X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fsign%2Fmod.rs;h=17a907d19d6313103750274910ed96e652cf099e;hb=c39c398f0618835201fb741b1976952c3f9180fa;hp=04c4446e2c0c8c75bd4f2f7e3b415b8f35296cf2;hpb=7aefa3131c6b0ee826ba4d86510745c9b2f95d1d;p=rust-lightning

diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index 04c4446e..17a907d1 100644
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -12,13 +12,16 @@
 //! The provided output descriptors follow a custom LDK data format and are currently not fully
 //! compatible with Bitcoin Core output descriptors.
 
-use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn, EcdsaSighashType};
-use bitcoin::blockdata::script::{Script, Builder};
+use bitcoin::blockdata::locktime::absolute::LockTime;
+use bitcoin::blockdata::transaction::{Transaction, TxOut, TxIn};
+use bitcoin::blockdata::script::{Script, ScriptBuf, Builder};
 use bitcoin::blockdata::opcodes;
+use bitcoin::ecdsa::Signature as EcdsaSignature;
 use bitcoin::network::constants::Network;
 use bitcoin::psbt::PartiallySignedTransaction;
-use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
-use bitcoin::util::sighash;
+use bitcoin::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
+use bitcoin::sighash;
+use bitcoin::sighash::EcdsaSighashType;
 
 use bitcoin::bech32::u5;
 use bitcoin::hashes::{Hash, HashEngine};
@@ -26,21 +29,25 @@ 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};
 use bitcoin::secp256k1::schnorr;
-use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness};
+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::events::bump_transaction::HTLCDescriptor;
 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
 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;
@@ -49,15 +56,24 @@ 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.
 ///
@@ -81,7 +97,7 @@ pub struct DelayedPaymentOutputDescriptor {
 	pub output: TxOut,
 	/// The revocation point specific to the commitment transaction which was broadcast. Used to
 	/// derive the witnessScript for this output.
-	pub revocation_pubkey: PublicKey,
+	pub revocation_pubkey: RevocationKey,
 	/// Arbitrary identification information returned by a call to [`ChannelSigner::channel_keys_id`].
 	/// This may be useful in re-deriving keys used in the channel to spend the output.
 	pub channel_keys_id: [u8; 32],
@@ -94,7 +110,7 @@ impl DelayedPaymentOutputDescriptor {
 	/// shorter.
 	// Calculated as 1 byte length + 73 byte signature, 1 byte empty vec push, 1 byte length plus
 	// redeemscript push length.
-	pub const MAX_WITNESS_LENGTH: usize = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH + 1;
+	pub const MAX_WITNESS_LENGTH: u64 = 1 + 73 + 1 + chan_utils::REVOKEABLE_REDEEMSCRIPT_MAX_LENGTH as u64 + 1;
 }
 
