 /// [`BaseSign::channel_keys_id`].
460 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
461 /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting
462 /// onion packets and for temporary channel IDs. There is no requirement that these be
463 /// persisted anywhere, though they must be unique across restarts.
465 /// This method must return a different value each time it is called.
466 fn get_secure_random_bytes(&self) -> [u8; 32];
468 /// Reads a `Signer` for this `KeysInterface` from the given input stream.
469 /// This is only called during deserialization of other objects which contain
470 /// `Sign`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s).
471 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
472 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
473 /// you've read all of the provided bytes to ensure no corruption occurred.
475 /// This method is slowly being phased out -- it will only be called when reading objects
476 /// written by LDK versions prior to 0.0.113.
477 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
480 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
481 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
482 /// blindly signing the hash.
483 /// The hrp is ascii bytes, while the invoice data is base32.
485 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
487 /// Errors if the `Recipient` variant is not supported by the implementation.
488 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], receipient: Recipient) -> Result<RecoverableSignature, ()>;
490 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
492 /// If the implementor of this trait supports [phantom node payments], then every node that is
493 /// intended to be included in the phantom invoice route hints must return the same value from
495 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
496 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
497 // nodes, they must share the key that encrypts this payment data.
499 /// This method must return the same value each time it is called.
501 /// [phantom node payments]: PhantomKeysManager
502 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
506 /// A simple implementation of Sign that just keeps the private keys in memory.
508 /// This implementation performs no policy checks and is insufficient by itself as
509 /// a secure external signer.
510 pub struct InMemorySigner {
511 /// Private key of anchor tx
512 pub funding_key: SecretKey,
513 /// Holder secret key for blinded revocation pubkey
514 pub revocation_base_key: SecretKey,
515 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions
516 pub payment_key: SecretKey,
517 /// Holder secret key used in HTLC tx
518 pub delayed_payment_base_key: SecretKey,
519 /// Holder htlc secret key used in commitment tx htlc outputs
520 pub htlc_base_key: SecretKey,
522 pub commitment_seed: [u8; 32],
523 /// Holder public keys and basepoints
524 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
525 /// Private key of our node secret, used for signing channel announcements
526 node_secret: SecretKey,
527 /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance
528 channel_parameters: Option<ChannelTransactionParameters>,
529 /// The total value of this channel
530 channel_value_satoshis: u64,
531 /// Key derivation parameters
532 channel_keys_id: [u8; 32],
535 impl InMemorySigner {
536 /// Create a new InMemorySigner
537 pub fn new<C: Signing>(
538 secp_ctx: &Secp256k1<C>,
539 node_secret: SecretKey,
540 funding_key: SecretKey,
541 revocation_base_key: SecretKey,
542 payment_key: SecretKey,
543 delayed_payment_base_key: SecretKey,
544 htlc_base_key: SecretKey,
545 commitment_seed: [u8; 32],
546 channel_value_satoshis: u64,
547 channel_keys_id: [u8; 32],
548 ) -> InMemorySigner {
549 let holder_channel_pubkeys =
550 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
551 &payment_key, &delayed_payment_base_key,
557 delayed_payment_base_key,
561 channel_value_satoshis,
562 holder_channel_pubkeys,
563 channel_parameters: None,
568 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
569 funding_key: &SecretKey,
570 revocation_base_key: &SecretKey,
571 payment_key: &SecretKey,
572 delayed_payment_base_key: &SecretKey,
573 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
574 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
576 funding_pubkey: from_secret(&funding_key),
577 revocation_basepoint: from_secret(&revocation_base_key),
578 payment_point: from_secret(&payment_key),
579 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
580 htlc_basepoint: from_secret(&htlc_base_key),
584 /// Counterparty pubkeys.
585 /// Will panic if provide_channel_parameters wasn't called.
586 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
588 /// The contest_delay value specified by our counterparty and applied on holder-broadcastable
589 /// transactions, ie the amount of time that we have to wait to recover our funds if we
590 /// broadcast a transaction.
591 /// Will panic if provide_channel_parameters wasn't called.
592 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
594 /// The contest_delay value specified by us and applied on transactions broadcastable
595 /// by our counterparty, ie the amount of time that they have to wait to recover their funds
596 /// if they broadcast a transaction.
597 /// Will panic if provide_channel_parameters wasn't called.
598 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
600 /// Whether the holder is the initiator
601 /// Will panic if provide_channel_parameters wasn't called.
602 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
605 /// Will panic if provide_channel_parameters wasn't called.
