X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=2617bec03f03a113f45850ce7195b0bf6fd97a2a;hb=ff00f6f8861419b73269e6c51d75ac9de75f1d1f;hp=97c9fa6789b3c4a2045539281c27b1a28cf1d0b4;hpb=4ed148a64de3d3b30eb81774438b9944263c0f87;p=rust-lightning

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 97c9fa67..2617bec0 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -1,12 +1,20 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
 use bitcoin::blockdata::block::BlockHeader;
 use bitcoin::blockdata::script::{Script,Builder};
 use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
 use bitcoin::blockdata::opcodes;
-use bitcoin::util::hash::BitcoinHash;
 use bitcoin::util::bip143;
 use bitcoin::consensus::encode;
 
-use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::Hash;
 use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hash_types::{Txid, BlockHash, WPubkeyHash};
 
@@ -17,15 +25,15 @@ use bitcoin::secp256k1;
 use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
-use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, HTLC_FAIL_BACK_BUFFER};
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, PaymentPreimage, PaymentHash, BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
-use ln::chan_utils::{CounterpartyCommitmentSecrets, LocalCommitmentTransaction, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys};
+use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor};
 use ln::chan_utils;
 use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
-use chain::transaction::OutPoint;
-use chain::keysinterface::{ChannelKeys, KeysInterface};
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, HTLC_FAIL_BACK_BUFFER};
+use chain::transaction::{OutPoint, TransactionData};
+use chain::keysinterface::{Sign, KeysInterface};
 use util::transaction_utils;
-use util::ser::{Readable, Writeable, Writer};
+use util::ser::{Readable, ReadableArgs, Writeable, Writer, VecWriter};
 use util::logger::Logger;
 use util::errors::APIError;
 use util::config::{UserConfig,ChannelConfig};
@@ -34,6 +42,9 @@ use std;
 use std::default::Default;
 use std::{cmp,mem,fmt};
 use std::ops::Deref;
+#[cfg(any(test, feature = "fuzztarget"))]
+use std::sync::Mutex;
+use bitcoin::hashes::hex::ToHex;
 
 #[cfg(test)]
 pub struct ChannelValueStat {
@@ -43,8 +54,8 @@ pub struct ChannelValueStat {
 	pub pending_outbound_htlcs_amount_msat: u64,
 	pub pending_inbound_htlcs_amount_msat: u64,
 	pub holding_cell_outbound_amount_msat: u64,
-	pub their_max_htlc_value_in_flight_msat: u64, // outgoing
-	pub their_dust_limit_msat: u64,
+	pub counterparty_max_htlc_value_in_flight_msat: u64, // outgoing
+	pub counterparty_dust_limit_msat: u64,
 }
 
 enum InboundHTLCRemovalReason {
@@ -102,7 +113,7 @@ enum InboundHTLCState {
 	/// anyway). That said, ChannelMonitor does this for us (see
 	/// ChannelMonitor::would_broadcast_at_height) so we actually remove the HTLC from our own
 	/// local state before then, once we're sure that the next commitment_signed and
-	/// ChannelMonitor::provide_latest_local_commitment_tx_info will not include this HTLC.
+	/// ChannelMonitor::provide_latest_local_commitment_tx will not include this HTLC.
 	LocalRemoved(InboundHTLCRemovalReason),
 }
 
@@ -233,7 +244,7 @@ enum ChannelState {
 const BOTH_SIDES_SHUTDOWN_MASK: u32 = ChannelState::LocalShutdownSent as u32 | ChannelState::RemoteShutdownSent as u32;
 const MULTI_STATE_FLAGS: u32 = BOTH_SIDES_SHUTDOWN_MASK | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32;
 
-const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
+pub const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
 
 /// Liveness is called to fluctuate given peer disconnecton/monitor failures/closing.
 /// If channel is public, network should have a liveness view announced by us on a
@@ -249,27 +260,50 @@ enum UpdateStatus {
 	DisabledStaged,
 }
 
+/// An enum indicating whether the local or remote side offered a given HTLC.
+enum HTLCInitiator {
+	LocalOffered,
+	RemoteOffered,
+}
+
+/// Used when calculating whether we or the remote can afford an additional HTLC.
+struct HTLCCandidate {
+	amount_msat: u64,
+	origin: HTLCInitiator,
+}
+
+impl HTLCCandidate {
+	fn new(amount_msat: u64, origin: HTLCInitiator) -> Self {
+		Self {
+			amount_msat,
+			origin,
+		}
+	}
+}
+
 // TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking
 // has been completed, and then turn into a Channel to get compiler-time enforcement of things like
 // calling channel_id() before we're set up or things like get_outbound_funding_signed on an
 // inbound channel.
-pub(super) struct Channel<ChanSigner: ChannelKeys> {
+//
+// Holder designates channel data owned for the benefice of the user client.
+// Counterparty designates channel data owned by the another channel participant entity.
+pub(super) struct Channel<Signer: Sign> {
 	config: ChannelConfig,
 
 	user_id: u64,
 
 	channel_id: [u8; 32],
 	channel_state: u32,
-	channel_outbound: bool,
 	secp_ctx: Secp256k1<secp256k1::All>,
 	channel_value_satoshis: u64,
 
 	latest_monitor_update_id: u64,
 
 	#[cfg(not(test))]
-	local_keys: ChanSigner,
+	holder_keys: Signer,
 	#[cfg(test)]
-	pub(super) local_keys: ChanSigner,
+	pub(super) holder_keys: Signer,
 	shutdown_pubkey: PublicKey,
 	destination_script: Script,
 
@@ -277,8 +311,8 @@ pub(super) struct Channel<ChanSigner: ChannelKeys> {
 	// generation start at 0 and count up...this simplifies some parts of implementation at the
 	// cost of others, but should really just be changed.
 
-	cur_local_commitment_transaction_number: u64,
-	cur_remote_commitment_transaction_number: u64,
+	cur_holder_commitment_transaction_number: u64,
+	cur_counterparty_commitment_transaction_number: u64,
 	value_to_self_msat: u64, // Excluding all pending_htlcs, excluding fees
 	pending_inbound_htlcs: Vec<InboundHTLCOutput>,
 	pending_outbound_htlcs: Vec<OutboundHTLCOutput>,
@@ -316,21 +350,19 @@ pub(super) struct Channel<ChanSigner: ChannelKeys> {
 	// is received. holding_cell_update_fee is updated when there are additional
 	// update_fee() during ChannelState::AwaitingRemoteRevoke.
 	holding_cell_update_fee: Option<u32>,
-	next_local_htlc_id: u64,
-	next_remote_htlc_id: u64,
+	next_holder_htlc_id: u64,
+	next_counterparty_htlc_id: u64,
 	update_time_counter: u32,
 	feerate_per_kw: u32,
 
 	#[cfg(debug_assertions)]
 	/// Max to_local and to_remote outputs in a locally-generated commitment transaction
-	max_commitment_tx_output_local: ::std::sync::Mutex<(u64, u64)>,
+	holder_max_commitment_tx_output: ::std::sync::Mutex<(u64, u64)>,
 	#[cfg(debug_assertions)]
 	/// Max to_local and to_remote outputs in a remote-generated commitment transaction
-	max_commitment_tx_output_remote: ::std::sync::Mutex<(u64, u64)>,
-
-	last_sent_closing_fee: Option<(u32, u64, Signature)>, // (feerate, fee, our_sig)
+	counterparty_max_commitment_tx_output: ::std::sync::Mutex<(u64, u64)>,
 
-	funding_txo: Option<OutPoint>,
+	last_sent_closing_fee: Option<(u32, u64, Signature)>, // (feerate, fee, holder_sig)
 
 	/// The hash of the block in which the funding transaction reached our CONF_TARGET. We use this
 	/// to detect unconfirmation after a serialize-unserialize roundtrip where we may not see a full
@@ -343,45 +375,58 @@ pub(super) struct Channel<ChanSigner: ChannelKeys> {
 	pub(super) last_block_connected: BlockHash,
 	funding_tx_confirmations: u64,
 
-	their_dust_limit_satoshis: u64,
+	counterparty_dust_limit_satoshis: u64,
 	#[cfg(test)]
-	pub(super) our_dust_limit_satoshis: u64,
+	pub(super) holder_dust_limit_satoshis: u64,
 	#[cfg(not(test))]
-	our_dust_limit_satoshis: u64,
+	holder_dust_limit_satoshis: u64,
 	#[cfg(test)]
-	pub(super) their_max_htlc_value_in_flight_msat: u64,
+	pub(super) counterparty_max_htlc_value_in_flight_msat: u64,
 	#[cfg(not(test))]
-	their_max_htlc_value_in_flight_msat: u64,
-	//get_our_max_htlc_value_in_flight_msat(): u64,
+	counterparty_max_htlc_value_in_flight_msat: u64,
+	//get_holder_max_htlc_value_in_flight_msat(): u64,
 	/// minimum channel reserve for self to maintain - set by them.
-	local_channel_reserve_satoshis: u64,
-	// get_remote_channel_reserve_satoshis(channel_value_sats: u64): u64
-	their_htlc_minimum_msat: u64,
-	our_htlc_minimum_msat: u64,
-	their_to_self_delay: u16,
-	our_to_self_delay: u16,
+	counterparty_selected_channel_reserve_satoshis: u64,
+	// get_holder_selected_channel_reserve_satoshis(channel_value_sats: u64): u64
+	counterparty_htlc_minimum_msat: u64,
+	holder_htlc_minimum_msat: u64,
 	#[cfg(test)]
-	pub their_max_accepted_htlcs: u16,
+	pub counterparty_max_accepted_htlcs: u16,
 	#[cfg(not(test))]
-	their_max_accepted_htlcs: u16,
-	//implied by OUR_MAX_HTLCS: our_max_accepted_htlcs: u16,
+	counterparty_max_accepted_htlcs: u16,
+	//implied by OUR_MAX_HTLCS: max_accepted_htlcs: u16,
 	minimum_depth: u32,
 
-	their_pubkeys: Option<ChannelPublicKeys>,
+	pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 
-	their_cur_commitment_point: Option<PublicKey>,
+	counterparty_cur_commitment_point: Option<PublicKey>,
 
-	their_prev_commitment_point: Option<PublicKey>,
-	their_node_id: PublicKey,
+	counterparty_prev_commitment_point: Option<PublicKey>,
+	counterparty_node_id: PublicKey,
 
-	their_shutdown_scriptpubkey: Option<Script>,
+	counterparty_shutdown_scriptpubkey: Option<Script>,
 
-	/// Used exclusively to broadcast the latest local state, mostly a historical quirk that this
-	/// is here:
-	channel_monitor: Option<ChannelMonitor<ChanSigner>>,
 	commitment_secrets: CounterpartyCommitmentSecrets,
 
 	network_sync: UpdateStatus,
+
+	// We save these values so we can make sure `next_local_commit_tx_fee_msat` and
+	// `next_remote_commit_tx_fee_msat` properly predict what the next commitment transaction fee will
+	// be, by comparing the cached values to the fee of the tranaction generated by
+	// `build_commitment_transaction`.
+	#[cfg(any(test, feature = "fuzztarget"))]
+	next_local_commitment_tx_fee_info_cached: Mutex<Option<CommitmentTxInfoCached>>,
+	#[cfg(any(test, feature = "fuzztarget"))]
+	next_remote_commitment_tx_fee_info_cached: Mutex<Option<CommitmentTxInfoCached>>,
+}
+
+#[cfg(any(test, feature = "fuzztarget"))]
+struct CommitmentTxInfoCached {
+	fee: u64,
+	total_pending_htlcs: usize,
+	next_holder_htlc_id: u64,
+	next_counterparty_htlc_id: u64,
+	feerate: u32,
 }
 
 pub const OUR_MAX_HTLCS: u16 = 50; //TODO
@@ -409,17 +454,17 @@ pub const MAX_FUNDING_SATOSHIS: u64 = 1 << 24;
 /// msgs::ErrorAction::SendErrorMessage or msgs::ErrorAction::IgnoreError as appropriate with our
 /// channel_id in ChannelManager.
 pub(super) enum ChannelError {
-	Ignore(&'static str),
-	Close(&'static str),
-	CloseDelayBroadcast(&'static str),
+	Ignore(String),
+	Close(String),
+	CloseDelayBroadcast(String),
 }
 
 impl fmt::Debug for ChannelError {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match self {
-			&ChannelError::Ignore(e) => write!(f, "Ignore : {}", e),
-			&ChannelError::Close(e) => write!(f, "Close : {}", e),
-			&ChannelError::CloseDelayBroadcast(e) => write!(f, "CloseDelayBroadcast : {}", e)
+			&ChannelError::Ignore(ref e) => write!(f, "Ignore : {}", e),
+			&ChannelError::Close(ref e) => write!(f, "Close : {}", e),
+			&ChannelError::CloseDelayBroadcast(ref e) => write!(f, "CloseDelayBroadcast : {}", e)
 		}
 	}
 }
@@ -433,9 +478,9 @@ macro_rules! secp_check {
 	};
 }
 
-impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
+impl<Signer: Sign> Channel<Signer> {
 	// Convert constants + channel value to limits:
-	fn get_our_max_htlc_value_in_flight_msat(channel_value_satoshis: u64) -> u64 {
+	fn get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis: u64) -> u64 {
 		channel_value_satoshis * 1000 / 10 //TODO
 	}
 
@@ -443,59 +488,58 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// required by us.
 	///
 	/// Guaranteed to return a value no larger than channel_value_satoshis
-	pub(crate) fn get_remote_channel_reserve_satoshis(channel_value_satoshis: u64) -> u64 {
+	pub(crate) fn get_holder_selected_channel_reserve_satoshis(channel_value_satoshis: u64) -> u64 {
 		let (q, _) = channel_value_satoshis.overflowing_div(100);
 		cmp::min(channel_value_satoshis, cmp::max(q, 1000)) //TODO
 	}
 
-	fn derive_our_dust_limit_satoshis(at_open_background_feerate: u32) -> u64 {
+	fn derive_holder_dust_limit_satoshis(at_open_background_feerate: u32) -> u64 {
 		cmp::max(at_open_background_feerate as u64 * B_OUTPUT_PLUS_SPENDING_INPUT_WEIGHT / 1000, 546) //TODO
 	}
 
 	// Constructors:
-	pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, their_node_id: PublicKey, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<ChanSigner>, APIError>
-	where K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
+	pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, APIError>
+	where K::Target: KeysInterface<Signer = Signer>,
 	      F::Target: FeeEstimator,
 	{
-		let chan_keys = keys_provider.get_channel_keys(false, channel_value_satoshis);
+		let holder_selected_contest_delay = config.own_channel_config.our_to_self_delay;
+		let chan_keys = keys_provider.get_channel_signer(false, channel_value_satoshis);
+		let pubkeys = chan_keys.pubkeys().clone();
 
 		if channel_value_satoshis >= MAX_FUNDING_SATOSHIS {
-			return Err(APIError::APIMisuseError{err: "funding value > 2^24"});
+			return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than {}, it was {}", MAX_FUNDING_SATOSHIS, channel_value_satoshis)});
 		}
-
-		if push_msat > channel_value_satoshis * 1000 {
-			return Err(APIError::APIMisuseError{err: "push value > channel value"});
+		let channel_value_msat = channel_value_satoshis * 1000;
+		if push_msat > channel_value_msat {
+			return Err(APIError::APIMisuseError { err: format!("Push value ({}) was larger than channel_value ({})", push_msat, channel_value_msat) });
 		}
-		if config.own_channel_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
-			return Err(APIError::APIMisuseError{err: "Configured with an unreasonable our_to_self_delay putting user funds at risks"});
+		if holder_selected_contest_delay < BREAKDOWN_TIMEOUT {
+			return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
 		}
-
-
 		let background_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
-		if Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(channel_value_satoshis) < Channel::<ChanSigner>::derive_our_dust_limit_satoshis(background_feerate) {
+		if Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(channel_value_satoshis) < Channel::<Signer>::derive_holder_dust_limit_satoshis(background_feerate) {
 			return Err(APIError::FeeRateTooHigh{err: format!("Not enough reserve above dust limit can be found at current fee rate({})", background_feerate), feerate: background_feerate});
 		}
 
 		let feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 
 		Ok(Channel {
-			user_id: user_id,
+			user_id,
 			config: config.channel_options.clone(),
 
-			channel_id: keys_provider.get_channel_id(),
+			channel_id: keys_provider.get_secure_random_bytes(),
 			channel_state: ChannelState::OurInitSent as u32,
-			channel_outbound: true,
 			secp_ctx: Secp256k1::new(),
-			channel_value_satoshis: channel_value_satoshis,
+			channel_value_satoshis,
 
 			latest_monitor_update_id: 0,
 
-			local_keys: chan_keys,
+			holder_keys: chan_keys,
 			shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
 			destination_script: keys_provider.get_destination_script(),
 
-			cur_local_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-			cur_remote_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+			cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+			cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
 			value_to_self_msat: channel_value_satoshis * 1000 - push_msat,
 
 			pending_inbound_htlcs: Vec::new(),
@@ -503,8 +547,8 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			holding_cell_htlc_updates: Vec::new(),
 			pending_update_fee: None,
 			holding_cell_update_fee: None,
-			next_local_htlc_id: 0,
-			next_remote_htlc_id: 0,
+			next_holder_htlc_id: 0,
+			next_counterparty_htlc_id: 0,
 			update_time_counter: 1,
 
 			resend_order: RAACommitmentOrder::CommitmentFirst,
@@ -516,171 +560,184 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			monitor_pending_failures: Vec::new(),
 
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_local: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+			holder_max_commitment_tx_output: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_remote: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+			counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
 
 			last_sent_closing_fee: None,
 
-			funding_txo: None,
 			funding_tx_confirmed_in: None,
 			short_channel_id: None,
 			last_block_connected: Default::default(),
 			funding_tx_confirmations: 0,
 
 			feerate_per_kw: feerate,
-			their_dust_limit_satoshis: 0,
-			our_dust_limit_satoshis: Channel::<ChanSigner>::derive_our_dust_limit_satoshis(background_feerate),
-			their_max_htlc_value_in_flight_msat: 0,
-			local_channel_reserve_satoshis: 0,
-			their_htlc_minimum_msat: 0,
-			our_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
-			their_to_self_delay: 0,
-			our_to_self_delay: config.own_channel_config.our_to_self_delay,
-			their_max_accepted_htlcs: 0,
+			counterparty_dust_limit_satoshis: 0,
+			holder_dust_limit_satoshis: Channel::<Signer>::derive_holder_dust_limit_satoshis(background_feerate),
+			counterparty_max_htlc_value_in_flight_msat: 0,
+			counterparty_selected_channel_reserve_satoshis: 0,
+			counterparty_htlc_minimum_msat: 0,
+			holder_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
+			counterparty_max_accepted_htlcs: 0,
 			minimum_depth: 0, // Filled in in accept_channel
 
-			their_pubkeys: None,
-			their_cur_commitment_point: None,
+			channel_transaction_parameters: ChannelTransactionParameters {
+				holder_pubkeys: pubkeys,
+				holder_selected_contest_delay: config.own_channel_config.our_to_self_delay,
+				is_outbound_from_holder: true,
+				counterparty_parameters: None,
+				funding_outpoint: None
+			},
+			counterparty_cur_commitment_point: None,
 
-			their_prev_commitment_point: None,
-			their_node_id: their_node_id,
+			counterparty_prev_commitment_point: None,
+			counterparty_node_id,
 
-			their_shutdown_scriptpubkey: None,
+			counterparty_shutdown_scriptpubkey: None,
 
-			channel_monitor: None,
 			commitment_secrets: CounterpartyCommitmentSecrets::new(),
 
 			network_sync: UpdateStatus::Fresh,
+
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
 		})
 	}
 
 	fn check_remote_fee<F: Deref>(fee_estimator: &F, feerate_per_kw: u32) -> Result<(), ChannelError>
 		where F::Target: FeeEstimator
 	{
-		if feerate_per_kw < fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background) {
-			return Err(ChannelError::Close("Peer's feerate much too low"));
+		let lower_limit = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
+		if feerate_per_kw < lower_limit {
+			return Err(ChannelError::Close(format!("Peer's feerate much too low. Actual: {}. Our expected lower limit: {}", feerate_per_kw, lower_limit)));
 		}
-		if feerate_per_kw as u64 > fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64  * 2 {
-			return Err(ChannelError::Close("Peer's feerate much too high"));
+		let upper_limit = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64  * 2;
+		if feerate_per_kw as u64 > upper_limit {
+			return Err(ChannelError::Close(format!("Peer's feerate much too high. Actual: {}. Our expected upper limit: {}", feerate_per_kw, upper_limit)));
 		}
 		Ok(())
 	}
 
 	/// Creates a new channel from a remote sides' request for one.
 	/// Assumes chain_hash has already been checked and corresponds with what we expect!
-	pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, their_node_id: PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<ChanSigner>, ChannelError>
-		where K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
+	pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, ChannelError>
+		where K::Target: KeysInterface<Signer = Signer>,
           F::Target: FeeEstimator
 	{
-		let mut chan_keys = keys_provider.get_channel_keys(true, msg.funding_satoshis);
-		let their_pubkeys = ChannelPublicKeys {
+		let chan_keys = keys_provider.get_channel_signer(true, msg.funding_satoshis);
+		let pubkeys = chan_keys.pubkeys().clone();
+		let counterparty_pubkeys = ChannelPublicKeys {
 			funding_pubkey: msg.funding_pubkey,
 			revocation_basepoint: msg.revocation_basepoint,
 			payment_point: msg.payment_point,
 			delayed_payment_basepoint: msg.delayed_payment_basepoint,
 			htlc_basepoint: msg.htlc_basepoint
 		};
-		chan_keys.set_remote_channel_pubkeys(&their_pubkeys);
 		let mut local_config = (*config).channel_options.clone();
 
 		if config.own_channel_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
-			return Err(ChannelError::Close("Configured with an unreasonable our_to_self_delay putting user funds at risks"));
+			return Err(ChannelError::Close(format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks. It must be greater than {}", config.own_channel_config.our_to_self_delay, BREAKDOWN_TIMEOUT)));
 		}
 
 		// Check sanity of message fields:
 		if msg.funding_satoshis >= MAX_FUNDING_SATOSHIS {
-			return Err(ChannelError::Close("funding value > 2^24"));
+			return Err(ChannelError::Close(format!("Funding must be smaller than {}. It was {}", MAX_FUNDING_SATOSHIS, msg.funding_satoshis)));
 		}
 		if msg.channel_reserve_satoshis > msg.funding_satoshis {
-			return Err(ChannelError::Close("Bogus channel_reserve_satoshis"));
+			return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be not greater than funding_satoshis: {}", msg.channel_reserve_satoshis, msg.funding_satoshis)));
 		}
-		if msg.push_msat > (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000 {
-			return Err(ChannelError::Close("push_msat larger than funding value"));
+		let funding_value = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
+		if msg.push_msat > funding_value {
+			return Err(ChannelError::Close(format!("push_msat {} was larger than funding value {}", msg.push_msat, funding_value)));
 		}
 		if msg.dust_limit_satoshis > msg.funding_satoshis {
-			return Err(ChannelError::Close("Peer never wants payout outputs?"));
+			return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than funding_satoshis {}. Peer never wants payout outputs?", msg.dust_limit_satoshis, msg.funding_satoshis)));
 		}
 		if msg.dust_limit_satoshis > msg.channel_reserve_satoshis {
-			return Err(ChannelError::Close("Bogus; channel reserve is less than dust limit"));
+			return Err(ChannelError::Close(format!("Bogus; channel reserve ({}) is less than dust limit ({})", msg.channel_reserve_satoshis, msg.dust_limit_satoshis)));
 		}
-		if msg.htlc_minimum_msat >= (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000 {
-			return Err(ChannelError::Close("Minimum htlc value is full channel value"));
+		let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
+		if msg.htlc_minimum_msat >= full_channel_value_msat {
+			return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
 		}
-		Channel::<ChanSigner>::check_remote_fee(fee_estimator, msg.feerate_per_kw)?;
+		Channel::<Signer>::check_remote_fee(fee_estimator, msg.feerate_per_kw)?;
 
-		if msg.to_self_delay > config.peer_channel_config_limits.their_to_self_delay || msg.to_self_delay > MAX_LOCAL_BREAKDOWN_TIMEOUT {
-			return Err(ChannelError::Close("They wanted our payments to be delayed by a needlessly long period"));
+		let max_counterparty_selected_contest_delay = u16::min(config.peer_channel_config_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
+		if msg.to_self_delay > max_counterparty_selected_contest_delay {
+			return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_counterparty_selected_contest_delay, msg.to_self_delay)));
 		}
 		if msg.max_accepted_htlcs < 1 {
-			return Err(ChannelError::Close("0 max_accpted_htlcs makes for a useless channel"));
+			return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
 		}
-		if msg.max_accepted_htlcs > 483 {
-			return Err(ChannelError::Close("max_accpted_htlcs > 483"));
+		if msg.max_accepted_htlcs > MAX_HTLCS {
+			return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
 		}
 
 		// Now check against optional parameters as set by config...
 		if msg.funding_satoshis < config.peer_channel_config_limits.min_funding_satoshis {
-			return Err(ChannelError::Close("funding satoshis is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("Funding satoshis ({}) is less than the user specified limit ({})", msg.funding_satoshis, config.peer_channel_config_limits.min_funding_satoshis)));
 		}
 		if msg.htlc_minimum_msat > config.peer_channel_config_limits.max_htlc_minimum_msat {
-			return Err(ChannelError::Close("htlc minimum msat is higher than the user specified limit"));
+			return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat,  config.peer_channel_config_limits.max_htlc_minimum_msat)));
 		}
 		if msg.max_htlc_value_in_flight_msat < config.peer_channel_config_limits.min_max_htlc_value_in_flight_msat {
-			return Err(ChannelError::Close("max htlc value in flight msat is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, config.peer_channel_config_limits.min_max_htlc_value_in_flight_msat)));
 		}
 		if msg.channel_reserve_satoshis > config.peer_channel_config_limits.max_channel_reserve_satoshis {
-			return Err(ChannelError::Close("channel reserve satoshis is higher than the user specified limit"));
+			return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, config.peer_channel_config_limits.max_channel_reserve_satoshis)));
 		}
 		if msg.max_accepted_htlcs < config.peer_channel_config_limits.min_max_accepted_htlcs {
-			return Err(ChannelError::Close("max accepted htlcs is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.peer_channel_config_limits.min_max_accepted_htlcs)));
 		}
 		if msg.dust_limit_satoshis < config.peer_channel_config_limits.min_dust_limit_satoshis {
-			return Err(ChannelError::Close("dust limit satoshis is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the user specified limit ({})", msg.dust_limit_satoshis, config.peer_channel_config_limits.min_dust_limit_satoshis)));
 		}
 		if msg.dust_limit_satoshis > config.peer_channel_config_limits.max_dust_limit_satoshis {
-			return Err(ChannelError::Close("dust limit satoshis is greater than the user specified limit"));
+			return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the user specified limit ({})", msg.dust_limit_satoshis, config.peer_channel_config_limits.max_dust_limit_satoshis)));
 		}
 