 impl_writeable_tlv_based!(DelayedPaymentOutputDescriptor, {
@@ -138,7 +154,7 @@ impl StaticPaymentOutputDescriptor {
 	///
 	/// Note that this will only return `Some` for [`StaticPaymentOutputDescriptor`]s that
 	/// originated from an anchor outputs channel, as they take the form of a P2WSH script.
-	pub fn witness_script(&self) -> Option<Script> {
+	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() {
@@ -153,7 +169,7 @@ impl StaticPaymentOutputDescriptor {
 	/// The maximum length a well-formed witness spending one of these should have.
 	/// Note: If you have the grind_signatures feature enabled, this will be at least 1 byte
 	/// shorter.
-	pub fn max_witness_length(&self) -> usize {
+	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)
@@ -163,7 +179,7 @@ impl StaticPaymentOutputDescriptor {
 			1 /* num witness items */ + 1 /* sig push */ + 73 /* sig including sighash flag */ +
 				1 /* witness script push */ + witness_script_weight
 		} else {
-			P2WPKH_WITNESS_WEIGHT as usize
+			P2WPKH_WITNESS_WEIGHT
 		}
 	}
 }
@@ -199,6 +215,15 @@ pub enum SpendableOutputDescriptor {
 		outpoint: OutPoint,
 		/// The output which is referenced by the given outpoint.
 		output: TxOut,
+		/// The `channel_keys_id` for the channel which this output came from.
+		///
+		/// For channels which were generated on LDK 0.0.119 or later, this is the value which was
+		/// passed to the [`SignerProvider::get_destination_script`] call which provided this
+		/// output script.
+		///
+		/// For channels which were generated prior to LDK 0.0.119, no such argument existed,
+		/// however this field may still be filled in if such data is available.
+		channel_keys_id: Option<[u8; 32]>
 	},
 	/// An output to a P2WSH script which can be spent with a single signature after an `OP_CSV`
 	/// delay.
@@ -222,8 +247,8 @@ pub enum SpendableOutputDescriptor {
 	/// To derive the delayed payment key which is used to sign this input, you must pass the
 	/// holder [`InMemorySigner::delayed_payment_base_key`] (i.e., the private key which corresponds to the
 	/// [`ChannelPublicKeys::delayed_payment_basepoint`] in [`ChannelSigner::pubkeys`]) and the provided
-	/// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The public key can be
-	/// generated without the secret key using [`chan_utils::derive_public_key`] and only the
+	/// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to [`chan_utils::derive_private_key`]. The DelayedPaymentKey can be
+	/// generated without the secret key using [`DelayedPaymentKey::from_basepoint`] and only the
 	/// [`ChannelPublicKeys::delayed_payment_basepoint`] which appears in [`ChannelSigner::pubkeys`].
 	///
 	/// To derive the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] provided here (which is
@@ -231,7 +256,7 @@ pub enum SpendableOutputDescriptor {
 	/// [`ChannelPublicKeys::revocation_basepoint`] (which appears in the call to
 	/// [`ChannelSigner::provide_channel_parameters`]) and the provided
 	/// [`DelayedPaymentOutputDescriptor::per_commitment_point`] to
-	/// [`chan_utils::derive_public_revocation_key`].
+	/// [`RevocationKey`].
 	///
 	/// The witness script which is hashed and included in the output `script_pubkey` may be
 	/// regenerated by passing the [`DelayedPaymentOutputDescriptor::revocation_pubkey`] (derived
@@ -262,6 +287,7 @@ pub enum SpendableOutputDescriptor {
 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
 	(0, StaticOutput) => {
 		(0, outpoint, required),
+		(1, channel_keys_id, option),
 		(2, output, required),
 	},
 ;
@@ -320,11 +346,11 @@ impl SpendableOutputDescriptor {
 	/// does not match the one we can spend.
 	///
 	/// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
-	pub fn create_spendable_outputs_psbt(descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>) -> Result<(PartiallySignedTransaction, usize), ()> {
+	pub fn create_spendable_outputs_psbt(descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>) -> Result<(PartiallySignedTransaction, u64), ()> {
 		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) => {
@@ -340,7 +366,7 @@ impl SpendableOutputDescriptor {
 						};
 					input.push(TxIn {
 						previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
-						script_sig: Script::new(),
+						script_sig: ScriptBuf::new(),
 						sequence,
 						witness: Witness::new(),
 					});
@@ -353,7 +379,7 @@ impl SpendableOutputDescriptor {
 					if !output_set.insert(descriptor.outpoint) { return Err(()); }
 					input.push(TxIn {
 						previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
-						script_sig: Script::new(),
+						script_sig: ScriptBuf::new(),
 						sequence: Sequence(descriptor.to_self_delay as u32),
 						witness: Witness::new(),
 					});
@@ -362,11 +388,11 @@ impl SpendableOutputDescriptor {
 					{ witness_weight -= 1; } // Guarantees a low R signature
 					input_value += descriptor.output.value;
 				},
-				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
 					if !output_set.insert(*outpoint) { return Err(()); }
 					input.push(TxIn {
 						previous_output: outpoint.into_bitcoin_outpoint(),
-						script_sig: Script::new(),
+						script_sig: ScriptBuf::new(),
 						sequence: Sequence::ZERO,
 						witness: Witness::new(),
 					});
@@ -380,7 +406,7 @@ impl SpendableOutputDescriptor {
 		}
 		let mut tx = Transaction {
 			version: 2,
-			lock_time: locktime.unwrap_or(PackedLockTime::ZERO),
+			lock_time: locktime.unwrap_or(LockTime::ZERO),
 			input,
 			output: outputs,
 		};
@@ -401,6 +427,147 @@ impl SpendableOutputDescriptor {
 	}
 }
 
