X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fsign%2Fmod.rs;h=1459151de1c043964d80d77ca4403fa92f6211aa;hb=d8021c7891ca039751b250511fbcc06da32e9e7e;hp=5912b7b84e16e393daffb3a144c6b12ee2e4331b;hpb=1f399b0984d591019320459d804cbad859c608ae;p=rust-lightning

diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index 5912b7b8..1459151d 100644
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -12,51 +12,73 @@
 //! 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::bip32::{ChildNumber, ExtendedPrivKey, ExtendedPubKey};
+use bitcoin::blockdata::locktime::absolute::LockTime;
 use bitcoin::blockdata::opcodes;
+use bitcoin::blockdata::script::{Builder, Script, ScriptBuf};
+use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut};
+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::sighash;
+use bitcoin::sighash::EcdsaSighashType;
 
 use bitcoin::bech32::u5;
-use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hash_types::WPubkeyHash;
 use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
-use bitcoin::hash_types::WPubkeyHash;
+use bitcoin::hashes::{Hash, HashEngine};
 
-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, Txid};
+#[cfg(taproot)]
+use bitcoin::secp256k1::All;
+use bitcoin::secp256k1::{KeyPair, PublicKey, Scalar, Secp256k1, SecretKey, Signing};
+use bitcoin::{secp256k1, Sequence, Txid, Witness};
 
-use crate::util::transaction_utils;
-use crate::util::crypto::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
-use crate::util::ser::{Writeable, Writer, Readable, ReadableArgs};
 use crate::chain::transaction::OutPoint;
+use crate::crypto::utils::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
+use crate::ln::chan_utils::{
+	make_funding_redeemscript, ChannelPublicKeys, ChannelTransactionParameters, ClosingTransaction,
+	CommitmentTransaction, HTLCOutputInCommitment, HolderCommitmentTransaction,
+};
 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, HtlcBasepoint, HtlcKey, RevocationBasepoint,
+	RevocationKey,
+};
+#[cfg(taproot)]
+use crate::ln::msgs::PartialSignatureWithNonce;
 use crate::ln::msgs::{UnsignedChannelAnnouncement, UnsignedGossipMessage};
 use crate::ln::script::ShutdownScript;
+use crate::ln::{chan_utils, PaymentPreimage};
 use crate::offers::invoice::UnsignedBolt12Invoice;
 use crate::offers::invoice_request::UnsignedInvoiceRequest;
+use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer};
+use crate::util::transaction_utils;
 
-use crate::prelude::*;
-use core::convert::TryInto;
-use core::ops::Deref;
-use core::sync::atomic::{AtomicUsize, Ordering};
+use crate::crypto::chacha20::ChaCha20;
 use crate::io::{self, Error};
 use crate::ln::features::ChannelTypeFeatures;
 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
+use crate::prelude::*;
+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::util::invoice::construct_invoice_preimage;
+use core::ops::Deref;
+use core::sync::atomic::{AtomicUsize, Ordering};
+#[cfg(taproot)]
+use musig2::types::{PartialSignature, PublicNonce};
 
 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.
 ///
@@ -80,7 +102,7 @@ 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],
@@ -93,7 +115,8 @@ 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, {
@@ -137,32 +160,28 @@ 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> {
-		self.channel_transaction_parameters.as_ref()
-			.and_then(|channel_params|
-				 if channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx() {
-					let payment_point = channel_params.holder_pubkeys.payment_point;
-					Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
-				 } else {
-					 None
-				 }
-			)
+	pub fn witness_script(&self) -> Option<ScriptBuf> {
+		self.channel_transaction_parameters.as_ref().and_then(|channel_params| {
+			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 {
+				None
+			}
+		})
 	}
 
 	/// 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 {
-		if self.channel_transaction_parameters.as_ref()
-			.map(|channel_params| channel_params.channel_type_features.supports_anchors_zero_fee_htlc_tx())
-			.unwrap_or(false)
-		{
+	pub fn max_witness_length(&self) -> u64 {
+		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 */;
 			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
 		}
 	}
 }
@@ -198,6 +217,15 @@ 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.
@@ -221,8 +249,8 @@ 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
@@ -230,7 +258,7 @@ 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
@@ -261,6 +289,7 @@ pub enum SpendableOutputDescriptor {
 impl_writeable_tlv_based_enum!(SpendableOutputDescriptor,
 	(0, StaticOutput) => {
 		(0, outpoint, required),
+		(1, channel_keys_id, option),
 		(2, output, required),
 	},
 ;
@@ -281,10 +310,7 @@ impl SpendableOutputDescriptor {
 		match self {
 			SpendableOutputDescriptor::StaticOutput { output, .. } => {
 				// Is a standard P2WPKH, no need for witness script
-				bitcoin::psbt::Input {
-					witness_utxo: Some(output.clone()),
-					..Default::default()
-				}
+				bitcoin::psbt::Input { witness_utxo: Some(output.clone()), ..Default::default() }
 			},
 			SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) => {
 				// TODO we could add the witness script as well
@@ -319,72 +345,98 @@ 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) => {
-					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)
-						{
-							Sequence::from_consensus(1)
-						} else {
-							Sequence::ZERO
-						};
+					if !output_set.insert(descriptor.outpoint) {
+						return Err(());
+					}
+					let sequence = if descriptor
+						.channel_transaction_parameters
+						.as_ref()
+						.map_or(false, |p| p.supports_anchors())
+					{
+						Sequence::from_consensus(1)
+					} else {
+						Sequence::ZERO
+					};
 					input.push(TxIn {
 						previous_output: descriptor.outpoint.into_bitcoin_outpoint(),
-						script_sig: Script::new(),
+						script_sig: ScriptBuf::new(),
 						sequence,
 						witness: Witness::new(),
 					});
 					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) => {
-					if !output_set.insert(descriptor.outpoint) { return Err(()); }
+					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(),
 					});
 					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 } => {
-					if !output_set.insert(*outpoint) { return Err(()); }
+				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(),
 					});
 					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;
-				}
+				},
+			}
+			if input_value > MAX_VALUE_MSAT / 1000 {
+				return Err(());
 			}
-			if input_value > MAX_VALUE_MSAT / 1000 { return Err(()); }
 		}
 		let mut tx = Transaction {
 			version: 2,
-			lock_time: locktime.unwrap_or(PackedLockTime::ZERO),
+			lock_time: locktime.unwrap_or(LockTime::ZERO),
 			input,
 			output: outputs,
 		};
-		let expected_max_weight =
-			transaction_utils::maybe_add_change_output(&mut tx, input_value, witness_weight, feerate_sat_per_1000_weight, change_destination_script)?;
+		let expected_max_weight = transaction_utils::maybe_add_change_output(
+			&mut tx,
+			input_value,
+			witness_weight,
+			feerate_sat_per_1000_weight,
+			change_destination_script,
+		)?;
 
