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::{byte_utils, 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::sync::atomic::{AtomicUsize, Ordering};
47 use crate::io::{self, Error};
48 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
49 use crate::util::invoice::construct_invoice_preimage;
51 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
52 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
53 /// (C-not exported) as we just use [u8; 32] directly
54 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
55 pub struct KeyMaterial(pub [u8; 32]);
57 /// Information about a spendable output to a P2WSH script. See
58 /// SpendableOutputDescriptor::DelayedPaymentOutput for more details on how to spend this.
59 #[derive(Clone, Debug, PartialEq, Eq)]
60 pub struct DelayedPaymentOutputDescriptor {
61 /// The outpoint which is spendable
62 pub outpoint: OutPoint,
63 /// Per commitment point to derive delayed_payment_key by key holder
64 pub per_commitment_point: PublicKey,
65 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
66 /// the witness_script.
67 pub to_self_delay: u16,
68 /// The output which is referenced by the given outpoint
70 /// The revocation point specific to the commitment transaction which was broadcast. Used to
71 /// derive the witnessScript for this output.
72 pub revocation_pubkey: PublicKey,
73 /// Arbitrary identification information returned by a call to
74 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
75 /// the channel to spend the output.
76 pub channel_keys_id: [u8; 32],
77 /// The value of the channel which this output originated from, possibly indirectly.
78 pub channel_value_satoshis: u64,
80 impl DelayedPaymentOutputDescriptor {
81 /// The maximum length a well-formed witness spending one of these should have.
82 // Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
83 // redeemscript push length.
84 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
87 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
88 (0, outpoint, required),
89 (2, per_commitment_point, required),
90 (4, to_self_delay, required),
91 (6, output, required),
92 (8, revocation_pubkey, required),
93 (10, channel_keys_id, required),
94 (12, channel_value_satoshis, required),
97 /// Information about a spendable output to our "payment key". See
98 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
99 #[derive(Clone, Debug, PartialEq, Eq)]
100 pub struct StaticPaymentOutputDescriptor {
101 /// The outpoint which is spendable
102 pub outpoint: OutPoint,
103 /// The output which is referenced by the given outpoint
105 /// Arbitrary identification information returned by a call to
106 /// `Sign::channel_keys_id()`. This may be useful in re-deriving keys used in
107 /// the channel to spend the output.
108 pub channel_keys_id: [u8; 32],
109 /// The value of the channel which this transactions spends.
110 pub channel_value_satoshis: u64,
112 impl StaticPaymentOutputDescriptor {
113 /// The maximum length a well-formed witness spending one of these should have.
114 // Calculated as 1 byte legnth + 73 byte signature, 1 byte empty vec push, 1 byte length plus
115 // redeemscript push length.
116 pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
118 impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
119 (0, outpoint, required),
120 (2, output, required),
121 (4, channel_keys_id, required),
122 (6, channel_value_satoshis, required),
125 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
126 /// claim at any point in the future) an event is generated which you must track and be able to
127 /// spend on-chain. The information needed to do this is provided in this enum, including the
128 /// outpoint describing which txid and output index is available, the full output which exists at
129 /// that txid/index, and any keys or other information required to sign.
130 #[derive(Clone, Debug, PartialEq, Eq)]
131 pub enum SpendableOutputDescriptor {
132 /// An output to a script which was provided via KeysInterface directly, either from
133 /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
134 /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
135 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
136 /// on-chain using the payment preimage or after it has timed out.
138 /// The outpoint which is spendable
140 /// The output which is referenced by the given outpoint.
143 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
145 /// The witness in the spending input should be:
146 /// <BIP 143 signature> <empty vector> (MINIMALIF standard rule) <provided witnessScript>
148 /// Note that the nSequence field in the spending input must be set to to_self_delay
149 /// (which means the transaction is not broadcastable until at least to_self_delay
150 /// blocks after the outpoint confirms).
152 /// These are generally the result of a "revocable" output to us, spendable only by us unless
153 /// it is an output from an old state which we broadcast (which should never happen).
155 /// To derive the delayed_payment key which is used to sign for this input, you must pass the
156 /// holder delayed_payment_base_key (ie the private key which corresponds to the pubkey in
157 /// Sign::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to
158 /// chan_utils::derive_private_key. The public key can be generated without the secret key
159 /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in
162 /// To derive the revocation_pubkey provided here (which is used in the witness
163 /// script generation), you must pass the counterparty revocation_basepoint (which appears in the
164 /// call to Sign::provide_channel_parameters) and the provided per_commitment point
165 /// to chan_utils::derive_public_revocation_key.
167 /// The witness script which is hashed and included in the output script_pubkey may be
168 /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey
169 /// (derived as above), and the to_self_delay contained here to
170 /// chan_utils::get_revokeable_redeemscript.
171 DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
172 /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which
173 /// corresponds to the public key in Sign::pubkeys().payment_point).
