Move low-R comments into blocks
[rust-lightning] / lightning / src / sign / mod.rs
index d27a64be79364c7fc0d9ea8e2bcf1daaae3a42c6..fd992a594c489fe2e6ada0491f1cdc3c5fe8d0e9 100644 (file)
@@ -29,6 +29,8 @@ use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hash_types::WPubkeyHash;
 
+#[cfg(taproot)]
+use bitcoin::secp256k1::All;
 use bitcoin::secp256k1::{KeyPair, PublicKey, Scalar, Secp256k1, SecretKey, Signing};
 use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1::ecdsa::{RecoverableSignature, Signature};
@@ -36,7 +38,7 @@ use bitcoin::secp256k1::schnorr;
 use bitcoin::{secp256k1, Sequence, Witness, Txid};
 
 use crate::util::transaction_utils;
-use crate::util::crypto::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
+use crate::crypto::utils::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
 use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
 use crate::chain::transaction::OutPoint;
 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
@@ -44,23 +46,33 @@ use crate::ln::{chan_utils, PaymentPreimage};
 use crate::ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, HolderCommitmentTransaction, ChannelTransactionParameters, CommitmentTransaction, ClosingTransaction};
 use crate::ln::channel_keys::{DelayedPaymentBasepoint, DelayedPaymentKey, HtlcKey, HtlcBasepoint, RevocationKey, RevocationBasepoint};
 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
+#[cfg(taproot)]
+use crate::ln::msgs::PartialSignatureWithNonce;
 use crate::ln::script::ShutdownScript;
 use crate::offers::invoice::UnsignedBolt12Invoice;
 use crate::offers::invoice_request::UnsignedInvoiceRequest;
 
 use crate::prelude::*;
-use core::convert::TryInto;
 use core::ops::Deref;
 use core::sync::atomic::{AtomicUsize, Ordering};
+#[cfg(taproot)]
+use musig2::types::{PartialSignature, PublicNonce};
 use crate::io::{self, Error};
 use crate::ln::features::ChannelTypeFeatures;
 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
+use crate::sign::ecdsa::{EcdsaChannelSigner, WriteableEcdsaChannelSigner};
+#[cfg(taproot)]
+use crate::sign::taproot::TaprootChannelSigner;
 use crate::util::atomic_counter::AtomicCounter;
-use crate::util::chacha20::ChaCha20;
+use crate::crypto::chacha20::ChaCha20;
 use crate::util::invoice::construct_invoice_preimage;
 
 pub(crate) mod type_resolver;
 