+/// The parameters required to derive a channel signer via [`SignerProvider`].
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ChannelDerivationParameters {
+	/// The value in satoshis of the channel we're attempting to spend the anchor output of.
+	pub value_satoshis: u64,
+	/// The unique identifier to re-derive the signer for the associated channel.
+	pub keys_id: [u8; 32],
+	/// The necessary channel parameters that need to be provided to the re-derived signer through
+	/// [`ChannelSigner::provide_channel_parameters`].
+	pub transaction_parameters: ChannelTransactionParameters,
+}
+
+impl_writeable_tlv_based!(ChannelDerivationParameters, {
+    (0, value_satoshis, required),
+    (2, keys_id, required),
+    (4, transaction_parameters, required),
+});
+
+/// A descriptor used to sign for a commitment transaction's HTLC output.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct HTLCDescriptor {
+	/// The parameters required to derive the signer for the HTLC input.
+	pub channel_derivation_parameters: ChannelDerivationParameters,
+	/// The txid of the commitment transaction in which the HTLC output lives.
+	pub commitment_txid: Txid,
+	/// The number of the commitment transaction in which the HTLC output lives.
+	pub per_commitment_number: u64,
+	/// The key tweak corresponding to the number of the commitment transaction in which the HTLC
+	/// output lives. This tweak is applied to all the basepoints for both parties in the channel to
+	/// arrive at unique keys per commitment.
+	///
+	/// See <https://github.com/lightning/bolts/blob/master/03-transactions.md#keys> for more info.
+	pub per_commitment_point: PublicKey,
+	/// The feerate to use on the HTLC claiming transaction. This is always `0` for HTLCs
+	/// originating from a channel supporting anchor outputs, otherwise it is the channel's
+	/// negotiated feerate at the time the commitment transaction was built.
+	pub feerate_per_kw: u32,
+	/// The details of the HTLC as it appears in the commitment transaction.
+	pub htlc: HTLCOutputInCommitment,
+	/// The preimage, if `Some`, to claim the HTLC output with. If `None`, the timeout path must be
+	/// taken.
+	pub preimage: Option<PaymentPreimage>,
+	/// The counterparty's signature required to spend the HTLC output.
+	pub counterparty_sig: Signature
+}
+
+impl_writeable_tlv_based!(HTLCDescriptor, {
+	(0, channel_derivation_parameters, required),
+	(1, feerate_per_kw, (default_value, 0)),
+	(2, commitment_txid, required),
+	(4, per_commitment_number, required),
+	(6, per_commitment_point, required),
+	(8, htlc, required),
+	(10, preimage, option),
+	(12, counterparty_sig, required),
+});
+
+impl HTLCDescriptor {
+	/// Returns the outpoint of the HTLC output in the commitment transaction. This is the outpoint
+	/// being spent by the HTLC input in the HTLC transaction.
+	pub fn outpoint(&self) -> bitcoin::OutPoint {
+		bitcoin::OutPoint {
+			txid: self.commitment_txid,
+			vout: self.htlc.transaction_output_index.unwrap(),
+		}
+	}
+
+	/// Returns the UTXO to be spent by the HTLC input, which can be obtained via
+	/// [`Self::unsigned_tx_input`].
+	pub fn previous_utxo<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
+		TxOut {
+			script_pubkey: self.witness_script(secp).to_v0_p2wsh(),
+			value: self.htlc.amount_msat / 1000,
+		}
+	}
+
+	/// Returns the unsigned transaction input spending the HTLC output in the commitment
+	/// transaction.
+	pub fn unsigned_tx_input(&self) -> TxIn {
+		chan_utils::build_htlc_input(
+			&self.commitment_txid, &self.htlc, &self.channel_derivation_parameters.transaction_parameters.channel_type_features
+		)
+	}
+
+	/// Returns the delayed output created as a result of spending the HTLC output in the commitment
+	/// transaction.
+	pub fn tx_output<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
+		let channel_params = self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
+		let broadcaster_keys = channel_params.broadcaster_pubkeys();
+		let counterparty_keys = channel_params.countersignatory_pubkeys();
+		let broadcaster_delayed_key = DelayedPaymentKey::from_basepoint(
+			secp, &broadcaster_keys.delayed_payment_basepoint, &self.per_commitment_point
+		);
+		let counterparty_revocation_key = &RevocationKey::from_basepoint(&secp, &counterparty_keys.revocation_basepoint, &self.per_commitment_point);
+		chan_utils::build_htlc_output(
