+ #[cfg(anchors)]
+ fn sign_holder_htlc_transaction(
+ &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
+ secp_ctx: &Secp256k1<secp256k1::All>
+ ) -> Result<Signature, ()> {
+ let per_commitment_point = self.get_per_commitment_point(
+ htlc_descriptor.per_commitment_number, &secp_ctx
+ );
+ let witness_script = htlc_descriptor.witness_script(&per_commitment_point, secp_ctx);
+ let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
+ input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
+ ).map_err(|_| ())?;
+ let our_htlc_private_key = chan_utils::derive_private_key(
+ &secp_ctx, &per_commitment_point, &self.htlc_base_key
+ );
+ Ok(sign(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key))
+ }
+