 		let psbt_inputs = descriptors.iter().map(|d| d.to_psbt_input()).collect::<Vec<_>>();
 		let psbt = PartiallySignedTransaction {
@@ -413,9 +465,9 @@ pub struct ChannelDerivationParameters {
 }
 
 impl_writeable_tlv_based!(ChannelDerivationParameters, {
-    (0, value_satoshis, required),
-    (2, keys_id, required),
-    (4, transaction_parameters, required),
+	(0, value_satoshis, required),
+	(2, keys_id, required),
+	(4, transaction_parameters, required),
 });
 
 /// A descriptor used to sign for a commitment transaction's HTLC output.
@@ -443,7 +495,7 @@ pub struct HTLCDescriptor {
 	/// taken.
 	pub preimage: Option<PaymentPreimage>,
 	/// The counterparty's signature required to spend the HTLC output.
-	pub counterparty_sig: Signature
+	pub counterparty_sig: Signature,
 }
 
 impl_writeable_tlv_based!(HTLCDescriptor, {
@@ -469,7 +521,9 @@ impl HTLCDescriptor {
 
 	/// 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 {
+	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,
@@ -480,44 +534,69 @@ impl HTLCDescriptor {
 	/// 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
+			&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();
+	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 = chan_utils::derive_public_key(
-			secp, &self.per_commitment_point, &broadcaster_keys.delayed_payment_basepoint
+		let broadcaster_delayed_key = DelayedPaymentKey::from_basepoint(
+			secp,
+			&broadcaster_keys.delayed_payment_basepoint,
+			&self.per_commitment_point,
 		);
-		let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
-			secp, &self.per_commitment_point, &counterparty_keys.revocation_basepoint
+		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
+			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>) -> Script {
-		let channel_params = self.channel_derivation_parameters.transaction_parameters.as_holder_broadcastable();
+	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 = chan_utils::derive_public_key(
-			secp, &self.per_commitment_point, &broadcaster_keys.htlc_basepoint
+		let broadcaster_htlc_key = HtlcKey::from_basepoint(
+			secp,
+			&broadcaster_keys.htlc_basepoint,
+			&self.per_commitment_point,
 		);
-		let counterparty_htlc_key = chan_utils::derive_public_key(
-			secp, &self.per_commitment_point, &counterparty_keys.htlc_basepoint
+		let counterparty_htlc_key = HtlcKey::from_basepoint(
+			secp,
+			&counterparty_keys.htlc_basepoint,
+			&self.per_commitment_point,
 		);
-		let counterparty_revocation_key = chan_utils::derive_public_revocation_key(
-			secp, &self.per_commitment_point, &counterparty_keys.revocation_basepoint
+		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,
+			&self.htlc,
+			channel_params.channel_type_features(),
+			&broadcaster_htlc_key,
+			&counterparty_htlc_key,
 			&counterparty_revocation_key,
 		)
 	}
@@ -526,21 +605,27 @@ impl HTLCDescriptor {
 	/// 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
+			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
+	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,
 			self.channel_derivation_parameters.keys_id,
 		);
-		signer.provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
+		signer
+			.provide_channel_parameters(&self.channel_derivation_parameters.transaction_parameters);
 		signer
 	}
 }
@@ -551,7 +636,8 @@ pub trait ChannelSigner {
 	/// Gets the per-commitment point for a specific commitment number
 	///
 	/// Note that the commitment number starts at `(1 << 48) - 1` and counts backwards.
-	fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey;
+	fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>)
+		-> PublicKey;
 
 	/// Gets the commitment secret for a specific commitment number as part of the revocation process
 	///
@@ -571,14 +657,22 @@ 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<(), ()>;
+	fn validate_holder_commitment(
+		&self, holder_tx: &HolderCommitmentTransaction,
+		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;
@@ -600,162 +694,6 @@ 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.
-	///
-	/// [`EcdsaSighashType::All`]: bitcoin::blockdata::transaction::EcdsaSighashType::All
-	/// [`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
@@ -809,7 +747,9 @@ pub trait NodeSigner {
 	/// should be resolved to allow LDK to resume forwarding HTLCs.
 	///
 	/// Errors if the [`Recipient`] variant is not supported by the implementation.
-	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()>;
+	fn ecdh(
+		&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
+	) -> Result<SharedSecret, ()>;
 
 	/// Sign an invoice.
 	///
@@ -822,7 +762,9 @@ pub trait NodeSigner {
 	/// The secret key used to sign the invoice is dependent on the [`Recipient`].
 	///
 	/// Errors if the [`Recipient`] variant is not supported by the implementation.
-	fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()>;
+	fn sign_invoice(
+		&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
+	) -> Result<RecoverableSignature, ()>;
 