+			self.feerate_per_kw, channel_params.contest_delay(), &self.htlc,
+			channel_params.channel_type_features(), &broadcaster_delayed_key, &counterparty_revocation_key
+		)
+	}
+
+	/// Returns the witness script of the HTLC output in the commitment transaction.
+	pub fn witness_script<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> ScriptBuf {
+		let channel_params = self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
+		let broadcaster_keys = channel_params.broadcaster_pubkeys();
+		let counterparty_keys = channel_params.countersignatory_pubkeys();
+		let broadcaster_htlc_key = HtlcKey::from_basepoint(
+			secp, &broadcaster_keys.htlc_basepoint, &self.per_commitment_point
+		);
+		let counterparty_htlc_key = HtlcKey::from_basepoint(
+			secp, &counterparty_keys.htlc_basepoint, &self.per_commitment_point,
+		);
+		let counterparty_revocation_key = &RevocationKey::from_basepoint(&secp, &counterparty_keys.revocation_basepoint, &self.per_commitment_point);
+		chan_utils::get_htlc_redeemscript_with_explicit_keys(
+			&self.htlc, channel_params.channel_type_features(), &broadcaster_htlc_key, &counterparty_htlc_key,
+			&counterparty_revocation_key,
+		)
+	}
+
+	/// Returns the fully signed witness required to spend the HTLC output in the commitment
+	/// transaction.
+	pub fn tx_input_witness(&self, signature: &Signature, witness_script: &Script) -> Witness {
+		chan_utils::build_htlc_input_witness(
+			signature, &self.counterparty_sig, &self.preimage, witness_script,
+			&self.channel_derivation_parameters.transaction_parameters.channel_type_features
+		)
+	}
+
+	/// 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<EcdsaSigner= S>
+	{
+		let mut signer = signer_provider.derive_channel_signer(
+			self.channel_derivation_parameters.value_satoshis,
+			self.channel_derivation_parameters.keys_id,
+		);
+		signer.provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
+		signer
+	}
+}
+
 /// A trait to handle Lightning channel key material without concretizing the channel type or
 /// the signature mechanism.
 pub trait ChannelSigner {
@@ -427,14 +594,20 @@ 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;
@@ -456,164 +629,6 @@ 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 and its claiming HTLC transactions.
-	///
-	/// This will be called
-	/// - with a non-revoked `commitment_tx`.
-	/// - with the latest `commitment_tx` when we initiate a force-close.
-	/// - with the previous `commitment_tx`, just to get claiming HTLC
-	///   signatures, if we are reacting to a [`ChannelMonitor`]
-	///   [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas)
-	///   that decided to broadcast before it had been updated to the latest `commitment_tx`.
-	///
-	/// This may be called multiple times for the same transaction.
-	///
-	/// An external signer implementation should check that the commitment has not been revoked.
-	///
-	/// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
-	// TODO: Document the things someone using this interface should enforce before signing.
-	fn sign_holder_commitment_and_htlcs(&self, commitment_tx: &HolderCommitmentTransaction,
-		secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()>;
-	/// Same as [`sign_holder_commitment_and_htlcs`], 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_and_htlcs`] may
-	/// enforce that we only ever get called once.
-	#[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 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 should only be used to
-	/// sign HTLC transactions from channels supporting anchor outputs after all additional
-	/// inputs/outputs have been added to the transaction.
-	///
-	/// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
-	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
@@ -721,12 +736,28 @@ 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`.
@@ -740,7 +771,7 @@ 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
@@ -752,18 +783,19 @@ 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.
 	///
 	/// If this function returns an error, this will result in a channel failing to open.
 	///
 	/// 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) -> Result<Script, ()>;
+	/// on-chain funds across channels as controlled to the same user. `channel_keys_id` may be
+	/// used to derive a unique value for each channel.
+	fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()>;
 
