Drop requirement that ChannelKeys expose delayed_payment_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 secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
-	fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
 	/// 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
@@ -408,7 +406,6 @@ impl InMemoryChannelKeys {
 }
 
 impl ChannelKeys for InMemoryChannelKeys {
-	fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
 	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 }

lightning/src/ln/channel.rs

@@ -1094,11 +1094,11 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// TODO Some magic rust shit to compile-time check this?
 	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 = PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.delayed_payment_base_key());
+		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 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]
@@ -3317,7 +3317,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			funding_pubkey: local_keys.funding_pubkey,
 			revocation_basepoint: local_keys.revocation_basepoint,
 			payment_point: local_keys.payment_point,
-			delayed_payment_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.delayed_payment_base_key()),
+			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
 			htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()),
 			first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret),
 			channel_flags: if self.config.announced_channel {1} else {0},
@@ -3351,7 +3351,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			funding_pubkey: local_keys.funding_pubkey,
 			revocation_basepoint: local_keys.revocation_basepoint,
 			payment_point: local_keys.payment_point,
-			delayed_payment_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.delayed_payment_base_key()),
+			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
 			htlc_basepoint: PublicKey::from_secret_key(&self.secp_ctx, self.local_keys.htlc_base_key()),
 			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() })
@@ -4476,11 +4476,11 @@ mod tests {
 		// We can't just use build_local_transaction_keys here as the per_commitment_secret is not
 		// derived from a commitment_seed, so instead we copy it here and call
 		// build_commitment_transaction.
-		let delayed_payment_base = PublicKey::from_secret_key(&secp_ctx, chan.local_keys.delayed_payment_base_key());
+		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 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/ln/functional_tests.rs

@@ -4321,7 +4321,7 @@ macro_rules! check_spendable_outputs {
 									};
 									let secp_ctx = Secp256k1::new();
 									let keys = $keysinterface.derive_channel_keys($chan_value, key_derivation_params.0, key_derivation_params.1);
-									if let Ok(delayed_payment_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, keys.delayed_payment_base_key()) {
+									if let Ok(delayed_payment_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &keys.inner.delayed_payment_base_key) {
 
 										let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
 										let witness_script = chan_utils::get_revokeable_redeemscript(remote_revocation_pubkey, *to_self_delay, &delayed_payment_pubkey);

lightning/src/util/enforcing_trait_impls.rs

@@ -50,7 +50,6 @@ impl EnforcingChannelKeys {
 }
 
 impl ChannelKeys for EnforcingChannelKeys {
-	fn delayed_payment_base_key(&self) -> &SecretKey { self.inner.delayed_payment_base_key() }
 	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() }