 		// Convert things into internal flags and prep our state:
 
-		let their_announce = if (msg.channel_flags & 1) == 1 { true } else { false };
+		let announce = if (msg.channel_flags & 1) == 1 { true } else { false };
 		if config.peer_channel_config_limits.force_announced_channel_preference {
-			if local_config.announced_channel != their_announce {
-				return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours"));
+			if local_config.announced_channel != announce {
+				return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
 			}
 		}
 		// we either accept their preference or the preferences match
-		local_config.announced_channel = their_announce;
+		local_config.announced_channel = announce;
 
 		let background_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 
-		let our_dust_limit_satoshis = Channel::<ChanSigner>::derive_our_dust_limit_satoshis(background_feerate);
-		let remote_channel_reserve_satoshis = Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(msg.funding_satoshis);
-		if remote_channel_reserve_satoshis < our_dust_limit_satoshis {
-			return Err(ChannelError::Close("Suitable channel reserve not found. aborting"));
+		let holder_dust_limit_satoshis = Channel::<Signer>::derive_holder_dust_limit_satoshis(background_feerate);
+		let holder_selected_channel_reserve_satoshis = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis);
+		if holder_selected_channel_reserve_satoshis < holder_dust_limit_satoshis {
+			return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, holder_dust_limit_satoshis)));
 		}
-		if msg.channel_reserve_satoshis < our_dust_limit_satoshis {
-			return Err(ChannelError::Close("channel_reserve_satoshis too small"));
+		if msg.channel_reserve_satoshis < holder_dust_limit_satoshis {
+			return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is smaller than our dust limit ({})", msg.channel_reserve_satoshis, holder_dust_limit_satoshis)));
 		}
-		if remote_channel_reserve_satoshis < msg.dust_limit_satoshis {
-			return Err(ChannelError::Close("Dust limit too high for the channel reserve we require the remote to keep"));
+		if holder_selected_channel_reserve_satoshis < msg.dust_limit_satoshis {
+			return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", msg.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
 		}
 
 		// check if the funder's amount for the initial commitment tx is sufficient
 		// for full fee payment
 		let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat;
-		if funders_amount_msat < background_feerate as u64 * COMMITMENT_TX_BASE_WEIGHT {
-			return Err(ChannelError::Close("Insufficient funding amount for initial commitment"));
+		let lower_limit = background_feerate as u64 * COMMITMENT_TX_BASE_WEIGHT;
+		if funders_amount_msat < lower_limit {
+			return Err(ChannelError::Close(format!("Insufficient funding amount ({}) for initial commitment. Must be at least {}", funders_amount_msat, lower_limit)));
 		}
 
 		let to_local_msat = msg.push_msat;
 		let to_remote_msat = funders_amount_msat - background_feerate as u64 * COMMITMENT_TX_BASE_WEIGHT;
-		if to_local_msat <= msg.channel_reserve_satoshis * 1000 && to_remote_msat <= remote_channel_reserve_satoshis * 1000 {
-			return Err(ChannelError::Close("Insufficient funding amount for initial commitment"));
+		if to_local_msat <= msg.channel_reserve_satoshis * 1000 && to_remote_msat <= holder_selected_channel_reserve_satoshis * 1000 {
+			return Err(ChannelError::Close("Insufficient funding amount for initial commitment".to_owned()));
 		}
 
-		let their_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
+		let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
 			match &msg.shutdown_scriptpubkey {
 				&OptionalField::Present(ref script) => {
 					// Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. We enforce it while receiving shutdown msg
@@ -691,33 +748,32 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 						None
 					// Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
 					} else {
-						return Err(ChannelError::Close("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format"));
+						return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
 					}
 				},
 				// Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
 				&OptionalField::Absent => {
-					return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out"));
+					return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
 				}
 			}
 		} else { None };
 
 		let chan = Channel {
-			user_id: user_id,
+			user_id,
 			config: local_config,
 
 			channel_id: msg.temporary_channel_id,
 			channel_state: (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32),
-			channel_outbound: false,
 			secp_ctx: Secp256k1::new(),
 
 			latest_monitor_update_id: 0,
 
-			local_keys: chan_keys,
+			holder_keys: chan_keys,
 			shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
 			destination_script: keys_provider.get_destination_script(),
 
-			cur_local_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-			cur_remote_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+			cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+			cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
 			value_to_self_msat: msg.push_msat,
 
 			pending_inbound_htlcs: Vec::new(),
@@ -725,8 +781,8 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			holding_cell_htlc_updates: Vec::new(),
 			pending_update_fee: None,
 			holding_cell_update_fee: None,
-			next_local_htlc_id: 0,
-			next_remote_htlc_id: 0,
+			next_holder_htlc_id: 0,
+			next_counterparty_htlc_id: 0,
 			update_time_counter: 1,
 
 			resend_order: RAACommitmentOrder::CommitmentFirst,
@@ -738,13 +794,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			monitor_pending_failures: Vec::new(),
 
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_local: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+			holder_max_commitment_tx_output: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_remote: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+			counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
 
 			last_sent_closing_fee: None,
 
-			funding_txo: None,
 			funding_tx_confirmed_in: None,
 			short_channel_id: None,
 			last_block_connected: Default::default(),
@@ -752,64 +807,45 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 			feerate_per_kw: msg.feerate_per_kw,
 			channel_value_satoshis: msg.funding_satoshis,
-			their_dust_limit_satoshis: msg.dust_limit_satoshis,
-			our_dust_limit_satoshis: our_dust_limit_satoshis,
-			their_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
-			local_channel_reserve_satoshis: msg.channel_reserve_satoshis,
-			their_htlc_minimum_msat: msg.htlc_minimum_msat,
-			our_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
-			their_to_self_delay: msg.to_self_delay,
-			our_to_self_delay: config.own_channel_config.our_to_self_delay,
-			their_max_accepted_htlcs: msg.max_accepted_htlcs,
+			counterparty_dust_limit_satoshis: msg.dust_limit_satoshis,
+			holder_dust_limit_satoshis,
+			counterparty_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
+			counterparty_selected_channel_reserve_satoshis: msg.channel_reserve_satoshis,
+			counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
+			holder_htlc_minimum_msat: if config.own_channel_config.our_htlc_minimum_msat == 0 { 1 } else { config.own_channel_config.our_htlc_minimum_msat },
+			counterparty_max_accepted_htlcs: msg.max_accepted_htlcs,
 			minimum_depth: config.own_channel_config.minimum_depth,
 
-			their_pubkeys: Some(their_pubkeys),
-			their_cur_commitment_point: Some(msg.first_per_commitment_point),
+			channel_transaction_parameters: ChannelTransactionParameters {
+				holder_pubkeys: pubkeys,
+				holder_selected_contest_delay: config.own_channel_config.our_to_self_delay,
+				is_outbound_from_holder: false,
+				counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
+					selected_contest_delay: msg.to_self_delay,
+					pubkeys: counterparty_pubkeys,
+				}),
+				funding_outpoint: None
+			},
+			counterparty_cur_commitment_point: Some(msg.first_per_commitment_point),
 
-			their_prev_commitment_point: None,
-			their_node_id: their_node_id,
+			counterparty_prev_commitment_point: None,
+			counterparty_node_id,
 
-			their_shutdown_scriptpubkey,
+			counterparty_shutdown_scriptpubkey,
 
-			channel_monitor: None,
 			commitment_secrets: CounterpartyCommitmentSecrets::new(),
 
 			network_sync: UpdateStatus::Fresh,
+
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
 		};
 
 		Ok(chan)
 	}
 
-	// Utilities to derive keys:
-
-	fn build_local_commitment_secret(&self, idx: u64) -> SecretKey {
-		let res = chan_utils::build_commitment_secret(self.local_keys.commitment_seed(), idx);
-		SecretKey::from_slice(&res).unwrap()
-	}
-
-	// Utilities to build transactions:
-
-	fn get_commitment_transaction_number_obscure_factor(&self) -> u64 {
-		let mut sha = Sha256::engine();
-
-		let their_payment_point = &self.their_pubkeys.as_ref().unwrap().payment_point.serialize();
-		if self.channel_outbound {
-			sha.input(&self.local_keys.pubkeys().payment_point.serialize());
-			sha.input(their_payment_point);
-		} else {
-			sha.input(their_payment_point);
-			sha.input(&self.local_keys.pubkeys().payment_point.serialize());
-		}
-		let res = Sha256::from_engine(sha).into_inner();
-
-		((res[26] as u64) << 5*8) |
-		((res[27] as u64) << 4*8) |
-		((res[28] as u64) << 3*8) |
-		((res[29] as u64) << 2*8) |
-		((res[30] as u64) << 1*8) |
-		((res[31] as u64) << 0*8)
-	}
-
 	/// Transaction nomenclature is somewhat confusing here as there are many different cases - a
 	/// transaction is referred to as "a's transaction" implying that a will be able to broadcast
 	/// the transaction. Thus, b will generally be sending a signature over such a transaction to
@@ -823,34 +859,22 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// have not yet committed it. Such HTLCs will only be included in transactions which are being
 	/// generated by the peer which proposed adding the HTLCs, and thus we need to understand both
 	/// which peer generated this transaction and "to whom" this transaction flows.
-	/// Returns (the transaction built, the number of HTLC outputs which were present in the
+	/// Returns (the transaction info, the number of HTLC outputs which were present in the
 	/// transaction, the list of HTLCs which were not ignored when building the transaction).
 	/// Note that below-dust HTLCs are included in the third return value, but not the second, and
 	/// sources are provided only for outbound HTLCs in the third return value.
 	#[inline]
-	fn build_commitment_transaction<L: Deref>(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, feerate_per_kw: u32, logger: &L) -> (Transaction, usize, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>) where L::Target: Logger {
-		let obscured_commitment_transaction_number = self.get_commitment_transaction_number_obscure_factor() ^ (INITIAL_COMMITMENT_NUMBER - commitment_number);
-
-		let txins = {
-			let mut ins: Vec<TxIn> = Vec::new();
-			ins.push(TxIn {
-				previous_output: self.funding_txo.unwrap().into_bitcoin_outpoint(),
-				script_sig: Script::new(),
-				sequence: ((0x80 as u32) << 8*3) | ((obscured_commitment_transaction_number >> 3*8) as u32),
-				witness: Vec::new(),
-			});
-			ins
-		};
-
-		let mut txouts: Vec<(TxOut, Option<(HTLCOutputInCommitment, Option<&HTLCSource>)>)> = Vec::with_capacity(self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len() + 2);
+	fn build_commitment_transaction<L: Deref>(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, feerate_per_kw: u32, logger: &L) -> (CommitmentTransaction, usize, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>) where L::Target: Logger {
 		let mut included_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::new();
+		let num_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len();
+		let mut included_non_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(num_htlcs);
 
-		let dust_limit_satoshis = if local { self.our_dust_limit_satoshis } else { self.their_dust_limit_satoshis };
+		let broadcaster_dust_limit_satoshis = if local { self.holder_dust_limit_satoshis } else { self.counterparty_dust_limit_satoshis };
 		let mut remote_htlc_total_msat = 0;
 		let mut local_htlc_total_msat = 0;
 		let mut value_to_self_msat_offset = 0;
 
-		log_trace!(logger, "Building commitment transaction number {} (really {} xor {}) for {}, generated by {} with fee {}...", commitment_number, (INITIAL_COMMITMENT_NUMBER - commitment_number), self.get_commitment_transaction_number_obscure_factor(), if local { "us" } else { "remote" }, if generated_by_local { "us" } else { "remote" }, feerate_per_kw);
+		log_trace!(logger, "Building commitment transaction number {} (really {} xor {}) for {}, generated by {} with fee {}...", commitment_number, (INITIAL_COMMITMENT_NUMBER - commitment_number), get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound()), if local { "us" } else { "remote" }, if generated_by_local { "us" } else { "remote" }, feerate_per_kw);
 
 		macro_rules! get_htlc_in_commitment {
 			($htlc: expr, $offered: expr) => {
@@ -868,24 +892,18 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			($htlc: expr, $outbound: expr, $source: expr, $state_name: expr) => {
 				if $outbound == local { // "offered HTLC output"
 					let htlc_in_tx = get_htlc_in_commitment!($htlc, true);
-					if $htlc.amount_msat / 1000 >= dust_limit_satoshis + (feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) {
+					if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + (feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) {
 						log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-						txouts.push((TxOut {
-							script_pubkey: chan_utils::get_htlc_redeemscript(&htlc_in_tx, &keys).to_v0_p2wsh(),
-							value: $htlc.amount_msat / 1000
-						}, Some((htlc_in_tx, $source))));
+						included_non_dust_htlcs.push((htlc_in_tx, $source));
 					} else {
 						log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {} due to dust limit", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
 						included_dust_htlcs.push((htlc_in_tx, $source));
 					}
 				} else {
 					let htlc_in_tx = get_htlc_in_commitment!($htlc, false);
-					if $htlc.amount_msat / 1000 >= dust_limit_satoshis + (feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) {
+					if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + (feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) {
 						log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-						txouts.push((TxOut { // "received HTLC output"
-							script_pubkey: chan_utils::get_htlc_redeemscript(&htlc_in_tx, &keys).to_v0_p2wsh(),
-							value: $htlc.amount_msat / 1000
-						}, Some((htlc_in_tx, $source))));
+						included_non_dust_htlcs.push((htlc_in_tx, $source));
 					} else {
 						log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
 						included_dust_htlcs.push((htlc_in_tx, $source));
@@ -962,95 +980,91 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		{
 			// Make sure that the to_self/to_remote is always either past the appropriate
 			// channel_reserve *or* it is making progress towards it.
-			let mut max_commitment_tx_output = if generated_by_local {
-				self.max_commitment_tx_output_local.lock().unwrap()
+			let mut broadcaster_max_commitment_tx_output = if generated_by_local {
+				self.holder_max_commitment_tx_output.lock().unwrap()
 			} else {
-				self.max_commitment_tx_output_remote.lock().unwrap()
+				self.counterparty_max_commitment_tx_output.lock().unwrap()
 			};
-			debug_assert!(max_commitment_tx_output.0 <= value_to_self_msat as u64 || value_to_self_msat / 1000 >= self.local_channel_reserve_satoshis as i64);
-			max_commitment_tx_output.0 = cmp::max(max_commitment_tx_output.0, value_to_self_msat as u64);
-			debug_assert!(max_commitment_tx_output.1 <= value_to_remote_msat as u64 || value_to_remote_msat / 1000 >= Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis) as i64);
-			max_commitment_tx_output.1 = cmp::max(max_commitment_tx_output.1, value_to_remote_msat as u64);
+			debug_assert!(broadcaster_max_commitment_tx_output.0 <= value_to_self_msat as u64 || value_to_self_msat / 1000 >= self.counterparty_selected_channel_reserve_satoshis as i64);
+			broadcaster_max_commitment_tx_output.0 = cmp::max(broadcaster_max_commitment_tx_output.0, value_to_self_msat as u64);
+			debug_assert!(broadcaster_max_commitment_tx_output.1 <= value_to_remote_msat as u64 || value_to_remote_msat / 1000 >= Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) as i64);
+			broadcaster_max_commitment_tx_output.1 = cmp::max(broadcaster_max_commitment_tx_output.1, value_to_remote_msat as u64);
 		}
 
-		let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (txouts.len() as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
-		let (value_to_self, value_to_remote) = if self.channel_outbound {
+		let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (included_non_dust_htlcs.len() as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
+		let (value_to_self, value_to_remote) = if self.is_outbound() {
 			(value_to_self_msat / 1000 - total_fee as i64, value_to_remote_msat / 1000)
 		} else {
 			(value_to_self_msat / 1000, value_to_remote_msat / 1000 - total_fee as i64)
 		};
 
-		let value_to_a = if local { value_to_self } else { value_to_remote };
-		let value_to_b = if local { value_to_remote } else { value_to_self };
+		let mut value_to_a = if local { value_to_self } else { value_to_remote };
+		let mut value_to_b = if local { value_to_remote } else { value_to_self };
 
-		if value_to_a >= (dust_limit_satoshis as i64) {
+		if value_to_a >= (broadcaster_dust_limit_satoshis as i64) {
 			log_trace!(logger, "   ...including {} output with value {}", if local { "to_local" } else { "to_remote" }, value_to_a);
-			txouts.push((TxOut {
-				script_pubkey: chan_utils::get_revokeable_redeemscript(&keys.revocation_key,
-				                                                       if local { self.their_to_self_delay } else { self.our_to_self_delay },
-				                                                       &keys.a_delayed_payment_key).to_v0_p2wsh(),
-				value: value_to_a as u64
-			}, None));
+		} else {
+			value_to_a = 0;
 		}
 
-		if value_to_b >= (dust_limit_satoshis as i64) {
+		if value_to_b >= (broadcaster_dust_limit_satoshis as i64) {
 			log_trace!(logger, "   ...including {} output with value {}", if local { "to_remote" } else { "to_local" }, value_to_b);
-			let static_payment_pk = if local {
-				self.their_pubkeys.as_ref().unwrap().payment_point
-			} else {
-				self.local_keys.pubkeys().payment_point
-			}.serialize();
-			txouts.push((TxOut {
-				script_pubkey: Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
-				                             .push_slice(&WPubkeyHash::hash(&static_payment_pk)[..])
-				                             .into_script(),
-				value: value_to_b as u64
-			}, None));
-		}
-
-		transaction_utils::sort_outputs(&mut txouts, |a, b| {
-			if let &Some(ref a_htlc) = a {
-				if let &Some(ref b_htlc) = b {
-					a_htlc.0.cltv_expiry.cmp(&b_htlc.0.cltv_expiry)
-						// Note that due to hash collisions, we have to have a fallback comparison
-						// here for fuzztarget mode (otherwise at least chanmon_fail_consistency
-						// may fail)!
-						.then(a_htlc.0.payment_hash.0.cmp(&b_htlc.0.payment_hash.0))
-				// For non-HTLC outputs, if they're copying our SPK we don't really care if we
-				// close the channel due to mismatches - they're doing something dumb:
-				} else { cmp::Ordering::Equal }
-			} else { cmp::Ordering::Equal }
-		});
-
-		let mut outputs: Vec<TxOut> = Vec::with_capacity(txouts.len());
-		let mut htlcs_included: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(txouts.len() + included_dust_htlcs.len());
-		for (idx, mut out) in txouts.drain(..).enumerate() {
-			outputs.push(out.0);
-			if let Some((mut htlc, source_option)) = out.1.take() {
-				htlc.transaction_output_index = Some(idx as u32);
-				htlcs_included.push((htlc, source_option));
-			}
+		} else {
+			value_to_b = 0;
 		}
-		let non_dust_htlc_count = htlcs_included.len();
+
+		let num_nondust_htlcs = included_non_dust_htlcs.len();
+
+		let channel_parameters =
+			if local { self.channel_transaction_parameters.as_holder_broadcastable() }
+			else { self.channel_transaction_parameters.as_counterparty_broadcastable() };
+		let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(commitment_number,
+		                                                             value_to_a as u64,
+		                                                             value_to_b as u64,
+		                                                             keys.clone(),
+		                                                             feerate_per_kw,
+		                                                             &mut included_non_dust_htlcs,
+		                                                             &channel_parameters
+		);
+		let mut htlcs_included = included_non_dust_htlcs;
+		// The unwrap is safe, because all non-dust HTLCs have been assigned an output index
+		htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap());
 		htlcs_included.append(&mut included_dust_htlcs);
 
-		(Transaction {
-			version: 2,
-			lock_time: ((0x20 as u32) << 8*3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
-			input: txins,
-			output: outputs,
-		}, non_dust_htlc_count, htlcs_included)
+		(tx, num_nondust_htlcs, htlcs_included)
 	}
 
 	#[inline]
 	fn get_closing_scriptpubkey(&self) -> Script {
-		let our_channel_close_key_hash = WPubkeyHash::hash(&self.shutdown_pubkey.serialize());
-		Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&our_channel_close_key_hash[..]).into_script()
+		let channel_close_key_hash = WPubkeyHash::hash(&self.shutdown_pubkey.serialize());
+		Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_close_key_hash[..]).into_script()
 	}
 
 	#[inline]
-	fn get_closing_transaction_weight(a_scriptpubkey: &Script, b_scriptpubkey: &Script) -> u64 {
-		(4 + 1 + 36 + 4 + 1 + 1 + 2*(8+1) + 4 + a_scriptpubkey.len() as u64 + b_scriptpubkey.len() as u64)*4 + 2 + 1 + 1 + 2*(1 + 72)
+	fn get_closing_transaction_weight(&self, a_scriptpubkey: Option<&Script>, b_scriptpubkey: Option<&Script>) -> u64 {
+		let mut ret =
+		(4 +                                           // version
+		 1 +                                           // input count
+		 36 +                                          // prevout
+		 1 +                                           // script length (0)
+		 4 +                                           // sequence
+		 1 +                                           // output count
+		 4                                             // lock time
+		 )*4 +                                         // * 4 for non-witness parts
+		2 +                                            // witness marker and flag
+		1 +                                            // witness element count
+		4 +                                            // 4 element lengths (2 sigs, multisig dummy, and witness script)
+		self.get_funding_redeemscript().len() as u64 + // funding witness script
+		2*(1 + 71);                                    // two signatures + sighash type flags
+		if let Some(spk) = a_scriptpubkey {
+			ret += ((8+1) +                            // output values and script length
+				spk.len() as u64) * 4;                 // scriptpubkey and witness multiplier
+		}
+		if let Some(spk) = b_scriptpubkey {
+			ret += ((8+1) +                            // output values and script length
+				spk.len() as u64) * 4;                 // scriptpubkey and witness multiplier
+		}
+		ret
 	}
 
 	#[inline]
@@ -1058,7 +1072,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let txins = {
 			let mut ins: Vec<TxIn> = Vec::new();
 			ins.push(TxIn {
-				previous_output: self.funding_txo.unwrap().into_bitcoin_outpoint(),
+				previous_output: self.funding_outpoint().into_bitcoin_outpoint(),
 				script_sig: Script::new(),
 				sequence: 0xffffffff,
 				witness: Vec::new(),
@@ -1071,25 +1085,25 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let mut txouts: Vec<(TxOut, ())> = Vec::new();
 
 		let mut total_fee_satoshis = proposed_total_fee_satoshis;
-		let value_to_self: i64 = (self.value_to_self_msat as i64) / 1000 - if self.channel_outbound { total_fee_satoshis as i64 } else { 0 };
-		let value_to_remote: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.channel_outbound { 0 } else { total_fee_satoshis as i64 };
+		let value_to_self: i64 = (self.value_to_self_msat as i64) / 1000 - if self.is_outbound() { total_fee_satoshis as i64 } else { 0 };
+		let value_to_remote: i64 = ((self.channel_value_satoshis * 1000 - self.value_to_self_msat) as i64 / 1000) - if self.is_outbound() { 0 } else { total_fee_satoshis as i64 };
 
 		if value_to_self < 0 {
-			assert!(self.channel_outbound);
+			assert!(self.is_outbound());
 			total_fee_satoshis += (-value_to_self) as u64;
 		} else if value_to_remote < 0 {
-			assert!(!self.channel_outbound);
+			assert!(!self.is_outbound());
 			total_fee_satoshis += (-value_to_remote) as u64;
 		}
 
-		if !skip_remote_output && value_to_remote as u64 > self.our_dust_limit_satoshis {
+		if !skip_remote_output && value_to_remote as u64 > self.holder_dust_limit_satoshis {
 			txouts.push((TxOut {
-				script_pubkey: self.their_shutdown_scriptpubkey.clone().unwrap(),
+				script_pubkey: self.counterparty_shutdown_scriptpubkey.clone().unwrap(),
 				value: value_to_remote as u64
 			}, ()));
 		}
 
-		if value_to_self as u64 > self.our_dust_limit_satoshis {
+		if value_to_self as u64 > self.holder_dust_limit_satoshis {
 			txouts.push((TxOut {
 				script_pubkey: self.get_closing_scriptpubkey(),
 				value: value_to_self as u64
@@ -1111,19 +1125,23 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}, total_fee_satoshis)
 	}
 
+	fn funding_outpoint(&self) -> OutPoint {
+		self.channel_transaction_parameters.funding_outpoint.unwrap()
+	}
+
 	#[inline]
 	/// Creates a set of keys for build_commitment_transaction to generate a transaction which our
 	/// counterparty will sign (ie DO NOT send signatures over a transaction created by this to
 	/// our counterparty!)
-	/// The result is a transaction which we can revoke ownership of (ie a "local" transaction)
+	/// The result is a transaction which we can revoke broadcastership of (ie a "local" transaction)
 	/// TODO Some magic rust shit to compile-time check this?
-	fn build_local_transaction_keys(&self, commitment_number: u64) -> Result<TxCreationKeys, ChannelError> {
-		let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(commitment_number));
-		let delayed_payment_base = &self.local_keys.pubkeys().delayed_payment_basepoint;
-		let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint;
-		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
+	fn build_holder_transaction_keys(&self, commitment_number: u64) -> Result<TxCreationKeys, ChannelError> {
+		let per_commitment_point = self.holder_keys.get_per_commitment_point(commitment_number, &self.secp_ctx);
+		let delayed_payment_base = &self.get_holder_pubkeys().delayed_payment_basepoint;
+		let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
+		let counterparty_pubkeys = self.get_counterparty_pubkeys();
 
-		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys"))
+		Ok(secp_check!(TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint), "Local tx keys generation got bogus keys".to_owned()))
 	}
 
 	#[inline]
@@ -1133,25 +1151,25 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	fn build_remote_transaction_keys(&self) -> Result<TxCreationKeys, ChannelError> {
 		//TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we
 		//may see payments to it!
-		let revocation_basepoint = &self.local_keys.pubkeys().revocation_basepoint;
-		let htlc_basepoint = &self.local_keys.pubkeys().htlc_basepoint;
-		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
+		let revocation_basepoint = &self.get_holder_pubkeys().revocation_basepoint;
+		let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
+		let counterparty_pubkeys = self.get_counterparty_pubkeys();
 