174 /// The witness in the spending input, is, thus, simply:
175 /// <BIP 143 signature> <payment key>
177 /// These are generally the result of our counterparty having broadcast the current state,
178 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
179 StaticPaymentOutput(StaticPaymentOutputDescriptor),
182 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
183 (0, StaticOutput) => {
184 (0, outpoint, required),
185 (2, output, required),
188 (1, DelayedPaymentOutput),
189 (2, StaticPaymentOutput),
192 /// A trait to sign lightning channel transactions as described in BOLT 3.
194 /// Signing services could be implemented on a hardware wallet. In this case,
195 /// the current Sign would be a front-end on top of a communication
196 /// channel connected to your secure device and lightning key material wouldn't
197 /// reside on a hot server. Nevertheless, a this deployment would still need
198 /// to trust the ChannelManager to avoid loss of funds as this latest component
199 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
201 /// A more secure iteration would be to use hashlock (or payment points) to pair
202 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
203 /// at the price of more state and computation on the hardware wallet side. In the future,
204 /// we are looking forward to design such interface.
206 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
207 /// to act, as liveness and breach reply correctness are always going to be hard requirements
208 /// of LN security model, orthogonal of key management issues.
209 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
210 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
212 /// Gets the per-commitment point for a specific commitment number
214 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
215 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
216 /// Gets the commitment secret for a specific commitment number as part of the revocation process
218 /// An external signer implementation should error here if the commitment was already signed
219 /// and should refuse to sign it in the future.
221 /// May be called more than once for the same index.
223 /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
224 // TODO: return a Result so we can signal a validation error
225 fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
226 /// Validate the counterparty's signatures on the holder commitment transaction and HTLCs.
228 /// This is required in order for the signer to make sure that releasing a commitment
229 /// secret won't leave us without a broadcastable holder transaction.
230 /// Policy checks should be implemented in this function, including checking the amount
231 /// sent to us and checking the HTLCs.
233 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
234 /// A validating signer should ensure that an HTLC output is removed only when the matching
235 /// preimage is provided, or when the value to holder is restored.
237 /// NOTE: all the relevant preimages will be provided, but there may also be additional
238 /// irrelevant or duplicate preimages.
239 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
240 /// Gets the holder's channel public keys and basepoints
241 fn pubkeys(&self) -> &ChannelPublicKeys;
242 /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
243 /// some SpendableOutputDescriptor types. This should be sufficient to identify this
244 /// Sign object uniquely and lookup or re-derive its keys.
245 fn channel_keys_id(&self) -> [u8; 32];
247 /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
249 /// Note that if signing fails or is rejected, the channel will be force-closed.
251 /// Policy checks should be implemented in this function, including checking the amount
252 /// sent to us and checking the HTLCs.
254 /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
255 /// A validating signer should ensure that an HTLC output is removed only when the matching
256 /// preimage is provided, or when the value to holder is restored.
258 /// NOTE: all the relevant preimages will be provided, but there may also be additional
259 /// irrelevant or duplicate preimages.
261 // TODO: Document the things someone using this interface should enforce before signing.
262 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
263 /// Validate the counterparty's revocation.
265 /// This is required in order for the signer to make sure that the state has moved
266 /// forward and it is safe to sign the next counterparty commitment.
267 fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
269 /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
270 /// This will only ever be called with a non-revoked commitment_tx. This will be called with the
271 /// latest commitment_tx when we initiate a force-close.
272 /// This will be called with the previous latest, just to get claiming HTLC signatures, if we are
273 /// reacting to a ChannelMonitor replica that decided to broadcast before it had been updated to
275 /// This may be called multiple times for the same transaction.
277 /// An external signer implementation should check that the commitment has not been revoked.
279 /// May return Err if key derivation fails. Callers, such as ChannelMonitor, will panic in such a case.
281 // TODO: Document the things someone using this interface should enforce before signing.
282 // TODO: Key derivation failure should panic rather than Err
283 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
285 /// Same as sign_holder_commitment, but exists only for tests to get access to holder commitment
286 /// transactions which will be broadcasted later, after the channel has moved on to a newer
287 /// state. Thus, needs its own method as sign_holder_commitment may enforce that we only ever
289 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
290 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
292 /// Create a signature for the given input in a transaction spending an HTLC transaction output
293 /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
295 /// A justice transaction may claim multiple outputs at the same time if timelocks are
296 /// similar, but only a signature for the input at index `input` should be signed for here.
297 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
298 /// to an upcoming timelock expiration.
300 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
302 /// per_commitment_key is revocation secret which was provided by our counterparty when they
303 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
304 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
306 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
308 /// Create a signature for the given input in a transaction spending a commitment transaction
309 /// HTLC output when our counterparty broadcasts an old state.
311 /// A justice transaction may claim multiple outputs at the same time if timelocks are
312 /// similar, but only a signature for the input at index `input` should be signed for here.
313 /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
314 /// to an upcoming timelock expiration.
316 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
318 /// per_commitment_key is revocation secret which was provided by our counterparty when they
319 /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
320 /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
323 /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
324 /// (which is committed to in the BIP 143 signatures).
325 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, ()>;
327 /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
328 /// transaction, either offered or received.
330 /// Such a transaction may claim multiples offered outputs at same time if we know the
331 /// preimage for each when we create it, but only the input at index `input` should be
332 /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
333 /// needed with regards to an upcoming timelock expiration.
