Allow BaseSign validation functions to return an Err
[rust-lightning] / lightning / src / chain / keysinterface.rs
index 9714e992d5912276f004d964f10eb5e6b10ce235..44a03d09f8e717019c19c070159a7b7556b24723 100644 (file)
@@ -26,6 +26,7 @@ use bitcoin::hash_types::WPubkeyHash;
 
 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
 use bitcoin::secp256k1::{Secp256k1, Signature, Signing};
+use bitcoin::secp256k1::recovery::RecoverableSignature;
 use bitcoin::secp256k1;
 
 use util::{byte_utils, transaction_utils};
@@ -35,10 +36,11 @@ use chain::transaction::OutPoint;
 use ln::chan_utils;
 use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction};
 use ln::msgs::UnsignedChannelAnnouncement;
+use ln::script::ShutdownScript;
 
-use std::collections::HashSet;
-use std::sync::atomic::{AtomicUsize, Ordering};
-use std::io::Error;
+use prelude::*;
+use core::sync::atomic::{AtomicUsize, Ordering};
+use io::{self, Error};
 use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 
 /// Information about a spendable output to a P2WSH script. See
@@ -71,6 +73,16 @@ impl DelayedPaymentOutputDescriptor {
        pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
 }
 
+impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
+       (0, outpoint, required),
+       (2, per_commitment_point, required),
+       (4, to_self_delay, required),
+       (6, output, required),
+       (8, revocation_pubkey, required),
+       (10, channel_keys_id, required),
+       (12, channel_value_satoshis, required),
+});
+
 /// Information about a spendable output to our "payment key". See
 /// SpendableOutputDescriptor::StaticPaymentOutput for more details on how to spend this.
 #[derive(Clone, Debug, PartialEq)]
@@ -92,6 +104,12 @@ impl StaticPaymentOutputDescriptor {
        // redeemscript push length.
        pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 34;
 }
+impl_writeable_tlv_based!(StaticPaymentOutputDescriptor, {
+       (0, outpoint, required),
+       (2, output, required),
+       (4, channel_keys_id, required),
+       (6, channel_value_satoshis, required),
+});
 
 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
 /// claim at any point in the future) an event is generated which you must track and be able to
@@ -101,8 +119,8 @@ impl StaticPaymentOutputDescriptor {
 #[derive(Clone, Debug, PartialEq)]
 pub enum SpendableOutputDescriptor {
        /// An output to a script which was provided via KeysInterface directly, either from
-       /// `get_destination_script()` or `get_shutdown_pubkey()`, thus you should already know how to
-       /// spend it. No secret keys are provided as rust-lightning was never given any key.
+       /// `get_destination_script()` or `get_shutdown_scriptpubkey()`, thus you should already know
+       /// how to spend it. No secret keys are provided as rust-lightning was never given any key.
        /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
        /// on-chain using the payment preimage or after it has timed out.
        StaticOutput {
@@ -150,62 +168,15 @@ pub enum SpendableOutputDescriptor {
        StaticPaymentOutput(StaticPaymentOutputDescriptor),
 }
 