-		Ok(secp_check!(TxCreationKeys::new(&self.secp_ctx, &self.their_cur_commitment_point.unwrap(), &their_pubkeys.delayed_payment_basepoint, &their_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint), "Remote tx keys generation got bogus keys"))
+		Ok(secp_check!(TxCreationKeys::derive_new(&self.secp_ctx, &self.counterparty_cur_commitment_point.unwrap(), &counterparty_pubkeys.delayed_payment_basepoint, &counterparty_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint), "Remote tx keys generation got bogus keys".to_owned()))
 	}
 
 	/// Gets the redeemscript for the funding transaction output (ie the funding transaction output
 	/// pays to get_funding_redeemscript().to_v0_p2wsh()).
 	/// Panics if called before accept_channel/new_from_req
 	pub fn get_funding_redeemscript(&self) -> Script {
-		make_funding_redeemscript(&self.local_keys.pubkeys().funding_pubkey, self.their_funding_pubkey())
+		make_funding_redeemscript(&self.get_holder_pubkeys().funding_pubkey, self.counterparty_funding_pubkey())
 	}
 
 	/// Builds the htlc-success or htlc-timeout transaction which spends a given HTLC output
 	/// @local is used only to convert relevant internal structures which refer to remote vs local
 	/// to decide value of outputs and direction of HTLCs.
 	fn build_htlc_transaction(&self, prev_hash: &Txid, htlc: &HTLCOutputInCommitment, local: bool, keys: &TxCreationKeys, feerate_per_kw: u32) -> Transaction {
-		chan_utils::build_htlc_transaction(prev_hash, feerate_per_kw, if local { self.their_to_self_delay } else { self.our_to_self_delay }, htlc, &keys.a_delayed_payment_key, &keys.revocation_key)
+		chan_utils::build_htlc_transaction(prev_hash, feerate_per_kw, if local { self.get_counterparty_selected_contest_delay() } else { self.get_holder_selected_contest_delay() }, htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key)
 	}
 
 	/// Per HTLC, only one get_update_fail_htlc or get_update_fulfill_htlc call may be made.
@@ -1200,7 +1218,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 		}
 		if pending_idx == std::usize::MAX {
-			return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID"));
+			return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
 		}
 
 		// Now update local state:
@@ -1214,7 +1232,6 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				payment_preimage: payment_preimage_arg.clone(),
 			}],
 		};
-		self.channel_monitor.as_mut().unwrap().update_monitor_ooo(monitor_update.clone(), logger).unwrap();
 
 		if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32)) != 0 {
 			for pending_update in self.holding_cell_htlc_updates.iter() {
@@ -1310,14 +1327,14 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 					},
 					_ => {
 						debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
-						return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID"));
+						return Err(ChannelError::Ignore(format!("Unable to find a pending HTLC which matched the given HTLC ID ({})", htlc.htlc_id)));
 					}
 				}
 				pending_idx = idx;
 			}
 		}
 		if pending_idx == std::usize::MAX {
-			return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID"));
+			return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
 		}
 
 		// Now update local state:
@@ -1327,13 +1344,13 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 					&HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
 						if htlc_id_arg == htlc_id {
 							debug_assert!(false, "Tried to fail an HTLC that was already fulfilled");
-							return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID"));
+							return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
 						}
 					},
 					&HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
 						if htlc_id_arg == htlc_id {
 							debug_assert!(false, "Tried to fail an HTLC that was already failed");
-							return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID"));
+							return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
 						}
 					},
 					_ => {}
@@ -1362,64 +1379,67 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 	pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: InitFeatures) -> Result<(), ChannelError> {
 		// Check sanity of message fields:
-		if !self.channel_outbound {
-			return Err(ChannelError::Close("Got an accept_channel message from an inbound peer"));
+		if !self.is_outbound() {
+			return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
 		}
 		if self.channel_state != ChannelState::OurInitSent as u32 {
-			return Err(ChannelError::Close("Got an accept_channel message at a strange time"));
+			return Err(ChannelError::Close("Got an accept_channel message at a strange time".to_owned()));
 		}
 		if msg.dust_limit_satoshis > 21000000 * 100000000 {
-			return Err(ChannelError::Close("Peer never wants payout outputs?"));
+			return Err(ChannelError::Close(format!("Peer never wants payout outputs? dust_limit_satoshis was {}", msg.dust_limit_satoshis)));
 		}
 		if msg.channel_reserve_satoshis > self.channel_value_satoshis {
-			return Err(ChannelError::Close("Bogus channel_reserve_satoshis"));
+			return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than ({})", msg.channel_reserve_satoshis, self.channel_value_satoshis)));
 		}
 		if msg.dust_limit_satoshis > msg.channel_reserve_satoshis {
-			return Err(ChannelError::Close("Bogus channel_reserve and dust_limit"));
+			return Err(ChannelError::Close(format!("Bogus channel_reserve ({}) and dust_limit ({})", msg.channel_reserve_satoshis, msg.dust_limit_satoshis)));
 		}
-		if msg.channel_reserve_satoshis < self.our_dust_limit_satoshis {
-			return Err(ChannelError::Close("Peer never wants payout outputs?"));
+		if msg.channel_reserve_satoshis < self.holder_dust_limit_satoshis {
+			return Err(ChannelError::Close(format!("Peer never wants payout outputs? channel_reserve_satoshis was ({}). dust_limit is ({})", msg.channel_reserve_satoshis, self.holder_dust_limit_satoshis)));
 		}
-		if msg.dust_limit_satoshis > Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis) {
-			return Err(ChannelError::Close("Dust limit is bigger than our channel reverse"));
+		let remote_reserve = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis);
+		if msg.dust_limit_satoshis > remote_reserve {
+			return Err(ChannelError::Close(format!("Dust limit ({}) is bigger than our channel reserve ({})", msg.dust_limit_satoshis, remote_reserve)));
 		}
-		if msg.htlc_minimum_msat >= (self.channel_value_satoshis - msg.channel_reserve_satoshis) * 1000 {
-			return Err(ChannelError::Close("Minimum htlc value is full channel value"));
+		let full_channel_value_msat = (self.channel_value_satoshis - msg.channel_reserve_satoshis) * 1000;
+		if msg.htlc_minimum_msat >= full_channel_value_msat {
+			return Err(ChannelError::Close(format!("Minimum htlc value ({}) is full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
 		}
-		if msg.to_self_delay > config.peer_channel_config_limits.their_to_self_delay || msg.to_self_delay > MAX_LOCAL_BREAKDOWN_TIMEOUT {
-			return Err(ChannelError::Close("They wanted our payments to be delayed by a needlessly long period"));
+		let max_delay_acceptable = u16::min(config.peer_channel_config_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
+		if msg.to_self_delay > max_delay_acceptable {
+			return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_delay_acceptable, msg.to_self_delay)));
 		}
 		if msg.max_accepted_htlcs < 1 {
-			return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel"));
+			return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
 		}
-		if msg.max_accepted_htlcs > 483 {
-			return Err(ChannelError::Close("max_accepted_htlcs > 483"));
+		if msg.max_accepted_htlcs > MAX_HTLCS {
+			return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
 		}
 
 		// Now check against optional parameters as set by config...
 		if msg.htlc_minimum_msat > config.peer_channel_config_limits.max_htlc_minimum_msat {
-			return Err(ChannelError::Close("htlc minimum msat is higher than the user specified limit"));
+			return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat, config.peer_channel_config_limits.max_htlc_minimum_msat)));
 		}
 		if msg.max_htlc_value_in_flight_msat < config.peer_channel_config_limits.min_max_htlc_value_in_flight_msat {
-			return Err(ChannelError::Close("max htlc value in flight msat is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, config.peer_channel_config_limits.min_max_htlc_value_in_flight_msat)));
 		}
 		if msg.channel_reserve_satoshis > config.peer_channel_config_limits.max_channel_reserve_satoshis {
-			return Err(ChannelError::Close("channel reserve satoshis is higher than the user specified limit"));
+			return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, config.peer_channel_config_limits.max_channel_reserve_satoshis)));
 		}
 		if msg.max_accepted_htlcs < config.peer_channel_config_limits.min_max_accepted_htlcs {
-			return Err(ChannelError::Close("max accepted htlcs is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.peer_channel_config_limits.min_max_accepted_htlcs)));
 		}
 		if msg.dust_limit_satoshis < config.peer_channel_config_limits.min_dust_limit_satoshis {
-			return Err(ChannelError::Close("dust limit satoshis is less than the user specified limit"));
+			return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the user specified limit ({})", msg.dust_limit_satoshis, config.peer_channel_config_limits.min_dust_limit_satoshis)));
 		}
 		if msg.dust_limit_satoshis > config.peer_channel_config_limits.max_dust_limit_satoshis {
-			return Err(ChannelError::Close("dust limit satoshis is greater than the user specified limit"));
+			return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the user specified limit ({})", msg.dust_limit_satoshis, config.peer_channel_config_limits.max_dust_limit_satoshis)));
 		}
 		if msg.minimum_depth > config.peer_channel_config_limits.max_minimum_depth {
-			return Err(ChannelError::Close("We consider the minimum depth to be unreasonably large"));
+			return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", config.peer_channel_config_limits.max_minimum_depth, msg.minimum_depth)));
 		}
 
-		let their_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
+		let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
 			match &msg.shutdown_scriptpubkey {
 				&OptionalField::Present(ref script) => {
 					// Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. We enforce it while receiving shutdown msg
@@ -1430,25 +1450,24 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 						None
 					// Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
 					} else {
-						return Err(ChannelError::Close("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format"));
+						return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. scriptpubkey: ({})", script.to_bytes().to_hex())));
 					}
 				},
 				// Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
 				&OptionalField::Absent => {
-					return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out"));
+					return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
 				}
 			}
 		} else { None };
 
-		self.their_dust_limit_satoshis = msg.dust_limit_satoshis;
-		self.their_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.channel_value_satoshis * 1000);
-		self.local_channel_reserve_satoshis = msg.channel_reserve_satoshis;
-		self.their_htlc_minimum_msat = msg.htlc_minimum_msat;
-		self.their_to_self_delay = msg.to_self_delay;
-		self.their_max_accepted_htlcs = msg.max_accepted_htlcs;
+		self.counterparty_dust_limit_satoshis = msg.dust_limit_satoshis;
+		self.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.channel_value_satoshis * 1000);
+		self.counterparty_selected_channel_reserve_satoshis = msg.channel_reserve_satoshis;
+		self.counterparty_htlc_minimum_msat = msg.htlc_minimum_msat;
+		self.counterparty_max_accepted_htlcs = msg.max_accepted_htlcs;
 		self.minimum_depth = msg.minimum_depth;
 
-		let their_pubkeys = ChannelPublicKeys {
+		let counterparty_pubkeys = ChannelPublicKeys {
 			funding_pubkey: msg.funding_pubkey,
 			revocation_basepoint: msg.revocation_basepoint,
 			payment_point: msg.payment_point,
@@ -1456,170 +1475,190 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			htlc_basepoint: msg.htlc_basepoint
 		};
 
-		self.local_keys.set_remote_channel_pubkeys(&their_pubkeys);
-		self.their_pubkeys = Some(their_pubkeys);
+		self.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters {
+			selected_contest_delay: msg.to_self_delay,
+			pubkeys: counterparty_pubkeys,
+		});
 
-		self.their_cur_commitment_point = Some(msg.first_per_commitment_point);
-		self.their_shutdown_scriptpubkey = their_shutdown_scriptpubkey;
+		self.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point);
+		self.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey;
 
 		self.channel_state = ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32;
 
 		Ok(())
 	}
 
-	fn funding_created_signature<L: Deref>(&mut self, sig: &Signature, logger: &L) -> Result<(Transaction, LocalCommitmentTransaction, Signature), ChannelError> where L::Target: Logger {
+	fn funding_created_signature<L: Deref>(&mut self, sig: &Signature, logger: &L) -> Result<(Txid, CommitmentTransaction, Signature), ChannelError> where L::Target: Logger {
 		let funding_script = self.get_funding_redeemscript();
 
-		let local_keys = self.build_local_transaction_keys(self.cur_local_commitment_transaction_number)?;
-		let local_initial_commitment_tx = self.build_commitment_transaction(self.cur_local_commitment_transaction_number, &local_keys, true, false, self.feerate_per_kw, logger).0;
-		let local_sighash = hash_to_message!(&bip143::SighashComponents::new(&local_initial_commitment_tx).sighash_all(&local_initial_commitment_tx.input[0], &funding_script, self.channel_value_satoshis)[..]);
+		let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?;
+		let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, self.feerate_per_kw, logger).0;
+		{
+			let trusted_tx = initial_commitment_tx.trust();
+			let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
+			let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis);
+			// They sign the holder commitment transaction...
+			log_trace!(logger, "Checking funding_created tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(sig.serialize_compact()[..]), log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&initial_commitment_bitcoin_tx.transaction), log_bytes!(sighash[..]), encode::serialize_hex(&funding_script));
+			secp_check!(self.secp_ctx.verify(&sighash, &sig, self.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned());
+		}
 
-		// They sign the "local" commitment transaction...
-		log_trace!(logger, "Checking funding_created tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(sig.serialize_compact()[..]), log_bytes!(self.their_funding_pubkey().serialize()), encode::serialize_hex(&local_initial_commitment_tx), log_bytes!(local_sighash[..]), encode::serialize_hex(&funding_script));
-		secp_check!(self.secp_ctx.verify(&local_sighash, &sig, self.their_funding_pubkey()), "Invalid funding_created signature from peer");
+		let counterparty_keys = self.build_remote_transaction_keys()?;
+		let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, self.feerate_per_kw, logger).0;
 
-		let localtx = LocalCommitmentTransaction::new_missing_local_sig(local_initial_commitment_tx, sig.clone(), &self.local_keys.pubkeys().funding_pubkey, self.their_funding_pubkey(), local_keys, self.feerate_per_kw, Vec::new());
+		let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
+		let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
+		log_trace!(logger, "Initial counterparty ID {} tx {}", counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-		let remote_keys = self.build_remote_transaction_keys()?;
-		let remote_initial_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw, logger).0;
-		let remote_signature = self.local_keys.sign_remote_commitment(self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
-				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0;
+		let counterparty_signature = self.holder_keys.sign_counterparty_commitment(&counterparty_initial_commitment_tx, &self.secp_ctx)
+				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0;
 
-		// We sign the "remote" commitment transaction, allowing them to broadcast the tx if they wish.
-		Ok((remote_initial_commitment_tx, localtx, remote_signature))
+		// We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
+		Ok((counterparty_initial_bitcoin_tx.txid, initial_commitment_tx, counterparty_signature))
 	}
 
-	fn their_funding_pubkey(&self) -> &PublicKey {
-		&self.their_pubkeys.as_ref().expect("their_funding_pubkey() only allowed after accept_channel").funding_pubkey
+	fn counterparty_funding_pubkey(&self) -> &PublicKey {
+		&self.get_counterparty_pubkeys().funding_pubkey
 	}
 
-	pub fn funding_created<L: Deref>(&mut self, msg: &msgs::FundingCreated, logger: &L) -> Result<(msgs::FundingSigned, ChannelMonitor<ChanSigner>), ChannelError> where L::Target: Logger {
-		if self.channel_outbound {
-			return Err(ChannelError::Close("Received funding_created for an outbound channel?"));
+	pub fn funding_created<L: Deref>(&mut self, msg: &msgs::FundingCreated, logger: &L) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError> where L::Target: Logger {
+		if self.is_outbound() {
+			return Err(ChannelError::Close("Received funding_created for an outbound channel?".to_owned()));
 		}
 		if self.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
 			// BOLT 2 says that if we disconnect before we send funding_signed we SHOULD NOT
 			// remember the channel, so it's safe to just send an error_message here and drop the
 			// channel.
-			return Err(ChannelError::Close("Received funding_created after we got the channel!"));
+			return Err(ChannelError::Close("Received funding_created after we got the channel!".to_owned()));
 		}
 		if self.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-				self.cur_remote_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-				self.cur_local_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+				self.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+				self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
 		}
 
-		let funding_txo = OutPoint{ txid: msg.funding_txid, index: msg.funding_output_index };
-		self.funding_txo = Some(funding_txo.clone());
+		let funding_txo = OutPoint { txid: msg.funding_txid, index: msg.funding_output_index };
+		self.channel_transaction_parameters.funding_outpoint = Some(funding_txo);
+		// This is an externally observable change before we finish all our checks.  In particular
+		// funding_created_signature may fail.
+		self.holder_keys.ready_channel(&self.channel_transaction_parameters);
 
-		let (remote_initial_commitment_tx, local_initial_commitment_tx, our_signature) = match self.funding_created_signature(&msg.signature, logger) {
+		let (counterparty_initial_commitment_txid, initial_commitment_tx, signature) = match self.funding_created_signature(&msg.signature, logger) {
 			Ok(res) => res,
+			Err(ChannelError::Close(e)) => {
+				self.channel_transaction_parameters.funding_outpoint = None;
+				return Err(ChannelError::Close(e));
+			},
 			Err(e) => {
-				self.funding_txo = None;
-				return Err(e);
+				// The only error we know how to handle is ChannelError::Close, so we fall over here
+				// to make sure we don't continue with an inconsistent state.
+				panic!("unexpected error type from funding_created_signature {:?}", e);
 			}
 		};
 
+		let holder_commitment_tx = HolderCommitmentTransaction::new(
+			initial_commitment_tx,
+			msg.signature,
+			Vec::new(),
+			&self.get_holder_pubkeys().funding_pubkey,
+			self.counterparty_funding_pubkey()
+		);
+
 		// Now that we're past error-generating stuff, update our local state:
 
-		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
 		let funding_redeemscript = self.get_funding_redeemscript();
 		let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
-		macro_rules! create_monitor {
-			() => { {
-				let mut channel_monitor = ChannelMonitor::new(self.local_keys.clone(),
-				                                              &self.shutdown_pubkey, self.our_to_self_delay,
-				                                              &self.destination_script, (funding_txo, funding_txo_script.clone()),
-				                                              &their_pubkeys.htlc_basepoint, &their_pubkeys.delayed_payment_basepoint,
-				                                              self.their_to_self_delay, funding_redeemscript.clone(), self.channel_value_satoshis,
-				                                              self.get_commitment_transaction_number_obscure_factor(),
-				                                              local_initial_commitment_tx.clone());
-
-				channel_monitor.provide_latest_remote_commitment_tx_info(&remote_initial_commitment_tx, Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap(), logger);
-				channel_monitor
-			} }
-		}
+		let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+		let mut channel_monitor = ChannelMonitor::new(self.holder_keys.clone(),
+		                                              &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+		                                              &self.destination_script, (funding_txo, funding_txo_script.clone()),
+		                                              &self.channel_transaction_parameters,
+		                                              funding_redeemscript.clone(), self.channel_value_satoshis,
+		                                              obscure_factor,
+		                                              holder_commitment_tx);
 
-		self.channel_monitor = Some(create_monitor!());
-		let channel_monitor = create_monitor!();
+		channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_commitment_txid, Vec::new(), self.cur_counterparty_commitment_transaction_number, self.counterparty_cur_commitment_point.unwrap(), logger);
 
 		self.channel_state = ChannelState::FundingSent as u32;
 		self.channel_id = funding_txo.to_channel_id();
-		self.cur_remote_commitment_transaction_number -= 1;
-		self.cur_local_commitment_transaction_number -= 1;
+		self.cur_counterparty_commitment_transaction_number -= 1;
+		self.cur_holder_commitment_transaction_number -= 1;
 
 		Ok((msgs::FundingSigned {
 			channel_id: self.channel_id,
-			signature: our_signature
+			signature
 		}, channel_monitor))
 	}
 
 	/// Handles a funding_signed message from the remote end.
 	/// If this call is successful, broadcast the funding transaction (and not before!)
-	pub fn funding_signed<L: Deref>(&mut self, msg: &msgs::FundingSigned, logger: &L) -> Result<ChannelMonitor<ChanSigner>, ChannelError> where L::Target: Logger {
-		if !self.channel_outbound {
-			return Err(ChannelError::Close("Received funding_signed for an inbound channel?"));
+	pub fn funding_signed<L: Deref>(&mut self, msg: &msgs::FundingSigned, logger: &L) -> Result<ChannelMonitor<Signer>, ChannelError> where L::Target: Logger {
+		if !self.is_outbound() {
+			return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
 		}
 		if self.channel_state & !(ChannelState::MonitorUpdateFailed as u32) != ChannelState::FundingCreated as u32 {
-			return Err(ChannelError::Close("Received funding_signed in strange state!"));
+			return Err(ChannelError::Close("Received funding_signed in strange state!".to_owned()));
 		}
 		if self.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-				self.cur_remote_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-				self.cur_local_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+				self.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+				self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
 		}
 
 		let funding_script = self.get_funding_redeemscript();
 
-		let remote_keys = self.build_remote_transaction_keys()?;
-		let remote_initial_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw, logger).0;
-
-		let local_keys = self.build_local_transaction_keys(self.cur_local_commitment_transaction_number)?;
-		let local_initial_commitment_tx = self.build_commitment_transaction(self.cur_local_commitment_transaction_number, &local_keys, true, false, self.feerate_per_kw, logger).0;
-		let local_sighash = hash_to_message!(&bip143::SighashComponents::new(&local_initial_commitment_tx).sighash_all(&local_initial_commitment_tx.input[0], &funding_script, self.channel_value_satoshis)[..]);
+		let counterparty_keys = self.build_remote_transaction_keys()?;
+		let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, self.feerate_per_kw, logger).0;
+		let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
+		let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
 
-		let their_funding_pubkey = &self.their_pubkeys.as_ref().unwrap().funding_pubkey;
+		log_trace!(logger, "Initial counterparty ID {} tx {}", counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-		// They sign the "local" commitment transaction, allowing us to broadcast the tx if we wish.
-		if let Err(_) = self.secp_ctx.verify(&local_sighash, &msg.signature, their_funding_pubkey) {
-			return Err(ChannelError::Close("Invalid funding_signed signature from peer"));
+		let holder_keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?;
+		let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &holder_keys, true, false, self.feerate_per_kw, logger).0;
+		{
+			let trusted_tx = initial_commitment_tx.trust();
+			let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
+			let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis);
+			// They sign our commitment transaction, allowing us to broadcast the tx if we wish.
+			if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
+				return Err(ChannelError::Close("Invalid funding_signed signature from peer".to_owned()));
+			}
 		}
 
-		let their_pubkeys = self.their_pubkeys.as_ref().unwrap();
+		let holder_commitment_tx = HolderCommitmentTransaction::new(
+			initial_commitment_tx,
+			msg.signature,
+			Vec::new(),
+			&self.get_holder_pubkeys().funding_pubkey,
+			self.counterparty_funding_pubkey()
+		);
+
+
 		let funding_redeemscript = self.get_funding_redeemscript();
-		let funding_txo = self.funding_txo.as_ref().unwrap();
+		let funding_txo = self.get_funding_txo().unwrap();
 		let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
-		macro_rules! create_monitor {
-			() => { {
-				let local_commitment_tx = LocalCommitmentTransaction::new_missing_local_sig(local_initial_commitment_tx.clone(), msg.signature.clone(), &self.local_keys.pubkeys().funding_pubkey, their_funding_pubkey, local_keys.clone(), self.feerate_per_kw, Vec::new());
-				let mut channel_monitor = ChannelMonitor::new(self.local_keys.clone(),
-				                                              &self.shutdown_pubkey, self.our_to_self_delay,
-				                                              &self.destination_script, (funding_txo.clone(), funding_txo_script.clone()),
-				                                              &their_pubkeys.htlc_basepoint, &their_pubkeys.delayed_payment_basepoint,
-				                                              self.their_to_self_delay, funding_redeemscript.clone(), self.channel_value_satoshis,
-				                                              self.get_commitment_transaction_number_obscure_factor(),
-				                                              local_commitment_tx);
-
-				channel_monitor.provide_latest_remote_commitment_tx_info(&remote_initial_commitment_tx, Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap(), logger);
-
-				channel_monitor
-			} }
-		}
+		let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+		let mut channel_monitor = ChannelMonitor::new(self.holder_keys.clone(),
+		                                              &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+		                                              &self.destination_script, (funding_txo, funding_txo_script),
+		                                              &self.channel_transaction_parameters,
+		                                              funding_redeemscript.clone(), self.channel_value_satoshis,
+		                                              obscure_factor,
+		                                              holder_commitment_tx);
 
-		self.channel_monitor = Some(create_monitor!());
-		let channel_monitor = create_monitor!();
+		channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_bitcoin_tx.txid, Vec::new(), self.cur_counterparty_commitment_transaction_number, self.counterparty_cur_commitment_point.unwrap(), logger);
 
 		assert_eq!(self.channel_state & (ChannelState::MonitorUpdateFailed as u32), 0); // We have no had any monitor(s) yet to fail update!
 		self.channel_state = ChannelState::FundingSent as u32;
-		self.cur_local_commitment_transaction_number -= 1;
-		self.cur_remote_commitment_transaction_number -= 1;
+		self.cur_holder_commitment_transaction_number -= 1;
+		self.cur_counterparty_commitment_transaction_number -= 1;
 
 		Ok(channel_monitor)
 	}
 
 	pub fn funding_locked(&mut self, msg: &msgs::FundingLocked) -> Result<(), ChannelError> {
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent funding_locked when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent funding_locked when we needed a channel_reestablish".to_owned()));
 		}
 
 		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
@@ -1631,22 +1670,22 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			self.update_time_counter += 1;
 		} else if (self.channel_state & (ChannelState::ChannelFunded as u32) != 0 &&
 				 // Note that funding_signed/funding_created will have decremented both by 1!
-				 self.cur_local_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 &&
-				 self.cur_remote_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1) ||
+				 self.cur_holder_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 &&
+				 self.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1) ||
 				// If we reconnected before sending our funding locked they may still resend theirs:
 				(self.channel_state & (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32) ==
 				                      (ChannelState::FundingSent as u32 | ChannelState::TheirFundingLocked as u32)) {
-			if self.their_cur_commitment_point != Some(msg.next_per_commitment_point) {
-				return Err(ChannelError::Close("Peer sent a reconnect funding_locked with a different point"));
+			if self.counterparty_cur_commitment_point != Some(msg.next_per_commitment_point) {
+				return Err(ChannelError::Close("Peer sent a reconnect funding_locked with a different point".to_owned()));
 			}
 			// They probably disconnected/reconnected and re-sent the funding_locked, which is required
 			return Ok(());
 		} else {
-			return Err(ChannelError::Close("Peer sent a funding_locked at a strange time"));
+			return Err(ChannelError::Close("Peer sent a funding_locked at a strange time".to_owned()));
 		}
 