606 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
608 /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or
609 /// building transactions.
611 /// Will panic if provide_channel_parameters wasn't called.
612 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
613 self.channel_parameters.as_ref().unwrap()
616 /// Whether anchors should be used.
617 /// Will panic if provide_channel_parameters wasn't called.
618 pub fn opt_anchors(&self) -> bool {
619 self.get_channel_parameters().opt_anchors.is_some()
622 /// Sign the single input of spend_tx at index `input_idx` which spends the output
623 /// described by descriptor, returning the witness stack for the input.
625 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
626 /// is not spending the outpoint described by `descriptor.outpoint`,
627 /// or if an output descriptor script_pubkey does not match the one we can spend.
628 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>>, ()> {
629 // TODO: We really should be taking the SigHashCache as a parameter here instead of
630 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
631 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
632 // bindings updates to support SigHashCache objects).
633 if spend_tx.input.len() <= input_idx { return Err(()); }
634 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
635 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
637 let remotepubkey = self.pubkeys().payment_point;
638 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
639 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
640 let remotesig = sign(secp_ctx, &sighash, &self.payment_key);
641 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
643 if payment_script != descriptor.output.script_pubkey { return Err(()); }
645 let mut witness = Vec::with_capacity(2);
646 witness.push(remotesig.serialize_der().to_vec());
647 witness[0].push(EcdsaSighashType::All as u8);
648 witness.push(remotepubkey.serialize().to_vec());
652 /// Sign the single input of spend_tx at index `input_idx` which spends the output
653 /// described by descriptor, returning the witness stack for the input.
655 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
656 /// is not spending the outpoint described by `descriptor.outpoint`, does not have a
657 /// sequence set to `descriptor.to_self_delay`, or if an output descriptor
658 /// script_pubkey does not match the one we can spend.
659 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>>, ()> {
660 // TODO: We really should be taking the SigHashCache as a parameter here instead of
661 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
662 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
663 // bindings updates to support SigHashCache objects).
664 if spend_tx.input.len() <= input_idx { return Err(()); }
665 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
666 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
667 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
669 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key)
670 .expect("We constructed the payment_base_key, so we can only fail here if the RNG is busted.");
671 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
672 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
673 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
674 let local_delayedsig = sign(secp_ctx, &sighash, &delayed_payment_key);
675 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
677 if descriptor.output.script_pubkey != payment_script { return Err(()); }
679 let mut witness = Vec::with_capacity(3);
680 witness.push(local_delayedsig.serialize_der().to_vec());
681 witness[0].push(EcdsaSighashType::All as u8);
682 witness.push(vec!()); //MINIMALIF
683 witness.push(witness_script.clone().into_bytes());
689 impl BaseSign for InMemorySigner {
690 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
691 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
692 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
695 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
696 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
699 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
703 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
704 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
706 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
707 let trusted_tx = commitment_tx.trust();
708 let keys = trusted_tx.keys();
710 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
711 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
713 let built_tx = trusted_tx.built_transaction();
714 let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
715 let commitment_txid = built_tx.txid;
717 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
718 for htlc in commitment_tx.htlcs() {
719 let channel_parameters = self.get_channel_parameters();
720 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, self.opt_anchors(), channel_parameters.opt_non_zero_fee_anchors.is_some(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
721 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
722 let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
723 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
724 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?;
725 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
728 Ok((commitment_sig, htlc_sigs))
731 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
735 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
736 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
737 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
738 let trusted_tx = commitment_tx.trust();
739 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
740 let channel_parameters = self.get_channel_parameters();
741 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
745 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
746 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
747 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
748 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
749 let trusted_tx = commitment_tx.trust();
750 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
751 let channel_parameters = self.get_channel_parameters();
752 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
756 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
757 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
758 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
759 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
760 let witness_script = {
761 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?;
762 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
764 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
765 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
766 return Ok(sign(secp_ctx, &sighash, &revocation_key))
769 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, ()> {
770 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
771 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
772 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
773 let witness_script = {
774 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?;
775 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?;
776 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
778 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
779 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
780 return Ok(sign(secp_ctx, &sighash, &revocation_key))
783 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, ()> {
784 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
785 let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
786 if let Ok(counterparty_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) {
787 if let Ok(htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
788 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey)
789 } else { return Err(()) }
790 } else { return Err(()) }
791 } else { return Err(()) };
792 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
793 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
794 return Ok(sign(secp_ctx, &sighash, &htlc_key))
799 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
800 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
801 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
802 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
805 fn sign_holder_anchor_input(
806 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
807 ) -> Result<Signature, ()> {
808 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
809 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
810 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
812 Ok(sign(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key))
815 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
816 -> Result<(Signature, Signature), ()> {
817 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
818 Ok((sign(secp_ctx, &msghash, &self.node_secret), sign(secp_ctx, &msghash, &self.funding_key)))
821 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
822 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
823 if self.channel_parameters.is_some() {
824 // The channel parameters were already set and they match, return early.