 	/// Get a script pubkey which we will send funds to when closing a channel.
 	///
@@ -803,11 +835,8 @@ 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 {
@@ -838,8 +867,7 @@ 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()),
 		}
 	}
 }
@@ -873,8 +901,7 @@ 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),
 		}
 	}
 
@@ -887,10 +914,10 @@ impl InMemorySigner {
 		let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
 		ChannelPublicKeys {
 			funding_pubkey: from_secret(&funding_key),
-			revocation_basepoint: from_secret(&revocation_base_key),
+			revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
 			payment_point: from_secret(&payment_key),
-			delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
-			htlc_basepoint: from_secret(&htlc_base_key),
+			delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(&delayed_payment_base_key)),
+			htlc_basepoint: HtlcBasepoint::from(from_secret(&htlc_base_key)),
 		}
 	}
 
@@ -966,7 +993,7 @@ impl InMemorySigner {
 	/// or if an output descriptor `script_pubkey` does not match the one we can spend.
 	///
 	/// [`descriptor.outpoint`]: StaticPaymentOutputDescriptor::outpoint
-	pub fn sign_counterparty_payment_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
+	pub fn sign_counterparty_payment_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &StaticPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Witness, ()> {
 		// TODO: We really should be taking the SigHashCache as a parameter here instead of
 		// spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
 		// so that we can check them. This requires upstream rust-bitcoin changes (as well as
@@ -985,14 +1012,14 @@ impl InMemorySigner {
 		let witness_script = if supports_anchors_zero_fee_htlc_tx {
 			chan_utils::get_to_countersignatory_with_anchors_redeemscript(&remotepubkey.inner)
 		} else {
-			Script::new_p2pkh(&remotepubkey.pubkey_hash())
+			ScriptBuf::new_p2pkh(&remotepubkey.pubkey_hash())
 		};
 		let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
 		let remotesig = sign_with_aux_rand(secp_ctx, &sighash, &self.payment_key, &self);
 		let payment_script = if supports_anchors_zero_fee_htlc_tx {
 			witness_script.to_v0_p2wsh()
 		} else {
-			Script::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
+			ScriptBuf::new_v0_p2wpkh(&remotepubkey.wpubkey_hash().unwrap())
 		};
 
 		if payment_script != descriptor.output.script_pubkey { return Err(()); }
@@ -1005,7 +1032,7 @@ impl InMemorySigner {
 		} else {
 			witness.push(remotepubkey.to_bytes());
 		}
-		Ok(witness)
+		Ok(witness.into())
 	}
 
 	/// Sign the single input of `spend_tx` at index `input_idx` which spends the output
@@ -1018,7 +1045,7 @@ impl InMemorySigner {
 	///
 	/// [`descriptor.outpoint`]: DelayedPaymentOutputDescriptor::outpoint
 	/// [`descriptor.to_self_delay`]: DelayedPaymentOutputDescriptor::to_self_delay
-	pub fn sign_dynamic_p2wsh_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Vec<Vec<u8>>, ()> {
+	pub fn sign_dynamic_p2wsh_input<C: Signing>(&self, spend_tx: &Transaction, input_idx: usize, descriptor: &DelayedPaymentOutputDescriptor, secp_ctx: &Secp256k1<C>) -> Result<Witness, ()> {
 		// TODO: We really should be taking the SigHashCache as a parameter here instead of
 		// spend_tx, but ideally the SigHashCache would expose the transaction's inputs read-only
 		// so that we can check them. This requires upstream rust-bitcoin changes (as well as
@@ -1029,29 +1056,28 @@ impl InMemorySigner {
 		if spend_tx.input[input_idx].sequence.0 != descriptor.to_self_delay as u32 { return Err(()); }
 