-		self.their_prev_commitment_point = self.their_cur_commitment_point;
-		self.their_cur_commitment_point = Some(msg.next_per_commitment_point);
+		self.counterparty_prev_commitment_point = self.counterparty_cur_commitment_point;
+		self.counterparty_cur_commitment_point = Some(msg.next_per_commitment_point);
 		Ok(())
 	}
 
@@ -1684,8 +1723,8 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// corner case properly.
 	pub fn get_inbound_outbound_available_balance_msat(&self) -> (u64, u64) {
 		// Note that we have to handle overflow due to the above case.
-		(cmp::min(self.channel_value_satoshis as i64 * 1000 - self.value_to_self_msat as i64 - self.get_inbound_pending_htlc_stats().1 as i64, 0) as u64,
-		cmp::min(self.value_to_self_msat as i64 - self.get_outbound_pending_htlc_stats().1 as i64, 0) as u64)
+		(cmp::max(self.channel_value_satoshis as i64 * 1000 - self.value_to_self_msat as i64 - self.get_inbound_pending_htlc_stats().1 as i64, 0) as u64,
+		cmp::max(self.value_to_self_msat as i64 - self.get_outbound_pending_htlc_stats().1 as i64, 0) as u64)
 	}
 
 	// Get the fee cost of a commitment tx with a given number of HTLC outputs.
@@ -1696,63 +1735,172 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		(COMMITMENT_TX_BASE_WEIGHT + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * self.feerate_per_kw as u64 / 1000 * 1000
 	}
 
-	// Get the commitment tx fee for the local (i.e our) next commitment transaction
-	// based on the number of pending HTLCs that are on track to be in our next
-	// commitment tx. `addl_htcs` is an optional parameter allowing the caller
-	// to add a number of additional HTLCs to the calculation. Note that dust
-	// HTLCs are excluded.
-	fn next_local_commit_tx_fee_msat(&self, addl_htlcs: usize) -> u64 {
-		assert!(self.channel_outbound);
+	// Get the commitment tx fee for the local's (i.e. our) next commitment transaction based on the
+	// number of pending HTLCs that are on track to be in our next commitment tx, plus an additional
+	// HTLC if `fee_spike_buffer_htlc` is Some, plus a new HTLC given by `new_htlc_amount`. Dust HTLCs
+	// are excluded.
+	fn next_local_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
+		assert!(self.is_outbound());
+
+		let real_dust_limit_success_sat = (self.feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+		let real_dust_limit_timeout_sat = (self.feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+
+		let mut addl_htlcs = 0;
+		if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
+		match htlc.origin {
+			HTLCInitiator::LocalOffered => {
+				if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
+					addl_htlcs += 1;
+				}
+			},
+			HTLCInitiator::RemoteOffered => {
+				if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
+					addl_htlcs += 1;
+				}
+			}
+		}
+
+		let mut included_htlcs = 0;
+		for ref htlc in self.pending_inbound_htlcs.iter() {
+			if htlc.amount_msat / 1000 < real_dust_limit_success_sat {
+				continue
+			}
+			// We include LocalRemoved HTLCs here because we may still need to broadcast a commitment
+			// transaction including this HTLC if it times out before they RAA.
+			included_htlcs += 1;
+		}
 
-		let mut their_acked_htlcs = self.pending_inbound_htlcs.len();
 		for ref htlc in self.pending_outbound_htlcs.iter() {
-			if htlc.amount_msat / 1000 <= self.our_dust_limit_satoshis {
+			if htlc.amount_msat / 1000 < real_dust_limit_timeout_sat {
 				continue
 			}
 			match htlc.state {
-				OutboundHTLCState::Committed => their_acked_htlcs += 1,
-				OutboundHTLCState::RemoteRemoved {..} => their_acked_htlcs += 1,
-				OutboundHTLCState::LocalAnnounced {..} => their_acked_htlcs += 1,
+				OutboundHTLCState::LocalAnnounced {..} => included_htlcs += 1,
+				OutboundHTLCState::Committed => included_htlcs += 1,
+				OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
+				// We don't include AwaitingRemoteRevokeToRemove HTLCs because our next commitment
+				// transaction won't be generated until they send us their next RAA, which will mean
+				// dropping any HTLCs in this state.
 				_ => {},
 			}
 		}
 
 		for htlc in self.holding_cell_htlc_updates.iter() {
 			match htlc {
-				&HTLCUpdateAwaitingACK::AddHTLC { .. } => their_acked_htlcs += 1,
-				_ => {},
+				&HTLCUpdateAwaitingACK::AddHTLC { amount_msat, .. } => {
+					if amount_msat / 1000 < real_dust_limit_timeout_sat {
+						continue
+					}
+					included_htlcs += 1
+				},
+				_ => {}, // Don't include claims/fails that are awaiting ack, because once we get the
+				         // ack we're guaranteed to never include them in commitment txs anymore.
 			}
 		}
 
-		self.commit_tx_fee_msat(their_acked_htlcs + addl_htlcs)
+		let num_htlcs = included_htlcs + addl_htlcs;
+		let res = self.commit_tx_fee_msat(num_htlcs);
+		#[cfg(any(test, feature = "fuzztarget"))]
+		{
+			let mut fee = res;
+			if fee_spike_buffer_htlc.is_some() {
+				fee = self.commit_tx_fee_msat(num_htlcs - 1);
+			}
+			let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len()
+				+ self.holding_cell_htlc_updates.len();
+			let commitment_tx_info = CommitmentTxInfoCached {
+				fee,
+				total_pending_htlcs,
+				next_holder_htlc_id: match htlc.origin {
+					HTLCInitiator::LocalOffered => self.next_holder_htlc_id + 1,
+					HTLCInitiator::RemoteOffered => self.next_holder_htlc_id,
+				},
+				next_counterparty_htlc_id: match htlc.origin {
+					HTLCInitiator::LocalOffered => self.next_counterparty_htlc_id,
+					HTLCInitiator::RemoteOffered => self.next_counterparty_htlc_id + 1,
+				},
+				feerate: self.feerate_per_kw,
+			};
+			*self.next_local_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
+		}
+		res
 	}
 
-	// Get the commitment tx fee for the remote's next commitment transaction
-	// based on the number of pending HTLCs that are on track to be in their
-	// next commitment tx. `addl_htcs` is an optional parameter allowing the caller
-	// to add a number of additional HTLCs to the calculation. Note that dust HTLCs
-	// are excluded.
-	fn next_remote_commit_tx_fee_msat(&self, addl_htlcs: usize) -> u64 {
-		assert!(!self.channel_outbound);
+	// Get the commitment tx fee for the remote's next commitment transaction based on the number of
+	// pending HTLCs that are on track to be in their next commitment tx, plus an additional HTLC if
+	// `fee_spike_buffer_htlc` is Some, plus a new HTLC given by `new_htlc_amount`. Dust HTLCs are
+	// excluded.
+	fn next_remote_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
+		assert!(!self.is_outbound());
+
+		let real_dust_limit_success_sat = (self.feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+		let real_dust_limit_timeout_sat = (self.feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+
+		let mut addl_htlcs = 0;
+		if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
+		match htlc.origin {
+			HTLCInitiator::LocalOffered => {
+				if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
+					addl_htlcs += 1;
+				}
+			},
+			HTLCInitiator::RemoteOffered => {
+				if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
+					addl_htlcs += 1;
+				}
+			}
+		}
+
+		// When calculating the set of HTLCs which will be included in their next commitment_signed, all
+		// non-dust inbound HTLCs are included (as all states imply it will be included) and only
+		// committed outbound HTLCs, see below.
+		let mut included_htlcs = 0;
+		for ref htlc in self.pending_inbound_htlcs.iter() {
+			if htlc.amount_msat / 1000 <= real_dust_limit_timeout_sat {
+				continue
+			}
+			included_htlcs += 1;
+		}
 
-		// When calculating the set of HTLCs which will be included in their next
-		// commitment_signed, all inbound HTLCs are included (as all states imply it will be
-		// included) and only committed outbound HTLCs, see below.
-		let mut their_acked_htlcs = self.pending_inbound_htlcs.len();
 		for ref htlc in self.pending_outbound_htlcs.iter() {
-			if htlc.amount_msat / 1000 <= self.their_dust_limit_satoshis {
+			if htlc.amount_msat / 1000 <= real_dust_limit_success_sat {
 				continue
 			}
-			// We only include outbound HTLCs if it will not be included in their next
-			// commitment_signed, i.e. if they've responded to us with an RAA after announcement.
+			// We only include outbound HTLCs if it will not be included in their next commitment_signed,
+			// i.e. if they've responded to us with an RAA after announcement.
 			match htlc.state {
-				OutboundHTLCState::Committed => their_acked_htlcs += 1,
-				OutboundHTLCState::RemoteRemoved {..} => their_acked_htlcs += 1,
+				OutboundHTLCState::Committed => included_htlcs += 1,
+				OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
+				OutboundHTLCState::LocalAnnounced { .. } => included_htlcs += 1,
 				_ => {},
 			}
 		}
 
-		self.commit_tx_fee_msat(their_acked_htlcs + addl_htlcs)
+		let num_htlcs = included_htlcs + addl_htlcs;
+		let res = self.commit_tx_fee_msat(num_htlcs);
+		#[cfg(any(test, feature = "fuzztarget"))]
+		{
+			let mut fee = res;
+			if fee_spike_buffer_htlc.is_some() {
+				fee = self.commit_tx_fee_msat(num_htlcs - 1);
+			}
+			let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len();
+			let commitment_tx_info = CommitmentTxInfoCached {
+				fee,
+				total_pending_htlcs,
+				next_holder_htlc_id: match htlc.origin {
+					HTLCInitiator::LocalOffered => self.next_holder_htlc_id + 1,
+					HTLCInitiator::RemoteOffered => self.next_holder_htlc_id,
+				},
+				next_counterparty_htlc_id: match htlc.origin {
+					HTLCInitiator::LocalOffered => self.next_counterparty_htlc_id,
+					HTLCInitiator::RemoteOffered => self.next_counterparty_htlc_id + 1,
+				},
+				feerate: self.feerate_per_kw,
+			};
+			*self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
+		}
+		res
 	}
 
 	pub fn update_add_htlc<F, L: Deref>(&mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus, create_pending_htlc_status: F, logger: &L) -> Result<(), ChannelError>
@@ -1765,30 +1913,30 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// If the remote has sent a shutdown prior to adding this HTLC, then they are in violation of the spec.
 		let remote_sent_shutdown = (self.channel_state & (ChannelState::ChannelFunded as u32 | ChannelState::RemoteShutdownSent as u32)) != (ChannelState::ChannelFunded as u32);
 		if remote_sent_shutdown {
-			return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state"));
+			return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent update_add_htlc when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent update_add_htlc when we needed a channel_reestablish".to_owned()));
 		}
 		if msg.amount_msat > self.channel_value_satoshis * 1000 {
-			return Err(ChannelError::Close("Remote side tried to send more than the total value of the channel"));
+			return Err(ChannelError::Close("Remote side tried to send more than the total value of the channel".to_owned()));
 		}
 		if msg.amount_msat == 0 {
-			return Err(ChannelError::Close("Remote side tried to send a 0-msat HTLC"));
+			return Err(ChannelError::Close("Remote side tried to send a 0-msat HTLC".to_owned()));
 		}
-		if msg.amount_msat < self.our_htlc_minimum_msat {
-			return Err(ChannelError::Close("Remote side tried to send less than our minimum HTLC value"));
+		if msg.amount_msat < self.holder_htlc_minimum_msat {
+			return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.holder_htlc_minimum_msat, msg.amount_msat)));
 		}
 
 		let (inbound_htlc_count, htlc_inbound_value_msat) = self.get_inbound_pending_htlc_stats();
 		if inbound_htlc_count + 1 > OUR_MAX_HTLCS as u32 {
-			return Err(ChannelError::Close("Remote tried to push more than our max accepted HTLCs"));
+			return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", OUR_MAX_HTLCS)));
 		}
-		// Check our_max_htlc_value_in_flight_msat
-		if htlc_inbound_value_msat + msg.amount_msat > Channel::<ChanSigner>::get_our_max_htlc_value_in_flight_msat(self.channel_value_satoshis) {
-			return Err(ChannelError::Close("Remote HTLC add would put them over our max HTLC value"));
+		let holder_max_htlc_value_in_flight_msat = Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis);
+		if htlc_inbound_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
+			return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", holder_max_htlc_value_in_flight_msat)));
 		}
-		// Check remote_channel_reserve_satoshis (we're getting paid, so they have to at least meet
+		// Check holder_selected_channel_reserve_satoshis (we're getting paid, so they have to at least meet
 		// the reserve_satoshis we told them to always have as direct payment so that they lose
 		// something if we punish them for broadcasting an old state).
 		// Note that we don't really care about having a small/no to_remote output in our local
@@ -1814,34 +1962,36 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		let pending_remote_value_msat =
 			self.channel_value_satoshis * 1000 - pending_value_to_self_msat;
 		if pending_remote_value_msat < msg.amount_msat {
-			return Err(ChannelError::Close("Remote HTLC add would overdraw remaining funds"));
+			return Err(ChannelError::Close("Remote HTLC add would overdraw remaining funds".to_owned()));
 		}
 
 		// Check that the remote can afford to pay for this HTLC on-chain at the current
 		// feerate_per_kw, while maintaining their channel reserve (as required by the spec).
-		let remote_commit_tx_fee_msat = if self.channel_outbound { 0 } else {
-			// +1 for this HTLC.
-			self.next_remote_commit_tx_fee_msat(1)
+		let remote_commit_tx_fee_msat = if self.is_outbound() { 0 } else {
+			let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
+			self.next_remote_commit_tx_fee_msat(htlc_candidate, None) // Don't include the extra fee spike buffer HTLC in calculations
 		};
 		if pending_remote_value_msat - msg.amount_msat < remote_commit_tx_fee_msat {
-			return Err(ChannelError::Close("Remote HTLC add would not leave enough to pay for fees"));
+			return Err(ChannelError::Close("Remote HTLC add would not leave enough to pay for fees".to_owned()));
 		};
 
 		let chan_reserve_msat =
-			Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis) * 1000;
+			Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) * 1000;
 		if pending_remote_value_msat - msg.amount_msat - remote_commit_tx_fee_msat < chan_reserve_msat {
-			return Err(ChannelError::Close("Remote HTLC add would put them under remote reserve value"));
-		}
-
-		if !self.channel_outbound {
-			// `+1` for this HTLC, `2 *` and `+1` fee spike buffer we keep for the remote. This deviates from the
-			// spec because in the spec, the fee spike buffer requirement doesn't exist on the receiver's side,
-			// only on the sender's.
-			// Note that when we eventually remove support for fee updates and switch to anchor output fees,
-			// we will drop the `2 *`, since we no longer be as sensitive to fee spikes. But, keep the extra +1
-			// as we should still be able to afford adding this HTLC plus one more future HTLC, regardless of
-			// being sensitive to fee spikes.
-			let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.next_remote_commit_tx_fee_msat(1 + 1);
+			return Err(ChannelError::Close("Remote HTLC add would put them under remote reserve value".to_owned()));
+		}
+
+		if !self.is_outbound() {
+			// `2 *` and `Some(())` is for the fee spike buffer we keep for the remote. This deviates from
+			// the spec because in the spec, the fee spike buffer requirement doesn't exist on the
+			// receiver's side, only on the sender's.
+			// Note that when we eventually remove support for fee updates and switch to anchor output
+			// fees, we will drop the `2 *`, since we no longer be as sensitive to fee spikes. But, keep
+			// the extra htlc when calculating the next remote commitment transaction fee as we should
+			// still be able to afford adding this HTLC plus one more future HTLC, regardless of being
+			// sensitive to fee spikes.
+			let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
+			let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
 			if pending_remote_value_msat - msg.amount_msat - chan_reserve_msat < remote_fee_cost_incl_stuck_buffer_msat {
 				// Note that if the pending_forward_status is not updated here, then it's because we're already failing
 				// the HTLC, i.e. its status is already set to failing.
@@ -1850,19 +2000,17 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 		} else {
 			// Check that they won't violate our local required channel reserve by adding this HTLC.
-
-			// +1 for this HTLC.
-			let local_commit_tx_fee_msat = self.next_local_commit_tx_fee_msat(1);
-			if self.value_to_self_msat < self.local_channel_reserve_satoshis * 1000 + local_commit_tx_fee_msat {
-				return Err(ChannelError::Close("Cannot receive value that would put us under local channel reserve value"));
+			let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
+			let local_commit_tx_fee_msat = self.next_local_commit_tx_fee_msat(htlc_candidate, None);
+			if self.value_to_self_msat < self.counterparty_selected_channel_reserve_satoshis * 1000 + local_commit_tx_fee_msat {
+				return Err(ChannelError::Close("Cannot accept HTLC that would put our balance under counterparty-announced channel reserve value".to_owned()));
 			}
 		}
-
-		if self.next_remote_htlc_id != msg.htlc_id {
-			return Err(ChannelError::Close("Remote skipped HTLC ID"));
+		if self.next_counterparty_htlc_id != msg.htlc_id {
+			return Err(ChannelError::Close(format!("Remote skipped HTLC ID (skipped ID: {})", self.next_counterparty_htlc_id)));
 		}
 		if msg.cltv_expiry >= 500000000 {
-			return Err(ChannelError::Close("Remote provided CLTV expiry in seconds instead of block height"));
+			return Err(ChannelError::Close("Remote provided CLTV expiry in seconds instead of block height".to_owned()));
 		}
 
 		if self.channel_state & ChannelState::LocalShutdownSent as u32 != 0 {
@@ -1872,7 +2020,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 
 		// Now update local state:
-		self.next_remote_htlc_id += 1;
+		self.next_counterparty_htlc_id += 1;
 		self.pending_inbound_htlcs.push(InboundHTLCOutput {
 			htlc_id: msg.htlc_id,
 			amount_msat: msg.amount_msat,
@@ -1892,30 +2040,30 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 					None => {},
 					Some(payment_hash) =>
 						if payment_hash != htlc.payment_hash {
-							return Err(ChannelError::Close("Remote tried to fulfill HTLC with an incorrect preimage"));
+							return Err(ChannelError::Close(format!("Remote tried to fulfill HTLC ({}) with an incorrect preimage", htlc_id)));
 						}
 				};
 				match htlc.state {
 					OutboundHTLCState::LocalAnnounced(_) =>
-						return Err(ChannelError::Close("Remote tried to fulfill/fail HTLC before it had been committed")),
+						return Err(ChannelError::Close(format!("Remote tried to fulfill/fail HTLC ({}) before it had been committed", htlc_id))),
 					OutboundHTLCState::Committed => {
 						htlc.state = OutboundHTLCState::RemoteRemoved(fail_reason);
 					},
 					OutboundHTLCState::AwaitingRemoteRevokeToRemove(_) | OutboundHTLCState::AwaitingRemovedRemoteRevoke(_) | OutboundHTLCState::RemoteRemoved(_) =>
-						return Err(ChannelError::Close("Remote tried to fulfill/fail HTLC that they'd already fulfilled/failed")),
+						return Err(ChannelError::Close(format!("Remote tried to fulfill/fail HTLC ({}) that they'd already fulfilled/failed", htlc_id))),
 				}
 				return Ok(&htlc.source);
 			}
 		}
-		Err(ChannelError::Close("Remote tried to fulfill/fail an HTLC we couldn't find"))
+		Err(ChannelError::Close("Remote tried to fulfill/fail an HTLC we couldn't find".to_owned()))
 	}
 
 	pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<HTLCSource, ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state"));
+			return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent update_fulfill_htlc when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent update_fulfill_htlc when we needed a channel_reestablish".to_owned()));
 		}
 
 		let payment_hash = PaymentHash(Sha256::hash(&msg.payment_preimage.0[..]).into_inner());
@@ -1924,10 +2072,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 	pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err(ChannelError::Close("Got fail HTLC message when channel was not in an operational state"));
+			return Err(ChannelError::Close("Got fail HTLC message when channel was not in an operational state".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent update_fail_htlc when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent update_fail_htlc when we needed a channel_reestablish".to_owned()));
 		}
 
 		self.mark_outbound_htlc_removed(msg.htlc_id, None, Some(fail_reason))?;
@@ -1936,10 +2084,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 	pub fn update_fail_malformed_htlc(&mut self, msg: &msgs::UpdateFailMalformedHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err(ChannelError::Close("Got fail malformed HTLC message when channel was not in an operational state"));
+			return Err(ChannelError::Close("Got fail malformed HTLC message when channel was not in an operational state".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent update_fail_malformed_htlc when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent update_fail_malformed_htlc when we needed a channel_reestablish".to_owned()));
 		}
 
 		self.mark_outbound_htlc_removed(msg.htlc_id, None, Some(fail_reason))?;
@@ -1951,104 +2099,125 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				L::Target: Logger
 	{
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err((None, ChannelError::Close("Got commitment signed message when channel was not in an operational state")));
+			return Err((None, ChannelError::Close("Got commitment signed message when channel was not in an operational state".to_owned())));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err((None, ChannelError::Close("Peer sent commitment_signed when we needed a channel_reestablish")));
+			return Err((None, ChannelError::Close("Peer sent commitment_signed when we needed a channel_reestablish".to_owned())));
 		}
 		if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK == BOTH_SIDES_SHUTDOWN_MASK && self.last_sent_closing_fee.is_some() {
-			return Err((None, ChannelError::Close("Peer sent commitment_signed after we'd started exchanging closing_signeds")));
+			return Err((None, ChannelError::Close("Peer sent commitment_signed after we'd started exchanging closing_signeds".to_owned())));
 		}
 
 		let funding_script = self.get_funding_redeemscript();
 
-		let local_keys = self.build_local_transaction_keys(self.cur_local_commitment_transaction_number).map_err(|e| (None, e))?;
+		let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number).map_err(|e| (None, e))?;
 
 		let mut update_fee = false;
-		let feerate_per_kw = if !self.channel_outbound && self.pending_update_fee.is_some() {
+		let feerate_per_kw = if !self.is_outbound() && self.pending_update_fee.is_some() {
 			update_fee = true;
 			self.pending_update_fee.unwrap()
 		} else {
 			self.feerate_per_kw
 		};
 
-		let mut local_commitment_tx = {
-			let mut commitment_tx = self.build_commitment_transaction(self.cur_local_commitment_transaction_number, &local_keys, true, false, feerate_per_kw, logger);
-			let htlcs_cloned: Vec<_> = commitment_tx.2.drain(..).map(|htlc| (htlc.0, htlc.1.map(|h| h.clone()))).collect();
-			(commitment_tx.0, commitment_tx.1, htlcs_cloned)
+		let (num_htlcs, mut htlcs_cloned, commitment_tx, commitment_txid) = {
+			let commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, feerate_per_kw, logger);
+			let commitment_txid = {
+				let trusted_tx = commitment_tx.0.trust();
+				let bitcoin_tx = trusted_tx.built_transaction();
+				let sighash = bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis);
+
+				log_trace!(logger, "Checking commitment tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(msg.signature.serialize_compact()[..]), log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction), log_bytes!(sighash[..]), encode::serialize_hex(&funding_script));
+				if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) {
+					return Err((None, ChannelError::Close("Invalid commitment tx signature from peer".to_owned())));
+				}
+				bitcoin_tx.txid
+			};
+			let htlcs_cloned: Vec<_> = commitment_tx.2.iter().map(|htlc| (htlc.0.clone(), htlc.1.map(|h| h.clone()))).collect();
+			(commitment_tx.1, htlcs_cloned, commitment_tx.0, commitment_txid)
 		};
-		let local_commitment_txid = local_commitment_tx.0.txid();
-		let local_sighash = hash_to_message!(&bip143::SighashComponents::new(&local_commitment_tx.0).sighash_all(&local_commitment_tx.0.input[0], &funding_script, self.channel_value_satoshis)[..]);
-		log_trace!(logger, "Checking commitment tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(msg.signature.serialize_compact()[..]), log_bytes!(self.their_funding_pubkey().serialize()), encode::serialize_hex(&local_commitment_tx.0), log_bytes!(local_sighash[..]), encode::serialize_hex(&funding_script));
-		if let Err(_) = self.secp_ctx.verify(&local_sighash, &msg.signature, &self.their_funding_pubkey()) {
-			return Err((None, ChannelError::Close("Invalid commitment tx signature from peer")));
-		}
 
+		let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
 		//If channel fee was updated by funder confirm funder can afford the new fee rate when applied to the current local commitment transaction
 		if update_fee {
-			let num_htlcs = local_commitment_tx.1;
-			let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
-
-			let remote_reserve_we_require = Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis);
-			if self.channel_value_satoshis - self.value_to_self_msat / 1000 < total_fee + remote_reserve_we_require {
-				return Err((None, ChannelError::Close("Funding remote cannot afford proposed new fee")));
+			let counterparty_reserve_we_require = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis);
+			if self.channel_value_satoshis - self.value_to_self_msat / 1000 < total_fee + counterparty_reserve_we_require {
+				return Err((None, ChannelError::Close("Funding remote cannot afford proposed new fee".to_owned())));
+			}
+		}
+		#[cfg(any(test, feature = "fuzztarget"))]
+		{
+			if self.is_outbound() {
+				let projected_commit_tx_info = self.next_local_commitment_tx_fee_info_cached.lock().unwrap().take();
+				*self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = None;
+				if let Some(info) = projected_commit_tx_info {
+					let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len()
+						+ self.holding_cell_htlc_updates.len();
+					if info.total_pending_htlcs == total_pending_htlcs
+						&& info.next_holder_htlc_id == self.next_holder_htlc_id
+						&& info.next_counterparty_htlc_id == self.next_counterparty_htlc_id
+						&& info.feerate == self.feerate_per_kw {
+							assert_eq!(total_fee, info.fee / 1000);
+						}
+				}
 			}
 		}
 