335 /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC
338 /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
340 /// Per_commitment_point is the dynamic point corresponding to the channel state
341 /// detected onchain. It has been generated by our counterparty and is used to derive
342 /// channel state keys, which are then included in the witness script and committed to in the
343 /// BIP 143 signature.
344 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, ()>;
346 /// Create a signature for a (proposed) closing transaction.
348 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
349 /// chosen to forgo their output as dust.
350 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
352 /// Computes the signature for a commitment transaction's anchor output used as an
353 /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
354 fn sign_holder_anchor_input(
355 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
356 ) -> Result<Signature, ()>;
358 /// Signs a channel announcement message with our funding key and our node secret key (aka
359 /// node_id or network_key), proving it comes from one of the channel participants.
361 /// The first returned signature should be from our node secret key, the second from our
364 /// Note that if this fails or is rejected, the channel will not be publicly announced and
365 /// our counterparty may (though likely will not) close the channel on us for violating the
367 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
368 -> Result<(Signature, Signature), ()>;
370 /// Set the counterparty static channel data, including basepoints,
371 /// counterparty_selected/holder_selected_contest_delay and funding outpoint. Since these are
372 /// static channel data, they MUST NOT be allowed to change to different values once set, as LDK
373 /// may call this method more than once.
375 /// channel_parameters.is_populated() MUST be true.
376 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
379 /// A writeable signer.
381 /// There will always be two instances of a signer per channel, one occupied by the
382 /// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
384 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
385 /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
386 pub trait Sign: BaseSign + Writeable {
389 /// Specifies the recipient of an invoice, to indicate to [`KeysInterface::sign_invoice`] what node
390 /// secret key should be used to sign the invoice.
392 /// The invoice should be signed with the local node secret key.
394 /// The invoice should be signed with the phantom node secret key. This secret key must be the
395 /// same for all nodes participating in the [phantom node payment].
397 /// [phantom node payment]: PhantomKeysManager
401 /// A trait to describe an object which can get user secrets and key material.
402 pub trait KeysInterface {
403 /// A type which implements Sign which will be returned by derive_channel_signer.
406 /// Get node secret key based on the provided [`Recipient`].
408 /// The node_id/network_key is the public key that corresponds to this secret key.
410 /// This method must return the same value each time it is called with a given `Recipient`
413 /// Errors if the `Recipient` variant is not supported by the implementation.
414 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()>;
415 /// Get node id based on the provided [`Recipient`]. This public key corresponds to the secret in
416 /// [`get_node_secret`].
418 /// This method must return the same value each time it is called with a given `Recipient`
421 /// Errors if the `Recipient` variant is not supported by the implementation.
423 /// [`get_node_secret`]: KeysInterface::get_node_secret
424 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
425 let secp_ctx = Secp256k1::signing_only();
426 Ok(PublicKey::from_secret_key(&secp_ctx, &self.get_node_secret(recipient)?))
428 /// Gets the ECDH shared secret of our [`node secret`] and `other_key`, multiplying by `tweak` if
429 /// one is provided. Note that this tweak can be applied to `other_key` instead of our node
430 /// secret, though this is less efficient.
432 /// Errors if the `Recipient` variant is not supported by the implementation.
434 /// [`node secret`]: Self::get_node_secret
435 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
436 /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
438 /// This method should return a different value each time it is called, to avoid linking
439 /// on-chain funds across channels as controlled to the same user.
440 fn get_destination_script(&self) -> Script;
441 /// Get a script pubkey which we will send funds to when closing a channel.
443 /// This method should return a different value each time it is called, to avoid linking
444 /// on-chain funds across channels as controlled to the same user.
445 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
446 /// Generates a unique `channel_keys_id` that can be used to obtain a `Signer` through
447 /// [`KeysInterface::derive_channel_signer`]. The `user_channel_id` is provided to allow
448 /// implementations of `KeysInterface` to maintain a mapping between it and the generated
449 /// `channel_keys_id`.
451 /// This method must return a different value each time it is called.
452 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
453 /// Derives the private key material backing a `Signer`.
455 /// To derive a new `Signer`, a fresh `channel_keys_id` should be obtained through
456 /// [`KeysInterface::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
457 /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
458 /// [`BaseSign::channel_keys_id`].
459 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
460 /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting
461 /// onion packets and for temporary channel IDs. There is no requirement that these be
462 /// persisted anywhere, though they must be unique across restarts.
464 /// This method must return a different value each time it is called.
465 fn get_secure_random_bytes(&self) -> [u8; 32];
467 /// Reads a `Signer` for this `KeysInterface` from the given input stream.
468 /// This is only called during deserialization of other objects which contain
469 /// `Sign`-implementing objects (ie `ChannelMonitor`s and `ChannelManager`s).
470 /// The bytes are exactly those which `<Self::Signer as Writeable>::write()` writes, and
471 /// contain no versioning scheme. You may wish to include your own version prefix and ensure
472 /// you've read all of the provided bytes to ensure no corruption occurred.
474 /// This method is slowly being phased out -- it will only be called when reading objects
475 /// written by LDK versions prior to 0.0.113.