827 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
828 self.channel_parameters = Some(channel_parameters.clone());
832 const SERIALIZATION_VERSION: u8 = 1;
833 const MIN_SERIALIZATION_VERSION: u8 = 1;
835 impl Sign for InMemorySigner {}
837 impl Writeable for InMemorySigner {
838 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
839 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
841 self.funding_key.write(writer)?;
842 self.revocation_base_key.write(writer)?;
843 self.payment_key.write(writer)?;
844 self.delayed_payment_base_key.write(writer)?;
845 self.htlc_base_key.write(writer)?;
846 self.commitment_seed.write(writer)?;
847 self.channel_parameters.write(writer)?;
848 self.channel_value_satoshis.write(writer)?;
849 self.channel_keys_id.write(writer)?;
851 write_tlv_fields!(writer, {});
857 impl ReadableArgs<SecretKey> for InMemorySigner {
858 fn read<R: io::Read>(reader: &mut R, node_secret: SecretKey) -> Result<Self, DecodeError> {
859 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
861 let funding_key = Readable::read(reader)?;
862 let revocation_base_key = Readable::read(reader)?;
863 let payment_key = Readable::read(reader)?;
864 let delayed_payment_base_key = Readable::read(reader)?;
865 let htlc_base_key = Readable::read(reader)?;
866 let commitment_seed = Readable::read(reader)?;
867 let counterparty_channel_data = Readable::read(reader)?;
868 let channel_value_satoshis = Readable::read(reader)?;
869 let secp_ctx = Secp256k1::signing_only();
870 let holder_channel_pubkeys =
871 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
872 &payment_key, &delayed_payment_base_key,
874 let keys_id = Readable::read(reader)?;
876 read_tlv_fields!(reader, {});
882 delayed_payment_base_key,
886 channel_value_satoshis,
887 holder_channel_pubkeys,
888 channel_parameters: counterparty_channel_data,
889 channel_keys_id: keys_id,
894 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
895 /// and derives keys from that.
897 /// Your node_id is seed/0'
898 /// ChannelMonitor closes may use seed/1'
899 /// Cooperative closes may use seed/2'
900 /// The two close keys may be needed to claim on-chain funds!
902 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
903 /// [`PhantomKeysManager`] must be used instead.
905 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
906 /// previously issued invoices and attempts to pay previous invoices will fail.
907 pub struct KeysManager {
908 secp_ctx: Secp256k1<secp256k1::All>,
909 node_secret: SecretKey,
911 inbound_payment_key: KeyMaterial,
912 destination_script: Script,
913 shutdown_pubkey: PublicKey,
914 channel_master_key: ExtendedPrivKey,
915 channel_child_index: AtomicUsize,
917 rand_bytes_master_key: ExtendedPrivKey,
918 rand_bytes_child_index: AtomicUsize,
919 rand_bytes_unique_start: Sha256State,
922 starting_time_secs: u64,
923 starting_time_nanos: u32,
927 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
928 /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
929 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
930 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
931 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
932 /// simply use the current time (with very high precision).
934 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
935 /// obviously, starting_time should be unique every time you reload the library - it is only
936 /// used to generate new ephemeral key data (which will be stored by the individual channel if
939 /// Note that the seed is required to recover certain on-chain funds independent of
940 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
941 /// channel, and some on-chain during-closing funds.
943 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
944 /// versions. Once the library is more fully supported, the docs will be updated to include a
945 /// detailed description of the guarantee.