 	/// Signs the [`TaggedHash`] of a BOLT 12 invoice request.
 	///
@@ -836,7 +778,7 @@ pub trait NodeSigner {
 	///
 	/// [`TaggedHash`]: crate::offers::merkle::TaggedHash
 	fn sign_bolt12_invoice_request(
-		&self, invoice_request: &UnsignedInvoiceRequest
+		&self, invoice_request: &UnsignedInvoiceRequest,
 	) -> Result<schnorr::Signature, ()>;
 
 	/// Signs the [`TaggedHash`] of a BOLT 12 invoice.
@@ -851,7 +793,7 @@ pub trait NodeSigner {
 	///
 	/// [`TaggedHash`]: crate::offers::merkle::TaggedHash
 	fn sign_bolt12_invoice(
-		&self, invoice: &UnsignedBolt12Invoice
+		&self, invoice: &UnsignedBolt12Invoice,
 	) -> Result<schnorr::Signature, ()>;
 
 	/// Sign a gossip message.
@@ -863,18 +805,59 @@ pub trait NodeSigner {
 	fn sign_gossip_message(&self, msg: UnsignedGossipMessage) -> Result<Signature, ()>;
 }
 
+/// A trait that describes a wallet capable of creating a spending [`Transaction`] from a set of
+/// [`SpendableOutputDescriptor`]s.
+pub trait OutputSpender {
+	/// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
+	/// output to the given change destination (if sufficient change value remains). The
+	/// transaction will have a feerate, at least, of the given value.
+	///
+	/// The `locktime` argument is used to set the transaction's locktime. If `None`, the
+	/// transaction will have a locktime of 0. It it recommended to set this to the current block
+	/// height to avoid fee sniping, unless you have some specific reason to use a different
+	/// locktime.
+	///
+	/// Returns `Err(())` if the output value is greater than the input value minus required fee,
+	/// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
+	/// does not match the one we can spend.
+	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, ()>;
+}
+
+// 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`.
 	///
 	/// This method must return a different value each time it is called.
-	fn generate_channel_keys_id(&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128) -> [u8; 32];
+	fn generate_channel_keys_id(
+		&self, inbound: bool, channel_value_satoshis: u64, user_channel_id: u128,
+	) -> [u8; 32];
 
 	/// Derives the private key material backing a `Signer`.
 	///
@@ -882,7 +865,9 @@ 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
@@ -894,18 +879,19 @@ 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.
 	///
@@ -945,25 +931,22 @@ 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 {
 	fn eq(&self, other: &Self) -> bool {
-		self.funding_key == other.funding_key &&
-			self.revocation_base_key == other.revocation_base_key &&
-			self.payment_key == other.payment_key &&
-			self.delayed_payment_base_key == other.delayed_payment_base_key &&
-			self.htlc_base_key == other.htlc_base_key &&
-			self.commitment_seed == other.commitment_seed &&
-			self.holder_channel_pubkeys == other.holder_channel_pubkeys &&
-			self.channel_parameters == other.channel_parameters &&
-			self.channel_value_satoshis == other.channel_value_satoshis &&
-			self.channel_keys_id == other.channel_keys_id
+		self.funding_key == other.funding_key
+			&& self.revocation_base_key == other.revocation_base_key
+			&& self.payment_key == other.payment_key
+			&& self.delayed_payment_base_key == other.delayed_payment_base_key
+			&& self.htlc_base_key == other.htlc_base_key
+			&& self.commitment_seed == other.commitment_seed
+			&& self.holder_channel_pubkeys == other.holder_channel_pubkeys
+			&& self.channel_parameters == other.channel_parameters
+			&& self.channel_value_satoshis == other.channel_value_satoshis
+			&& self.channel_keys_id == other.channel_keys_id
 	}
 }
 
@@ -980,8 +963,7 @@ 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()),
 		}
 	}
 }
@@ -989,21 +971,19 @@ impl Clone for InMemorySigner {
 impl InMemorySigner {
 	/// Creates a new [`InMemorySigner`].
 	pub fn new<C: Signing>(
-		secp_ctx: &Secp256k1<C>,
-		funding_key: SecretKey,
-		revocation_base_key: SecretKey,
-		payment_key: SecretKey,
-		delayed_payment_base_key: SecretKey,
-		htlc_base_key: SecretKey,
-		commitment_seed: [u8; 32],
-		channel_value_satoshis: u64,
-		channel_keys_id: [u8; 32],
+		secp_ctx: &Secp256k1<C>, funding_key: SecretKey, revocation_base_key: SecretKey,
+		payment_key: SecretKey, delayed_payment_base_key: SecretKey, htlc_base_key: SecretKey,
+		commitment_seed: [u8; 32], channel_value_satoshis: u64, channel_keys_id: [u8; 32],
 		rand_bytes_unique_start: [u8; 32],
 	) -> InMemorySigner {
-		let holder_channel_pubkeys =
-			InMemorySigner::make_holder_keys(secp_ctx, &funding_key, &revocation_base_key,
-				&payment_key, &delayed_payment_base_key,
-				&htlc_base_key);
+		let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
+			secp_ctx,
+			&funding_key,
+			&revocation_base_key,
+			&payment_key,
+			&delayed_payment_base_key,
+			&htlc_base_key,
+		);
 		InMemorySigner {
 			funding_key,
 			revocation_base_key,
@@ -1015,24 +995,23 @@ 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),
 		}
 	}
 
-	fn make_holder_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
-			funding_key: &SecretKey,
-			revocation_base_key: &SecretKey,
-			payment_key: &SecretKey,
-			delayed_payment_base_key: &SecretKey,
-			htlc_base_key: &SecretKey) -> ChannelPublicKeys {
+	fn make_holder_keys<C: Signing>(
+		secp_ctx: &Secp256k1<C>, funding_key: &SecretKey, revocation_base_key: &SecretKey,
+		payment_key: &SecretKey, delayed_payment_base_key: &SecretKey, htlc_base_key: &SecretKey,
+	) -> ChannelPublicKeys {
 		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)),
 		}
 	}
 
