Trait ChannelSigner

pub trait ChannelSigner {
    // Required methods
    fn get_per_commitment_point(
        &self,
        idx: u64,
        secp_ctx: &Secp256k1<All>,
    ) -> PublicKey;
    fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
    fn validate_holder_commitment(
        &self,
        holder_tx: &HolderCommitmentTransaction,
        preimages: Vec<PaymentPreimage>,
    ) -> Result<(), ()>;
    fn pubkeys(&self) -> &ChannelPublicKeys;
    fn channel_keys_id(&self) -> [u8; 32];
    fn provide_channel_parameters(
        &mut self,
        channel_parameters: &ChannelTransactionParameters,
    );
}

A trait to handle Lightning channel key material without concretizing the channel type or the signature mechanism.

Required Methods

fn get_per_commitment_point( &self, idx: u64, secp_ctx: &Secp256k1<All>, ) -> PublicKey

Gets the per-commitment point for a specific commitment number

Note that the commitment number starts at (1 << 48) - 1 and counts backwards.

fn release_commitment_secret(&self, idx: u64) -> [u8; 32]

Gets the commitment secret for a specific commitment number as part of the revocation process

An external signer implementation should error here if the commitment was already signed and should refuse to sign it in the future.

May be called more than once for the same index.

Note that the commitment number starts at (1 << 48) - 1 and counts backwards.

fn validate_holder_commitment( &self, holder_tx: &HolderCommitmentTransaction, preimages: Vec<PaymentPreimage>, ) -> Result<(), ()>

Validate the counterparty’s signatures on the holder commitment transaction and HTLCs.

This is required in order for the signer to make sure that releasing a commitment secret won’t leave us without a broadcastable holder transaction. 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.

fn pubkeys(&self) -> &ChannelPublicKeys

Returns the holder’s channel public keys and basepoints.

fn channel_keys_id(&self) -> [u8; 32]

Returns an arbitrary identifier describing the set of keys which are provided back to you in some SpendableOutputDescriptor types. This should be sufficient to identify this EcdsaChannelSigner object uniquely and lookup or re-derive its keys.

fn provide_channel_parameters( &mut self, channel_parameters: &ChannelTransactionParameters, )

Set the counterparty static channel data, including basepoints, counterparty_selected/holder_selected_contest_delay and funding outpoint.

This data is static, and will never change for a channel once set. For a given ChannelSigner instance, LDK will call this method exactly once - either immediately after construction (not including if done via SignerProvider::read_chan_signer) or when the funding information has been generated.

channel_parameters.is_populated() MUST be true.

Implementors

impl ChannelSigner for InMemorySigner