+pub mod ecdsa;
+#[cfg(taproot)]
+pub mod taproot;
+
 /// Used as initial key material, to be expanded into multiple secret keys (but not to be used
 /// directly). This is used within LDK to encrypt/decrypt inbound payment data.
 ///
@@ -144,7 +156,7 @@ impl StaticPaymentOutputDescriptor {
        pub fn witness_script(&self) -> Option<ScriptBuf> {
                self.channel_transaction_parameters.as_ref()
                        .and_then(|channel_params|
-                                if channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx() {
+                                if channel_params.supports_anchors() {
                                        let payment_point = channel_params.holder_pubkeys.payment_point;
                                        Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
                                 } else {
@@ -157,9 +169,7 @@ impl StaticPaymentOutputDescriptor {
        /// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
        /// shorter.
        pub fn max_witness_length(&self) -> u64 {
-               if self.channel_transaction_parameters.as_ref()
-                       .map(|channel_params| channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx())
-                       .unwrap_or(false)
+               if self.channel_transaction_parameters.as_ref().map_or(false, |p| p.supports_anchors())
                {
                        let witness_script_weight = 1 /* pubkey push */ + 33 /* pubkey */ +
                                1 /* OP_CHECKSIGVERIFY */ + 1 /* OP_1 */ + 1 /* OP_CHECKSEQUENCEVERIFY */;
@@ -337,15 +347,14 @@ impl SpendableOutputDescriptor {
                let mut input = Vec::with_capacity(descriptors.len());
                let mut input_value = 0;
                let mut witness_weight = 0;
-               let mut output_set = HashSet::with_capacity(descriptors.len());
+               let mut output_set = hash_set_with_capacity(descriptors.len());
                for outp in descriptors {
                        match outp {
                                SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
                                        if !output_set.insert(descriptor.outpoint) { return Err(()); }
                                        let sequence =
                                                if descriptor.channel_transaction_parameters.as_ref()
-                                                       .map(|channel_params| channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx())
-                                                       .unwrap_or(false)
+                                                       .map_or(false, |p| p.supports_anchors())
                                                {
                                                        Sequence::from_consensus(1)
                                                } else {
@@ -359,7 +368,9 @@ impl SpendableOutputDescriptor {
                                        });
                                        witness_weight += descriptor.max_witness_length();
                                        #[cfg(feature = "grind_signatures")]
-                                       { witness_weight -= 1; } // Guarantees a low R signature
+                                       { // Guarantees a low R signature
+                                               witness_weight -= 1;
+                                       }
                                        input_value += descriptor.output.value;
                                },
                                SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
@@ -372,7 +383,9 @@ impl SpendableOutputDescriptor {
                                        });
                                        witness_weight += DelayedPaymentOutputDescriptor::MAX_WITNESS_LENGTH;
                                        #[cfg(feature = "grind_signatures")]
-                                       { witness_weight -= 1; } // Guarantees a low R signature
+                                       { // Guarantees a low R signature
+                                               witness_weight -= 1;
+                                       }
                                        input_value += descriptor.output.value;
                                },
                                SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
@@ -385,7 +398,9 @@ impl SpendableOutputDescriptor {
                                        });
                                        witness_weight += 1 + 73 + 34;
                                        #[cfg(feature = "grind_signatures")]
-                                       { witness_weight -= 1; } // Guarantees a low R signature
+                                       { // Guarantees a low R signature
+                                               witness_weight -= 1;
+                                       }
                                        input_value += output.value;
                                }
                        }
@@ -544,7 +559,7 @@ impl HTLCDescriptor {
        /// Derives the channel signer required to sign the HTLC input.
        pub fn derive_channel_signer<S: WriteableEcdsaChannelSigner, SP: Deref>(&self, signer_provider: &SP) -> S
        where
-               SP::Target: SignerProvider<Signer = S>
+               SP::Target: SignerProvider<EcdsaSigner= S>
        {
                let mut signer = signer_provider.derive_channel_signer(
                        self.channel_derivation_parameters.value_satoshis,
@@ -581,14 +596,20 @@ pub trait ChannelSigner {
        /// Policy checks should be implemented in this function, including checking the amount
        /// sent to us and checking the HTLCs.
        ///
-       /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
+       /// The preimages of outbound HTLCs that were fulfilled since the last commitment are provided.
        /// A validating signer should ensure that an HTLC output is removed only when the matching
        /// preimage is provided, or when the value to holder is restored.
        ///
        /// Note that all the relevant preimages will be provided, but there may also be additional
        /// irrelevant or duplicate preimages.
        fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction,
-               preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
+               outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()>;
+
+       /// 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<(), ()>;
 
        /// Returns the holder's channel public keys and basepoints.
        fn pubkeys(&self) -> &ChannelPublicKeys;
@@ -610,161 +631,6 @@ pub trait ChannelSigner {
        fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters);
 }
 