@@ -1041,8 +1020,9 @@ impl InMemorySigner {
 	/// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
 	/// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
 	pub fn counterparty_pubkeys(&self) -> Option<&ChannelPublicKeys> {
-		self.get_channel_parameters()
-			.and_then(|params| params.counterparty_parameters.as_ref().map(|params| &params.pubkeys))
+		self.get_channel_parameters().and_then(|params| {
+			params.counterparty_parameters.as_ref().map(|params| &params.pubkeys)
+		})
 	}
 
 	/// Returns the `contest_delay` value specified by our counterparty and applied on holder-broadcastable
@@ -1052,8 +1032,9 @@ impl InMemorySigner {
 	/// Will return `None` if [`ChannelSigner::provide_channel_parameters`] has not been called.
 	/// In general, this is safe to `unwrap` only in [`ChannelSigner`] implementation.
 	pub fn counterparty_selected_contest_delay(&self) -> Option<u16> {
-		self.get_channel_parameters()
-			.and_then(|params| params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay))
+		self.get_channel_parameters().and_then(|params| {
+			params.counterparty_parameters.as_ref().map(|params| params.selected_contest_delay)
+		})
 	}
 
 	/// Returns the `contest_delay` value specified by us and applied on transactions broadcastable
@@ -1108,36 +1089,58 @@ 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
 		// bindings updates to support SigHashCache objects).
-		if spend_tx.input.len() <= input_idx { return Err(()); }
-		if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
-		if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
+		if spend_tx.input.len() <= input_idx {
+			return Err(());
+		}
+		if !spend_tx.input[input_idx].script_sig.is_empty() {
+			return Err(());
+		}
+		if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
+		{
+			return Err(());
+		}
 
 		let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
 		// We cannot always assume that `channel_parameters` is set, so can't just call
 		// `self.channel_parameters()` or anything that relies on it
-		let supports_anchors_zero_fee_htlc_tx = self.channel_type_features()
+		let supports_anchors_zero_fee_htlc_tx = self
+			.channel_type_features()
 			.map(|features| features.supports_anchors_zero_fee_htlc_tx())
 			.unwrap_or(false);
 
 		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 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(()); }
+		if payment_script != descriptor.output.script_pubkey {
+			return Err(());
+		}
 
 		let mut witness = Vec::with_capacity(2);
 		witness.push(remotesig.serialize_der().to_vec());
@@ -1147,7 +1150,7 @@ 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
@@ -1160,46 +1163,82 @@ 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
 		// bindings updates to support SigHashCache objects).
-		if spend_tx.input.len() <= input_idx { return Err(()); }
-		if !spend_tx.input[input_idx].script_sig.is_empty() { return Err(()); }
-		if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint() { return Err(()); }
-		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 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 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)
+		if spend_tx.input.len() <= input_idx {
+			return Err(());
+		}
+		if !spend_tx.input[input_idx].script_sig.is_empty() {
+			return Err(());
+		}
+		if spend_tx.input[input_idx].previous_output != descriptor.outpoint.into_bitcoin_outpoint()
+		{
+			return Err(());
+		}
+		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 =
+			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 = 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(());
+		}
+
+		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()
 	}
 }
 
 impl ChannelSigner for InMemorySigner {
-	fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
-		let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap();
+	fn get_per_commitment_point(
+		&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>,
+	) -> PublicKey {
+		let commitment_secret =
+			SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx))
+				.unwrap();
 		PublicKey::from_secret_key(secp_ctx, &commitment_secret)
 	}
 
@@ -1207,16 +1246,30 @@ 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(())
 	}
 
-	fn pubkeys(&self) -> &ChannelPublicKeys { &self.holder_channel_pubkeys }
+	fn pubkeys(&self) -> &ChannelPublicKeys {
+		&self.holder_channel_pubkeys
+	}
 
-	fn channel_keys_id(&self) -> [u8; 32] { self.channel_keys_id }
+	fn channel_keys_id(&self) -> [u8; 32] {
+		self.channel_keys_id
+	}
 
 	fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
-		assert!(self.channel_parameters.is_none() || self.channel_parameters.as_ref().unwrap() == channel_parameters);
+		assert!(
+			self.channel_parameters.is_none()
+				|| self.channel_parameters.as_ref().unwrap() == channel_parameters
+		);
 		if self.channel_parameters.is_some() {
 			// The channel parameters were already set and they match, return early.
 			return;
@@ -1226,19 +1279,30 @@ impl ChannelSigner for InMemorySigner {
 	}
 }
 
-const MISSING_PARAMS_ERR: &'static str = "ChannelSigner::provide_channel_parameters must be called before signing operations";
+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();
 
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
 		let counterparty_keys = self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR);
-		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
+		let channel_funding_redeemscript =
+			make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
 
 		let built_tx = trusted_tx.built_transaction();
-		let commitment_sig = built_tx.sign_counterparty_commitment(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx);
+		let commitment_sig = built_tx.sign_counterparty_commitment(
+			&self.funding_key,
+			&channel_funding_redeemscript,
+			self.channel_value_satoshis,
+			secp_ctx,
+		);
 		let commitment_txid = built_tx.txid;
 