476 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
479 /// By parameterizing by the raw invoice bytes instead of the hash, we allow implementors of
480 /// this trait to parse the invoice and make sure they're signing what they expect, rather than
481 /// blindly signing the hash.
482 /// The hrp is ascii bytes, while the invoice data is base32.
484 /// The secret key used to sign the invoice is dependent on the [`Recipient`].
486 /// Errors if the `Recipient` variant is not supported by the implementation.
487 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], receipient: Recipient) -> Result<RecoverableSignature, ()>;
489 /// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
491 /// If the implementor of this trait supports [phantom node payments], then every node that is
492 /// intended to be included in the phantom invoice route hints must return the same value from
494 // This is because LDK avoids storing inbound payment data by encrypting payment data in the
495 // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
496 // nodes, they must share the key that encrypts this payment data.
498 /// This method must return the same value each time it is called.
500 /// [phantom node payments]: PhantomKeysManager
501 fn get_inbound_payment_key_material(&self) -> KeyMaterial;
505 /// A simple implementation of Sign that just keeps the private keys in memory.
507 /// This implementation performs no policy checks and is insufficient by itself as
508 /// a secure external signer.
509 pub struct InMemorySigner {
510 /// Private key of anchor tx
511 pub funding_key: SecretKey,
512 /// Holder secret key for blinded revocation pubkey
513 pub revocation_base_key: SecretKey,
514 /// Holder secret key used for our balance in counterparty-broadcasted commitment transactions
515 pub payment_key: SecretKey,
516 /// Holder secret key used in HTLC tx
517 pub delayed_payment_base_key: SecretKey,
518 /// Holder htlc secret key used in commitment tx htlc outputs
519 pub htlc_base_key: SecretKey,
521 pub commitment_seed: [u8; 32],
522 /// Holder public keys and basepoints
523 pub(crate) holder_channel_pubkeys: ChannelPublicKeys,
524 /// Private key of our node secret, used for signing channel announcements
525 node_secret: SecretKey,
526 /// Counterparty public keys and counterparty/holder selected_contest_delay, populated on channel acceptance
527 channel_parameters: Option<ChannelTransactionParameters>,
528 /// The total value of this channel
529 channel_value_satoshis: u64,
530 /// Key derivation parameters
531 channel_keys_id: [u8; 32],
534 impl InMemorySigner {
535 /// Create a new InMemorySigner
536 pub fn new<C: Signing>(
537 secp_ctx: &Secp256k1<C>,
538 node_secret: SecretKey,
539 funding_key: SecretKey,
540 revocation_base_key: SecretKey,
541 payment_key: SecretKey,
542 delayed_payment_base_key: SecretKey,
543 htlc_base_key: SecretKey,
544 commitment_seed: [u8; 32],
545 channel_value_satoshis: u64,
546 channel_keys_id: [u8; 32],
547 ) -> InMemorySigner {
548 let holder_channel_pubkeys =
549 InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
550 &payment_key, &delayed_payment_base_key,
556 delayed_payment_base_key,
560 channel_value_satoshis,
561 holder_channel_pubkeys,
562 channel_parameters: None,
567 fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
568 funding_key: &SecretKey,
569 revocation_base_key: &SecretKey,
570 payment_key: &SecretKey,
571 delayed_payment_base_key: &SecretKey,
572 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
573 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
575 funding_pubkey: from_secret(&funding_key),
576 revocation_basepoint: from_secret(&revocation_base_key),
577 payment_point: from_secret(&payment_key),
578 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
579 htlc_basepoint: from_secret(&htlc_base_key),
583 /// Counterparty pubkeys.
584 /// Will panic if provide_channel_parameters wasn't called.
585 pub fn counterparty_pubkeys(&self) -> &ChannelPublicKeys { &self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().pubkeys }
587 /// The contest_delay value specified by our counterparty and applied on holder-broadcastable
588 /// transactions, ie the amount of time that we have to wait to recover our funds if we
589 /// broadcast a transaction.
590 /// Will panic if provide_channel_parameters wasn't called.
591 pub fn counterparty_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().counterparty_parameters.as_ref().unwrap().selected_contest_delay }
593 /// The contest_delay value specified by us and applied on transactions broadcastable
594 /// by our counterparty, ie the amount of time that they have to wait to recover their funds
595 /// if they broadcast a transaction.
596 /// Will panic if provide_channel_parameters wasn't called.
597 pub fn holder_selected_contest_delay(&self) -> u16 { self.get_channel_parameters().holder_selected_contest_delay }
599 /// Whether the holder is the initiator
600 /// Will panic if provide_channel_parameters wasn't called.
601 pub fn is_outbound(&self) -> bool { self.get_channel_parameters().is_outbound_from_holder }
604 /// Will panic if provide_channel_parameters wasn't called.
605 pub fn funding_outpoint(&self) -> &OutPoint { self.get_channel_parameters().funding_outpoint.as_ref().unwrap() }
607 /// Obtain a ChannelTransactionParameters for this channel, to be used when verifying or
608 /// building transactions.
610 /// Will panic if provide_channel_parameters wasn't called.
