Drop requirement that all ChannelKeys expose htlc_basepoint

Author: TheBlueMatt

lightning/src/chain/keysinterface.rs

@@ -195,8 +195,6 @@ impl Readable for SpendableOutputDescriptor {
 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
 pub trait ChannelKeys : Send+Clone {
-	/// Gets the local htlc secret key used in commitment tx htlc outputs
-	fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
 	/// Gets the commitment seed
 	fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
 	/// Gets the local channel public keys and basepoints
@@ -406,7 +404,6 @@ impl InMemoryChannelKeys {
 }
 
 impl ChannelKeys for InMemoryChannelKeys {
-	fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
 	fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
 	fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
 	fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params }

lightning/src/ln/channel.rs

@@ -1095,10 +1095,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	fn build_local_transaction_keys(&self, commitment_number: u64) -> Result<TxCreationKeys, ChannelError> {
 		let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(commitment_number));
 		let delayed_payment_base = &self.local_keys.pubkeys().delayed_payment_basepoint;
-		let htlc_basepoint = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key());
+		let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint;
 		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
 
-		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, &htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys"))
+		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys"))
 	}
 
 	#[inline]
@@ -1109,10 +1109,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		//TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we
 		//may see payments to it!
 		let revocation_basepoint = &self.local_keys.pubkeys().revocation_basepoint;
-		let htlc_basepoint = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key());
+		let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint;
 		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
 
-		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &self.their_cur_commitment_point.unwrap(), &their_pubkeys.delayed_payment_basepoint, &their_pubkeys.htlc_basepoint, revocation_basepoint, &htlc_basepoint), "Remote tx keys generation got bogus keys"))
+		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &self.their_cur_commitment_point.unwrap(), &their_pubkeys.delayed_payment_basepoint, &their_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint), "Remote tx keys generation got bogus keys"))
 	}
 
 	/// Gets the redeemscript for the funding transaction output (ie the funding transaction output
@@ -3318,7 +3318,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			revocation_basepoint: local_keys.revocation_basepoint,
 			payment_point: local_keys.payment_point,
 			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
-			htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()),
+			htlc_basepoint: local_keys.htlc_basepoint,
 			first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret),
 			channel_flags: if self.config.announced_channel {1} else {0},
 			shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
@@ -3352,7 +3352,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			revocation_basepoint: local_keys.revocation_basepoint,
 			payment_point: local_keys.payment_point,
 			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
-			htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()),
+			htlc_basepoint: local_keys.htlc_basepoint,
 			first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret),
 			shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
 		}
@@ -4479,8 +4479,8 @@ mod tests {
 		let delayed_payment_base = &chan.local_keys.pubkeys().delayed_payment_basepoint;
 		let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap();
 		let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
-		let htlc_basepoint = PublicKey::from_secret_key(&secp_ctx, chan.local_keys.htlc_base_key());
-		let keys = TxCreationKeys::new(&secp_ctx, &per_commitment_point, delayed_payment_base, &htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint).unwrap();
+		let htlc_basepoint = &chan.local_keys.pubkeys().htlc_basepoint;
+		let keys = TxCreationKeys::new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint).unwrap();
 
 		chan.their_pubkeys = Some(their_pubkeys);
 

lightning/src/util/enforcing_trait_impls.rs

@@ -35,22 +35,19 @@ impl EnforcingChannelKeys {
 impl EnforcingChannelKeys {
 	fn check_keys<T: secp256k1::Signing + secp256k1::Verification>(&self, secp_ctx: &Secp256k1<T>,
 	                                                               keys: &TxCreationKeys) {
-		let htlc_base = PublicKey::from_secret_key(secp_ctx, &self.inner.htlc_base_key());
-
 		let remote_points = self.inner.remote_channel_pubkeys.as_ref().unwrap();
 
 		let keys_expected = TxCreationKeys::new(secp_ctx,
 		                                        &keys.per_commitment_point,
 		                                        &remote_points.delayed_payment_basepoint,
 		                                        &remote_points.htlc_basepoint,
 		                                        &self.inner.pubkeys().revocation_basepoint,
-		                                        &htlc_base).unwrap();
+		                                        &self.inner.pubkeys().htlc_basepoint).unwrap();
 		if keys != &keys_expected { panic!("derived different per-tx keys") }
 	}
 }
 
 impl ChannelKeys for EnforcingChannelKeys {
-	fn htlc_base_key(&self) -> &SecretKey { self.inner.htlc_base_key() }
 	fn commitment_seed(&self) -> &[u8; 32] { self.inner.commitment_seed() }
 	fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.inner.pubkeys() }
 	fn key_derivation_params(&self) -> (u64, u64) { self.inner.key_derivation_params() }