 		let mut htlc_sigs = Vec::with_capacity(commitment_tx.htlcs().len());
@@ -1247,122 +1311,323 @@ impl EcdsaChannelSigner for InMemorySigner {
 			let holder_selected_contest_delay =
 				self.holder_selected_contest_delay().expect(MISSING_PARAMS_ERR);
 			let chan_type = &channel_parameters.channel_type_features;
-			let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_tx.feerate_per_kw(), holder_selected_contest_delay, htlc, chan_type, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
+			let htlc_tx = chan_utils::build_htlc_transaction(
+				&commitment_txid,
+				commitment_tx.feerate_per_kw(),
+				holder_selected_contest_delay,
+				htlc,
+				chan_type,
+				&keys.broadcaster_delayed_payment_key,
+				&keys.revocation_key,
+			);
 			let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, chan_type, &keys);
-			let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };
-			let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
-			let holder_htlc_key = chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key);
+			let htlc_sighashtype = if chan_type.supports_anchors_zero_fee_htlc_tx() {
+				EcdsaSighashType::SinglePlusAnyoneCanPay
+			} else {
+				EcdsaSighashType::All
+			};
+			let htlc_sighash = hash_to_message!(
+				&sighash::SighashCache::new(&htlc_tx)
+					.segwit_signature_hash(
+						0,
+						&htlc_redeemscript,
+						htlc.amount_msat / 1000,
+						htlc_sighashtype
+					)
+					.unwrap()[..]
+			);
+			let holder_htlc_key = chan_utils::derive_private_key(
+				&secp_ctx,
+				&keys.per_commitment_point,
+				&self.htlc_base_key,
+			);
 			htlc_sigs.push(sign(secp_ctx, &htlc_sighash, &holder_htlc_key));
 		}
 
 		Ok((commitment_sig, htlc_sigs))
 	}
 
-	fn validate_counterparty_revocation(&self, _idx: u64, _secret: &SecretKey) -> Result<(), ()> {
-		Ok(())
-	}
-
-	fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<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 funding_redeemscript =
+			make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
 		let trusted_tx = commitment_tx.trust();
-		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(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+		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(
+		&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 funding_redeemscript =
+			make_funding_redeemscript(&funding_pubkey, &counterparty_keys.funding_pubkey);
 		let trusted_tx = commitment_tx.trust();
-		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);
+		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);
-			chan_utils::get_revokeable_redeemscript(&revocation_pubkey, holder_selected_contest_delay, &counterparty_delayedpubkey)
+			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);
-		let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
-		return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
+		let sighash = hash_to_message!(
+			&sighash_parts
+				.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
+				.unwrap()[..]
+		);
+		return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
 	}
 
-	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);
+	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)
+			chan_utils::get_htlc_redeemscript_with_explicit_keys(
+				&htlc,
+				chan_type,
+				&counterparty_htlcpubkey,
+				&holder_htlcpubkey,
+				&revocation_pubkey,
+			)
 		};
 		let mut sighash_parts = sighash::SighashCache::new(justice_tx);
-		let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
-		return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self))
+		let sighash = hash_to_message!(
+			&sighash_parts
+				.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
+				.unwrap()[..]
+		);
+		return Ok(sign_with_aux_rand(secp_ctx, &sighash, &revocation_key, &self));
 	}
 
 	fn sign_holder_htlc_transaction(
 		&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
-		secp_ctx: &Secp256k1<secp256k1::All>
+		secp_ctx: &Secp256k1<secp256k1::All>,
 	) -> Result<Signature, ()> {
 		let witness_script = htlc_descriptor.witness_script(secp_ctx);
-		let sighash = &sighash::SighashCache::new(&*htlc_tx).segwit_signature_hash(
-			input, &witness_script, htlc_descriptor.htlc.amount_msat / 1000, EcdsaSighashType::All
-		).map_err(|_| ())?;
+		let sighash = &sighash::SighashCache::new(&*htlc_tx)
+			.segwit_signature_hash(
+				input,
+				&witness_script,
+				htlc_descriptor.htlc.amount_msat / 1000,
+				EcdsaSighashType::All,
+			)
+			.map_err(|_| ())?;
 		let our_htlc_private_key = chan_utils::derive_private_key(
-			&secp_ctx, &htlc_descriptor.per_commitment_point, &self.htlc_base_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))
+		let sighash = hash_to_message!(sighash.as_byte_array());
+		Ok(sign_with_aux_rand(&secp_ctx, &sighash, &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);
+	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 = 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 htlc_basepoint = self.pubkeys().htlc_basepoint;
+		let htlcpubkey = HtlcKey::from_basepoint(&secp_ctx, &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 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);
-		let sighash = hash_to_message!(&sighash_parts.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All).unwrap()[..]);
+		let sighash = hash_to_message!(
+			&sighash_parts
+				.segwit_signature_hash(input, &witness_script, amount, EcdsaSighashType::All)
+				.unwrap()[..]
+		);
 		Ok(sign_with_aux_rand(secp_ctx, &sighash, &htlc_key, &self))
 	}
 
-	fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
+	fn sign_closing_transaction(
+		&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>,
+	) -> Result<Signature, ()> {
 		let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
-		let counterparty_funding_key = &self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
-		let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
-		Ok(closing_tx.trust().sign(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
+		let counterparty_funding_key =
+			&self.counterparty_pubkeys().expect(MISSING_PARAMS_ERR).funding_pubkey;
+		let channel_funding_redeemscript =
+			make_funding_redeemscript(&funding_pubkey, counterparty_funding_key);
+		Ok(closing_tx.trust().sign(
+			&self.funding_key,
+			&channel_funding_redeemscript,
+			self.channel_value_satoshis,
+			secp_ctx,
+		))
 	}
 
 	fn sign_holder_anchor_input(
 		&self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
 	) -> Result<Signature, ()> {
-		let witness_script = chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
-		let sighash = sighash::SighashCache::new(&*anchor_tx).segwit_signature_hash(
-			input, &witness_script, ANCHOR_OUTPUT_VALUE_SATOSHI, EcdsaSighashType::All,
-		).unwrap();
+		let witness_script =
+			chan_utils::get_anchor_redeemscript(&self.holder_channel_pubkeys.funding_pubkey);
+		let sighash = sighash::SighashCache::new(&*anchor_tx)
+			.segwit_signature_hash(
+				input,
+				&witness_script,
+				ANCHOR_OUTPUT_VALUE_SATOSHI,
+				EcdsaSighashType::All,
+			)
+			.unwrap();
 		Ok(sign_with_aux_rand(secp_ctx, &hash_to_message!(&sighash[..]), &self.funding_key, &self))
 	}
 
 	fn sign_channel_announcement_with_funding_key(
-		&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
+		&self, msg: &UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>,
 	) -> Result<Signature, ()> {
 		let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
 		Ok(secp_ctx.sign_ecdsa(&msghash, &self.funding_key))
 	}
 }
 