611 pub fn get_channel_parameters(&self) -> &ChannelTransactionParameters {
612 self.channel_parameters.as_ref().unwrap()
615 /// Whether anchors should be used.
616 /// Will panic if provide_channel_parameters wasn't called.
617 pub fn opt_anchors(&self) -> bool {
618 self.get_channel_parameters().opt_anchors.is_some()
621 /// Sign the single input of spend_tx at index `input_idx` which spends the output
622 /// described by descriptor, returning the witness stack for the input.
624 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
625 /// is not spending the outpoint described by `descriptor.outpoint`,
626 /// or if an output descriptor script_pubkey does not match the one we can spend.
627 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>>, ()> {
628 // TODO: We really should be taking the SigHashCache as a parameter here instead of
629 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
630 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
631 // bindings updates to support SigHashCache objects).
632 if spend_tx.input.len() <= input_idx { return Err(()); }
633 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
634 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
636 let remotepubkey = self.pubkeys().payment_point;
637 let witness_script = bitcoin::Address::p2pkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Testnet).script_pubkey();
638 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
639 let remotesig = sign(secp_ctx, &sighash, &self.payment_key);
640 let payment_script = bitcoin::Address::p2wpkh(&::bitcoin::PublicKey{compressed: true, inner: remotepubkey}, Network::Bitcoin).unwrap().script_pubkey();
642 if payment_script != descriptor.output.script_pubkey { return Err(()); }
644 let mut witness = Vec::with_capacity(2);
645 witness.push(remotesig.serialize_der().to_vec());
646 witness[0].push(EcdsaSighashType::All as u8);
647 witness.push(remotepubkey.serialize().to_vec());
651 /// Sign the single input of spend_tx at index `input_idx` which spends the output
652 /// described by descriptor, returning the witness stack for the input.
654 /// Returns an Err if the input at input_idx does not exist, has a non-empty script_sig,
655 /// is not spending the outpoint described by `descriptor.outpoint`, does not have a
656 /// sequence set to `descriptor.to_self_delay`, or if an output descriptor
657 /// script_pubkey does not match the one we can spend.
658 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>>, ()> {
659 // TODO: We really should be taking the SigHashCache as a parameter here instead of
660 // spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
661 // so that we can check them. This requires upstream rust-bitcoin changes (as well as
662 // bindings updates to support SigHashCache objects).
663 if spend_tx.input.len() <= input_idx { return Err(()); }
664 if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
665 if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
666 if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
668 let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key)
669 .expect("We constructed the payment_base_key, so we can only fail here if the RNG is busted.");
670 let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
671 let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
672 let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
673 let local_delayedsig = sign(secp_ctx, &sighash, &delayed_payment_key);
674 let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
676 if descriptor.output.script_pubkey != payment_script { return Err(()); }
678 let mut witness = Vec::with_capacity(3);
679 witness.push(local_delayedsig.serialize_der().to_vec());
680 witness[0].push(EcdsaSighashType::All as u8);
681 witness.push(vec!()); //MINIMALIF
682 witness.push(witness_script.clone().into_bytes());
688 impl BaseSign for InMemorySigner {
689 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
690 let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
691 PublicKey::from_secret_key(secp_ctx, &commitment_secret)
694 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
695 chan_utils::build_commitment_secret(&self.commitment_seed, idx)
698 fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
702 fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
703 fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
705 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
706 let trusted_tx = commitment_tx.trust();
707 let keys = trusted_tx.keys();
709 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
710 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
712 let built_tx = trusted_tx.built_transaction();
713 let commitment_sig = built_tx.sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
714 let commitment_txid = built_tx.txid;
716 let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
717 for htlc in commitment_tx.htlcs() {
718 let channel_parameters = self.get_channel_parameters();
719 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);
720 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys);
721 let htlc_sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
722 let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
723 let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?;
724 htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
727 Ok((commitment_sig, htlc_sigs))
730 fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
734 fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
735 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
736 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
737 let trusted_tx = commitment_tx.trust();
738 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
739 let channel_parameters = self.get_channel_parameters();
740 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
744 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
745 fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
746 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
747 let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
748 let trusted_tx = commitment_tx.trust();
749 let sig = trusted_tx.built_transaction().sign(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, secp_ctx);
750 let channel_parameters = self.get_channel_parameters();
751 let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), secp_ctx)?;
755 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
756 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
757 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
758 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
759 let witness_script = {
760 let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?;
761 chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
763 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
764 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
765 return Ok(sign(secp_ctx, &sighash, &revocation_key))
768 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, ()> {
769 let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
770 let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
771 let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
772 let witness_script = {
773 let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?;
774 let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?;
775 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
777 let mut sighash_parts = sighash::SighashCache::new(justice_tx);
778 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
779 return Ok(sign(secp_ctx, &sighash, &revocation_key))
782 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, ()> {
783 if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) {
784 let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
785 if let Ok(counterparty_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) {
786 if let Ok(htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
787 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, self.opt_anchors(), &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey)
788 } else { return Err(()) }
789 } else { return Err(()) }
790 } else { return Err(()) };
791 let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
792 let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
793 return Ok(sign(secp_ctx, &sighash, &htlc_key))
798 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
799 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
800 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
801 Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
804 fn sign_holder_anchor_input(
805 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
806 ) -> Result<Signature, ()> {
807 let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
808 let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
809 input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
811 Ok(sign(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key))
814 fn sign_channel_announcement(&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>)
815 -> Result<(Signature, Signature), ()> {
816 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
817 Ok((sign(secp_ctx, &msghash, &self.node_secret), sign(secp_ctx, &msghash, &self.funding_key)))
820 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
821 assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
822 if self.channel_parameters.is_some() {
823 // The channel parameters were already set and they match, return early.