-		if msg.htlc_signatures.len() != local_commitment_tx.1 {
-			return Err((None, ChannelError::Close("Got wrong number of HTLC signatures from remote")));
+		if msg.htlc_signatures.len() != num_htlcs {
+			return Err((None, ChannelError::Close(format!("Got wrong number of HTLC signatures ({}) from remote. It must be {}", msg.htlc_signatures.len(), num_htlcs))));
 		}
 
-		// TODO: Merge these two, sadly they are currently both required to be passed separately to
-		// ChannelMonitor:
-		let mut htlcs_without_source = Vec::with_capacity(local_commitment_tx.2.len());
-		let mut htlcs_and_sigs = Vec::with_capacity(local_commitment_tx.2.len());
-		for (idx, (htlc, source)) in local_commitment_tx.2.drain(..).enumerate() {
+		// TODO: Sadly, we pass HTLCs twice to ChannelMonitor: once via the HolderCommitmentTransaction and once via the update
+		let mut htlcs_and_sigs = Vec::with_capacity(htlcs_cloned.len());
+		for (idx, (htlc, source)) in htlcs_cloned.drain(..).enumerate() {
 			if let Some(_) = htlc.transaction_output_index {
-				let htlc_tx = self.build_htlc_transaction(&local_commitment_txid, &htlc, true, &local_keys, feerate_per_kw);
-				let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &local_keys);
-				let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
-				log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(local_keys.b_htlc_key.serialize()), encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript));
-				if let Err(_) = self.secp_ctx.verify(&htlc_sighash, &msg.htlc_signatures[idx], &local_keys.b_htlc_key) {
-					return Err((None, ChannelError::Close("Invalid HTLC tx signature from peer")));
+				let htlc_tx = self.build_htlc_transaction(&commitment_txid, &htlc, true, &keys, feerate_per_kw);
+				let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
+				let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]);
+				log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {}", log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(keys.countersignatory_htlc_key.serialize()), encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript));
+				if let Err(_) = self.secp_ctx.verify(&htlc_sighash, &msg.htlc_signatures[idx], &keys.countersignatory_htlc_key) {
+					return Err((None, ChannelError::Close("Invalid HTLC tx signature from peer".to_owned())));
 				}
-				htlcs_without_source.push((htlc.clone(), Some(msg.htlc_signatures[idx])));
 				htlcs_and_sigs.push((htlc, Some(msg.htlc_signatures[idx]), source));
 			} else {
-				htlcs_without_source.push((htlc.clone(), None));
 				htlcs_and_sigs.push((htlc, None, source));
 			}
 		}
 
-		let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(self.cur_local_commitment_transaction_number - 1));
-		let per_commitment_secret = chan_utils::build_commitment_secret(self.local_keys.commitment_seed(), self.cur_local_commitment_transaction_number + 1);
+		let holder_commitment_tx = HolderCommitmentTransaction::new(
+			commitment_tx,
+			msg.signature,
+			msg.htlc_signatures.clone(),
+			&self.get_holder_pubkeys().funding_pubkey,
+			self.counterparty_funding_pubkey()
+		);
+
+		let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number - 1, &self.secp_ctx);
+		let per_commitment_secret = self.holder_keys.release_commitment_secret(self.cur_holder_commitment_transaction_number + 1);
 
 		// Update state now that we've passed all the can-fail calls...
-		let mut need_our_commitment = false;
-		if !self.channel_outbound {
+		let mut need_commitment = false;
+		if !self.is_outbound() {
 			if let Some(fee_update) = self.pending_update_fee {
 				self.feerate_per_kw = fee_update;
 				// We later use the presence of pending_update_fee to indicate we should generate a
 				// commitment_signed upon receipt of revoke_and_ack, so we can only set it to None
 				// if we're not awaiting a revoke (ie will send a commitment_signed now).
 				if (self.channel_state & ChannelState::AwaitingRemoteRevoke as u32) == 0 {
-					need_our_commitment = true;
+					need_commitment = true;
 					self.pending_update_fee = None;
 				}
 			}
 		}
 
-		let their_funding_pubkey = self.their_pubkeys.as_ref().unwrap().funding_pubkey;
-
 		self.latest_monitor_update_id += 1;
 		let mut monitor_update = ChannelMonitorUpdate {
 			update_id: self.latest_monitor_update_id,
-			updates: vec![ChannelMonitorUpdateStep::LatestLocalCommitmentTXInfo {
-				commitment_tx: LocalCommitmentTransaction::new_missing_local_sig(local_commitment_tx.0, msg.signature.clone(), &self.local_keys.pubkeys().funding_pubkey, &their_funding_pubkey, local_keys, self.feerate_per_kw, htlcs_without_source),
+			updates: vec![ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo {
+				commitment_tx: holder_commitment_tx,
 				htlc_outputs: htlcs_and_sigs
 			}]
 		};
-		self.channel_monitor.as_mut().unwrap().update_monitor_ooo(monitor_update.clone(), logger).unwrap();
 
 		for htlc in self.pending_inbound_htlcs.iter_mut() {
 			let new_forward = if let &InboundHTLCState::RemoteAnnounced(ref forward_info) = &htlc.state {
@@ -2056,7 +2225,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			} else { None };
 			if let Some(forward_info) = new_forward {
 				htlc.state = InboundHTLCState::AwaitingRemoteRevokeToAnnounce(forward_info);
-				need_our_commitment = true;
+				need_commitment = true;
 			}
 		}
 		for htlc in self.pending_outbound_htlcs.iter_mut() {
@@ -2064,12 +2233,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				Some(fail_reason.take())
 			} else { None } {
 				htlc.state = OutboundHTLCState::AwaitingRemoteRevokeToRemove(fail_reason);
-				need_our_commitment = true;
+				need_commitment = true;
 			}
 		}
 
-		self.cur_local_commitment_transaction_number -= 1;
-		// Note that if we need_our_commitment & !AwaitingRemoteRevoke we'll call
+		self.cur_holder_commitment_transaction_number -= 1;
+		// Note that if we need_commitment & !AwaitingRemoteRevoke we'll call
 		// send_commitment_no_status_check() next which will reset this to RAAFirst.
 		self.resend_order = RAACommitmentOrder::CommitmentFirst;
 
@@ -2077,7 +2246,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			// In case we initially failed monitor updating without requiring a response, we need
 			// to make sure the RAA gets sent first.
 			self.monitor_pending_revoke_and_ack = true;
-			if need_our_commitment && (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
+			if need_commitment && (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
 				// If we were going to send a commitment_signed after the RAA, go ahead and do all
 				// the corresponding HTLC status updates so that get_last_commitment_update
 				// includes the right HTLCs.
@@ -2090,10 +2259,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 			// TODO: Call maybe_propose_first_closing_signed on restoration (or call it here and
 			// re-send the message on restoration)
-			return Err((Some(monitor_update), ChannelError::Ignore("Previous monitor update failure prevented generation of RAA")));
+			return Err((Some(monitor_update), ChannelError::Ignore("Previous monitor update failure prevented generation of RAA".to_owned())));
 		}
 
-		let (our_commitment_signed, closing_signed) = if need_our_commitment && (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
+		let (commitment_signed, closing_signed) = if need_commitment && (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
 			// If we're AwaitingRemoteRevoke we can't send a new commitment here, but that's ok -
 			// we'll send one right away when we get the revoke_and_ack when we
 			// free_holding_cell_htlcs().
@@ -2103,20 +2272,20 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			self.latest_monitor_update_id = monitor_update.update_id;
 			monitor_update.updates.append(&mut additional_update.updates);
 			(Some(msg), None)
-		} else if !need_our_commitment {
+		} else if !need_commitment {
 			(None, self.maybe_propose_first_closing_signed(fee_estimator))
 		} else { (None, None) };
 
 		Ok((msgs::RevokeAndACK {
 			channel_id: self.channel_id,
-			per_commitment_secret: per_commitment_secret,
-			next_per_commitment_point: next_per_commitment_point,
-		}, our_commitment_signed, closing_signed, monitor_update))
+			per_commitment_secret,
+			next_per_commitment_point,
+		}, commitment_signed, closing_signed, monitor_update))
 	}
 
 	/// Used to fulfill holding_cell_htlcs when we get a remote ack (or implicitly get it by them
 	/// fulfilling or failing the last pending HTLC)
-	fn free_holding_cell_htlcs<L: Deref>(&mut self, logger: &L) -> Result<Option<(msgs::CommitmentUpdate, ChannelMonitorUpdate)>, ChannelError> where L::Target: Logger {
+	fn free_holding_cell_htlcs<L: Deref>(&mut self, logger: &L) -> Result<(Option<(msgs::CommitmentUpdate, ChannelMonitorUpdate)>, Vec<(HTLCSource, PaymentHash)>), ChannelError> where L::Target: Logger {
 		assert_eq!(self.channel_state & ChannelState::MonitorUpdateFailed as u32, 0);
 		if self.holding_cell_htlc_updates.len() != 0 || self.holding_cell_update_fee.is_some() {
 			log_trace!(logger, "Freeing holding cell with {} HTLC updates{}", self.holding_cell_htlc_updates.len(), if self.holding_cell_update_fee.is_some() { " and a fee update" } else { "" });
@@ -2131,110 +2300,94 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			let mut update_add_htlcs = Vec::with_capacity(htlc_updates.len());
 			let mut update_fulfill_htlcs = Vec::with_capacity(htlc_updates.len());
 			let mut update_fail_htlcs = Vec::with_capacity(htlc_updates.len());
-			let mut err = None;
+			let mut htlcs_to_fail = Vec::new();
 			for htlc_update in htlc_updates.drain(..) {
 				// Note that this *can* fail, though it should be due to rather-rare conditions on
 				// fee races with adding too many outputs which push our total payments just over
 				// the limit. In case it's less rare than I anticipate, we may want to revisit
 				// handling this case better and maybe fulfilling some of the HTLCs while attempting
 				// to rebalance channels.
-				if err.is_some() { // We're back to AwaitingRemoteRevoke (or are about to fail the channel)
-					self.holding_cell_htlc_updates.push(htlc_update);
-				} else {
-					match &htlc_update {
-						&HTLCUpdateAwaitingACK::AddHTLC {amount_msat, cltv_expiry, ref payment_hash, ref source, ref onion_routing_packet, ..} => {
-							match self.send_htlc(amount_msat, *payment_hash, cltv_expiry, source.clone(), onion_routing_packet.clone()) {
-								Ok(update_add_msg_option) => update_add_htlcs.push(update_add_msg_option.unwrap()),
-								Err(e) => {
-									match e {
-										ChannelError::Ignore(ref msg) => {
-											log_info!(logger, "Failed to send HTLC with payment_hash {} due to {}", log_bytes!(payment_hash.0), msg);
-										},
-										_ => {
-											log_info!(logger, "Failed to send HTLC with payment_hash {} resulting in a channel closure during holding_cell freeing", log_bytes!(payment_hash.0));
-										},
-									}
-									err = Some(e);
+				match &htlc_update {
+					&HTLCUpdateAwaitingACK::AddHTLC {amount_msat, cltv_expiry, ref payment_hash, ref source, ref onion_routing_packet, ..} => {
+						match self.send_htlc(amount_msat, *payment_hash, cltv_expiry, source.clone(), onion_routing_packet.clone()) {
+							Ok(update_add_msg_option) => update_add_htlcs.push(update_add_msg_option.unwrap()),
+							Err(e) => {
+								match e {
+									ChannelError::Ignore(ref msg) => {
+										log_info!(logger, "Failed to send HTLC with payment_hash {} due to {}", log_bytes!(payment_hash.0), msg);
+										// If we fail to send here, then this HTLC should
+										// be failed backwards. Failing to send here
+										// indicates that this HTLC may keep being put back
+										// into the holding cell without ever being
+										// successfully forwarded/failed/fulfilled, causing
+										// our counterparty to eventually close on us.
+										htlcs_to_fail.push((source.clone(), *payment_hash));
+									},
+									_ => {
+										panic!("Got a non-IgnoreError action trying to send holding cell HTLC");
+									},
 								}
 							}
-						},
-						&HTLCUpdateAwaitingACK::ClaimHTLC { ref payment_preimage, htlc_id, .. } => {
-							match self.get_update_fulfill_htlc(htlc_id, *payment_preimage, logger) {
-								Ok((update_fulfill_msg_option, additional_monitor_update_opt)) => {
-									update_fulfill_htlcs.push(update_fulfill_msg_option.unwrap());
-									if let Some(mut additional_monitor_update) = additional_monitor_update_opt {
-										monitor_update.updates.append(&mut additional_monitor_update.updates);
-									}
-								},
-								Err(e) => {
-									if let ChannelError::Ignore(_) = e {}
-									else {
-										panic!("Got a non-IgnoreError action trying to fulfill holding cell HTLC");
-									}
+						}
+					},
+					&HTLCUpdateAwaitingACK::ClaimHTLC { ref payment_preimage, htlc_id, .. } => {
+						match self.get_update_fulfill_htlc(htlc_id, *payment_preimage, logger) {
+							Ok((update_fulfill_msg_option, additional_monitor_update_opt)) => {
+								update_fulfill_htlcs.push(update_fulfill_msg_option.unwrap());
+								if let Some(mut additional_monitor_update) = additional_monitor_update_opt {
+									monitor_update.updates.append(&mut additional_monitor_update.updates);
+								}
+							},
+							Err(e) => {
+								if let ChannelError::Ignore(_) = e {}
+								else {
+									panic!("Got a non-IgnoreError action trying to fulfill holding cell HTLC");
 								}
 							}
-						},
-						&HTLCUpdateAwaitingACK::FailHTLC { htlc_id, ref err_packet } => {
-							match self.get_update_fail_htlc(htlc_id, err_packet.clone()) {
-								Ok(update_fail_msg_option) => update_fail_htlcs.push(update_fail_msg_option.unwrap()),
-								Err(e) => {
-									if let ChannelError::Ignore(_) = e {}
-									else {
-										panic!("Got a non-IgnoreError action trying to fail holding cell HTLC");
-									}
+						}
+					},
+					&HTLCUpdateAwaitingACK::FailHTLC { htlc_id, ref err_packet } => {
+						match self.get_update_fail_htlc(htlc_id, err_packet.clone()) {
+							Ok(update_fail_msg_option) => update_fail_htlcs.push(update_fail_msg_option.unwrap()),
+							Err(e) => {
+								if let ChannelError::Ignore(_) = e {}
+								else {
+									panic!("Got a non-IgnoreError action trying to fail holding cell HTLC");
 								}
 							}
-						},
-					}
-					if err.is_some() {
-						self.holding_cell_htlc_updates.push(htlc_update);
-						if let Some(ChannelError::Ignore(_)) = err {
-							// If we failed to add the HTLC, but got an Ignore error, we should
-							// still send the new commitment_signed, so reset the err to None.
-							err = None;
 						}
-					}
+					},
 				}
 			}
-			//TODO: Need to examine the type of err - if it's a fee issue or similar we may want to
-			//fail it back the route, if it's a temporary issue we can ignore it...
-			match err {
-				None => {
-					if update_add_htlcs.is_empty() && update_fulfill_htlcs.is_empty() && update_fail_htlcs.is_empty() && self.holding_cell_update_fee.is_none() {
-						// This should never actually happen and indicates we got some Errs back
-						// from update_fulfill_htlc/update_fail_htlc, but we handle it anyway in
-						// case there is some strange way to hit duplicate HTLC removes.
-						return Ok(None);
-					}
-					let update_fee = if let Some(feerate) = self.holding_cell_update_fee {
-							self.pending_update_fee = self.holding_cell_update_fee.take();
-							Some(msgs::UpdateFee {
-								channel_id: self.channel_id,
-								feerate_per_kw: feerate as u32,
-							})
-						} else {
-							None
-						};
+			if update_add_htlcs.is_empty() && update_fulfill_htlcs.is_empty() && update_fail_htlcs.is_empty() && self.holding_cell_update_fee.is_none() {
+				return Ok((None, htlcs_to_fail));
+			}
+			let update_fee = if let Some(feerate) = self.holding_cell_update_fee {
+				self.pending_update_fee = self.holding_cell_update_fee.take();
+				Some(msgs::UpdateFee {
+					channel_id: self.channel_id,
+					feerate_per_kw: feerate as u32,
+				})
+			} else {
+				None
+			};
 
-					let (commitment_signed, mut additional_update) = self.send_commitment_no_status_check(logger)?;
-					// send_commitment_no_status_check and get_update_fulfill_htlc may bump latest_monitor_id
-					// but we want them to be strictly increasing by one, so reset it here.
-					self.latest_monitor_update_id = monitor_update.update_id;
-					monitor_update.updates.append(&mut additional_update.updates);
+			let (commitment_signed, mut additional_update) = self.send_commitment_no_status_check(logger)?;
+			// send_commitment_no_status_check and get_update_fulfill_htlc may bump latest_monitor_id
+			// but we want them to be strictly increasing by one, so reset it here.
+			self.latest_monitor_update_id = monitor_update.update_id;
+			monitor_update.updates.append(&mut additional_update.updates);
 
-					Ok(Some((msgs::CommitmentUpdate {
-						update_add_htlcs,
-						update_fulfill_htlcs,
-						update_fail_htlcs,
-						update_fail_malformed_htlcs: Vec::new(),
-						update_fee: update_fee,
-						commitment_signed,
-					}, monitor_update)))
-				},
-				Some(e) => Err(e)
-			}
+			Ok((Some((msgs::CommitmentUpdate {
+				update_add_htlcs,
+				update_fulfill_htlcs,
+				update_fail_htlcs,
+				update_fail_malformed_htlcs: Vec::new(),
+				update_fee,
+				commitment_signed,
+			}, monitor_update)), htlcs_to_fail))
 		} else {
-			Ok(None)
+			Ok((None, Vec::new()))
 		}
 	}
 
@@ -2243,23 +2396,23 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// waiting on this revoke_and_ack. The generation of this new commitment_signed may also fail,
 	/// generating an appropriate error *after* the channel state has been updated based on the
 	/// revoke_and_ack message.
-	pub fn revoke_and_ack<F: Deref, L: Deref>(&mut self, msg: &msgs::RevokeAndACK, fee_estimator: &F, logger: &L) -> Result<(Option<msgs::CommitmentUpdate>, Vec<(PendingHTLCInfo, u64)>, Vec<(HTLCSource, PaymentHash, HTLCFailReason)>, Option<msgs::ClosingSigned>, ChannelMonitorUpdate), ChannelError>
+	pub fn revoke_and_ack<F: Deref, L: Deref>(&mut self, msg: &msgs::RevokeAndACK, fee_estimator: &F, logger: &L) -> Result<(Option<msgs::CommitmentUpdate>, Vec<(PendingHTLCInfo, u64)>, Vec<(HTLCSource, PaymentHash, HTLCFailReason)>, Option<msgs::ClosingSigned>, ChannelMonitorUpdate, Vec<(HTLCSource, PaymentHash)>), ChannelError>
 		where F::Target: FeeEstimator,
 					L::Target: Logger,
 	{
 		if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
-			return Err(ChannelError::Close("Got revoke/ACK message when channel was not in an operational state"));
+			return Err(ChannelError::Close("Got revoke/ACK message when channel was not in an operational state".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent revoke_and_ack when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent revoke_and_ack when we needed a channel_reestablish".to_owned()));
 		}
 		if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK == BOTH_SIDES_SHUTDOWN_MASK && self.last_sent_closing_fee.is_some() {
-			return Err(ChannelError::Close("Peer sent revoke_and_ack after we'd started exchanging closing_signeds"));
+			return Err(ChannelError::Close("Peer sent revoke_and_ack after we'd started exchanging closing_signeds".to_owned()));
 		}
 
-		if let Some(their_prev_commitment_point) = self.their_prev_commitment_point {
-			if PublicKey::from_secret_key(&self.secp_ctx, &secp_check!(SecretKey::from_slice(&msg.per_commitment_secret), "Peer provided an invalid per_commitment_secret")) != their_prev_commitment_point {
-				return Err(ChannelError::Close("Got a revoke commitment secret which didn't correspond to their current pubkey"));
+		if let Some(counterparty_prev_commitment_point) = self.counterparty_prev_commitment_point {
+			if PublicKey::from_secret_key(&self.secp_ctx, &secp_check!(SecretKey::from_slice(&msg.per_commitment_secret), "Peer provided an invalid per_commitment_secret".to_owned())) != counterparty_prev_commitment_point {
+				return Err(ChannelError::Close("Got a revoke commitment secret which didn't correspond to their current pubkey".to_owned()));
 			}
 		}
 
@@ -2271,29 +2424,34 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			// lot of work, and there's some chance this is all a misunderstanding anyway.
 			// We have to do *something*, though, since our signer may get mad at us for otherwise
 			// jumping a remote commitment number, so best to just force-close and move on.
-			return Err(ChannelError::Close("Received an unexpected revoke_and_ack"));
+			return Err(ChannelError::Close("Received an unexpected revoke_and_ack".to_owned()));
 		}
 
-		self.commitment_secrets.provide_secret(self.cur_remote_commitment_transaction_number + 1, msg.per_commitment_secret)
-			.map_err(|_| ChannelError::Close("Previous secrets did not match new one"))?;
+		#[cfg(any(test, feature = "fuzztarget"))]
+		{
+			*self.next_local_commitment_tx_fee_info_cached.lock().unwrap() = None;
+			*self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = None;
+		}
+
+		self.commitment_secrets.provide_secret(self.cur_counterparty_commitment_transaction_number + 1, msg.per_commitment_secret)
+			.map_err(|_| ChannelError::Close("Previous secrets did not match new one".to_owned()))?;
 		self.latest_monitor_update_id += 1;
 		let mut monitor_update = ChannelMonitorUpdate {
 			update_id: self.latest_monitor_update_id,
 			updates: vec![ChannelMonitorUpdateStep::CommitmentSecret {
-				idx: self.cur_remote_commitment_transaction_number + 1,
+				idx: self.cur_counterparty_commitment_transaction_number + 1,
 				secret: msg.per_commitment_secret,
 			}],
 		};
-		self.channel_monitor.as_mut().unwrap().update_monitor_ooo(monitor_update.clone(), logger).unwrap();
 
 		// Update state now that we've passed all the can-fail calls...
 		// (note that we may still fail to generate the new commitment_signed message, but that's
 		// OK, we step the channel here and *then* if the new generation fails we can fail the
 		// channel based on that, but stepping stuff here should be safe either way.
 		self.channel_state &= !(ChannelState::AwaitingRemoteRevoke as u32);
-		self.their_prev_commitment_point = self.their_cur_commitment_point;
-		self.their_cur_commitment_point = Some(msg.next_per_commitment_point);
-		self.cur_remote_commitment_transaction_number -= 1;
+		self.counterparty_prev_commitment_point = self.counterparty_cur_commitment_point;
+		self.counterparty_cur_commitment_point = Some(msg.next_per_commitment_point);
+		self.cur_counterparty_commitment_transaction_number -= 1;
 
 		log_trace!(logger, "Updating HTLCs on receipt of RAA...");
 		let mut to_forward_infos = Vec::new();
@@ -2384,7 +2542,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 		self.value_to_self_msat = (self.value_to_self_msat as i64 + value_to_self_msat_diff) as u64;
 
-		if self.channel_outbound {
+		if self.is_outbound() {
 			if let Some(feerate) = self.pending_update_fee.take() {
 				self.feerate_per_kw = feerate;
 			}
@@ -2418,11 +2576,11 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 			self.monitor_pending_forwards.append(&mut to_forward_infos);
 			self.monitor_pending_failures.append(&mut revoked_htlcs);
-			return Ok((None, Vec::new(), Vec::new(), None, monitor_update))
+			return Ok((None, Vec::new(), Vec::new(), None, monitor_update, Vec::new()))
 		}
 
 		match self.free_holding_cell_htlcs(logger)? {
-			Some((mut commitment_update, mut additional_update)) => {
+			(Some((mut commitment_update, mut additional_update)), htlcs_to_fail) => {
 				commitment_update.update_fail_htlcs.reserve(update_fail_htlcs.len());
 				for fail_msg in update_fail_htlcs.drain(..) {
 					commitment_update.update_fail_htlcs.push(fail_msg);
@@ -2437,9 +2595,9 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				self.latest_monitor_update_id = monitor_update.update_id;
 				monitor_update.updates.append(&mut additional_update.updates);
 
-				Ok((Some(commitment_update), to_forward_infos, revoked_htlcs, None, monitor_update))
+				Ok((Some(commitment_update), to_forward_infos, revoked_htlcs, None, monitor_update, htlcs_to_fail))
 			},
-			None => {
+			(None, htlcs_to_fail) => {
 				if require_commitment {
 					let (commitment_signed, mut additional_update) = self.send_commitment_no_status_check(logger)?;
 
@@ -2455,9 +2613,9 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 						update_fail_malformed_htlcs,
 						update_fee: None,
 						commitment_signed
-					}), to_forward_infos, revoked_htlcs, None, monitor_update))
+					}), to_forward_infos, revoked_htlcs, None, monitor_update, htlcs_to_fail))
 				} else {
-					Ok((None, to_forward_infos, revoked_htlcs, self.maybe_propose_first_closing_signed(fee_estimator), monitor_update))
+					Ok((None, to_forward_infos, revoked_htlcs, self.maybe_propose_first_closing_signed(fee_estimator), monitor_update, htlcs_to_fail))
 				}
 			}
 		}
@@ -2468,7 +2626,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// further details on the optionness of the return value.
 	/// You MUST call send_commitment prior to any other calls on this Channel
 	fn send_update_fee(&mut self, feerate_per_kw: u32) -> Option<msgs::UpdateFee> {
-		if !self.channel_outbound {
+		if !self.is_outbound() {
 			panic!("Cannot send fee from inbound channel");
 		}
 		if !self.is_usable() {
@@ -2488,7 +2646,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		Some(msgs::UpdateFee {
 			channel_id: self.channel_id,
-			feerate_per_kw: feerate_per_kw,
+			feerate_per_kw,
 		})
 	}
 
