-/// A trait to sign Lightning channel transactions as described in
-/// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
-///
-/// Signing services could be implemented on a hardware wallet and should implement signing
-/// policies in order to be secure. Please refer to the [VLS Policy
-/// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
-/// for an example of such policies.
-pub trait EcdsaChannelSigner: ChannelSigner {
- /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
- ///
- /// Note that if signing fails or is rejected, the channel will be force-closed.
- ///
- /// Policy checks should be implemented in this function, including checking the amount
- /// sent to us and checking the HTLCs.
- ///
- /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
- /// A validating signer should ensure that an HTLC output is removed only when the matching
- /// preimage is provided, or when the value to holder is restored.
- ///
- /// Note that all the relevant preimages will be provided, but there may also be additional
- /// irrelevant or duplicate preimages.
- //
- // TODO: Document the things someone using this interface should enforce before signing.
- fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction,
- preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>
- ) -> Result<(Signature, Vec<Signature>), ()>;
- /// Validate the counterparty's revocation.
- ///
- /// This is required in order for the signer to make sure that the state has moved
- /// forward and it is safe to sign the next counterparty commitment.
- fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
- /// Creates a signature for a holder's commitment transaction.
- ///
- /// This will be called
- /// - with a non-revoked `commitment_tx`.
- /// - with the latest `commitment_tx` when we initiate a force-close.
- ///
- /// This may be called multiple times for the same transaction.
- ///
- /// An external signer implementation should check that the commitment has not been revoked.
- //
- // TODO: Document the things someone using this interface should enforce before signing.
- fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction,
- secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
- /// Same as [`sign_holder_commitment`], but exists only for tests to get access to holder
- /// commitment transactions which will be broadcasted later, after the channel has moved on to a
- /// newer state. Thus, needs its own method as [`sign_holder_commitment`] may enforce that we
- /// only ever get called once.
- #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
- fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction,
- secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
- /// Create a signature for the given input in a transaction spending an HTLC transaction output
- /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
- ///
- /// A justice transaction may claim multiple outputs at the same time if timelocks are
- /// similar, but only a signature for the input at index `input` should be signed for here.
- /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
- /// to an upcoming timelock expiration.
- ///
- /// Amount is value of the output spent by this input, committed to in the BIP 143 signature.
- ///
- /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
- /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
- /// not allow the spending of any funds by itself (you need our holder `revocation_secret` to do
- /// so).
- fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64,
- per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>
- ) -> Result<Signature, ()>;
- /// Create a signature for the given input in a transaction spending a commitment transaction
- /// HTLC output when our counterparty broadcasts an old state.
- ///
- /// A justice transaction may claim multiple outputs at the same time if timelocks are
- /// similar, but only a signature for the input at index `input` should be signed for here.
- /// It may be called multiple times for same output(s) if a fee-bump is needed with regards
- /// to an upcoming timelock expiration.
- ///
- /// `amount` is the value of the output spent by this input, committed to in the BIP 143
- /// signature.
- ///
- /// `per_commitment_key` is revocation secret which was provided by our counterparty when they
- /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
- /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
- /// so).
- ///
- /// `htlc` holds HTLC elements (hash, timelock), thus changing the format of the witness script
- /// (which is committed to in the BIP 143 signatures).
- 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, ()>;
- /// Computes the signature for a commitment transaction's HTLC output used as an input within
- /// `htlc_tx`, which spends the commitment transaction at index `input`. The signature returned
- /// must be be computed using [`EcdsaSighashType::All`].
- ///
- /// Note that this may be called for HTLCs in the penultimate commitment transaction if a
- /// [`ChannelMonitor`] [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
- /// broadcasts it before receiving the update for the latest commitment transaction.
- ///
- /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
- fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize,
- htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<secp256k1::All>
- ) -> Result<Signature, ()>;
- /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
- /// transaction, either offered or received.
- ///
- /// Such a transaction may claim multiples offered outputs at same time if we know the
- /// preimage for each when we create it, but only the input at index `input` should be
- /// signed for here. It may be called multiple times for same output(s) if a fee-bump is
- /// needed with regards to an upcoming timelock expiration.
- ///
- /// `witness_script` is either an offered or received script as defined in BOLT3 for HTLC
- /// outputs.
- ///
- /// `amount` is value of the output spent by this input, committed to in the BIP 143 signature.
- ///
- /// `per_commitment_point` is the dynamic point corresponding to the channel state
- /// detected onchain. It has been generated by our counterparty and is used to derive
- /// channel state keys, which are then included in the witness script and committed to in the
- /// BIP 143 signature.
- 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, ()>;
- /// Create a signature for a (proposed) closing transaction.
- ///
- /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
- /// chosen to forgo their output as dust.
- fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction,
- secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
- /// Computes the signature for a commitment transaction's anchor output used as an
- /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
- fn sign_holder_anchor_input(
- &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
- ) -> Result<Signature, ()>;
- /// Signs a channel announcement message with our funding key proving it comes from one of the
- /// channel participants.
- ///
- /// Channel announcements also require a signature from each node's network key. Our node
- /// signature is computed through [`NodeSigner::sign_gossip_message`].
- ///
- /// Note that if this fails or is rejected, the channel will not be publicly announced and
- /// our counterparty may (though likely will not) close the channel on us for violating the
- /// protocol.
- fn sign_channel_announcement_with_funding_key(
- &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
- ) -> Result<Signature, ()>;
-}
-
-/// A writeable signer.
-///
-/// There will always be two instances of a signer per channel, one occupied by the
-/// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
-///
-/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
-/// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
-pub trait WriteableEcdsaChannelSigner: EcdsaChannelSigner + Writeable {}
-