-impl Writeable for SpendableOutputDescriptor {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
-               match self {
-                       &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
-                               0u8.write(writer)?;
-                               outpoint.write(writer)?;
-                               output.write(writer)?;
-                       },
-                       &SpendableOutputDescriptor::DelayedPaymentOutput(ref descriptor) => {
-                               1u8.write(writer)?;
-                               descriptor.outpoint.write(writer)?;
-                               descriptor.per_commitment_point.write(writer)?;
-                               descriptor.to_self_delay.write(writer)?;
-                               descriptor.output.write(writer)?;
-                               descriptor.revocation_pubkey.write(writer)?;
-                               descriptor.channel_keys_id.write(writer)?;
-                               descriptor.channel_value_satoshis.write(writer)?;
-                       },
-                       &SpendableOutputDescriptor::StaticPaymentOutput(ref descriptor) => {
-                               2u8.write(writer)?;
-                               descriptor.outpoint.write(writer)?;
-                               descriptor.output.write(writer)?;
-                               descriptor.channel_keys_id.write(writer)?;
-                               descriptor.channel_value_satoshis.write(writer)?;
-                       },
-               }
-               Ok(())
-       }
-}
-
-impl Readable for SpendableOutputDescriptor {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
-               match Readable::read(reader)? {
-                       0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
-                               outpoint: Readable::read(reader)?,
-                               output: Readable::read(reader)?,
-                       }),
-                       1u8 => Ok(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
-                               outpoint: Readable::read(reader)?,
-                               per_commitment_point: Readable::read(reader)?,
-                               to_self_delay: Readable::read(reader)?,
-                               output: Readable::read(reader)?,
-                               revocation_pubkey: Readable::read(reader)?,
-                               channel_keys_id: Readable::read(reader)?,
-                               channel_value_satoshis: Readable::read(reader)?,
-                       })),
-                       2u8 => Ok(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor {
-                               outpoint: Readable::read(reader)?,
-                               output: Readable::read(reader)?,
-                               channel_keys_id: Readable::read(reader)?,
-                               channel_value_satoshis: Readable::read(reader)?,
-                       })),
-                       _ => Err(DecodeError::InvalidValue),
-               }
-       }
-}
+impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
+       (0, StaticOutput) => {
+               (0, outpoint, required),
+               (2, output, required),
+       },
+;
+       (1, DelayedPaymentOutput),
+       (2, StaticPaymentOutput),
+);
 
 /// A trait to sign lightning channel transactions as described in BOLT 3.
 ///
@@ -226,7 +197,7 @@ impl Readable for SpendableOutputDescriptor {
 /// of LN security model, orthogonal of key management issues.
 // TODO: We should remove Clone by instead requesting a new Sign copy when we create
 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
-pub trait BaseSign : Send {
+pub trait BaseSign {
        /// Gets the per-commitment point for a specific commitment number
        ///
        /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
@@ -241,6 +212,13 @@ pub trait BaseSign : Send {
        /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards.
        // TODO: return a Result so we can signal a validation error
        fn release_commitment_secret(&self, idx: u64) -> [u8; 32];
+       /// 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.
+       fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction) -> Result<(), ()>;
        /// Gets the holder's channel public keys and basepoints
        fn pubkeys(&self) -> &ChannelPublicKeys;
        /// Gets an arbitrary identifier describing the set of keys which are provided back to you in
@@ -251,9 +229,17 @@ pub trait BaseSign : Send {
        /// Create a signature for a counterparty's commitment transaction and associated HTLC transactions.
        ///
        /// Note that if signing fails or is rejected, the channel will be force-closed.
+       ///
+       /// Policy checks should be implemented in this function, including checking the amount
+       /// sent to us and checking the HTLCs.
        //
        // TODO: Document the things someone using this interface should enforce before signing.
        fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
+       /// Validate the counterparty's revocation.
+       ///
+       /// This is required in order for the signer to make sure that the state has moved
+       /// forward and it is safe to sign the next counterparty commitment.
+       fn validate_counterparty_revocation(&self, idx: u64, secret: &SecretKey) -> Result<(), ()>;
 
        /// Create a signatures for a holder's commitment transaction and its claiming HTLC transactions.
        /// This will only ever be called with a non-revoked commitment_tx.  This will be called with the
@@ -278,12 +264,12 @@ pub trait BaseSign : Send {
        #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
        fn unsafe_sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<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.
+       /// Create a signature for the given input in a transaction spending an HTLC transaction output
+       /// or a commitment transaction `to_local` output when our counterparty broadcasts an old state.
        ///
-       /// A justice transaction may claim multiples outputs at the same time if timelocks are
+       /// A justice transaction may claim multiple 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
+       /// It may be called multiple times 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.
@@ -292,11 +278,26 @@ pub trait BaseSign : Send {
        /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does
        /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
        /// so).
+       fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
+
+       /// Create a signature for the given input in a transaction spending a commitment transaction
+       /// HTLC output when our counterparty broadcasts an old state.
+       ///
+       /// A justice transaction may claim multiple 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 multiple times for same output(s) if a fee-bump is needed with regards
+       /// to an upcoming timelock expiration.
        ///
-       /// 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).
-       fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
+       /// 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 _holder_ secret key and does
+       /// not allow the spending of any funds by itself (you need our holder revocation_secret to do
+       /// so).
+       ///
+       /// htlc holds HTLC elements (hash, timelock), thus changing the format of the witness script
+       /// (which is committed to in the BIP 143 signatures).
+       fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
 