826 assert!(channel_parameters.is_populated(), "Channel parameters must be fully populated");
827 self.channel_parameters = Some(channel_parameters.clone());
831 const SERIALIZATION_VERSION: u8 = 1;
832 const MIN_SERIALIZATION_VERSION: u8 = 1;
834 impl Sign for InMemorySigner {}
836 impl Writeable for InMemorySigner {
837 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
838 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
840 self.funding_key.write(writer)?;
841 self.revocation_base_key.write(writer)?;
842 self.payment_key.write(writer)?;
843 self.delayed_payment_base_key.write(writer)?;
844 self.htlc_base_key.write(writer)?;
845 self.commitment_seed.write(writer)?;
846 self.channel_parameters.write(writer)?;
847 self.channel_value_satoshis.write(writer)?;
848 self.channel_keys_id.write(writer)?;
850 write_tlv_fields!(writer, {});
856 impl ReadableArgs<SecretKey> for InMemorySigner {
857 fn read<R: io::Read>(reader: &mut R, node_secret: SecretKey) -> Result<Self, DecodeError> {
858 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
860 let funding_key = Readable::read(reader)?;
861 let revocation_base_key = Readable::read(reader)?;
862 let payment_key = Readable::read(reader)?;
863 let delayed_payment_base_key = Readable::read(reader)?;
864 let htlc_base_key = Readable::read(reader)?;
865 let commitment_seed = Readable::read(reader)?;
866 let counterparty_channel_data = Readable::read(reader)?;
867 let channel_value_satoshis = Readable::read(reader)?;
868 let secp_ctx = Secp256k1::signing_only();
869 let holder_channel_pubkeys =
870 InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
871 &payment_key, &delayed_payment_base_key,
873 let keys_id = Readable::read(reader)?;
875 read_tlv_fields!(reader, {});
881 delayed_payment_base_key,
885 channel_value_satoshis,
886 holder_channel_pubkeys,
887 channel_parameters: counterparty_channel_data,
888 channel_keys_id: keys_id,
893 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
894 /// and derives keys from that.
896 /// Your node_id is seed/0'
897 /// ChannelMonitor closes may use seed/1'
898 /// Cooperative closes may use seed/2'
899 /// The two close keys may be needed to claim on-chain funds!
901 /// This struct cannot be used for nodes that wish to support receiving phantom payments;
902 /// [`PhantomKeysManager`] must be used instead.
904 /// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
905 /// previously issued invoices and attempts to pay previous invoices will fail.
906 pub struct KeysManager {
907 secp_ctx: Secp256k1<secp256k1::All>,
908 node_secret: SecretKey,
910 inbound_payment_key: KeyMaterial,
911 destination_script: Script,
912 shutdown_pubkey: PublicKey,
913 channel_master_key: ExtendedPrivKey,
914 channel_child_index: AtomicUsize,
916 rand_bytes_master_key: ExtendedPrivKey,
917 rand_bytes_child_index: AtomicUsize,
918 rand_bytes_unique_start: Sha256State,
921 starting_time_secs: u64,
922 starting_time_nanos: u32,
926 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
927 /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds).
928 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
929 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
930 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
931 /// simply use the current time (with very high precision).
933 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
934 /// obviously, starting_time should be unique every time you reload the library - it is only
935 /// used to generate new ephemeral key data (which will be stored by the individual channel if
938 /// Note that the seed is required to recover certain on-chain funds independent of
939 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
940 /// channel, and some on-chain during-closing funds.
942 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
943 /// versions. Once the library is more fully supported, the docs will be updated to include a
944 /// detailed description of the guarantee.
945 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32) -> Self {
946 let secp_ctx = Secp256k1::new();
947 // Note that when we aren't serializing the key, network doesn't matter
948 match ExtendedPrivKey::new_master(Network::Testnet, seed) {
950 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
951 let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
952 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
953 Ok(destination_key) => {
954 let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
955 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
956 .push_slice(&wpubkey_hash.into_inner())
959 Err(_) => panic!("Your RNG is busted"),
961 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
962 Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
963 Err(_) => panic!("Your RNG is busted"),
965 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
966 let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
967 let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
968 let mut inbound_pmt_key_bytes = [0; 32];
969 inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
971 let mut rand_bytes_unique_start = Sha256::engine();
972 rand_bytes_unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
973 rand_bytes_unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
974 rand_bytes_unique_start.input(seed);
976 let mut res = KeysManager {
980 inbound_payment_key: KeyMaterial(inbound_pmt_key_bytes),
986 channel_child_index: AtomicUsize::new(0),
988 rand_bytes_master_key,
989 rand_bytes_child_index: AtomicUsize::new(0),
990 rand_bytes_unique_start,
996 let secp_seed = res.get_secure_random_bytes();
997 res.secp_ctx.seeded_randomize(&secp_seed);
1000 Err(_) => panic!("Your rng is busted"),
1003 /// Derive an old Sign containing per-channel secrets based on a key derivation parameters.