@@ -2546,7 +2704,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				},
 			}
 		});
-		self.next_remote_htlc_id -= inbound_drop_count;
+		self.next_counterparty_htlc_id -= inbound_drop_count;
 
 		for htlc in self.pending_outbound_htlcs.iter_mut() {
 			if let OutboundHTLCState::RemoteRemoved(_) = htlc.state {
@@ -2559,6 +2717,11 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		self.holding_cell_htlc_updates.retain(|htlc_update| {
 			match htlc_update {
+				// Note that currently on channel reestablish we assert that there are
+				// no holding cell HTLC update_adds, so if in the future we stop
+				// dropping added HTLCs here and failing them backwards, then there will
+				// need to be corresponding changes made in the Channel's re-establish
+				// logic.
 				&HTLCUpdateAwaitingACK::AddHTLC { ref payment_hash, ref source, .. } => {
 					outbound_drops.push((source.clone(), payment_hash.clone()));
 					false
@@ -2595,7 +2758,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		assert_eq!(self.channel_state & ChannelState::MonitorUpdateFailed as u32, ChannelState::MonitorUpdateFailed as u32);
 		self.channel_state &= !(ChannelState::MonitorUpdateFailed as u32);
 
-		let needs_broadcast_safe = self.channel_state & (ChannelState::FundingSent as u32) != 0 && self.channel_outbound;
+		let needs_broadcast_safe = self.channel_state & (ChannelState::FundingSent as u32) != 0 && self.is_outbound();
 
 		// Because we will never generate a FundingBroadcastSafe event when we're in
 		// MonitorUpdateFailed, if we assume the user only broadcast the funding transaction when
@@ -2604,13 +2767,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// monitor on funding_created, and we even got the funding transaction confirmed before the
 		// monitor was persisted.
 		let funding_locked = if self.monitor_pending_funding_locked {
-			assert!(!self.channel_outbound, "Funding transaction broadcast without FundingBroadcastSafe!");
+			assert!(!self.is_outbound(), "Funding transaction broadcast without FundingBroadcastSafe!");
 			self.monitor_pending_funding_locked = false;
-			let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-			let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret);
+			let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
 			Some(msgs::FundingLocked {
 				channel_id: self.channel_id(),
-				next_per_commitment_point: next_per_commitment_point,
+				next_per_commitment_point,
 			})
 		} else { None };
 
@@ -2646,21 +2808,21 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	pub fn update_fee<F: Deref>(&mut self, fee_estimator: &F, msg: &msgs::UpdateFee) -> Result<(), ChannelError>
 		where F::Target: FeeEstimator
 	{
-		if self.channel_outbound {
-			return Err(ChannelError::Close("Non-funding remote tried to update channel fee"));
+		if self.is_outbound() {
+			return Err(ChannelError::Close("Non-funding remote tried to update channel fee".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish".to_owned()));
 		}
-		Channel::<ChanSigner>::check_remote_fee(fee_estimator, msg.feerate_per_kw)?;
+		Channel::<Signer>::check_remote_fee(fee_estimator, msg.feerate_per_kw)?;
 		self.pending_update_fee = Some(msg.feerate_per_kw);
 		self.update_time_counter += 1;
 		Ok(())
 	}
 
 	fn get_last_revoke_and_ack(&self) -> msgs::RevokeAndACK {
-		let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &self.build_local_commitment_secret(self.cur_local_commitment_transaction_number));
-		let per_commitment_secret = chan_utils::build_commitment_secret(self.local_keys.commitment_seed(), self.cur_local_commitment_transaction_number + 2);
+		let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
+		let per_commitment_secret = self.holder_keys.release_commitment_secret(self.cur_holder_commitment_transaction_number + 2);
 		msgs::RevokeAndACK {
 			channel_id: self.channel_id,
 			per_commitment_secret,
@@ -2732,23 +2894,26 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			// While BOLT 2 doesn't indicate explicitly we should error this channel here, it
 			// almost certainly indicates we are going to end up out-of-sync in some way, so we
 			// just close here instead of trying to recover.
-			return Err(ChannelError::Close("Peer sent a loose channel_reestablish not after reconnect"));
+			return Err(ChannelError::Close("Peer sent a loose channel_reestablish not after reconnect".to_owned()));
 		}
 
 		if msg.next_local_commitment_number >= INITIAL_COMMITMENT_NUMBER || msg.next_remote_commitment_number >= INITIAL_COMMITMENT_NUMBER ||
 			msg.next_local_commitment_number == 0 {
-			return Err(ChannelError::Close("Peer sent a garbage channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent a garbage channel_reestablish".to_owned()));
 		}
 
 		if msg.next_remote_commitment_number > 0 {
 			match msg.data_loss_protect {
 				OptionalField::Present(ref data_loss) => {
-					if chan_utils::build_commitment_secret(self.local_keys.commitment_seed(), INITIAL_COMMITMENT_NUMBER - msg.next_remote_commitment_number + 1) != data_loss.your_last_per_commitment_secret {
-						return Err(ChannelError::Close("Peer sent a garbage channel_reestablish with secret key not matching the commitment height provided"));
+					let expected_point = self.holder_keys.get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - msg.next_remote_commitment_number + 1, &self.secp_ctx);
+					let given_secret = SecretKey::from_slice(&data_loss.your_last_per_commitment_secret)
+						.map_err(|_| ChannelError::Close("Peer sent a garbage channel_reestablish with unparseable secret key".to_owned()))?;
+					if expected_point != PublicKey::from_secret_key(&self.secp_ctx, &given_secret) {
+						return Err(ChannelError::Close("Peer sent a garbage channel_reestablish with secret key not matching the commitment height provided".to_owned()));
 					}
-					if msg.next_remote_commitment_number > INITIAL_COMMITMENT_NUMBER - self.cur_local_commitment_transaction_number {
+					if msg.next_remote_commitment_number > INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number {
 						return Err(ChannelError::CloseDelayBroadcast(
-							"We have fallen behind - we have received proof that if we broadcast remote is going to claim our funds - we can't do any automated broadcasting"
+							"We have fallen behind - we have received proof that if we broadcast remote is going to claim our funds - we can't do any automated broadcasting".to_owned()
 						));
 					}
 				},
@@ -2772,26 +2937,25 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			if self.channel_state & (ChannelState::OurFundingLocked as u32) == 0 ||
 					self.channel_state & (ChannelState::MonitorUpdateFailed as u32) != 0 {
 				if msg.next_remote_commitment_number != 0 {
-					return Err(ChannelError::Close("Peer claimed they saw a revoke_and_ack but we haven't sent funding_locked yet"));
+					return Err(ChannelError::Close("Peer claimed they saw a revoke_and_ack but we haven't sent funding_locked yet".to_owned()));
 				}
 				// Short circuit the whole handler as there is nothing we can resend them
 				return Ok((None, None, None, None, RAACommitmentOrder::CommitmentFirst, shutdown_msg));
 			}
 
 			// We have OurFundingLocked set!
-			let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-			let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret);
+			let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
 			return Ok((Some(msgs::FundingLocked {
 				channel_id: self.channel_id(),
-				next_per_commitment_point: next_per_commitment_point,
+				next_per_commitment_point,
 			}), None, None, None, RAACommitmentOrder::CommitmentFirst, shutdown_msg));
 		}
 
-		let required_revoke = if msg.next_remote_commitment_number + 1 == INITIAL_COMMITMENT_NUMBER - self.cur_local_commitment_transaction_number {
+		let required_revoke = if msg.next_remote_commitment_number + 1 == INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number {
 			// Remote isn't waiting on any RevokeAndACK from us!
 			// Note that if we need to repeat our FundingLocked we'll do that in the next if block.
 			None
-		} else if msg.next_remote_commitment_number + 1 == (INITIAL_COMMITMENT_NUMBER - 1) - self.cur_local_commitment_transaction_number {
+		} else if msg.next_remote_commitment_number + 1 == (INITIAL_COMMITMENT_NUMBER - 1) - self.cur_holder_commitment_transaction_number {
 			if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) != 0 {
 				self.monitor_pending_revoke_and_ack = true;
 				None
@@ -2799,26 +2963,25 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				Some(self.get_last_revoke_and_ack())
 			}
 		} else {
-			return Err(ChannelError::Close("Peer attempted to reestablish channel with a very old local commitment transaction"));
+			return Err(ChannelError::Close("Peer attempted to reestablish channel with a very old local commitment transaction".to_owned()));
 		};
 
-		// We increment cur_remote_commitment_transaction_number only upon receipt of
+		// We increment cur_counterparty_commitment_transaction_number only upon receipt of
 		// revoke_and_ack, not on sending commitment_signed, so we add one if have
 		// AwaitingRemoteRevoke set, which indicates we sent a commitment_signed but haven't gotten
 		// the corresponding revoke_and_ack back yet.
-		let our_next_remote_commitment_number = INITIAL_COMMITMENT_NUMBER - self.cur_remote_commitment_transaction_number + if (self.channel_state & ChannelState::AwaitingRemoteRevoke as u32) != 0 { 1 } else { 0 };
+		let next_counterparty_commitment_number = INITIAL_COMMITMENT_NUMBER - self.cur_counterparty_commitment_transaction_number + if (self.channel_state & ChannelState::AwaitingRemoteRevoke as u32) != 0 { 1 } else { 0 };
 
-		let resend_funding_locked = if msg.next_local_commitment_number == 1 && INITIAL_COMMITMENT_NUMBER - self.cur_local_commitment_transaction_number == 1 {
+		let resend_funding_locked = if msg.next_local_commitment_number == 1 && INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number == 1 {
 			// We should never have to worry about MonitorUpdateFailed resending FundingLocked
-			let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-			let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret);
+			let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
 			Some(msgs::FundingLocked {
 				channel_id: self.channel_id(),
-				next_per_commitment_point: next_per_commitment_point,
+				next_per_commitment_point,
 			})
 		} else { None };
 
-		if msg.next_local_commitment_number == our_next_remote_commitment_number {
+		if msg.next_local_commitment_number == next_counterparty_commitment_number {
 			if required_revoke.is_some() {
 				log_debug!(logger, "Reconnected channel {} with only lost outbound RAA", log_bytes!(self.channel_id()));
 			} else {
@@ -2826,6 +2989,14 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 
 			if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::MonitorUpdateFailed as u32)) == 0 {
+				// Note that if in the future we no longer drop holding cell update_adds on peer
+				// disconnect, this logic will need to be updated.
+				for htlc_update in self.holding_cell_htlc_updates.iter() {
+					if let &HTLCUpdateAwaitingACK::AddHTLC { .. } = htlc_update {
+						debug_assert!(false, "There shouldn't be any add-HTLCs in the holding cell now because they should have been dropped on peer disconnect. Panic here because said HTLCs won't be handled correctly.");
+					}
+				}
+
 				// We're up-to-date and not waiting on a remote revoke (if we are our
 				// channel_reestablish should result in them sending a revoke_and_ack), but we may
 				// have received some updates while we were disconnected. Free the holding cell
@@ -2833,13 +3004,23 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				match self.free_holding_cell_htlcs(logger) {
 					Err(ChannelError::Close(msg)) => return Err(ChannelError::Close(msg)),
 					Err(ChannelError::Ignore(_)) | Err(ChannelError::CloseDelayBroadcast(_)) => panic!("Got non-channel-failing result from free_holding_cell_htlcs"),
-					Ok(Some((commitment_update, monitor_update))) => return Ok((resend_funding_locked, required_revoke, Some(commitment_update), Some(monitor_update), self.resend_order.clone(), shutdown_msg)),
-					Ok(None) => return Ok((resend_funding_locked, required_revoke, None, None, self.resend_order.clone(), shutdown_msg)),
+					Ok((Some((commitment_update, monitor_update)), htlcs_to_fail)) => {
+						// If in the future we no longer drop holding cell update_adds on peer
+						// disconnect, we may be handed some HTLCs to fail backwards here.
+						assert!(htlcs_to_fail.is_empty());
+						return Ok((resend_funding_locked, required_revoke, Some(commitment_update), Some(monitor_update), self.resend_order.clone(), shutdown_msg));
+					},
+					Ok((None, htlcs_to_fail)) => {
+						// If in the future we no longer drop holding cell update_adds on peer
+						// disconnect, we may be handed some HTLCs to fail backwards here.
+						assert!(htlcs_to_fail.is_empty());
+						return Ok((resend_funding_locked, required_revoke, None, None, self.resend_order.clone(), shutdown_msg));
+					},
 				}
 			} else {
 				return Ok((resend_funding_locked, required_revoke, None, None, self.resend_order.clone(), shutdown_msg));
 			}
-		} else if msg.next_local_commitment_number == our_next_remote_commitment_number - 1 {
+		} else if msg.next_local_commitment_number == next_counterparty_commitment_number - 1 {
 			if required_revoke.is_some() {
 				log_debug!(logger, "Reconnected channel {} with lost outbound RAA and lost remote commitment tx", log_bytes!(self.channel_id()));
 			} else {
@@ -2853,14 +3034,14 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 			return Ok((resend_funding_locked, required_revoke, Some(self.get_last_commitment_update(logger)), None, self.resend_order.clone(), shutdown_msg));
 		} else {
-			return Err(ChannelError::Close("Peer attempted to reestablish channel with a very old remote commitment transaction"));
+			return Err(ChannelError::Close("Peer attempted to reestablish channel with a very old remote commitment transaction".to_owned()));
 		}
 	}
 
 	fn maybe_propose_first_closing_signed<F: Deref>(&mut self, fee_estimator: &F) -> Option<msgs::ClosingSigned>
 		where F::Target: FeeEstimator
 	{
-		if !self.channel_outbound || !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() ||
+		if !self.is_outbound() || !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() ||
 				self.channel_state & (BOTH_SIDES_SHUTDOWN_MASK | ChannelState::AwaitingRemoteRevoke as u32) != BOTH_SIDES_SHUTDOWN_MASK ||
 				self.last_sent_closing_fee.is_some() || self.pending_update_fee.is_some() {
 			return None;
@@ -2870,20 +3051,21 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		if self.feerate_per_kw > proposed_feerate {
 			proposed_feerate = self.feerate_per_kw;
 		}
-		let tx_weight = Self::get_closing_transaction_weight(&self.get_closing_scriptpubkey(), self.their_shutdown_scriptpubkey.as_ref().unwrap());
+		let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
 		let proposed_total_fee_satoshis = proposed_feerate as u64 * tx_weight / 1000;
 
 		let (closing_tx, total_fee_satoshis) = self.build_closing_transaction(proposed_total_fee_satoshis, false);
-		let our_sig = self.local_keys
+		let sig = self.holder_keys
 			.sign_closing_transaction(&closing_tx, &self.secp_ctx)
 			.ok();
-		if our_sig.is_none() { return None; }
+		assert!(closing_tx.get_weight() as u64 <= tx_weight);
+		if sig.is_none() { return None; }
 
-		self.last_sent_closing_fee = Some((proposed_feerate, total_fee_satoshis, our_sig.clone().unwrap()));
+		self.last_sent_closing_fee = Some((proposed_feerate, total_fee_satoshis, sig.clone().unwrap()));
 		Some(msgs::ClosingSigned {
 			channel_id: self.channel_id,
 			fee_satoshis: total_fee_satoshis,
-			signature: our_sig.unwrap(),
+			signature: sig.unwrap(),
 		})
 	}
 
@@ -2891,38 +3073,38 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		where F::Target: FeeEstimator
 	{
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent shutdown when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent shutdown when we needed a channel_reestablish".to_owned()));
 		}
 		if self.channel_state < ChannelState::FundingSent as u32 {
 			// Spec says we should fail the connection, not the channel, but that's nonsense, there
 			// are plenty of reasons you may want to fail a channel pre-funding, and spec says you
 			// can do that via error message without getting a connection fail anyway...
-			return Err(ChannelError::Close("Peer sent shutdown pre-funding generation"));
+			return Err(ChannelError::Close("Peer sent shutdown pre-funding generation".to_owned()));
 		}
 		for htlc in self.pending_inbound_htlcs.iter() {
 			if let InboundHTLCState::RemoteAnnounced(_) = htlc.state {
-				return Err(ChannelError::Close("Got shutdown with remote pending HTLCs"));
+				return Err(ChannelError::Close("Got shutdown with remote pending HTLCs".to_owned()));
 			}
 		}
 		assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
 		// BOLT 2 says we must only send a scriptpubkey of certain standard forms, which are up to
 		// 34 bytes in length, so don't let the remote peer feed us some super fee-heavy script.
-		if self.channel_outbound && msg.scriptpubkey.len() > 34 {
-			return Err(ChannelError::Close("Got shutdown_scriptpubkey of absurd length from remote peer"));
+		if self.is_outbound() && msg.scriptpubkey.len() > 34 {
+			return Err(ChannelError::Close(format!("Got counterparty shutdown_scriptpubkey ({}) of absurd length from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
 		}
 
-		//Check shutdown_scriptpubkey form as BOLT says we must
+		//Check counterparty_shutdown_scriptpubkey form as BOLT says we must
 		if !msg.scriptpubkey.is_p2pkh() && !msg.scriptpubkey.is_p2sh() && !msg.scriptpubkey.is_v0_p2wpkh() && !msg.scriptpubkey.is_v0_p2wsh() {
-			return Err(ChannelError::Close("Got a nonstandard scriptpubkey from remote peer"));
+			return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
 		}
 
-		if self.their_shutdown_scriptpubkey.is_some() {
-			if Some(&msg.scriptpubkey) != self.their_shutdown_scriptpubkey.as_ref() {
-				return Err(ChannelError::Close("Got shutdown request with a scriptpubkey which did not match their previous scriptpubkey"));
+		if self.counterparty_shutdown_scriptpubkey.is_some() {
+			if Some(&msg.scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
+				return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", msg.scriptpubkey.to_bytes().to_hex())));
 			}
 		} else {
-			self.their_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone());
+			self.counterparty_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone());
 		}
 
 		// From here on out, we may not fail!
@@ -2948,7 +3130,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// immediately after the commitment dance, but we can send a Shutdown cause we won't send
 		// any further commitment updates after we set LocalShutdownSent.
 
-		let our_shutdown = if (self.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
+		let shutdown = if (self.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
 			None
 		} else {
 			Some(msgs::Shutdown {
@@ -2960,24 +3142,24 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		self.channel_state |= ChannelState::LocalShutdownSent as u32;
 		self.update_time_counter += 1;
 
-		Ok((our_shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
+		Ok((shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
 	}
 
-	fn build_signed_closing_transaction(&self, tx: &mut Transaction, their_sig: &Signature, our_sig: &Signature) {
+	fn build_signed_closing_transaction(&self, tx: &mut Transaction, counterparty_sig: &Signature, sig: &Signature) {
 		if tx.input.len() != 1 { panic!("Tried to sign closing transaction that had input count != 1!"); }
 		if tx.input[0].witness.len() != 0 { panic!("Tried to re-sign closing transaction"); }
 		if tx.output.len() > 2 { panic!("Tried to sign bogus closing transaction"); }
 
 		tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
 
-		let our_funding_key = self.local_keys.pubkeys().funding_pubkey.serialize();
-		let their_funding_key = self.their_funding_pubkey().serialize();
-		if our_funding_key[..] < their_funding_key[..] {
-			tx.input[0].witness.push(our_sig.serialize_der().to_vec());
-			tx.input[0].witness.push(their_sig.serialize_der().to_vec());
+		let funding_key = self.get_holder_pubkeys().funding_pubkey.serialize();
+		let counterparty_funding_key = self.counterparty_funding_pubkey().serialize();
+		if funding_key[..] < counterparty_funding_key[..] {
+			tx.input[0].witness.push(sig.serialize_der().to_vec());
+			tx.input[0].witness.push(counterparty_sig.serialize_der().to_vec());
 		} else {
-			tx.input[0].witness.push(their_sig.serialize_der().to_vec());
-			tx.input[0].witness.push(our_sig.serialize_der().to_vec());
+			tx.input[0].witness.push(counterparty_sig.serialize_der().to_vec());
+			tx.input[0].witness.push(sig.serialize_der().to_vec());
 		}
 		tx.input[0].witness[1].push(SigHashType::All as u8);
 		tx.input[0].witness[2].push(SigHashType::All as u8);
@@ -2989,41 +3171,44 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		where F::Target: FeeEstimator
 	{
 		if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != BOTH_SIDES_SHUTDOWN_MASK {
-			return Err(ChannelError::Close("Remote end sent us a closing_signed before both sides provided a shutdown"));
+			return Err(ChannelError::Close("Remote end sent us a closing_signed before both sides provided a shutdown".to_owned()));
 		}
 		if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-			return Err(ChannelError::Close("Peer sent closing_signed when we needed a channel_reestablish"));
+			return Err(ChannelError::Close("Peer sent closing_signed when we needed a channel_reestablish".to_owned()));
 		}
 		if !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() {
-			return Err(ChannelError::Close("Remote end sent us a closing_signed while there were still pending HTLCs"));
+			return Err(ChannelError::Close("Remote end sent us a closing_signed while there were still pending HTLCs".to_owned()));
 		}
-		if msg.fee_satoshis > 21000000 * 10000000 { //this is required to stop potential overflow in build_closing_transaction
-			return Err(ChannelError::Close("Remote tried to send us a closing tx with > 21 million BTC fee"));
+		if msg.fee_satoshis > 21_000_000 * 1_0000_0000 { //this is required to stop potential overflow in build_closing_transaction
+			return Err(ChannelError::Close("Remote tried to send us a closing tx with > 21 million BTC fee".to_owned()));
 		}
 
 		let funding_redeemscript = self.get_funding_redeemscript();
 		let (mut closing_tx, used_total_fee) = self.build_closing_transaction(msg.fee_satoshis, false);
 		if used_total_fee != msg.fee_satoshis {
-			return Err(ChannelError::Close("Remote sent us a closing_signed with a fee greater than the value they can claim"));
+			return Err(ChannelError::Close(format!("Remote sent us a closing_signed with a fee greater than the value they can claim. Fee in message: {}", msg.fee_satoshis)));
 		}
-		let mut sighash = hash_to_message!(&bip143::SighashComponents::new(&closing_tx).sighash_all(&closing_tx.input[0], &funding_redeemscript, self.channel_value_satoshis)[..]);
+		let mut sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
 
-		let their_funding_pubkey = &self.their_pubkeys.as_ref().unwrap().funding_pubkey;
-
-		match self.secp_ctx.verify(&sighash, &msg.signature, their_funding_pubkey) {
+		match self.secp_ctx.verify(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
 			Ok(_) => {},
 			Err(_e) => {
 				// The remote end may have decided to revoke their output due to inconsistent dust
 				// limits, so check for that case by re-checking the signature here.
 				closing_tx = self.build_closing_transaction(msg.fee_satoshis, true).0;
-				sighash = hash_to_message!(&bip143::SighashComponents::new(&closing_tx).sighash_all(&closing_tx.input[0], &funding_redeemscript, self.channel_value_satoshis)[..]);
-				secp_check!(self.secp_ctx.verify(&sighash, &msg.signature, self.their_funding_pubkey()), "Invalid closing tx signature from peer");
+				sighash = hash_to_message!(&bip143::SigHashCache::new(&closing_tx).signature_hash(0, &funding_redeemscript, self.channel_value_satoshis, SigHashType::All)[..]);
+				secp_check!(self.secp_ctx.verify(&sighash, &msg.signature, self.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
 			},
 		};
 
-		if let Some((_, last_fee, our_sig)) = self.last_sent_closing_fee {
+		let closing_tx_max_weight = self.get_closing_transaction_weight(
+			if let Some(oup) = closing_tx.output.get(0) { Some(&oup.script_pubkey) } else { None },
+			if let Some(oup) = closing_tx.output.get(1) { Some(&oup.script_pubkey) } else { None });
+		if let Some((_, last_fee, sig)) = self.last_sent_closing_fee {
 			if last_fee == msg.fee_satoshis {
-				self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &our_sig);
+				self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
+				assert!(closing_tx.get_weight() as u64 <= closing_tx_max_weight);
+				debug_assert!(closing_tx.get_weight() as u64 >= closing_tx_max_weight - 2);
 				self.channel_state = ChannelState::ShutdownComplete as u32;
 				self.update_time_counter += 1;
 				return Ok((None, Some(closing_tx)));
@@ -3032,47 +3217,50 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		macro_rules! propose_new_feerate {
 			($new_feerate: expr) => {
-				let closing_tx_max_weight = Self::get_closing_transaction_weight(&self.get_closing_scriptpubkey(), self.their_shutdown_scriptpubkey.as_ref().unwrap());
-				let (closing_tx, used_total_fee) = self.build_closing_transaction($new_feerate as u64 * closing_tx_max_weight / 1000, false);
-				let our_sig = self.local_keys
+				let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
+				let (closing_tx, used_total_fee) = self.build_closing_transaction($new_feerate as u64 * tx_weight / 1000, false);
+				let sig = self.holder_keys
 					.sign_closing_transaction(&closing_tx, &self.secp_ctx)
-					.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction"))?;
-				self.last_sent_closing_fee = Some(($new_feerate, used_total_fee, our_sig.clone()));
+					.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction".to_owned()))?;
+				assert!(closing_tx.get_weight() as u64 <= tx_weight);
+				self.last_sent_closing_fee = Some(($new_feerate, used_total_fee, sig.clone()));
 				return Ok((Some(msgs::ClosingSigned {
 					channel_id: self.channel_id,
 					fee_satoshis: used_total_fee,
-					signature: our_sig,
+					signature: sig,
 				}), None))
 			}
 		}
 
-		let proposed_sat_per_kw = msg.fee_satoshis  * 1000 / closing_tx.get_weight() as u64;
-		if self.channel_outbound {
-			let our_max_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
-			if (proposed_sat_per_kw as u32) > our_max_feerate {
+		let mut min_feerate = 253;
+		if self.is_outbound() {
+			let max_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
+			if (msg.fee_satoshis as u64) > max_feerate as u64 * closing_tx_max_weight / 1000 {
 				if let Some((last_feerate, _, _)) = self.last_sent_closing_fee {
-					if our_max_feerate <= last_feerate {
-						return Err(ChannelError::Close("Unable to come to consensus about closing feerate, remote wanted something higher than our Normal feerate"));
+					if max_feerate <= last_feerate {
+						return Err(ChannelError::Close(format!("Unable to come to consensus about closing feerate, remote wanted something higher ({}) than our Normal feerate ({})", last_feerate, max_feerate)));
 					}
 				}
-				propose_new_feerate!(our_max_feerate);
+				propose_new_feerate!(max_feerate);
 			}
 		} else {
-			let our_min_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
-			if (proposed_sat_per_kw as u32) < our_min_feerate {
-				if let Some((last_feerate, _, _)) = self.last_sent_closing_fee {
-					if our_min_feerate >= last_feerate {
-						return Err(ChannelError::Close("Unable to come to consensus about closing feerate, remote wanted something lower than our Background feerate"));
-					}
+			min_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
+		}
+		if (msg.fee_satoshis as u64) < min_feerate as u64 * closing_tx_max_weight / 1000 {
+			if let Some((last_feerate, _, _)) = self.last_sent_closing_fee {
+				if min_feerate >= last_feerate {
+					return Err(ChannelError::Close(format!("Unable to come to consensus about closing feerate, remote wanted something lower ({}) than our Background feerate ({}).", last_feerate, min_feerate)));
 				}
-				propose_new_feerate!(our_min_feerate);
 			}
+			propose_new_feerate!(min_feerate);
 		}
 