+#[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;
@@ -1389,7 +1654,10 @@ impl Writeable for InMemorySigner {
 	}
 }
 
-impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySource {
+impl<ES: Deref> ReadableArgs<ES> for InMemorySigner
+where
+	ES::Target: EntropySource,
+{
 	fn read<R: io::Read>(reader: &mut R, entropy_source: ES) -> Result<Self, DecodeError> {
 		let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 
@@ -1402,9 +1670,14 @@ impl<ES: Deref> ReadableArgs<ES> for InMemorySigner where ES::Target: EntropySou
 		let counterparty_channel_data = Readable::read(reader)?;
 		let channel_value_satoshis = Readable::read(reader)?;
 		let secp_ctx = Secp256k1::signing_only();
-		let holder_channel_pubkeys =
-			InMemorySigner::make_holder_keys(&secp_ctx, &funding_key, &revocation_base_key,
-				 &payment_key, &delayed_payment_base_key, &htlc_base_key);
+		let holder_channel_pubkeys = InMemorySigner::make_holder_keys(
+			&secp_ctx,
+			&funding_key,
+			&revocation_base_key,
+			&payment_key,
+			&delayed_payment_base_key,
+			&htlc_base_key,
+		);
 		let keys_id = Readable::read(reader)?;
 
 		read_tlv_fields!(reader, {});
@@ -1420,8 +1693,7 @@ 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()),
 		})
 	}
 }
@@ -1444,13 +1716,12 @@ 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,
@@ -1480,23 +1751,42 @@ impl KeysManager {
 		// Note that when we aren't serializing the key, network doesn't matter
 		match ExtendedPrivKey::new_master(Network::Testnet, seed) {
 			Ok(master_key) => {
-				let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key;
+				let node_secret = master_key
+					.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap())
+					.expect("Your RNG is busted")
+					.private_key;
 				let node_id = PublicKey::from_secret_key(&secp_ctx, &node_secret);
-				let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
+				let destination_script = match master_key
+					.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap())
+				{
 					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())
+						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.to_byte_array())
 							.into_script()
 					},
 					Err(_) => panic!("Your RNG is busted"),
 				};
-				let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
-					Ok(shutdown_key) => ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key,
+				let shutdown_pubkey = match master_key
+					.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap())
+				{
+					Ok(shutdown_key) => {
+						ExtendedPubKey::from_priv(&secp_ctx, &shutdown_key).public_key
+					},
 					Err(_) => panic!("Your RNG is busted"),
 				};
-				let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
-				let inbound_payment_key: SecretKey = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted").private_key;
+				let channel_master_key = master_key
+					.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap())
+					.expect("Your RNG is busted");
+				let inbound_payment_key: SecretKey = master_key
+					.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap())
+					.expect("Your RNG is busted")
+					.private_key;
 				let mut inbound_pmt_key_bytes = [0; 32];
 				inbound_pmt_key_bytes.copy_from_slice(&inbound_payment_key[..]);
 
@@ -1505,7 +1795,8 @@ 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,
@@ -1519,8 +1810,7 @@ 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,
@@ -1540,7 +1830,9 @@ impl KeysManager {
 	}
 