 		let delayed_payment_key = chan_utils::derive_private_key(&secp_ctx, &descriptor.per_commitment_point, &self.delayed_payment_base_key);
-		let delayed_payment_pubkey = PublicKey::from_secret_key(&secp_ctx, &delayed_payment_key);
+		let delayed_payment_pubkey = DelayedPaymentKey::from_secret_key(&secp_ctx, &delayed_payment_key);
 		let witness_script = chan_utils::get_revokeable_redeemscript(&descriptor.revocation_pubkey, descriptor.to_self_delay, &delayed_payment_pubkey);
 		let sighash = hash_to_message!(&sighash::SighashCache::new(spend_tx).segwit_signature_hash(input_idx, &witness_script, descriptor.output.value, EcdsaSighashType::All).unwrap()[..]);
-		let local_delayedsig = sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self);
+		let local_delayedsig = EcdsaSignature {
+			sig: sign_with_aux_rand(secp_ctx, &sighash, &delayed_payment_key, &self),
+			hash_ty: EcdsaSighashType::All,
+		};
 		let payment_script = bitcoin::Address::p2wsh(&witness_script, Network::Bitcoin).script_pubkey();
 
 		if descriptor.output.script_pubkey != payment_script { return Err(()); }
 
-		let mut witness = Vec::with_capacity(3);
-		witness.push(local_delayedsig.serialize_der().to_vec());
-		witness[0].push(EcdsaSighashType::All as u8);
-		witness.push(vec!()); //MINIMALIF
-		witness.push(witness_script.clone().into_bytes());
-		Ok(witness)
+		Ok(Witness::from_slice(&[
+			&local_delayedsig.serialize()[..],
+			&[], // MINIMALIF
+			witness_script.as_bytes(),
+		]))
 	}
 }
 
 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()
 	}
 }
 
@@ -1065,7 +1091,11 @@ 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(())
 	}
 
@@ -1087,7 +1117,7 @@ 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();
 
@@ -1116,42 +1146,34 @@ impl EcdsaChannelSigner for InMemorySigner {
 		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>), ()> {
+	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);
 		let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
 		let trusted_tx = commitment_tx.trust();
-		let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
-		let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
-		let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
-		Ok((sig, htlc_sigs))
+		Ok(trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx))
 	}
 
 	#[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>), ()> {
+	fn unsafe_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);
 		let funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
 		let trusted_tx = commitment_tx.trust();
-		let sig = trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx);
-		let channel_parameters = self.get_channel_parameters().expect(MISSING_PARAMS_ERR);
-		let htlc_sigs = trusted_tx.get_htlc_sigs(&self.htlc_base_key, &channel_parameters.as_holder_broadcastable(), &self, secp_ctx)?;
-		Ok((sig, htlc_sigs))
+		Ok(trusted_tx.built_transaction().sign_holder_commitment(&self.funding_key, &funding_redeemscript, self.channel_value_satoshis, &self, secp_ctx))
 	}
 
 	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);
 		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);
+		let revocation_pubkey = RevocationKey::from_basepoint(
+			&secp_ctx,  &self.pubkeys().revocation_basepoint, &per_commitment_point,
+		);
 		let witness_script = {
 			let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
 			let holder_selected_contest_delay =
 				self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
-			let counterparty_delayedpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &counterparty_keys.delayed_payment_basepoint);
+			let counterparty_delayedpubkey = DelayedPaymentKey::from_basepoint(&secp_ctx, &counterparty_keys.delayed_payment_basepoint, &per_commitment_point);
 			chan_utils::get_revokeable_redeemscript(&revocation_pubkey, holder_selected_contest_delay, &counterparty_delayedpubkey)
 		};
 		let mut sighash_parts = sighash::SighashCache::new(justice_tx);
@@ -1162,11 +1184,17 @@ impl EcdsaChannelSigner for InMemorySigner {
 	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);
 		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);
+		let revocation_pubkey = RevocationKey::from_basepoint(
+			&secp_ctx,  &self.pubkeys().revocation_basepoint, &per_commitment_point,
+		);
 		let witness_script = {
 			let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
-			let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &counterparty_keys.htlc_basepoint);
-			let holder_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
+			let counterparty_htlcpubkey = HtlcKey::from_basepoint(
+				&secp_ctx, &counterparty_keys.htlc_basepoint, &per_commitment_point,
+			);
+			let holder_htlcpubkey = HtlcKey::from_basepoint(
+				&secp_ctx, &self.pubkeys().htlc_basepoint, &per_commitment_point,
+			);
 			let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
 			chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, chan_type, &counterparty_htlcpubkey, &holder_htlcpubkey, &revocation_pubkey)
 		};
@@ -1186,15 +1214,19 @@ impl EcdsaChannelSigner for InMemorySigner {
 		let our_htlc_private_key = chan_utils::derive_private_key(
 			&secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_key
 		);
-		Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash), &our_htlc_private_key, &self))
+		Ok(sign_with_aux_rand(&secp_ctx, &hash_to_message!(sighash.as_byte_array()), &our_htlc_private_key, &self))
 	}
 