946 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
947 let secp_ctx = Secp256k1::new();
948 // Note that when we aren't serializing the key, network doesn't matter
949 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
951 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
952 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
953 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
954 Ok(destination_key) => {
955 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
956 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
957 .push_slice(&wpubkey_hash.into_inner())
960 Err(_) => panic!("Your RNG is busted"),
962 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
963 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
964 Err(_) => panic!("Your RNG is busted"),
966 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
967 let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
968 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
969 let mut inbound_pmt_key_bytes = [0; 32];
970 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
972 let mut rand_bytes_unique_start = Sha256::engine();
973 rand_bytes_unique_start.input(&starting_time_secs.to_be_bytes());
974 rand_bytes_unique_start.input(&starting_time_nanos.to_be_bytes());
975 rand_bytes_unique_start.input(seed);
977 let mut res = KeysManager {
981 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
987 channel_child_index: AtomicUsize::new(0),
989 rand_bytes_master_key,
990 rand_bytes_child_index: AtomicUsize::new(0),
991 rand_bytes_unique_start,
997 let secp_seed = res.get_secure_random_bytes();
998 res.secp_ctx.seeded_randomize(&secp_seed);
1001 Err(_) => panic!("Your rng is busted"),
1004 /// Derive an old Sign containing per-channel secrets based on a key derivation parameters.
1005 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1006 let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
1007 let mut unique_start = Sha256::engine();
1008 unique_start.input(params);
1009 unique_start.input(&self.seed);
1011 // We only seriously intend to rely on the channel_master_key for true secure
1012 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1013 // starting_time provided in the constructor) to be unique.
1014 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");
1015 unique_start.input(&child_privkey.private_key[..]);
1017 let seed = Sha256::from_engine(unique_start).into_inner();
1019 let commitment_seed = {
1020 let mut sha = Sha256::engine();
1022 sha.input(&b"commitment seed"[..]);
1023 Sha256::from_engine(sha).into_inner()
1025 macro_rules! key_step {
1026 ($info: expr, $prev_key: expr) => {{
1027 let mut sha = Sha256::engine();
1029 sha.input(&$prev_key[..]);
1030 sha.input(&$info[..]);
1031 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1034 let funding_key = key_step!(b"funding key", commitment_seed);
1035 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1036 let payment_key = key_step!(b"payment key", revocation_base_key);
1037 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1038 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1040 InMemorySigner::new(
1044 revocation_base_key,
1046 delayed_payment_base_key,
1049 channel_value_satoshis,
1054 /// Creates a Transaction which spends the given descriptors to the given outputs, plus an
1055 /// output to the given change destination (if sufficient change value remains). The
1056 /// transaction will have a feerate, at least, of the given value.
1058 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1059 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1060 /// does not match the one we can spend.
1062 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1064 /// May panic if the `SpendableOutputDescriptor`s were not generated by Channels which used
1065 /// this KeysManager or one of the `InMemorySigner` created by this KeysManager.
1066 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, ()> {
1067 let mut input = Vec::new();
1068 let mut input_value = 0;
1069 let mut witness_weight = 0;
1070 let mut output_set = HashSet::with_capacity(descriptors.len());
1071 for outp in descriptors {
1073 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1075 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1076 script_sig: Script::new(),
1077 sequence: Sequence::ZERO,
1078 witness: Witness::new(),
1080 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1081 input_value += descriptor.output.value;
1082 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1084 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1086 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1087 script_sig: Script::new(),
1088 sequence: Sequence(descriptor.to_self_delay as u32),
1089 witness: Witness::new(),
1091 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1092 input_value += descriptor.output.value;
1093 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1095 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1097 previous_output: outpoint.into_bitcoin_outpoint(),
1098 script_sig: Script::new(),
1099 sequence: Sequence::ZERO,
1100 witness: Witness::new(),
1102 witness_weight += 1 + 73 + 34;
1103 input_value += output.value;
1104 if !output_set.insert(*outpoint) { return Err(()); }
1107 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
1109 let mut spend_tx = Transaction {
1111 lock_time: PackedLockTime(0),
1115 let expected_max_weight =
1116 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
1118 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1119 let mut input_idx = 0;
1120 for outp in descriptors {
1122 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1123 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1125 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1126 descriptor.channel_keys_id));
1128 spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
1130 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1131 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1133 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1134 descriptor.channel_keys_id));
1136 spend_tx.input[input_idx].witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&spend_tx, input_idx, &descriptor, &secp_ctx)?);
1138 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
1139 let derivation_idx = if output.script_pubkey == self.destination_script {
1145 // Note that when we aren't serializing the key, network doesn't matter
1146 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1148 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1150 Err(_) => panic!("Your RNG is busted"),
1153 Err(_) => panic!("Your rng is busted"),
1156 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1157 if derivation_idx == 2 {
1158 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1160 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1161 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1163 if payment_script != output.script_pubkey { return Err(()); };