-/// A trait to sign Lightning channel transactions as described in
-/// [BOLT 3](https://github.com/lightning/bolts/blob/master/03-transactions.md).
-///
-/// Signing services could be implemented on a hardware wallet and should implement signing
-/// policies in order to be secure. Please refer to the [VLS Policy
-/// Controls](https://gitlab.com/lightning-signer/validating-lightning-signer/-/blob/main/docs/policy-controls.md)
-/// for an example of such policies.
-pub trait EcdsaChannelSigner: ChannelSigner {
-       /// 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.
-       ///
-       /// The preimages of outgoing HTLCs that were fulfilled since the last commitment are provided.
-       /// A validating signer should ensure that an HTLC output is removed only when the matching
-       /// preimage is provided, or when the value to holder is restored.
-       ///
-       /// Note that all the relevant preimages will be provided, but there may also be additional
-       /// irrelevant or duplicate preimages.
-       //
-       // TODO: Document the things someone using this interface should enforce before signing.
-       fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction,
-               preimages: Vec<PaymentPreimage>, 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<(), ()>;
-       /// Creates a signature for a holder's commitment transaction.
-       ///
-       /// This will be called
-       /// - with a non-revoked `commitment_tx`.
-       /// - with the latest `commitment_tx` when we initiate a force-close.
-       ///
-       /// This may be called multiple times for the same transaction.
-       ///
-       /// An external signer implementation should check that the commitment has not been revoked.
-       //
-       // TODO: Document the things someone using this interface should enforce before signing.
-       fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction,
-               secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
-       /// Same as [`sign_holder_commitment`], but exists only for tests to get access to holder
-       /// commitment transactions which will be broadcasted later, after the channel has moved on to a
-       /// newer state. Thus, needs its own method as [`sign_holder_commitment`] may enforce that we
-       /// only ever get called once.
-       #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
-       fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction,
-               secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
-       /// 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 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.
-       ///
-       /// 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).
-       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.
-       ///
-       /// `amount` is the 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, ()>;
-       /// Computes the signature for a commitment transaction's HTLC output used as an input within
-       /// `htlc_tx`, which spends the commitment transaction at index `input`. The signature returned
-       /// must be be computed using [`EcdsaSighashType::All`].
-       ///
-       /// Note that this may be called for HTLCs in the penultimate commitment transaction if a
-       /// [`ChannelMonitor`] [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
-       /// broadcasts it before receiving the update for the latest commitment transaction.
-       ///
-       /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
-       fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize,
-               htlc_descriptor: &HTLCDescriptor, 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.
-       ///
-       /// Such a transaction may claim multiples offered outputs at same time if we know the
-       /// preimage for each when we create it, but only 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.
-       ///
-       /// `witness_script` is either an offered or received script as defined in BOLT3 for HTLC
-       /// outputs.
-       ///
-       /// `amount` is value of the output spent by this input, committed to in the BIP 143 signature.
-       ///
-       /// `per_commitment_point` is the dynamic point corresponding to the channel state
-       /// detected onchain. It has been generated by our counterparty and is used to derive
-       /// channel state keys, which are then included in the witness script and committed to in the
-       /// BIP 143 signature.
-       fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64,
-               per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment,
-               secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
-       /// Create a signature for a (proposed) closing transaction.
-       ///
-       /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
-       /// chosen to forgo their output as dust.
-       fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction,
-               secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()>;
-       /// Computes the signature for a commitment transaction's anchor output used as an
-       /// input within `anchor_tx`, which spends the commitment transaction, at index `input`.
-       fn sign_holder_anchor_input(
-               &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
-       ) -> Result<Signature, ()>;
-       /// Signs a channel announcement message with our funding key proving it comes from one of the
-       /// channel participants.
-       ///
-       /// Channel announcements also require a signature from each node's network key. Our node
-       /// signature is computed through [`NodeSigner::sign_gossip_message`].
-       ///
-       /// Note that if this fails or is rejected, the channel will not be publicly announced and
-       /// our counterparty may (though likely will not) close the channel on us for violating the
-       /// protocol.
-       fn sign_channel_announcement_with_funding_key(
-               &self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
-       ) -> Result<Signature, ()>;
-}
-
-/// A writeable signer.
-///
-/// There will always be two instances of a signer per channel, one occupied by the
-/// [`ChannelManager`] and another by the channel's [`ChannelMonitor`].
-///
-/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
-/// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
-pub trait WriteableEcdsaChannelSigner: EcdsaChannelSigner + Writeable {}
-
 /// Specifies the recipient of an invoice.
 ///
 /// This indicates to [`NodeSigner::sign_invoice`] what node secret key should be used to sign
@@ -872,12 +738,28 @@ pub trait NodeSigner {
        fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
 }
 