        /// Create a signature for a claiming transaction for a HTLC output on a counterparty's commitment
        /// transaction, either offered or received.
@@ -353,7 +354,7 @@ pub trait Sign: BaseSign + Writeable + Clone {
 }
 
 /// A trait to describe an object which can get user secrets and key material.
-pub trait KeysInterface: Send + Sync {
+pub trait KeysInterface {
        /// A type which implements Sign which will be returned by get_channel_signer.
        type Signer : Sign;
 
@@ -366,12 +367,11 @@ pub trait KeysInterface: Send + Sync {
        /// This method should return a different value each time it is called, to avoid linking
        /// on-chain funds across channels as controlled to the same user.
        fn get_destination_script(&self) -> Script;
-       /// Get a public key which we will send funds to (in the form of a P2WPKH output) when closing
-       /// a channel.
+       /// Get a script pubkey which we will send funds to when closing a channel.
        ///
        /// This method should return a different value each time it is called, to avoid linking
        /// on-chain funds across channels as controlled to the same user.
-       fn get_shutdown_pubkey(&self) -> PublicKey;
+       fn get_shutdown_scriptpubkey(&self) -> ShutdownScript;
        /// Get a new set of Sign for per-channel secrets. These MUST be unique even if you
        /// restarted with some stale data!
        ///
@@ -391,6 +391,12 @@ pub trait KeysInterface: Send + Sync {
        /// contain no versioning scheme. You may wish to include your own version prefix and ensure
        /// you've read all of the provided bytes to ensure no corruption occurred.
        fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
+
+       /// Sign an invoice's preimage (note that this is the preimage of the invoice, not the HTLC's
+       /// preimage). By parameterizing by the preimage instead of the hash, we allow implementors of
+       /// this trait to parse the invoice and make sure they're signing what they expect, rather than
+       /// blindly signing the hash.
+       fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()>;
 }
 
 #[derive(Clone)]
@@ -567,6 +573,10 @@ impl BaseSign for InMemorySigner {
                chan_utils::build_commitment_secret(&self.commitment_seed, idx)
        }
 
+       fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction) -> Result<(), ()> {
+               Ok(())
+       }
+
        fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
        fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
 
@@ -586,16 +596,17 @@ impl BaseSign for InMemorySigner {
                        let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), self.holder_selected_contest_delay(), htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
                        let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
                        let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]);
-                       let holder_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
-                               Ok(s) => s,
-                               Err(_) => return Err(()),
-                       };
+                       let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key).map_err(|_| ())?;
                        htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &holder_htlc_key));
                }
 
                Ok((commitment_sig, htlc_sigs))
        }
 
+       fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
+               Ok(())
+       }
+
        fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
                let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
                let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &self.counterparty_pubkeys().funding_pubkey);
@@ -617,32 +628,27 @@ impl BaseSign for InMemorySigner {
                Ok((sig, htlc_sigs))
        }
 