 	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, ()> {
 		let htlc_key = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key);
-		let revocation_pubkey = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint);
+		let revocation_pubkey = RevocationKey::from_basepoint(
+			&secp_ctx,  &self.pubkeys().revocation_basepoint, &per_commitment_point,
+		);
 		let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
-		let counterparty_htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &counterparty_keys.htlc_basepoint);
-		let htlcpubkey = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint);
+		let counterparty_htlcpubkey = HtlcKey::from_basepoint(
+			&secp_ctx, &counterparty_keys.htlc_basepoint, &per_commitment_point,
+		);
+		let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &self.pubkeys().htlc_basepoint, &per_commitment_point);
 		let chan_type = self.channel_type_features().expect(MISSING_PARAMS_ERR);
 		let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, chan_type, &counterparty_htlcpubkey, &htlcpubkey, &revocation_pubkey);
 		let mut sighash_parts = sighash::SighashCache::new(htlc_tx);
@@ -1227,6 +1259,45 @@ 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;
@@ -1284,8 +1355,7 @@ 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()),
 		})
 	}
 }
@@ -1308,13 +1378,12 @@ pub struct KeysManager {
 	node_secret: SecretKey,
 	node_id: PublicKey,
 	inbound_payment_key: KeyMaterial,
-	destination_script: Script,
+	destination_script: ScriptBuf,
 	shutdown_pubkey: PublicKey,
 	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,
@@ -1350,7 +1419,7 @@ impl KeysManager {
 					Ok(destination_key) => {
 						let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_priv(&secp_ctx, &destination_key).to_pub().to_bytes());
 						Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
-							.push_slice(&wpubkey_hash.into_inner())
+							.push_slice(&wpubkey_hash.to_byte_array())
 							.into_script()
 					},
 					Err(_) => panic!("Your RNG is busted"),
@@ -1369,7 +1438,7 @@ impl KeysManager {
 				rand_bytes_engine.input(&starting_time_nanos.to_be_bytes());
 				rand_bytes_engine.input(seed);
 				rand_bytes_engine.input(b"LDK PRNG Seed");
-				let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).into_inner();
+				let rand_bytes_unique_start = Sha256::from_engine(rand_bytes_engine).to_byte_array();
 
 				let mut res = KeysManager {
 					secp_ctx,
@@ -1383,8 +1452,7 @@ 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,
@@ -1418,13 +1486,13 @@ impl KeysManager {
 			).expect("Your RNG is busted");
 		unique_start.input(&child_privkey.private_key[..]);
 
-		let seed = Sha256::from_engine(unique_start).into_inner();
+		let seed = Sha256::from_engine(unique_start).to_byte_array();
 