+// Primarily needed in doctests because of https://github.com/rust-lang/rust/issues/67295
+/// A dynamic [`SignerProvider`] temporarily needed for doc tests.
+#[cfg(taproot)]
+#[doc(hidden)]
+#[deprecated(note = "Remove once taproot cfg is removed")]
+pub type DynSignerProvider = dyn SignerProvider<EcdsaSigner = InMemorySigner, TaprootSigner = InMemorySigner>;
+
+/// A dynamic [`SignerProvider`] temporarily needed for doc tests.
+#[cfg(not(taproot))]
+#[doc(hidden)]
+#[deprecated(note = "Remove once taproot cfg is removed")]
+pub type DynSignerProvider = dyn SignerProvider<EcdsaSigner = InMemorySigner>;
+
 /// A trait that can return signer instances for individual channels.
 pub trait SignerProvider {
        /// A type which implements [`WriteableEcdsaChannelSigner`] which will be returned by [`Self::derive_channel_signer`].
-       type Signer : WriteableEcdsaChannelSigner;
+       type EcdsaSigner: WriteableEcdsaChannelSigner;
+       #[cfg(taproot)]
+       /// A type which implements [`TaprootChannelSigner`]
+       type TaprootSigner: TaprootChannelSigner;
 
-       /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::Signer`] through
+       /// Generates a unique `channel_keys_id` that can be used to obtain a [`Self::EcdsaSigner`] through
        /// [`SignerProvider::derive_channel_signer`]. The `user_channel_id` is provided to allow
        /// implementations of [`SignerProvider`] to maintain a mapping between itself and the generated
        /// `channel_keys_id`.
@@ -891,7 +773,7 @@ pub trait SignerProvider {
        /// [`SignerProvider::generate_channel_keys_id`]. Otherwise, an existing `Signer` can be
        /// re-derived from its `channel_keys_id`, which can be obtained through its trait method
        /// [`ChannelSigner::channel_keys_id`].
-       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer;
+       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner;
 
        /// Reads a [`Signer`] for this [`SignerProvider`] from the given input stream.
        /// This is only called during deserialization of other objects which contain
@@ -903,10 +785,10 @@ pub trait SignerProvider {
        /// This method is slowly being phased out -- it will only be called when reading objects
        /// written by LDK versions prior to 0.0.113.
        ///
-       /// [`Signer`]: Self::Signer
+       /// [`Signer`]: Self::EcdsaSigner
        /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
        /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
-       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError>;
+       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError>;
 
        /// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
        ///
@@ -955,11 +837,8 @@ pub struct InMemorySigner {
        channel_value_satoshis: u64,
        /// Key derivation parameters.
        channel_keys_id: [u8; 32],
-       /// Seed from which all randomness produced is derived from.
-       rand_bytes_unique_start: [u8; 32],
-       /// Tracks the number of times we've produced randomness to ensure we don't return the same
-       /// bytes twice.
-       rand_bytes_index: AtomicCounter,
+       /// A source of random bytes.
+       entropy_source: RandomBytes,
 }
 