 	/// Derive an old [`WriteableEcdsaChannelSigner`] containing per-channel secrets based on a key derivation parameters.
-	pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
+	pub fn derive_channel_keys(
+		&self, channel_value_satoshis: u64, params: &[u8; 32],
+	) -> InMemorySigner {
 		let chan_id = u64::from_be_bytes(params[0..8].try_into().unwrap());
 		let mut unique_start = Sha256::engine();
 		unique_start.input(params);
@@ -1549,18 +1841,23 @@ impl KeysManager {
 		// We only seriously intend to rely on the channel_master_key for true secure
 		// entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
 		// starting_time provided in the constructor) to be unique.
-		let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx,
-				ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31)).expect("key space exhausted")
-			).expect("Your RNG is busted");
+		let child_privkey = self
+			.channel_master_key
+			.ckd_priv(
+				&self.secp_ctx,
+				ChildNumber::from_hardened_idx((chan_id as u32) % (1 << 31))
+					.expect("key space exhausted"),
+			)
+			.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, $prev_key: expr) => {{
@@ -1568,8 +1865,9 @@ impl KeysManager {
 				sha.input(&seed);
 				sha.input(&$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);
 		let revocation_base_key = key_step!(b"revocation base key", funding_key);
@@ -1600,48 +1898,82 @@ 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 sign_spendable_outputs_psbt<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction, secp_ctx: &Secp256k1<C>) -> Result<PartiallySignedTransaction, ()> {
+	pub fn sign_spendable_outputs_psbt<C: Signing>(
+		&self, descriptors: &[&SpendableOutputDescriptor], mut psbt: PartiallySignedTransaction,
+		secp_ctx: &Secp256k1<C>,
+	) -> Result<PartiallySignedTransaction, ()> {
 		let mut keys_cache: Option<(InMemorySigner, [u8; 32])> = None;
 		for outp in descriptors {
+			let get_input_idx = |outpoint: &OutPoint| {
+				psbt.unsigned_tx
+					.input
+					.iter()
+					.position(|i| i.previous_output == outpoint.into_bitcoin_outpoint())
+					.ok_or(())
+			};
 			match outp {
 				SpendableOutputDescriptor::StaticPaymentOutput(descriptor) => {
-					let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
-					if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
-						let mut signer = self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id);
-						if let Some(channel_params) = descriptor.channel_transaction_parameters.as_ref() {
+					let input_idx = get_input_idx(&descriptor.outpoint)?;
+					if keys_cache.is_none()
+						|| keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
+					{
+						let mut signer = self.derive_channel_keys(
+							descriptor.channel_value_satoshis,
+							&descriptor.channel_keys_id,
+						);
+						if let Some(channel_params) =
+							descriptor.channel_transaction_parameters.as_ref()
+						{
 							signer.provide_channel_parameters(channel_params);
 						}
 						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) => {
-					let input_idx = psbt.unsigned_tx.input.iter().position(|i| i.previous_output == descriptor.outpoint.into_bitcoin_outpoint()).ok_or(())?;
-					if keys_cache.is_none() || keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id {
+					let input_idx = get_input_idx(&descriptor.outpoint)?;
+					if keys_cache.is_none()
+						|| keys_cache.as_ref().unwrap().1 != descriptor.channel_keys_id
+					{
 						keys_cache = Some((
-							self.derive_channel_keys(descriptor.channel_value_satoshis, &descriptor.channel_keys_id),
-							descriptor.channel_keys_id));
+							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 } => {
-					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
-					} else {
-						2
-					};
+				SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output, .. } => {
+					let input_idx = get_input_idx(outpoint)?;
+					let derivation_idx =
+						if output.script_pubkey == self.destination_script { 1 } else { 2 };
 					let secret = {
 						// Note that when we aren't serializing the key, network doesn't matter
 						match ExtendedPrivKey::new_master(Network::Testnet, &self.seed) {
 							Ok(master_key) => {
-								match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(derivation_idx).expect("key space exhausted")) {
+								match master_key.ckd_priv(
+									&secp_ctx,
+									ChildNumber::from_hardened_idx(derivation_idx)
+										.expect("key space exhausted"),
+								) {
 									Ok(key) => key,
 									Err(_) => panic!("Your RNG is busted"),
 								}
-							}
+							},
 							Err(_) => panic!("Your rng is busted"),
 						}
 					};
@@ -1649,16 +1981,31 @@ impl KeysManager {
 					if derivation_idx == 2 {
 						assert_eq!(pubkey.inner, self.shutdown_pubkey);
 					}
-					let witness_script = bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
-					let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet).expect("uncompressed key found").script_pubkey();
-
-					if payment_script != output.script_pubkey { return Err(()); };
+					let witness_script =
+						bitcoin::Address::p2pkh(&pubkey, Network::Testnet).script_pubkey();
+					let payment_script = bitcoin::Address::p2wpkh(&pubkey, Network::Testnet)
+						.expect("uncompressed key found")
+						.script_pubkey();
+
+					if payment_script != output.script_pubkey {
+						return Err(());
+					};
 
-					let sighash = hash_to_message!(&sighash::SighashCache::new(&psbt.unsigned_tx).segwit_signature_hash(input_idx, &witness_script, output.value, EcdsaSighashType::All).unwrap()[..]);
+					let sighash = hash_to_message!(
+						&sighash::SighashCache::new(&psbt.unsigned_tx)
+							.segwit_signature_hash(
+								input_idx,
+								&witness_script,
+								output.value,
+								EcdsaSighashType::All
+							)
+							.unwrap()[..]
+					);
 					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);
 				},
 			}
@@ -1666,45 +2013,11 @@ impl KeysManager {
 
 		Ok(psbt)
 	}
-
-	/// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
-	/// output to the given change destination (if sufficient change value remains). The
-	/// transaction will have a feerate, at least, of the given value.
-	///
-	/// The `locktime` argument is used to set the transaction's locktime. If `None`, the
-	/// transaction will have a locktime of 0. It it recommended to set this to the current block
-	/// height to avoid fee sniping, unless you have some specific reason to use a different
-	/// locktime.
-	///
-	/// Returns `Err(())` if the output value is greater than the input value minus required fee,
-	/// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
-	/// 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.
-	///
-	/// 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, ()> {
-		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());
-		// 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);
-
-		Ok(spend_tx)
-	}
 }
 
 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()
 	}
 }
 
@@ -1712,14 +2025,16 @@ impl NodeSigner for KeysManager {
 	fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
 		match recipient {
 			Recipient::Node => Ok(self.node_id.clone()),
-			Recipient::PhantomNode => Err(())
+			Recipient::PhantomNode => Err(()),
 		}
 	}
 
-	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
+	fn ecdh(
+		&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
+	) -> Result<SharedSecret, ()> {
 		let mut node_secret = match recipient {
 			Recipient::Node => Ok(self.node_secret.clone()),
-			Recipient::PhantomNode => Err(())
+			Recipient::PhantomNode => Err(()),
 		}?;
 		if let Some(tweak) = tweak {
 			node_secret = node_secret.mul_tweak(tweak).map_err(|_| ())?;
@@ -1731,17 +2046,22 @@ impl NodeSigner for KeysManager {
 		self.inbound_payment_key.clone()
 	}
 
-	fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
+	fn sign_invoice(
+		&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
+	) -> Result<RecoverableSignature, ()> {
 		let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
 		let secret = match recipient {
 			Recipient::Node => Ok(&self.node_secret),
-			Recipient::PhantomNode => Err(())
+			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(
-		&self, invoice_request: &UnsignedInvoiceRequest
+		&self, invoice_request: &UnsignedInvoiceRequest,
 	) -> Result<schnorr::Signature, ()> {
 		let message = invoice_request.tagged_hash().as_digest();
 		let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
@@ -1750,7 +2070,7 @@ impl NodeSigner for KeysManager {
 	}
 
 	fn sign_bolt12_invoice(
-		&self, invoice: &UnsignedBolt12Invoice
+		&self, invoice: &UnsignedBolt12Invoice,
 	) -> Result<schnorr::Signature, ()> {
 		let message = invoice.tagged_hash().as_digest();
 		let keys = KeyPair::from_secret_key(&self.secp_ctx, &self.node_secret);
@@ -1764,10 +2084,52 @@ impl NodeSigner for KeysManager {
 	}
 }
 