1004 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1005 let chan_id = byte_utils::slice_to_be64(¶ms[0..8]);
1006 let mut unique_start = Sha256::engine();
1007 unique_start.input(params);
1008 unique_start.input(&self.seed);
1010 // We only seriously intend to rely on the channel_master_key for true secure
1011 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
1012 // starting_time provided in the constructor) to be unique.
1013 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");
1014 unique_start.input(&child_privkey.private_key[..]);
1016 let seed = Sha256::from_engine(unique_start).into_inner();
1018 let commitment_seed = {
1019 let mut sha = Sha256::engine();
1021 sha.input(&b"commitment seed"[..]);
1022 Sha256::from_engine(sha).into_inner()
1024 macro_rules! key_step {
1025 ($info: expr, $prev_key: expr) => {{
1026 let mut sha = Sha256::engine();
1028 sha.input(&$prev_key[..]);
1029 sha.input(&$info[..]);
1030 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
1033 let funding_key = key_step!(b"funding key", commitment_seed);
1034 let revocation_base_key = key_step!(b"revocation base key", funding_key);
1035 let payment_key = key_step!(b"payment key", revocation_base_key);
1036 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key);
1037 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
1039 InMemorySigner::new(
1043 revocation_base_key,
1045 delayed_payment_base_key,
1048 channel_value_satoshis,
1053 /// Creates a Transaction which spends the given descriptors to the given outputs, plus an
1054 /// output to the given change destination (if sufficient change value remains). The
1055 /// transaction will have a feerate, at least, of the given value.
1057 /// Returns `Err(())` if the output value is greater than the input value minus required fee,
1058 /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
1059 /// does not match the one we can spend.
1061 /// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
1063 /// May panic if the `SpendableOutputDescriptor`s were not generated by Channels which used
1064 /// this KeysManager or one of the `InMemorySigner` created by this KeysManager.
1065 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, ()> {
1066 let mut input = Vec::new();
1067 let mut input_value = 0;
1068 let mut witness_weight = 0;
1069 let mut output_set = HashSet::with_capacity(descriptors.len());
1070 for outp in descriptors {
1072 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1074 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1075 script_sig: Script::new(),
1076 sequence: Sequence::ZERO,
1077 witness: Witness::new(),
1079 witness_weight += StaticPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1080 input_value += descriptor.output.value;
1081 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1083 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1085 previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
1086 script_sig: Script::new(),
1087 sequence: Sequence(descriptor.to_self_delay as u32),
1088 witness: Witness::new(),
1090 witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
1091 input_value += descriptor.output.value;
1092 if !output_set.insert(descriptor.outpoint) { return Err(()); }
1094 SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
1096 previous_output: outpoint.into_bitcoin_outpoint(),
1097 script_sig: Script::new(),
1098 sequence: Sequence::ZERO,
1099 witness: Witness::new(),
1101 witness_weight += 1 + 73 + 34;
1102 input_value += output.value;
1103 if !output_set.insert(*outpoint) { return Err(()); }
1106 if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
1108 let mut spend_tx = Transaction {
1110 lock_time: PackedLockTime(0),
1114 let expected_max_weight =
1115 transaction_utils::maybe_add_change_output(&mut spend_tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
1117 let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
1118 let mut input_idx = 0;
1119 for outp in descriptors {
1121 SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
1122 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1124 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1125 descriptor.channel_keys_id));
1127 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)?);
1129 SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
1130 if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
1132 self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
1133 descriptor.channel_keys_id));
1135 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)?);
1137 SpendableOutputDescriptor::StaticOutput { ref output, .. } => {
1138 let derivation_idx = if output.script_pubkey == self.destination_script {
1144 // Note that when we aren't serializing the key, network doesn't matter
1145 match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
1147 match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
1149 Err(_) => panic!("Your RNG is busted"),
1152 Err(_) => panic!("Your rng is busted"),
1155 let pubkey = ExtendedPubKey::from_priv(&secp_ctx, &secret).to_pub();
1156 if derivation_idx == 2 {
1157 assert_eq!(pubkey.inner, self.shutdown_pubkey);
1159 let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
1160 let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
1162 if payment_script != output.script_pubkey { return Err(()); };
1164 let sighash = hash_to_message!(&sighash::SighashCache::new(&spend_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
1165 let sig = sign(secp_ctx, &sighash, &secret.private_key);
1166 let mut sig_ser = sig.serialize_der().to_vec();
1167 sig_ser.push(EcdsaSighashType::All as u8);
1168 spend_tx.input[input_idx].witness.push(sig_ser);
1169 spend_tx.input[input_idx].witness.push(pubkey.inner.serialize().to_vec());
1175 debug_assert!(expected_max_weight >= spend_tx.weight());
1176 // Note that witnesses with a signature vary somewhat in size, so allow
1177 // `expected_max_weight` to overshoot by up to 3 bytes per input.