1165 let sighash = hash_to_message!(&sighash::SighashCache::new(&spend_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1166 let sig = sign(secp_ctx, &sighash, &secret.private_key);
1167 let mut sig_ser = sig.serialize_der().to_vec();
1168 sig_ser.push(EcdsaSighashType::All as u8);
1169 spend_tx.input[input_idx].witness.push(sig_ser);
1170 spend_tx.input[input_idx].witness.push(pubkey.inner.serialize().to_vec());
1176 debug_assert!(expected_max_weight >= spend_tx.weight());
1177 // Note that witnesses with a signature vary somewhat in size, so allow
1178 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1179 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1185 impl KeysInterface for KeysManager {
1186 type Signer = InMemorySigner;
1188 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1190 Recipient::Node => Ok(self.node_secret.clone()),
1191 Recipient::PhantomNode => Err(())
1195 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1197 Recipient::Node => Ok(self.node_id.clone()),
1198 Recipient::PhantomNode => Err(())
1202 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1203 let mut node_secret = self.get_node_secret(recipient)?;
1204 if let Some(tweak) = tweak {
1205 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1207 Ok(SharedSecret::new(other_key, &node_secret))
1210 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1211 self.inbound_payment_key.clone()
1214 fn get_destination_script(&self) -> Script {
1215 self.destination_script.clone()
1218 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1219 ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
1222 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1223 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1224 assert!(child_idx <= core::u32::MAX as usize);
1225 let mut id = [0; 32];
1226 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1227 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1228 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1229 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1233 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1234 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1237 fn get_secure_random_bytes(&self) -> [u8; 32] {
1238 let mut sha = self.rand_bytes_unique_start.clone();
1240 let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel);
1241 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");
1242 sha.input(&child_privkey.private_key[..]);
1244 sha.input(b"Unique Secure Random Bytes Salt");
1245 Sha256::from_engine(sha).into_inner()
1248 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1249 InMemorySigner::read(&mut io::Cursor::new(reader), self.node_secret.clone())
1252 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1253 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1254 let secret = match recipient {
1255 Recipient::Node => self.get_node_secret(Recipient::Node)?,
1256 Recipient::PhantomNode => return Err(()),
1258 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1262 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1265 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1266 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1267 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1268 /// itself without ever needing to forward to this fake node.
1270 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1271 /// provide some fault tolerance, because payers will automatically retry paying other provided
1272 /// nodes in the case that one node goes down.
1274 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1275 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1276 // nodes to know when the full payment has been received (and the preimage can be released) without
1277 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1278 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1279 // is released too early.
1281 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1282 /// invoices and attempts to pay previous invoices will fail.
1283 pub struct PhantomKeysManager {
1285 inbound_payment_key: KeyMaterial,
1286 phantom_secret: SecretKey,
1287 phantom_node_id: PublicKey,
1290 impl KeysInterface for PhantomKeysManager {
1291 type Signer = InMemorySigner;
1293 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1295 Recipient::Node => self.inner.get_node_secret(Recipient::Node),
1296 Recipient::PhantomNode => Ok(self.phantom_secret.clone()),
1300 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1302 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1303 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1307 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1308 let mut node_secret = self.get_node_secret(recipient)?;
1309 if let Some(tweak) = tweak {
1310 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1312 Ok(SharedSecret::new(other_key, &node_secret))
1315 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1316 self.inbound_payment_key.clone()
1319 fn get_destination_script(&self) -> Script {
1320 self.inner.get_destination_script()
1323 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1324 self.inner.get_shutdown_scriptpubkey()
1327 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1328 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1331 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1332 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1335 fn get_secure_random_bytes(&self) -> [u8; 32] {
1336 self.inner.get_secure_random_bytes()
1339 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1340 self.inner.read_chan_signer(reader)
1343 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1344 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1345 let secret = self.get_node_secret(recipient)?;
1346 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1350 impl PhantomKeysManager {
1351 /// Constructs a `PhantomKeysManager` given a 32-byte seed and an additional `cross_node_seed`
1352 /// that is shared across all nodes that intend to participate in [phantom node payments] together.
1354 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1355 /// `starting_time_nanos`.
1357 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1358 /// same across restarts, or else inbound payments may fail.
1360 /// [phantom node payments]: PhantomKeysManager
1361 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1362 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1363 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1364 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1365 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1368 inbound_payment_key: KeyMaterial(inbound_key),
1374 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1375 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, ()> {
1376 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
1379 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1380 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1381 self.inner.derive_channel_keys(channel_value_satoshis, params)
1385 // Ensure that BaseSign can have a vtable
1388 let _signer: Box<dyn BaseSign>;