-		let our_sig = self.local_keys
+		let sig = self.holder_keys
 			.sign_closing_transaction(&closing_tx, &self.secp_ctx)
-			.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction"))?;
-		self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &our_sig);
+			.map_err(|_| ChannelError::Close("External signer refused to sign closing transaction".to_owned()))?;
+		self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
+		assert!(closing_tx.get_weight() as u64 <= closing_tx_max_weight);
+		debug_assert!(closing_tx.get_weight() as u64 >= closing_tx_max_weight - 2);
 
 		self.channel_state = ChannelState::ShutdownComplete as u32;
 		self.update_time_counter += 1;
@@ -3080,7 +3268,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		Ok((Some(msgs::ClosingSigned {
 			channel_id: self.channel_id,
 			fee_satoshis: msg.fee_satoshis,
-			signature: our_sig,
+			signature: sig,
 		}), Some(closing_tx)))
 	}
 
@@ -3096,14 +3284,6 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		self.user_id
 	}
 
-	/// May only be called after funding has been initiated (ie is_funding_initiated() is true)
-	pub fn channel_monitor(&mut self) -> &mut ChannelMonitor<ChanSigner> {
-		if self.channel_state < ChannelState::FundingSent as u32 {
-			panic!("Can't get a channel monitor until funding has been created");
-		}
-		self.channel_monitor.as_mut().unwrap()
-	}
-
 	/// Guaranteed to be Some after both FundingLocked messages have been exchanged (and, thus,
 	/// is_usable() returns true).
 	/// Allowed in any state (including after shutdown)
@@ -3114,22 +3294,51 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// Returns the funding_txo we either got from our peer, or were given by
 	/// get_outbound_funding_created.
 	pub fn get_funding_txo(&self) -> Option<OutPoint> {
-		self.funding_txo
+		self.channel_transaction_parameters.funding_outpoint
+	}
+
+	fn get_holder_selected_contest_delay(&self) -> u16 {
+		self.channel_transaction_parameters.holder_selected_contest_delay
+	}
+
+	fn get_holder_pubkeys(&self) -> &ChannelPublicKeys {
+		&self.channel_transaction_parameters.holder_pubkeys
+	}
+
+	fn get_counterparty_selected_contest_delay(&self) -> u16 {
+		self.channel_transaction_parameters.counterparty_parameters.as_ref().unwrap().selected_contest_delay
+	}
+
+	fn get_counterparty_pubkeys(&self) -> &ChannelPublicKeys {
+		&self.channel_transaction_parameters.counterparty_parameters.as_ref().unwrap().pubkeys
 	}
 
 	/// Allowed in any state (including after shutdown)
-	pub fn get_their_node_id(&self) -> PublicKey {
-		self.their_node_id
+	pub fn get_counterparty_node_id(&self) -> PublicKey {
+		self.counterparty_node_id
 	}
 
 	/// Allowed in any state (including after shutdown)
-	pub fn get_our_htlc_minimum_msat(&self) -> u64 {
-		self.our_htlc_minimum_msat
+	#[cfg(test)]
+	pub fn get_holder_htlc_minimum_msat(&self) -> u64 {
+		self.holder_htlc_minimum_msat
 	}
 
 	/// Allowed in any state (including after shutdown)
-	pub fn get_their_htlc_minimum_msat(&self) -> u64 {
-		self.our_htlc_minimum_msat
+	pub fn get_announced_htlc_max_msat(&self) -> u64 {
+		return cmp::min(
+			// Upper bound by capacity. We make it a bit less than full capacity to prevent attempts
+			// to use full capacity. This is an effort to reduce routing failures, because in many cases
+			// channel might have been used to route very small values (either by honest users or as DoS).
+			self.channel_value_satoshis * 9 / 10,
+
+			Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis)
+		);
+	}
+
+	/// Allowed in any state (including after shutdown)
+	pub fn get_counterparty_htlc_minimum_msat(&self) -> u64 {
+		self.counterparty_htlc_minimum_msat
 	}
 
 	pub fn get_value_satoshis(&self) -> u64 {
@@ -3145,21 +3354,21 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		self.feerate_per_kw
 	}
 
-	pub fn get_cur_local_commitment_transaction_number(&self) -> u64 {
-		self.cur_local_commitment_transaction_number + 1
+	pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
+		self.cur_holder_commitment_transaction_number + 1
 	}
 
-	pub fn get_cur_remote_commitment_transaction_number(&self) -> u64 {
-		self.cur_remote_commitment_transaction_number + 1 - if self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32) != 0 { 1 } else { 0 }
+	pub fn get_cur_counterparty_commitment_transaction_number(&self) -> u64 {
+		self.cur_counterparty_commitment_transaction_number + 1 - if self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32) != 0 { 1 } else { 0 }
 	}
 
-	pub fn get_revoked_remote_commitment_transaction_number(&self) -> u64 {
-		self.cur_remote_commitment_transaction_number + 2
+	pub fn get_revoked_counterparty_commitment_transaction_number(&self) -> u64 {
+		self.cur_counterparty_commitment_transaction_number + 2
 	}
 
 	#[cfg(test)]
-	pub fn get_local_keys(&self) -> &ChanSigner {
-		&self.local_keys
+	pub fn get_keys(&self) -> &Signer {
+		&self.holder_keys
 	}
 
 	#[cfg(test)]
@@ -3167,7 +3376,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		ChannelValueStat {
 			value_to_self_msat: self.value_to_self_msat,
 			channel_value_msat: self.channel_value_satoshis * 1000,
-			channel_reserve_msat: self.local_channel_reserve_satoshis * 1000,
+			channel_reserve_msat: self.counterparty_selected_channel_reserve_satoshis * 1000,
 			pending_outbound_htlcs_amount_msat: self.pending_outbound_htlcs.iter().map(|ref h| h.amount_msat).sum::<u64>(),
 			pending_inbound_htlcs_amount_msat: self.pending_inbound_htlcs.iter().map(|ref h| h.amount_msat).sum::<u64>(),
 			holding_cell_outbound_amount_msat: {
@@ -3182,8 +3391,8 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				}
 				res
 			},
-			their_max_htlc_value_in_flight_msat: self.their_max_htlc_value_in_flight_msat,
-			their_dust_limit_msat: self.their_dust_limit_satoshis * 1000,
+			counterparty_max_htlc_value_in_flight_msat: self.counterparty_max_htlc_value_in_flight_msat,
+			counterparty_dust_limit_msat: self.counterparty_dust_limit_satoshis * 1000,
 		}
 	}
 
@@ -3201,12 +3410,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	}
 
 	pub fn is_outbound(&self) -> bool {
-		self.channel_outbound
+		self.channel_transaction_parameters.is_outbound_from_holder
 	}
 
 	/// Gets the fee we'd want to charge for adding an HTLC output to this Channel
 	/// Allowed in any state (including after shutdown)
-	pub fn get_our_fee_base_msat<F: Deref>(&self, fee_estimator: &F) -> u32
+	pub fn get_holder_fee_base_msat<F: Deref>(&self, fee_estimator: &F) -> u32
 		where F::Target: FeeEstimator
 	{
 		// For lack of a better metric, we calculate what it would cost to consolidate the new HTLC
@@ -3215,7 +3424,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// the fee cost of the HTLC-Success/HTLC-Timeout transaction:
 		let mut res = self.feerate_per_kw as u64 * cmp::max(HTLC_TIMEOUT_TX_WEIGHT, HTLC_SUCCESS_TX_WEIGHT) / 1000;
 
-		if self.channel_outbound {
+		if self.is_outbound() {
 			// + the marginal fee increase cost to us in the commitment transaction:
 			res += self.feerate_per_kw as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC / 1000;
 		}
@@ -3300,7 +3509,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	///
 	/// May return some HTLCs (and their payment_hash) which have timed out and should be failed
 	/// back.
-	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
+	pub fn block_connected(&mut self, header: &BlockHeader, txdata: &TransactionData, height: u32) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
 		let mut timed_out_htlcs = Vec::new();
 		self.holding_cell_htlc_updates.retain(|htlc_update| {
 			match htlc_update {
@@ -3314,18 +3523,19 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			}
 		});
 		let non_shutdown_state = self.channel_state & (!MULTI_STATE_FLAGS);
-		if header.bitcoin_hash() != self.last_block_connected {
+		if header.block_hash() != self.last_block_connected {
 			if self.funding_tx_confirmations > 0 {
 				self.funding_tx_confirmations += 1;
 			}
 		}
 		if non_shutdown_state & !(ChannelState::TheirFundingLocked as u32) == ChannelState::FundingSent as u32 {
-			for (ref tx, index_in_block) in txn_matched.iter().zip(indexes_of_txn_matched) {
-				if tx.txid() == self.funding_txo.unwrap().txid {
-					let txo_idx = self.funding_txo.unwrap().index as usize;
+			for &(index_in_block, tx) in txdata.iter() {
+				let funding_txo = self.get_funding_txo().unwrap();
+				if tx.txid() == funding_txo.txid {
+					let txo_idx = funding_txo.index as usize;
 					if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.get_funding_redeemscript().to_v0_p2wsh() ||
 							tx.output[txo_idx].value != self.channel_value_satoshis {
-						if self.channel_outbound {
+						if self.is_outbound() {
 							// If we generated the funding transaction and it doesn't match what it
 							// should, the client is really broken and we should just panic and
 							// tell them off. That said, because hash collisions happen with high
@@ -3341,7 +3551,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 							data: "funding tx had wrong script/value".to_owned()
 						});
 					} else {
-						if self.channel_outbound {
+						if self.is_outbound() {
 							for input in tx.input.iter() {
 								if input.witness.is_empty() {
 									// We generated a malleable funding transaction, implying we've
@@ -3351,24 +3561,21 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 								}
 							}
 						}
-						if height > 0xff_ff_ff || (*index_in_block) > 0xff_ff_ff {
+						if height > 0xff_ff_ff || (index_in_block) > 0xff_ff_ff {
 							panic!("Block was bogus - either height 16 million or had > 16 million transactions");
 						}
 						assert!(txo_idx <= 0xffff); // txo_idx is a (u16 as usize), so this is just listed here for completeness
 						self.funding_tx_confirmations = 1;
-						self.short_channel_id = Some(((height as u64)          << (5*8)) |
-						                             ((*index_in_block as u64) << (2*8)) |
-						                             ((txo_idx as u64)         << (0*8)));
+						self.short_channel_id = Some(((height as u64)         << (5*8)) |
+						                             ((index_in_block as u64) << (2*8)) |
+						                             ((txo_idx as u64)        << (0*8)));
 					}
 				}
 			}
 		}
-		if header.bitcoin_hash() != self.last_block_connected {
-			self.last_block_connected = header.bitcoin_hash();
+		if header.block_hash() != self.last_block_connected {
+			self.last_block_connected = header.block_hash();
 			self.update_time_counter = cmp::max(self.update_time_counter, header.time);
-			if let Some(channel_monitor) = self.channel_monitor.as_mut() {
-				channel_monitor.last_block_hash = self.last_block_connected;
-			}
 			if self.funding_tx_confirmations > 0 {
 				if self.funding_tx_confirmations == self.minimum_depth as u64 {
 					let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
@@ -3389,7 +3596,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 						// funding_tx_confirmed_in and return.
 						false
 					};
-					self.funding_tx_confirmed_in = Some(header.bitcoin_hash());
+					self.funding_tx_confirmed_in = Some(self.last_block_connected);
 
 					//TODO: Note that this must be a duplicate of the previous commitment point they sent us,
 					//as otherwise we will have a commitment transaction that they can't revoke (well, kinda,
@@ -3397,11 +3604,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 					//a protocol oversight, but I assume I'm just missing something.
 					if need_commitment_update {
 						if self.channel_state & (ChannelState::MonitorUpdateFailed as u32) == 0 {
-							let next_per_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-							let next_per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &next_per_commitment_secret);
+							let next_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
 							return Ok((Some(msgs::FundingLocked {
 								channel_id: self.channel_id,
-								next_per_commitment_point: next_per_commitment_point,
+								next_per_commitment_point,
 							}), timed_out_htlcs));
 						} else {
 							self.monitor_pending_funding_locked = true;
@@ -3424,13 +3630,10 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				return true;
 			}
 		}
-		if Some(header.bitcoin_hash()) == self.funding_tx_confirmed_in {
+		self.last_block_connected = header.block_hash();
+		if Some(self.last_block_connected) == self.funding_tx_confirmed_in {
 			self.funding_tx_confirmations = self.minimum_depth as u64 - 1;
 		}
-		self.last_block_connected = header.bitcoin_hash();
-		if let Some(channel_monitor) = self.channel_monitor.as_mut() {
-			channel_monitor.last_block_hash = self.last_block_connected;
-		}
 		false
 	}
 
@@ -3438,82 +3641,82 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	// something in the handler for the message that prompted this message):
 
 	pub fn get_open_channel(&self, chain_hash: BlockHash) -> msgs::OpenChannel {
-		if !self.channel_outbound {
+		if !self.is_outbound() {
 			panic!("Tried to open a channel for an inbound channel?");
 		}
 		if self.channel_state != ChannelState::OurInitSent as u32 {
 			panic!("Cannot generate an open_channel after we've moved forward");
 		}
 
-		if self.cur_local_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+		if self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Tried to send an open_channel for a channel that has already advanced");
 		}
 
-		let local_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-		let local_keys = self.local_keys.pubkeys();
+		let first_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
+		let keys = self.get_holder_pubkeys();
 
 		msgs::OpenChannel {
-			chain_hash: chain_hash,
+			chain_hash,
 			temporary_channel_id: self.channel_id,
 			funding_satoshis: self.channel_value_satoshis,
 			push_msat: self.channel_value_satoshis * 1000 - self.value_to_self_msat,
-			dust_limit_satoshis: self.our_dust_limit_satoshis,
-			max_htlc_value_in_flight_msat: Channel::<ChanSigner>::get_our_max_htlc_value_in_flight_msat(self.channel_value_satoshis),
-			channel_reserve_satoshis: Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis),
-			htlc_minimum_msat: self.our_htlc_minimum_msat,
+			dust_limit_satoshis: self.holder_dust_limit_satoshis,
+			max_htlc_value_in_flight_msat: Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis),
+			channel_reserve_satoshis: Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis),
+			htlc_minimum_msat: self.holder_htlc_minimum_msat,
 			feerate_per_kw: self.feerate_per_kw as u32,
-			to_self_delay: self.our_to_self_delay,
+			to_self_delay: self.get_holder_selected_contest_delay(),
 			max_accepted_htlcs: OUR_MAX_HTLCS,
-			funding_pubkey: local_keys.funding_pubkey,
-			revocation_basepoint: local_keys.revocation_basepoint,
-			payment_point: local_keys.payment_point,
-			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
-			htlc_basepoint: local_keys.htlc_basepoint,
-			first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret),
+			funding_pubkey: keys.funding_pubkey,
+			revocation_basepoint: keys.revocation_basepoint,
+			payment_point: keys.payment_point,
+			delayed_payment_basepoint: keys.delayed_payment_basepoint,
+			htlc_basepoint: keys.htlc_basepoint,
+			first_per_commitment_point,
 			channel_flags: if self.config.announced_channel {1} else {0},
 			shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
 		}
 	}
 
 	pub fn get_accept_channel(&self) -> msgs::AcceptChannel {
-		if self.channel_outbound {
+		if self.is_outbound() {
 			panic!("Tried to send accept_channel for an outbound channel?");
 		}
 		if self.channel_state != (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32) {
 			panic!("Tried to send accept_channel after channel had moved forward");
 		}
-		if self.cur_local_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+		if self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Tried to send an accept_channel for a channel that has already advanced");
 		}
 
-		let local_commitment_secret = self.build_local_commitment_secret(self.cur_local_commitment_transaction_number);
-		let local_keys = self.local_keys.pubkeys();
+		let first_per_commitment_point = self.holder_keys.get_per_commitment_point(self.cur_holder_commitment_transaction_number, &self.secp_ctx);
+		let keys = self.get_holder_pubkeys();
 
 		msgs::AcceptChannel {
 			temporary_channel_id: self.channel_id,
-			dust_limit_satoshis: self.our_dust_limit_satoshis,
-			max_htlc_value_in_flight_msat: Channel::<ChanSigner>::get_our_max_htlc_value_in_flight_msat(self.channel_value_satoshis),
-			channel_reserve_satoshis: Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis),
-			htlc_minimum_msat: self.our_htlc_minimum_msat,
+			dust_limit_satoshis: self.holder_dust_limit_satoshis,
+			max_htlc_value_in_flight_msat: Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis),
+			channel_reserve_satoshis: Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis),
+			htlc_minimum_msat: self.holder_htlc_minimum_msat,
 			minimum_depth: self.minimum_depth,
-			to_self_delay: self.our_to_self_delay,
+			to_self_delay: self.get_holder_selected_contest_delay(),
 			max_accepted_htlcs: OUR_MAX_HTLCS,
-			funding_pubkey: local_keys.funding_pubkey,
-			revocation_basepoint: local_keys.revocation_basepoint,
-			payment_point: local_keys.payment_point,
-			delayed_payment_basepoint: local_keys.delayed_payment_basepoint,
-			htlc_basepoint: local_keys.htlc_basepoint,
-			first_per_commitment_point: PublicKey::from_secret_key(&self.secp_ctx, &local_commitment_secret),
+			funding_pubkey: keys.funding_pubkey,
+			revocation_basepoint: keys.revocation_basepoint,
+			payment_point: keys.payment_point,
+			delayed_payment_basepoint: keys.delayed_payment_basepoint,
+			htlc_basepoint: keys.htlc_basepoint,
+			first_per_commitment_point,
 			shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
 		}
 	}
 
 	/// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created)
 	fn get_outbound_funding_created_signature<L: Deref>(&mut self, logger: &L) -> Result<Signature, ChannelError> where L::Target: Logger {
-		let remote_keys = self.build_remote_transaction_keys()?;
-		let remote_initial_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, false, self.feerate_per_kw, logger).0;
-		Ok(self.local_keys.sign_remote_commitment(self.feerate_per_kw, &remote_initial_commitment_tx, &remote_keys, &Vec::new(), self.our_to_self_delay, &self.secp_ctx)
-				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?.0)
+		let counterparty_keys = self.build_remote_transaction_keys()?;
+		let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, self.feerate_per_kw, logger).0;
+		Ok(self.holder_keys.sign_counterparty_commitment(&counterparty_initial_commitment_tx, &self.secp_ctx)
+				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0)
 	}
 
 	/// Updates channel state with knowledge of the funding transaction's txid/index, and generates
@@ -3524,24 +3727,26 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// Do NOT broadcast the funding transaction until after a successful funding_signed call!
 	/// If an Err is returned, it is a ChannelError::Close.
 	pub fn get_outbound_funding_created<L: Deref>(&mut self, funding_txo: OutPoint, logger: &L) -> Result<msgs::FundingCreated, ChannelError> where L::Target: Logger {
-		if !self.channel_outbound {
+		if !self.is_outbound() {
 			panic!("Tried to create outbound funding_created message on an inbound channel!");
 		}
 		if self.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
 			panic!("Tried to get a funding_created messsage at a time other than immediately after initial handshake completion (or tried to get funding_created twice)");
 		}
 		if self.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-				self.cur_remote_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-				self.cur_local_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+				self.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+				self.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
 			panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
 		}
 
-		self.funding_txo = Some(funding_txo.clone());
-		let our_signature = match self.get_outbound_funding_created_signature(logger) {
+		self.channel_transaction_parameters.funding_outpoint = Some(funding_txo);
+		self.holder_keys.ready_channel(&self.channel_transaction_parameters);
+
+		let signature = match self.get_outbound_funding_created_signature(logger) {
 			Ok(res) => res,
 			Err(e) => {
 				log_error!(logger, "Got bad signatures: {:?}!", e);
-				self.funding_txo = None;
+				self.channel_transaction_parameters.funding_outpoint = None;
 				return Err(e);
 			}
 		};
@@ -3557,7 +3762,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			temporary_channel_id,
 			funding_txid: funding_txo.txid,
 			funding_output_index: funding_txo.index,
-			signature: our_signature
+			signature
 		})
 	}
 
@@ -3569,32 +3774,32 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// closing).
 	/// Note that the "channel must be funded" requirement is stricter than BOLT 7 requires - see
 	/// https://github.com/lightningnetwork/lightning-rfc/issues/468
-	pub fn get_channel_announcement(&self, our_node_id: PublicKey, chain_hash: BlockHash) -> Result<(msgs::UnsignedChannelAnnouncement, Signature), ChannelError> {
+	pub fn get_channel_announcement(&self, node_id: PublicKey, chain_hash: BlockHash) -> Result<(msgs::UnsignedChannelAnnouncement, Signature), ChannelError> {
 		if !self.config.announced_channel {
-			return Err(ChannelError::Ignore("Channel is not available for public announcements"));
+			return Err(ChannelError::Ignore("Channel is not available for public announcements".to_owned()));
 		}
 		if self.channel_state & (ChannelState::ChannelFunded as u32) == 0 {
-			return Err(ChannelError::Ignore("Cannot get a ChannelAnnouncement until the channel funding has been locked"));
+			return Err(ChannelError::Ignore("Cannot get a ChannelAnnouncement until the channel funding has been locked".to_owned()));
 		}
 		if (self.channel_state & (ChannelState::LocalShutdownSent as u32 | ChannelState::ShutdownComplete as u32)) != 0 {
-			return Err(ChannelError::Ignore("Cannot get a ChannelAnnouncement once the channel is closing"));
+			return Err(ChannelError::Ignore("Cannot get a ChannelAnnouncement once the channel is closing".to_owned()));
 		}
 
-		let were_node_one = our_node_id.serialize()[..] < self.their_node_id.serialize()[..];
+		let were_node_one = node_id.serialize()[..] < self.counterparty_node_id.serialize()[..];
 
 		let msg = msgs::UnsignedChannelAnnouncement {
 			features: ChannelFeatures::known(),
-			chain_hash: chain_hash,
+			chain_hash,
 			short_channel_id: self.get_short_channel_id().unwrap(),
-			node_id_1: if were_node_one { our_node_id } else { self.get_their_node_id() },
-			node_id_2: if were_node_one { self.get_their_node_id() } else { our_node_id },
-			bitcoin_key_1: if were_node_one { self.local_keys.pubkeys().funding_pubkey } else { self.their_funding_pubkey().clone() },
-			bitcoin_key_2: if were_node_one { self.their_funding_pubkey().clone() } else { self.local_keys.pubkeys().funding_pubkey },
+			node_id_1: if were_node_one { node_id } else { self.get_counterparty_node_id() },
+			node_id_2: if were_node_one { self.get_counterparty_node_id() } else { node_id },
+			bitcoin_key_1: if were_node_one { self.get_holder_pubkeys().funding_pubkey } else { self.counterparty_funding_pubkey().clone() },
+			bitcoin_key_2: if were_node_one { self.counterparty_funding_pubkey().clone() } else { self.get_holder_pubkeys().funding_pubkey },
 			excess_data: Vec::new(),
 		};
 
-		let sig = self.local_keys.sign_channel_announcement(&msg, &self.secp_ctx)
-			.map_err(|_| ChannelError::Ignore("Signer rejected channel_announcement"))?;
+		let sig = self.holder_keys.sign_channel_announcement(&msg, &self.secp_ctx)
+			.map_err(|_| ChannelError::Ignore("Signer rejected channel_announcement".to_owned()))?;
 
 		Ok((msg, sig))
 	}
@@ -3603,7 +3808,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// self.remove_uncommitted_htlcs_and_mark_paused()'d
 	pub fn get_channel_reestablish<L: Deref>(&self, logger: &L) -> msgs::ChannelReestablish where L::Target: Logger {
 		assert_eq!(self.channel_state & ChannelState::PeerDisconnected as u32, ChannelState::PeerDisconnected as u32);
-		assert_ne!(self.cur_remote_commitment_transaction_number, INITIAL_COMMITMENT_NUMBER);
+		assert_ne!(self.cur_counterparty_commitment_transaction_number, INITIAL_COMMITMENT_NUMBER);
 		// Prior to static_remotekey, my_current_per_commitment_point was critical to claiming
 		// current to_remote balances. However, it no longer has any use, and thus is now simply
 		// set to a dummy (but valid, as required by the spec) public key.
@@ -3612,8 +3817,8 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		// valid, and valid in fuzztarget mode's arbitrary validity criteria:
 		let mut pk = [2; 33]; pk[1] = 0xff;
 		let dummy_pubkey = PublicKey::from_slice(&pk).unwrap();
-		let data_loss_protect = if self.cur_remote_commitment_transaction_number + 1 < INITIAL_COMMITMENT_NUMBER {
-			let remote_last_secret = self.commitment_secrets.get_secret(self.cur_remote_commitment_transaction_number + 2).unwrap();
+		let data_loss_protect = if self.cur_counterparty_commitment_transaction_number + 1 < INITIAL_COMMITMENT_NUMBER {
+			let remote_last_secret = self.commitment_secrets.get_secret(self.cur_counterparty_commitment_transaction_number + 2).unwrap();
 			log_trace!(logger, "Enough info to generate a Data Loss Protect with per_commitment_secret {}", log_bytes!(remote_last_secret));
 			OptionalField::Present(DataLossProtect {
 				your_last_per_commitment_secret: remote_last_secret,
@@ -3637,15 +3842,15 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 			// next_local_commitment_number is the next commitment_signed number we expect to
 			// receive (indicating if they need to resend one that we missed).
-			next_local_commitment_number: INITIAL_COMMITMENT_NUMBER - self.cur_local_commitment_transaction_number,
+			next_local_commitment_number: INITIAL_COMMITMENT_NUMBER - self.cur_holder_commitment_transaction_number,
 			// We have to set next_remote_commitment_number to the next revoke_and_ack we expect to
 			// receive, however we track it by the next commitment number for a remote transaction
 			// (which is one further, as they always revoke previous commitment transaction, not
 			// the one we send) so we have to decrement by 1. Note that if
-			// cur_remote_commitment_transaction_number is INITIAL_COMMITMENT_NUMBER we will have
+			// cur_counterparty_commitment_transaction_number is INITIAL_COMMITMENT_NUMBER we will have
 			// dropped this channel on disconnect as it hasn't yet reached FundingSent so we can't
 			// overflow here.
-			next_remote_commitment_number: INITIAL_COMMITMENT_NUMBER - self.cur_remote_commitment_transaction_number - 1,
+			next_remote_commitment_number: INITIAL_COMMITMENT_NUMBER - self.cur_counterparty_commitment_transaction_number - 1,
 			data_loss_protect,
 		}
 	}
@@ -3662,19 +3867,19 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// If an Err is returned, it's a ChannelError::Ignore!
 	pub fn send_htlc(&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32, source: HTLCSource, onion_routing_packet: msgs::OnionPacket) -> Result<Option<msgs::UpdateAddHTLC>, ChannelError> {
 		if (self.channel_state & (ChannelState::ChannelFunded as u32 | BOTH_SIDES_SHUTDOWN_MASK)) != (ChannelState::ChannelFunded as u32) {
-			return Err(ChannelError::Ignore("Cannot send HTLC until channel is fully established and we haven't started shutting down"));
+			return Err(ChannelError::Ignore("Cannot send HTLC until channel is fully established and we haven't started shutting down".to_owned()));
 		}
-
-		if amount_msat > self.channel_value_satoshis * 1000 {
-			return Err(ChannelError::Ignore("Cannot send more than the total value of the channel"));
+		let channel_total_msat = self.channel_value_satoshis * 1000;
+		if amount_msat > channel_total_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send amount {}, because it is more than the total value of the channel {}", amount_msat, channel_total_msat)));
 		}
 
 		if amount_msat == 0 {
-			return Err(ChannelError::Ignore("Cannot send 0-msat HTLC"));
+			return Err(ChannelError::Ignore("Cannot send 0-msat HTLC".to_owned()));
 		}
 