-       fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option<HTLCOutputInCommitment>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
-               let revocation_key = match chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) {
-                       Ok(revocation_key) => revocation_key,
-                       Err(_) => return Err(())
-               };
+       fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+               let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
                let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
-               let revocation_pubkey = match chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) {
-                       Ok(revocation_pubkey) => revocation_pubkey,
-                       Err(_) => return Err(())
+               let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
+               let witness_script = {
+                       let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint).map_err(|_| ())?;
+                       chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
                };
-               let witness_script = if let &Some(ref htlc) = htlc {
-                       let counterparty_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint) {
-                               Ok(counterparty_htlcpubkey) => counterparty_htlcpubkey,
-                               Err(_) => return Err(())
-                       };
-                       let holder_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) {
-                               Ok(holder_htlcpubkey) => holder_htlcpubkey,
-                               Err(_) => return Err(())
-                       };
+               let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
+               let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
+               return Ok(secp_ctx.sign(&sighash, &revocation_key))
+       }
+
+       fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+               let revocation_key = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key).map_err(|_| ())?;
+               let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key);
+               let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint).map_err(|_| ())?;
+               let witness_script = {
+                       let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().htlc_basepoint).map_err(|_| ())?;
+                       let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint).map_err(|_| ())?;
                        chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
-               } else {
-                       let counterparty_delayedpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.counterparty_pubkeys().delayed_payment_basepoint) {
-                               Ok(counterparty_delayedpubkey) => counterparty_delayedpubkey,
-                               Err(_) => return Err(())
-                       };
-                       chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.holder_selected_contest_delay(), &counterparty_delayedpubkey)
                };
                let mut sighash_parts = bip143::SigHashCache::new(justice_tx);
                let sighash = hash_to_message!(&sighash_parts.signature_hash(input, &witness_script, amount, SigHashType::All)[..]);
@@ -690,10 +696,15 @@ impl BaseSign for InMemorySigner {
        }
 }
 
+const SERIALIZATION_VERSION: u8 = 1;
+const MIN_SERIALIZATION_VERSION: u8 = 1;
+
 impl Sign for InMemorySigner {}
 
 impl Writeable for InMemorySigner {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
+               write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
+
                self.funding_key.write(writer)?;
                self.revocation_base_key.write(writer)?;
                self.payment_key.write(writer)?;
@@ -704,12 +715,16 @@ impl Writeable for InMemorySigner {
                self.channel_value_satoshis.write(writer)?;
                self.channel_keys_id.write(writer)?;
 
+               write_tlv_fields!(writer, {});
+
                Ok(())
        }
 }
 
 impl Readable for InMemorySigner {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+               let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
+
                let funding_key = Readable::read(reader)?;
                let revocation_base_key = Readable::read(reader)?;
                let payment_key = Readable::read(reader)?;
@@ -725,6 +740,8 @@ impl Readable for InMemorySigner {
                                                             &htlc_base_key);
                let keys_id = Readable::read(reader)?;
 
+               read_tlv_fields!(reader, {});
+
                Ok(InMemorySigner {
                        funding_key,
                        revocation_base_key,
@@ -843,7 +860,7 @@ impl KeysManager {
        /// onchain output detection for which a corresponding delayed_payment_key must be derived.
        pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
                let chan_id = byte_utils::slice_to_be64(&params[0..8]);
-               assert!(chan_id <= std::u32::MAX as u64); // Otherwise the params field wasn't created by us
+               assert!(chan_id <= core::u32::MAX as u64); // Otherwise the params field wasn't created by us
                let mut unique_start = Sha256::engine();
                unique_start.input(params);
                unique_start.input(&self.seed);
@@ -1019,13 +1036,13 @@ impl KeysInterface for KeysManager {
                self.destination_script.clone()
        }
 
-       fn get_shutdown_pubkey(&self) -> PublicKey {
-               self.shutdown_pubkey.clone()
+       fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
+               ShutdownScript::new_p2wpkh_from_pubkey(self.shutdown_pubkey.clone())
        }
 
        fn get_channel_signer(&self, _inbound: bool, channel_value_satoshis: u64) -> Self::Signer {
                let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
-               assert!(child_ix <= std::u32::MAX as usize);
+               assert!(child_ix <= core::u32::MAX as usize);
                let mut id = [0; 32];
                id[0..8].copy_from_slice(&byte_utils::be64_to_array(child_ix as u64));
                id[8..16].copy_from_slice(&byte_utils::be64_to_array(self.starting_time_nanos as u64));
@@ -1045,7 +1062,11 @@ impl KeysInterface for KeysManager {
        }
 
        fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
-               InMemorySigner::read(&mut std::io::Cursor::new(reader))
+               InMemorySigner::read(&mut io::Cursor::new(reader))
+       }
+
+       fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()> {
+               Ok(self.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&invoice_preimage)), &self.get_node_secret()))
        }
 }
 
@@ -1053,4 +1074,4 @@ impl KeysInterface for KeysManager {
 #[test]
 pub fn dyn_sign() {
        let _signer: Box<dyn BaseSign>;
-}
\ No newline at end of file
+}