 impl PartialEq for InMemorySigner {
@@ -990,8 +869,7 @@ impl Clone for InMemorySigner {
                        channel_parameters: self.channel_parameters.clone(),
                        channel_value_satoshis: self.channel_value_satoshis,
                        channel_keys_id: self.channel_keys_id,
-                       rand_bytes_unique_start: self.get_secure_random_bytes(),
-                       rand_bytes_index: AtomicCounter::new(),
+                       entropy_source: RandomBytes::new(self.get_secure_random_bytes()),
                }
        }
 }
@@ -1025,8 +903,7 @@ impl InMemorySigner {
                        holder_channel_pubkeys,
                        channel_parameters: None,
                        channel_keys_id,
-                       rand_bytes_unique_start,
-                       rand_bytes_index: AtomicCounter::new(),
+                       entropy_source: RandomBytes::new(rand_bytes_unique_start),
                }
        }
 
@@ -1202,10 +1079,7 @@ impl InMemorySigner {
 
 impl EntropySource for InMemorySigner {
        fn get_secure_random_bytes(&self) -> [u8; 32] {
-               let index = self.rand_bytes_index.get_increment();
-               let mut nonce = [0u8; 16];
-               nonce[..8].copy_from_slice(&index.to_be_bytes());
-               ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
+               self.entropy_source.get_secure_random_bytes()
        }
 }
 
@@ -1219,7 +1093,11 @@ impl ChannelSigner for InMemorySigner {
                chan_utils::build_commitment_secret(&self.commitment_seed, idx)
        }
 
-       fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
+       fn validate_holder_commitment(&self, _holder_tx: &HolderCommitmentTransaction, _outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
+               Ok(())
+       }
+
+       fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
                Ok(())
        }
 
@@ -1241,7 +1119,7 @@ impl ChannelSigner for InMemorySigner {
 const MISSING_PARAMS_ERR: &'static str = "ChannelSigner::provide_channel_parameters must be called before signing operations";
 
 impl EcdsaChannelSigner for InMemorySigner {
-       fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
+       fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, _inbound_htlc_preimages: Vec<PaymentPreimage>, _outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
                let trusted_tx = commitment_tx.trust();
                let keys = trusted_tx.keys();
 
@@ -1270,10 +1148,6 @@ impl EcdsaChannelSigner for InMemorySigner {
                Ok((commitment_sig, htlc_sigs))
        }
 
-       fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
-               Ok(())
-       }
-
        fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
                let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
                let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
@@ -1387,6 +1261,45 @@ impl EcdsaChannelSigner for InMemorySigner {
        }
 }
 
+#[cfg(taproot)]
+impl TaprootChannelSigner for InMemorySigner {
+       fn generate_local_nonce_pair(&self, commitment_number: u64, secp_ctx: &Secp256k1<All>) -> PublicNonce {
+               todo!()
+       }
+
+       fn partially_sign_counterparty_commitment(&self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>) -> Result<(PartialSignatureWithNonce, Vec<schnorr::Signature>), ()> {
+               todo!()
+       }
+
+       fn finalize_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
+               todo!()
+       }
+
+       fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
+               todo!()
+       }
+
+       fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
+               todo!()
+       }
+
+       fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
+               todo!()
+       }
+
+       fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
+               todo!()
+       }
+
+       fn partially_sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
+               todo!()
+       }
+
+       fn sign_holder_anchor_input(&self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>) -> Result<schnorr::Signature, ()> {
+               todo!()
+       }
+}
+
 const SERIALIZATION_VERSION: u8 = 1;
 
 const MIN_SERIALIZATION_VERSION: u8 = 1;
@@ -1444,8 +1357,7 @@ impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySou
                        holder_channel_pubkeys,
                        channel_parameters: counterparty_channel_data,
                        channel_keys_id: keys_id,
-                       rand_bytes_unique_start: entropy_source.get_secure_random_bytes(),
-                       rand_bytes_index: AtomicCounter::new(),
+                       entropy_source: RandomBytes::new(entropy_source.get_secure_random_bytes()),
                })
        }
 }
@@ -1473,8 +1385,7 @@ pub struct KeysManager {
        channel_master_key: ExtendedPrivKey,
        channel_child_index: AtomicUsize,
 
