+ /// Unlike sign_local_commitment, this may be called multiple times with *different*
+ /// local_commitment_tx values. While this will never be called with a revoked
+ /// local_commitment_tx, it is possible that it is called with the second-latest
+ /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
+ /// ChannelMonitor decided to broadcast before it had been updated to the latest.
+ ///
+ /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
+ /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
+ /// (implying they were considered dust at the time the commitment transaction was negotiated),
+ /// a corresponding None should be included in the return value. All other positions in the
+ /// return value must contain a signature.
+ fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()>;
+
+ /// Create a signature for the given input in a transaction spending an HTLC or commitment
+ /// transaction output when our counterparty broadcasts an old state.
+ ///
+ /// A justice transaction may claim multiples 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 multiples time 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 _local_ secret key and does
+ /// not allow the spending of any funds by itself (you need our local revocation_secret to do
+ /// so).
+ ///
+ /// htlc holds HTLC elements (hash, timelock) if the output being spent is a HTLC output, thus
+ /// changing the format of the witness script (which is committed to in the BIP 143
+ /// signatures).
+ ///
+ /// on_remote_tx_csv is the relative lock-time that that our counterparty would have to set on
+ /// their transaction were they to spend the same output. It is included in the witness script
+ /// and thus committed to in the BIP 143 signature.
+ fn sign_justice_transaction<T: secp256k1::Signing + secp256k1::Verification>(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, on_remote_tx_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;