 		let commitment_seed = {
 			let mut sha = Sha256::engine();
 			sha.input(&seed);
 			sha.input(&b"commitment seed"[..]);
-			Sha256::from_engine(sha).into_inner()
+			Sha256::from_engine(sha).to_byte_array()
 		};
 		macro_rules! key_step {
 			($info: expr, $prev_key: expr) => {{
@@ -1432,7 +1500,7 @@ impl KeysManager {
 				sha.input(&seed);
 				sha.input(&$prev_key[..]);
 				sha.input(&$info[..]);
-				SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
+				SecretKey::from_slice(&Sha256::from_engine(sha).to_byte_array()).expect("SHA-256 is busted")
 			}}
 		}
 		let funding_key = key_step!(b"funding key", commitment_seed);
@@ -1477,7 +1545,7 @@ impl KeysManager {
 						}
 						keys_cache = Some((signer, descriptor.channel_keys_id));
 					}
-					let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
+					let witness = keys_cache.as_ref().unwrap().0.sign_counterparty_payment_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?;
 					psbt.inputs[input_idx].final_script_witness = Some(witness);
 				},
 				SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
@@ -1487,10 +1555,10 @@ impl KeysManager {
 							self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
 							descriptor.channel_keys_id));
 					}
-					let witness = Witness::from_vec(keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?);
+					let witness = keys_cache.as_ref().unwrap().0.sign_dynamic_p2wsh_input(&psbt.unsigned_tx, input_idx, &descriptor, &secp_ctx)?;
 					psbt.inputs[input_idx].final_script_witness = Some(witness);
 				},
-				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
+				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
 					let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == outpoint.into_bitcoin_outpoint()).ok_or(())?;
 					let derivation_idx = if output.script_pubkey == self.destination_script {
 						1
@@ -1522,7 +1590,7 @@ impl KeysManager {
 					let sig = sign_with_aux_rand(secp_ctx, &sighash, &secret.private_key, &self);
 					let mut sig_ser = sig.serialize_der().to_vec();
 					sig_ser.push(EcdsaSighashType::All as u8);
-					let witness = Witness::from_vec(vec![sig_ser, pubkey.inner.serialize().to_vec()]);
+					let witness = Witness::from_slice(&[&sig_ser, &pubkey.inner.serialize().to_vec()]);
 					psbt.inputs[input_idx].final_script_witness = Some(witness);
 				},
 			}
@@ -1548,16 +1616,16 @@ impl KeysManager {
 	///
 	/// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
 	/// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
-	pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
+	pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
 		let (mut psbt, expected_max_weight) = SpendableOutputDescriptor::create_spendable_outputs_psbt(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime)?;
 		psbt = self.sign_spendable_outputs_psbt(descriptors, psbt, secp_ctx)?;
 
 		let spend_tx = psbt.extract_tx();
 
-		debug_assert!(expected_max_weight >= spend_tx.weight());
+		debug_assert!(expected_max_weight >= spend_tx.weight().to_wu());
 		// Note that witnesses with a signature vary somewhat in size, so allow
 		// `expected_max_weight` to overshoot by up to 3 bytes per input.
-		debug_assert!(expected_max_weight <= spend_tx.weight() + descriptors.len() * 3);
+		debug_assert!(expected_max_weight <= spend_tx.weight().to_wu() + descriptors.len() as u64 * 3);
 
 		Ok(spend_tx)
 	}
@@ -1565,10 +1633,7 @@ 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()
 	}
 }
 
@@ -1601,7 +1666,7 @@ impl NodeSigner for KeysManager {
 			Recipient::Node => Ok(&self.node_secret),
 			Recipient::PhantomNode => Err(())
 		}?;
-		Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
+		Ok(self.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage).to_byte_array()), secret))
 	}
 
 	fn sign_bolt12_invoice_request(
@@ -1629,7 +1694,9 @@ 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);
@@ -1647,15 +1714,15 @@ 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)
 	}
 
-	fn get_destination_script(&self) -> Result<Script, ()> {
+	fn get_destination_script(&self, _channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
 		Ok(self.destination_script.clone())
 	}
 
@@ -1727,7 +1794,7 @@ impl NodeSigner for PhantomKeysManager {
 			Recipient::Node => &self.inner.node_secret,
 			Recipient::PhantomNode => &self.phantom_secret,
 		};
-		Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), secret))
+		Ok(self.inner.secp_ctx.sign_ecdsa_recoverable(&hash_to_message!(&Sha256::hash(&preimage).to_byte_array()), secret))
 	}
 
 	fn sign_bolt12_invoice_request(
@@ -1748,22 +1815,24 @@ 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)
 	}
 
-	fn get_destination_script(&self) -> Result<Script, ()> {
-		self.inner.get_destination_script()
+	fn get_destination_script(&self, channel_keys_id: [u8; 32]) -> Result<ScriptBuf, ()> {
+		self.inner.get_destination_script(channel_keys_id)
 	}
 
 	fn get_shutdown_scriptpubkey(&self) -> Result<ShutdownScript, ()> {
@@ -1797,7 +1866,7 @@ impl PhantomKeysManager {
 	}
 
 	/// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
-	pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, locktime: Option<PackedLockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
+	pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: ScriptBuf, feerate_sat_per_1000_weight: u32, locktime: Option<LockTime>, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
 		self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
 	}
 
@@ -1818,6 +1887,35 @@ 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() {