+impl OutputSpender for KeysManager {
+	/// Creates a [`Transaction`] which spends the given descriptors to the given outputs, plus an
+	/// output to the given change destination (if sufficient change value remains).
+	///
+	/// See [`OutputSpender::spend_spendable_outputs`] documentation for more information.
+	///
+	/// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
+	///
+	/// May panic if the [`SpendableOutputDescriptor`]s were not generated by channels which used
+	/// this [`KeysManager`] or one of the [`InMemorySigner`] created by this [`KeysManager`].
+	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().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().to_wu() + descriptors.len() as u64 * 3
+		);
+
+		Ok(spend_tx)
+	}
+}
+
 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] {
+	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);
 		// `child_idx` is the only thing guaranteed to make each channel unique without a restart
 		// (though `user_channel_id` should help, depending on user behavior). If it manages to
@@ -1783,15 +2145,17 @@ 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())
 	}
 
@@ -1842,7 +2206,9 @@ impl NodeSigner for PhantomKeysManager {
 		}
 	}
 
-	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>) -> Result<SharedSecret, ()> {
+	fn ecdh(
+		&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
+	) -> Result<SharedSecret, ()> {
 		let mut node_secret = match recipient {
 			Recipient::Node => self.inner.node_secret.clone(),
 			Recipient::PhantomNode => self.phantom_secret.clone(),
@@ -1857,23 +2223,28 @@ impl NodeSigner for PhantomKeysManager {
 		self.inbound_payment_key.clone()
 	}
 
-	fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
+	fn sign_invoice(
+		&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient,
+	) -> Result<RecoverableSignature, ()> {
 		let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
 		let secret = match recipient {
 			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(
-		&self, invoice_request: &UnsignedInvoiceRequest
+		&self, invoice_request: &UnsignedInvoiceRequest,
 	) -> Result<schnorr::Signature, ()> {
 		self.inner.sign_bolt12_invoice_request(invoice_request)
 	}
 
 	fn sign_bolt12_invoice(
-		&self, invoice: &UnsignedBolt12Invoice
+		&self, invoice: &UnsignedBolt12Invoice,
 	) -> Result<schnorr::Signature, ()> {
 		self.inner.sign_bolt12_invoice(invoice)
 	}
@@ -1883,23 +2254,48 @@ impl NodeSigner for PhantomKeysManager {
 	}
 }
 
+impl OutputSpender for PhantomKeysManager {
+	/// See [`OutputSpender::spend_spendable_outputs`] and [`KeysManager::spend_spendable_outputs`]
+	/// for documentation on this method.
+	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,
+		)
+	}
+}
+
 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] {
+	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, ()> {
@@ -1919,9 +2315,15 @@ impl PhantomKeysManager {
 	/// same across restarts, or else inbound payments may fail.
 	///
 	/// [phantom node payments]: PhantomKeysManager
-	pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
+	pub fn new(
+		seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32,
+		cross_node_seed: &[u8; 32],
+	) -> Self {
 		let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
-		let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
+		let (inbound_key, phantom_key) = hkdf_extract_expand_twice(
+			b"LDK Inbound and Phantom Payment Key Expansion",
+			cross_node_seed,
+		);
 		let phantom_secret = SecretKey::from_slice(&phantom_key).unwrap();
 		let phantom_node_id = PublicKey::from_secret_key(&inner.secp_ctx, &phantom_secret);
 		Self {
@@ -1932,13 +2334,10 @@ 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, ()> {
-		self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, locktime, secp_ctx)
-	}
-
 	/// See [`KeysManager::derive_channel_keys`] for documentation on this method.
-	pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
+	pub fn derive_channel_keys(
+		&self, channel_value_satoshis: u64, params: &[u8; 32],
+	) -> InMemorySigner {
 		self.inner.derive_channel_keys(channel_value_satoshis, params)
 	}
 
@@ -1954,6 +2353,32 @@ 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() {
@@ -1962,13 +2387,13 @@ pub fn dyn_sign() {
 
 #[cfg(ldk_bench)]
 pub mod benches {
-	use std::sync::{Arc, mpsc};
+	use crate::sign::{EntropySource, KeysManager};
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::Network;
 	use std::sync::mpsc::TryRecvError;
+	use std::sync::{mpsc, Arc};
 	use std::thread;
 	use std::time::Duration;
-	use bitcoin::blockdata::constants::genesis_block;
-	use bitcoin::Network;
-	use crate::sign::{EntropySource, KeysManager};
 
 	use criterion::Criterion;
 
@@ -1982,24 +2407,23 @@ pub mod benches {
 		for _ in 1..5 {
 			let keys_manager_clone = Arc::clone(&keys_manager);
 			let (stop_sender, stop_receiver) = mpsc::channel();
-			let handle = thread::spawn(move || {
-				loop {
-					keys_manager_clone.get_secure_random_bytes();
-					match stop_receiver.try_recv() {
-						Ok(_) | Err(TryRecvError::Disconnected) => {
-							println!("Terminating.");
-							break;
-						}
-						Err(TryRecvError::Empty) => {}
-					}
+			let handle = thread::spawn(move || loop {
+				keys_manager_clone.get_secure_random_bytes();
+				match stop_receiver.try_recv() {
+					Ok(_) | Err(TryRecvError::Disconnected) => {
+						println!("Terminating.");
+						break;
+					},
+					Err(TryRecvError::Empty) => {},
 				}
 			});
 			handles.push(handle);
 			stops.push(stop_sender);
 		}
 
-		bench.bench_function("get_secure_random_bytes", |b| b.iter(||
-			keys_manager.get_secure_random_bytes()));
+		bench.bench_function("get_secure_random_bytes", |b| {
+			b.iter(|| keys_manager.get_secure_random_bytes())
+		});
 
 		for stop in stops {
 			let _ = stop.send(());