-       rand_bytes_unique_start: [u8; 32],
-       rand_bytes_index: AtomicCounter,
+       entropy_source: RandomBytes,
 
        seed: [u8; 32],
        starting_time_secs: u64,
@@ -1543,8 +1454,7 @@ impl KeysManager {
                                        channel_master_key,
                                        channel_child_index: AtomicUsize::new(0),
 
-                                       rand_bytes_unique_start,
-                                       rand_bytes_index: AtomicCounter::new(),
+                                       entropy_source: RandomBytes::new(rand_bytes_unique_start),
 
                                        seed: *seed,
                                        starting_time_secs,
@@ -1725,10 +1635,7 @@ impl KeysManager {
 
 impl EntropySource for KeysManager {
        fn get_secure_random_bytes(&self) -> [u8; 32] {
-               let index = self.rand_bytes_index.get_increment();
-               let mut nonce = [0u8; 16];
-               nonce[..8].copy_from_slice(&index.to_be_bytes());
-               ChaCha20::get_single_block(&self.rand_bytes_unique_start, &nonce)
+               self.entropy_source.get_secure_random_bytes()
        }
 }
 
@@ -1789,7 +1696,9 @@ impl NodeSigner for KeysManager {
 }
 
 impl SignerProvider for KeysManager {
-       type Signer = InMemorySigner;
+       type EcdsaSigner = InMemorySigner;
+       #[cfg(taproot)]
+       type TaprootSigner = InMemorySigner;
 
        fn generate_channel_keys_id(&self, _inbound: bool, _channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
                let child_idx = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
@@ -1807,11 +1716,11 @@ impl SignerProvider for KeysManager {
                id
        }
 
-       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
+       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner {
                self.derive_channel_keys(channel_value_satoshis, &channel_keys_id)
        }
 
-       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
+       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
                InMemorySigner::read(&mut io::Cursor::new(reader), self)
        }
 
@@ -1908,17 +1817,19 @@ impl NodeSigner for PhantomKeysManager {
 }
 
 impl SignerProvider for PhantomKeysManager {
-       type Signer = InMemorySigner;
+       type EcdsaSigner = InMemorySigner;
+       #[cfg(taproot)]
+       type TaprootSigner = InMemorySigner;
 
        fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32] {
                self.inner.generate_channel_keys_id(inbound, channel_value_satoshis, user_channel_id)
        }
 
-       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::Signer {
+       fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> Self::EcdsaSigner {
                self.inner.derive_channel_signer(channel_value_satoshis, channel_keys_id)
        }
 
-       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
+       fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::EcdsaSigner, DecodeError> {
                self.inner.read_chan_signer(reader)
        }
 
@@ -1978,6 +1889,35 @@ impl PhantomKeysManager {
        }
 }
 
+/// An implementation of [`EntropySource`] using ChaCha20.
+#[derive(Debug)]
+pub struct RandomBytes {
+       /// Seed from which all randomness produced is derived from.
+       seed: [u8; 32],
+       /// Tracks the number of times we've produced randomness to ensure we don't return the same
+       /// bytes twice.
+       index: AtomicCounter,
+}
+
+impl RandomBytes {
+       /// Creates a new instance using the given seed.
+       pub fn new(seed: [u8; 32]) -> Self {
+               Self {
+                       seed,
+                       index: AtomicCounter::new(),
+               }
+       }
+}
+
+impl EntropySource for RandomBytes {
+       fn get_secure_random_bytes(&self) -> [u8; 32] {
+               let index = self.index.get_increment();
+               let mut nonce = [0u8; 16];
+               nonce[..8].copy_from_slice(&index.to_be_bytes());
+               ChaCha20::get_single_block(&self.seed, &nonce)
+       }
+}
+
 // Ensure that EcdsaChannelSigner can have a vtable
 #[test]
 pub fn dyn_sign() {