1178 debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
1184 impl KeysInterface for KeysManager {
1185 type Signer = InMemorySigner;
1187 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1189 Recipient::Node => Ok(self.node_secret.clone()),
1190 Recipient::PhantomNode => Err(())
1194 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1196 Recipient::Node => Ok(self.node_id.clone()),
1197 Recipient::PhantomNode => Err(())
1201 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1202 let mut node_secret = self.get_node_secret(recipient)?;
1203 if let Some(tweak) = tweak {
1204 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1206 Ok(SharedSecret::new(other_key, &node_secret))
1209 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1210 self.inbound_payment_key.clone()
1213 fn get_destination_script(&self) -> Script {
1214 self.destination_script.clone()
1217 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1218 ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
1221 fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1222 let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
1223 assert!(child_idx <= core::u32::MAX as usize);
1224 let mut id = [0; 32];
1225 id[0..4].copy_from_slice(&(child_idx as u32).to_be_bytes());
1226 id[4..8].copy_from_slice(&self.starting_time_nanos.to_be_bytes());
1227 id[8..16].copy_from_slice(&self.starting_time_secs.to_be_bytes());
1228 id[16..32].copy_from_slice(&user_channel_id.to_be_bytes());
1232 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1233 self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
1236 fn get_secure_random_bytes(&self) -> [u8; 32] {
1237 let mut sha = self.rand_bytes_unique_start.clone();
1239 let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel);
1240 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");
1241 sha.input(&child_privkey.private_key[..]);
1243 sha.input(b"Unique Secure Random Bytes Salt");
1244 Sha256::from_engine(sha).into_inner()
1247 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1248 InMemorySigner::read(&mut io::Cursor::new(reader), self.node_secret.clone())
1251 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1252 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1253 let secret = match recipient {
1254 Recipient::Node => self.get_node_secret(Recipient::Node)?,
1255 Recipient::PhantomNode => return Err(()),
1257 Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1261 /// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
1264 /// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
1265 /// paid to one of multiple nodes. This works because we encode the invoice route hints such that
1266 /// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
1267 /// itself without ever needing to forward to this fake node.
1269 /// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
1270 /// provide some fault tolerance, because payers will automatically retry paying other provided
1271 /// nodes in the case that one node goes down.
1273 /// Note that multi-path payments are not supported in phantom invoices for security reasons.
1274 // In the hypothetical case that we did support MPP phantom payments, there would be no way for
1275 // nodes to know when the full payment has been received (and the preimage can be released) without
1276 // significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
1277 // to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
1278 // is released too early.
1280 /// Switching between this struct and [`KeysManager`] will invalidate any previously issued
1281 /// invoices and attempts to pay previous invoices will fail.
1282 pub struct PhantomKeysManager {
1284 inbound_payment_key: KeyMaterial,
1285 phantom_secret: SecretKey,
1286 phantom_node_id: PublicKey,
1289 impl KeysInterface for PhantomKeysManager {
1290 type Signer = InMemorySigner;
1292 fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
1294 Recipient::Node => self.inner.get_node_secret(Recipient::Node),
1295 Recipient::PhantomNode => Ok(self.phantom_secret.clone()),
1299 fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
1301 Recipient::Node => self.inner.get_node_id(Recipient::Node),
1302 Recipient::PhantomNode => Ok(self.phantom_node_id.clone()),
1306 fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
1307 let mut node_secret = self.get_node_secret(recipient)?;
1308 if let Some(tweak) = tweak {
1309 node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
1311 Ok(SharedSecret::new(other_key, &node_secret))
1314 fn get_inbound_payment_key_material(&self) -> KeyMaterial {
1315 self.inbound_payment_key.clone()
1318 fn get_destination_script(&self) -> Script {
1319 self.inner.get_destination_script()
1322 fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
1323 self.inner.get_shutdown_scriptpubkey()
1326 fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
1327 self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
1330 fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
1331 self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
1334 fn get_secure_random_bytes(&self) -> [u8; 32] {
1335 self.inner.get_secure_random_bytes()
1338 fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
1339 self.inner.read_chan_signer(reader)
1342 fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
1343 let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
1344 let secret = self.get_node_secret(recipient)?;
1345 Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
1349 impl PhantomKeysManager {
1350 /// Constructs a `PhantomKeysManager` given a 32-byte seed and an additional `cross_node_seed`
1351 /// that is shared across all nodes that intend to participate in [phantom node payments] together.
1353 /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
1354 /// `starting_time_nanos`.
1356 /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
1357 /// same across restarts, or else inbound payments may fail.
1359 /// [phantom node payments]: PhantomKeysManager
1360 pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
1361 let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
1362 let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
1363 let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
1364 let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
1367 inbound_payment_key: KeyMaterial(inbound_key),
1373 /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
1374 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, ()> {
1375 self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
1378 /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
1379 pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
1380 self.inner.derive_channel_keys(channel_value_satoshis, params)
1384 // Ensure that BaseSign can have a vtable
1387 let _signer: Box<dyn BaseSign>;