-		if amount_msat < self.their_htlc_minimum_msat {
-			return Err(ChannelError::Ignore("Cannot send less than their minimum HTLC value"));
+		if amount_msat < self.counterparty_htlc_minimum_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send less than their minimum HTLC value ({})", self.counterparty_htlc_minimum_msat)));
 		}
 
 		if (self.channel_state & (ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32)) != 0 {
@@ -3684,49 +3889,48 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			// disconnected during the time the previous hop was doing the commitment dance we may
 			// end up getting here after the forwarding delay. In any case, returning an
 			// IgnoreError will get ChannelManager to do the right thing and fail backwards now.
-			return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected/frozen for channel monitor update"));
+			return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected/frozen for channel monitor update".to_owned()));
 		}
 
 		let (outbound_htlc_count, htlc_outbound_value_msat) = self.get_outbound_pending_htlc_stats();
-		if outbound_htlc_count + 1 > self.their_max_accepted_htlcs as u32 {
-			return Err(ChannelError::Ignore("Cannot push more than their max accepted HTLCs"));
+		if outbound_htlc_count + 1 > self.counterparty_max_accepted_htlcs as u32 {
+			return Err(ChannelError::Ignore(format!("Cannot push more than their max accepted HTLCs ({})", self.counterparty_max_accepted_htlcs)));
 		}
 		// Check their_max_htlc_value_in_flight_msat
-		if htlc_outbound_value_msat + amount_msat > self.their_max_htlc_value_in_flight_msat {
-			return Err(ChannelError::Ignore("Cannot send value that would put us over the max HTLC value in flight our peer will accept"));
+		if htlc_outbound_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send value that would put us over the max HTLC value in flight our peer will accept ({})", self.counterparty_max_htlc_value_in_flight_msat)));
 		}
 
-		if !self.channel_outbound {
+		if !self.is_outbound() {
 			// Check that we won't violate the remote channel reserve by adding this HTLC.
-
-			let remote_balance_msat = self.channel_value_satoshis * 1000 - self.value_to_self_msat;
-			let remote_chan_reserve_msat = Channel::<ChanSigner>::get_remote_channel_reserve_satoshis(self.channel_value_satoshis);
-			// 1 additional HTLC corresponding to this HTLC.
-			let remote_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(1);
-			if remote_balance_msat < remote_chan_reserve_msat + remote_commit_tx_fee_msat {
-				return Err(ChannelError::Ignore("Cannot send value that would put them under remote channel reserve value"));
+			let counterparty_balance_msat = self.channel_value_satoshis * 1000 - self.value_to_self_msat;
+			let holder_selected_chan_reserve_msat = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis);
+			let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered);
+			let counterparty_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+			if counterparty_balance_msat < holder_selected_chan_reserve_msat + counterparty_commit_tx_fee_msat {
+				return Err(ChannelError::Ignore("Cannot send value that would put counterparty balance under holder-announced channel reserve value".to_owned()));
 			}
 		}
 
 		let pending_value_to_self_msat = self.value_to_self_msat - htlc_outbound_value_msat;
 		if pending_value_to_self_msat < amount_msat {
-			return Err(ChannelError::Ignore("Cannot send value that would overdraw remaining funds"));
+			return Err(ChannelError::Ignore(format!("Cannot send value that would overdraw remaining funds. Amount: {}, pending value to self {}", amount_msat, pending_value_to_self_msat)));
 		}
 
-		// The `+1` is for the HTLC currently being added to the commitment tx and
-		// the `2 *` and `+1` are for the fee spike buffer.
-		let local_commit_tx_fee_msat = if self.channel_outbound {
-			2 * self.next_local_commit_tx_fee_msat(1 + 1)
+		// `2 *` and extra HTLC are for the fee spike buffer.
+		let commit_tx_fee_msat = if self.is_outbound() {
+			let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered);
+			2 * self.next_local_commit_tx_fee_msat(htlc_candidate, Some(()))
 		} else { 0 };
-		if pending_value_to_self_msat - amount_msat < local_commit_tx_fee_msat {
-			return Err(ChannelError::Ignore("Cannot send value that would not leave enough to pay for fees"));
+		if pending_value_to_self_msat - amount_msat < commit_tx_fee_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send value that would not leave enough to pay for fees. Pending value to self: {}. local_commit_tx_fee {}", pending_value_to_self_msat, commit_tx_fee_msat)));
 		}
 
-		// Check self.local_channel_reserve_satoshis (the amount we must keep as
+		// Check self.counterparty_selected_channel_reserve_satoshis (the amount we must keep as
 		// reserve for the remote to have something to claim if we misbehave)
-		let chan_reserve_msat = self.local_channel_reserve_satoshis * 1000;
-		if pending_value_to_self_msat - amount_msat - local_commit_tx_fee_msat < chan_reserve_msat {
-			return Err(ChannelError::Ignore("Cannot send value that would put us under local channel reserve value"));
+		let chan_reserve_msat = self.counterparty_selected_channel_reserve_satoshis * 1000;
+		if pending_value_to_self_msat - amount_msat - commit_tx_fee_msat < chan_reserve_msat {
+			return Err(ChannelError::Ignore(format!("Cannot send value that would put our balance under counterparty-announced channel reserve value ({})", chan_reserve_msat)));
 		}
 
 		// Now update local state:
@@ -3742,7 +3946,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 
 		self.pending_outbound_htlcs.push(OutboundHTLCOutput {
-			htlc_id: self.next_local_htlc_id,
+			htlc_id: self.next_holder_htlc_id,
 			amount_msat,
 			payment_hash: payment_hash.clone(),
 			cltv_expiry,
@@ -3752,13 +3956,13 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		let res = msgs::UpdateAddHTLC {
 			channel_id: self.channel_id,
-			htlc_id: self.next_local_htlc_id,
+			htlc_id: self.next_holder_htlc_id,
 			amount_msat,
 			payment_hash,
 			cltv_expiry,
 			onion_routing_packet,
 		};
-		self.next_local_htlc_id += 1;
+		self.next_holder_htlc_id += 1;
 
 		Ok(Some(res))
 	}
@@ -3820,12 +4024,12 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		}
 		self.resend_order = RAACommitmentOrder::RevokeAndACKFirst;
 
-		let (res, remote_commitment_tx, htlcs) = match self.send_commitment_no_state_update(logger) {
-			Ok((res, (remote_commitment_tx, mut htlcs))) => {
+		let (res, counterparty_commitment_txid, htlcs) = match self.send_commitment_no_state_update(logger) {
+			Ok((res, (counterparty_commitment_tx, mut htlcs))) => {
 				// Update state now that we've passed all the can-fail calls...
 				let htlcs_no_ref: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)> =
 					htlcs.drain(..).map(|(htlc, htlc_source)| (htlc, htlc_source.map(|source_ref| Box::new(source_ref.clone())))).collect();
-				(res, remote_commitment_tx, htlcs_no_ref)
+				(res, counterparty_commitment_tx, htlcs_no_ref)
 			},
 			Err(e) => return Err(e),
 		};
@@ -3833,53 +4037,71 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 		self.latest_monitor_update_id += 1;
 		let monitor_update = ChannelMonitorUpdate {
 			update_id: self.latest_monitor_update_id,
-			updates: vec![ChannelMonitorUpdateStep::LatestRemoteCommitmentTXInfo {
-				unsigned_commitment_tx: remote_commitment_tx.clone(),
+			updates: vec![ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo {
+				commitment_txid: counterparty_commitment_txid,
 				htlc_outputs: htlcs.clone(),
-				commitment_number: self.cur_remote_commitment_transaction_number,
-				their_revocation_point: self.their_cur_commitment_point.unwrap()
+				commitment_number: self.cur_counterparty_commitment_transaction_number,
+				their_revocation_point: self.counterparty_cur_commitment_point.unwrap()
 			}]
 		};
-		self.channel_monitor.as_mut().unwrap().update_monitor_ooo(monitor_update.clone(), logger).unwrap();
 		self.channel_state |= ChannelState::AwaitingRemoteRevoke as u32;
 		Ok((res, monitor_update))
 	}
 
 	/// Only fails in case of bad keys. Used for channel_reestablish commitment_signed generation
 	/// when we shouldn't change HTLC/channel state.
-	fn send_commitment_no_state_update<L: Deref>(&self, logger: &L) -> Result<(msgs::CommitmentSigned, (Transaction, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>)), ChannelError> where L::Target: Logger {
+	fn send_commitment_no_state_update<L: Deref>(&self, logger: &L) -> Result<(msgs::CommitmentSigned, (Txid, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>)), ChannelError> where L::Target: Logger {
 		let mut feerate_per_kw = self.feerate_per_kw;
 		if let Some(feerate) = self.pending_update_fee {
-			if self.channel_outbound {
+			if self.is_outbound() {
 				feerate_per_kw = feerate;
 			}
 		}
 
-		let remote_keys = self.build_remote_transaction_keys()?;
-		let remote_commitment_tx = self.build_commitment_transaction(self.cur_remote_commitment_transaction_number, &remote_keys, false, true, feerate_per_kw, logger);
+		let counterparty_keys = self.build_remote_transaction_keys()?;
+		let counterparty_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, feerate_per_kw, logger);
+		let counterparty_commitment_txid = counterparty_commitment_tx.0.trust().txid();
 		let (signature, htlc_signatures);
 
+		#[cfg(any(test, feature = "fuzztarget"))]
 		{
-			let mut htlcs = Vec::with_capacity(remote_commitment_tx.2.len());
-			for &(ref htlc, _) in remote_commitment_tx.2.iter() {
+			if !self.is_outbound() {
+				let projected_commit_tx_info = self.next_remote_commitment_tx_fee_info_cached.lock().unwrap().take();
+				*self.next_local_commitment_tx_fee_info_cached.lock().unwrap() = None;
+				if let Some(info) = projected_commit_tx_info {
+					let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len();
+					if info.total_pending_htlcs == total_pending_htlcs
+						&& info.next_holder_htlc_id == self.next_holder_htlc_id
+						&& info.next_counterparty_htlc_id == self.next_counterparty_htlc_id
+						&& info.feerate == self.feerate_per_kw {
+							let actual_fee = self.commit_tx_fee_msat(counterparty_commitment_tx.1);
+							assert_eq!(actual_fee, info.fee);
+						}
+				}
+			}
+		}
+
+		{
+			let mut htlcs = Vec::with_capacity(counterparty_commitment_tx.2.len());
+			for &(ref htlc, _) in counterparty_commitment_tx.2.iter() {
 				htlcs.push(htlc);
 			}
 
-			let res = self.local_keys.sign_remote_commitment(feerate_per_kw, &remote_commitment_tx.0, &remote_keys, &htlcs, self.our_to_self_delay, &self.secp_ctx)
-				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed"))?;
+			let res = self.holder_keys.sign_counterparty_commitment(&counterparty_commitment_tx.0, &self.secp_ctx)
+				.map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?;
 			signature = res.0;
 			htlc_signatures = res.1;
 
 			log_trace!(logger, "Signed remote commitment tx {} with redeemscript {} -> {}",
-				encode::serialize_hex(&remote_commitment_tx.0),
+				&counterparty_commitment_txid,
 				encode::serialize_hex(&self.get_funding_redeemscript()),
 				log_bytes!(signature.serialize_compact()[..]));
 
 			for (ref htlc_sig, ref htlc) in htlc_signatures.iter().zip(htlcs) {
 				log_trace!(logger, "Signed remote HTLC tx {} with redeemscript {} with pubkey {} -> {}",
-					encode::serialize_hex(&chan_utils::build_htlc_transaction(&remote_commitment_tx.0.txid(), feerate_per_kw, self.our_to_self_delay, htlc, &remote_keys.a_delayed_payment_key, &remote_keys.revocation_key)),
-					encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, &remote_keys)),
-					log_bytes!(remote_keys.a_htlc_key.serialize()),
+					encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, feerate_per_kw, self.get_holder_selected_contest_delay(), htlc, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)),
+					encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, &counterparty_keys)),
+					log_bytes!(counterparty_keys.broadcaster_htlc_key.serialize()),
 					log_bytes!(htlc_sig.serialize_compact()[..]));
 			}
 		}
@@ -3888,7 +4110,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 			channel_id: self.channel_id,
 			signature,
 			htlc_signatures,
-		}, (remote_commitment_tx.0, remote_commitment_tx.2)))
+		}, (counterparty_commitment_txid, counterparty_commitment_tx.2)))
 	}
 
 	/// Adds a pending outbound HTLC to this channel, and creates a signed commitment transaction
@@ -3910,23 +4132,23 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	pub fn get_shutdown(&mut self) -> Result<(msgs::Shutdown, Vec<(HTLCSource, PaymentHash)>), APIError> {
 		for htlc in self.pending_outbound_htlcs.iter() {
 			if let OutboundHTLCState::LocalAnnounced(_) = htlc.state {
-				return Err(APIError::APIMisuseError{err: "Cannot begin shutdown with pending HTLCs. Process pending events first"});
+				return Err(APIError::APIMisuseError{err: "Cannot begin shutdown with pending HTLCs. Process pending events first".to_owned()});
 			}
 		}
 		if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != 0 {
 			if (self.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
-				return Err(APIError::APIMisuseError{err: "Shutdown already in progress"});
+				return Err(APIError::APIMisuseError{err: "Shutdown already in progress".to_owned()});
 			}
 			else if (self.channel_state & ChannelState::RemoteShutdownSent as u32) == ChannelState::RemoteShutdownSent as u32 {
-				return Err(APIError::ChannelUnavailable{err: "Shutdown already in progress by remote"});
+				return Err(APIError::ChannelUnavailable{err: "Shutdown already in progress by remote".to_owned()});
 			}
 		}
 		assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
 		if self.channel_state & (ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateFailed as u32) != 0 {
-			return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?"});
+			return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?".to_owned()});
 		}
 
-		let our_closing_script = self.get_closing_scriptpubkey();
+		let closing_script = self.get_closing_scriptpubkey();
 
 		// From here on out, we may not fail!
 		if self.channel_state < ChannelState::FundingSent as u32 {
@@ -3952,7 +4174,7 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 
 		Ok((msgs::Shutdown {
 			channel_id: self.channel_id,
-			scriptpubkey: our_closing_script,
+			scriptpubkey: closing_script,
 		}, dropped_outbound_htlcs))
 	}
 
@@ -3975,17 +4197,23 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 				_ => {}
 			}
 		}
-
-		for _htlc in self.pending_outbound_htlcs.drain(..) {
-			//TODO: Do something with the remaining HTLCs
-			//(we need to have the ChannelManager monitor them so we can claim the inbound HTLCs
-			//which correspond)
-		}
+		let funding_txo = if let Some(funding_txo) = self.get_funding_txo() {
+			// If we haven't yet exchanged funding signatures (ie channel_state < FundingSent),
+			// returning a channel monitor update here would imply a channel monitor update before
+			// we even registered the channel monitor to begin with, which is invalid.
+			// Thus, if we aren't actually at a point where we could conceivably broadcast the
+			// funding transaction, don't return a funding txo (which prevents providing the
+			// monitor update to the user, even if we return one).
+			// See test_duplicate_chan_id and test_pre_lockin_no_chan_closed_update for more.
+			if self.channel_state & (ChannelState::FundingSent as u32 | ChannelState::ChannelFunded as u32 | ChannelState::ShutdownComplete as u32) != 0 {
+				Some(funding_txo.clone())
+			} else { None }
+		} else { None };
 
 		self.channel_state = ChannelState::ShutdownComplete as u32;
 		self.update_time_counter += 1;
 		self.latest_monitor_update_id += 1;
-		(self.funding_txo.clone(), ChannelMonitorUpdate {
+		(funding_txo, ChannelMonitorUpdate {
 			update_id: self.latest_monitor_update_id,
 			updates: vec![ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast }],
 		}, dropped_outbound_htlcs)
@@ -4027,7 +4255,7 @@ impl Readable for InboundHTLCRemovalReason {
 	}
 }
 
-impl<ChanSigner: ChannelKeys + Writeable> Writeable for Channel<ChanSigner> {
+impl<Signer: Sign> Writeable for Channel<Signer> {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 		// Note that we write out as if remove_uncommitted_htlcs_and_mark_paused had just been
 		// called but include holding cell updates (and obviously we don't modify self).
@@ -4040,17 +4268,22 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for Channel<ChanSigner> {
 
 		self.channel_id.write(writer)?;
 		(self.channel_state | ChannelState::PeerDisconnected as u32).write(writer)?;
-		self.channel_outbound.write(writer)?;
 		self.channel_value_satoshis.write(writer)?;
 
 		self.latest_monitor_update_id.write(writer)?;
 
-		self.local_keys.write(writer)?;
+		let mut key_data = VecWriter(Vec::new());
+		self.holder_keys.write(&mut key_data)?;
+		assert!(key_data.0.len() < std::usize::MAX);
+		assert!(key_data.0.len() < std::u32::MAX as usize);
+		(key_data.0.len() as u32).write(writer)?;
+		writer.write_all(&key_data.0[..])?;
+
 		self.shutdown_pubkey.write(writer)?;
 		self.destination_script.write(writer)?;
 
-		self.cur_local_commitment_transaction_number.write(writer)?;
-		self.cur_remote_commitment_transaction_number.write(writer)?;
+		self.cur_holder_commitment_transaction_number.write(writer)?;
+		self.cur_counterparty_commitment_transaction_number.write(writer)?;
 		self.value_to_self_msat.write(writer)?;
 
 		let mut dropped_inbound_htlcs = 0;
@@ -4167,8 +4400,8 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for Channel<ChanSigner> {
 		self.pending_update_fee.write(writer)?;
 		self.holding_cell_update_fee.write(writer)?;
 
-		self.next_local_htlc_id.write(writer)?;
-		(self.next_remote_htlc_id - dropped_inbound_htlcs).write(writer)?;
+		self.next_holder_htlc_id.write(writer)?;
+		(self.next_counterparty_htlc_id - dropped_inbound_htlcs).write(writer)?;
 		self.update_time_counter.write(writer)?;
 		self.feerate_per_kw.write(writer)?;
 
@@ -4182,41 +4415,38 @@ impl<ChanSigner: ChannelKeys + Writeable> Writeable for Channel<ChanSigner> {
 			None => 0u8.write(writer)?,
 		}
 
-		self.funding_txo.write(writer)?;
 		self.funding_tx_confirmed_in.write(writer)?;
 		self.short_channel_id.write(writer)?;
 
 		self.last_block_connected.write(writer)?;
 		self.funding_tx_confirmations.write(writer)?;
 
-		self.their_dust_limit_satoshis.write(writer)?;
-		self.our_dust_limit_satoshis.write(writer)?;
-		self.their_max_htlc_value_in_flight_msat.write(writer)?;
-		self.local_channel_reserve_satoshis.write(writer)?;
-		self.their_htlc_minimum_msat.write(writer)?;
-		self.our_htlc_minimum_msat.write(writer)?;
-		self.their_to_self_delay.write(writer)?;
-		self.our_to_self_delay.write(writer)?;
-		self.their_max_accepted_htlcs.write(writer)?;
+		self.counterparty_dust_limit_satoshis.write(writer)?;
+		self.holder_dust_limit_satoshis.write(writer)?;
+		self.counterparty_max_htlc_value_in_flight_msat.write(writer)?;
+		self.counterparty_selected_channel_reserve_satoshis.write(writer)?;
+		self.counterparty_htlc_minimum_msat.write(writer)?;
+		self.holder_htlc_minimum_msat.write(writer)?;
+		self.counterparty_max_accepted_htlcs.write(writer)?;
 		self.minimum_depth.write(writer)?;
 
-		self.their_pubkeys.write(writer)?;
-		self.their_cur_commitment_point.write(writer)?;
+		self.channel_transaction_parameters.write(writer)?;
+		self.counterparty_cur_commitment_point.write(writer)?;
 
-		self.their_prev_commitment_point.write(writer)?;
-		self.their_node_id.write(writer)?;
+		self.counterparty_prev_commitment_point.write(writer)?;
+		self.counterparty_node_id.write(writer)?;
 
-		self.their_shutdown_scriptpubkey.write(writer)?;
+		self.counterparty_shutdown_scriptpubkey.write(writer)?;
 
 		self.commitment_secrets.write(writer)?;
-
-		self.channel_monitor.as_ref().unwrap().write_for_disk(writer)?;
 		Ok(())
 	}
 }
 
-impl<ChanSigner: ChannelKeys + Readable> Readable for Channel<ChanSigner> {
-	fn read<R : ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+const MAX_ALLOC_SIZE: usize = 64*1024;
+impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
+		where K::Target: KeysInterface<Signer = Signer> {
+	fn read<R : ::std::io::Read>(reader: &mut R, keys_source: &'a K) -> Result<Self, DecodeError> {
 		let _ver: u8 = Readable::read(reader)?;
 		let min_ver: u8 = Readable::read(reader)?;
 		if min_ver > SERIALIZATION_VERSION {
@@ -4228,17 +4458,26 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for Channel<ChanSigner> {
 
 		let channel_id = Readable::read(reader)?;
 		let channel_state = Readable::read(reader)?;
-		let channel_outbound = Readable::read(reader)?;
 		let channel_value_satoshis = Readable::read(reader)?;
 
 		let latest_monitor_update_id = Readable::read(reader)?;
 
-		let local_keys = Readable::read(reader)?;
+		let keys_len: u32 = Readable::read(reader)?;
+		let mut keys_data = Vec::with_capacity(cmp::min(keys_len as usize, MAX_ALLOC_SIZE));
+		while keys_data.len() != keys_len as usize {
+			// Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
+			let mut data = [0; 1024];
+			let read_slice = &mut data[0..cmp::min(1024, keys_len as usize - keys_data.len())];
+			reader.read_exact(read_slice)?;
+			keys_data.extend_from_slice(read_slice);
+		}
+		let holder_keys = keys_source.read_chan_signer(&keys_data)?;
+
 		let shutdown_pubkey = Readable::read(reader)?;
 		let destination_script = Readable::read(reader)?;
 
-		let cur_local_commitment_transaction_number = Readable::read(reader)?;
-		let cur_remote_commitment_transaction_number = Readable::read(reader)?;
+		let cur_holder_commitment_transaction_number = Readable::read(reader)?;
+		let cur_counterparty_commitment_transaction_number = Readable::read(reader)?;
 		let value_to_self_msat = Readable::read(reader)?;
 
 		let pending_inbound_htlc_count: u64 = Readable::read(reader)?;
@@ -4327,8 +4566,8 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for Channel<ChanSigner> {
 		let pending_update_fee = Readable::read(reader)?;
 		let holding_cell_update_fee = Readable::read(reader)?;
 
-		let next_local_htlc_id = Readable::read(reader)?;
-		let next_remote_htlc_id = Readable::read(reader)?;
+		let next_holder_htlc_id = Readable::read(reader)?;
+		let next_counterparty_htlc_id = Readable::read(reader)?;
 		let update_time_counter = Readable::read(reader)?;
 		let feerate_per_kw = Readable::read(reader)?;
 
@@ -4338,58 +4577,47 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for Channel<ChanSigner> {
 			_ => return Err(DecodeError::InvalidValue),
 		};
 
-		let funding_txo = Readable::read(reader)?;
 		let funding_tx_confirmed_in = Readable::read(reader)?;
 		let short_channel_id = Readable::read(reader)?;
 
 		let last_block_connected = Readable::read(reader)?;
 		let funding_tx_confirmations = Readable::read(reader)?;
 
-		let their_dust_limit_satoshis = Readable::read(reader)?;
-		let our_dust_limit_satoshis = Readable::read(reader)?;
-		let their_max_htlc_value_in_flight_msat = Readable::read(reader)?;
-		let local_channel_reserve_satoshis = Readable::read(reader)?;
-		let their_htlc_minimum_msat = Readable::read(reader)?;
-		let our_htlc_minimum_msat = Readable::read(reader)?;
-		let their_to_self_delay = Readable::read(reader)?;
-		let our_to_self_delay = Readable::read(reader)?;
-		let their_max_accepted_htlcs = Readable::read(reader)?;
+		let counterparty_dust_limit_satoshis = Readable::read(reader)?;
+		let holder_dust_limit_satoshis = Readable::read(reader)?;
+		let counterparty_max_htlc_value_in_flight_msat = Readable::read(reader)?;
+		let counterparty_selected_channel_reserve_satoshis = Readable::read(reader)?;
+		let counterparty_htlc_minimum_msat = Readable::read(reader)?;
+		let holder_htlc_minimum_msat = Readable::read(reader)?;
+		let counterparty_max_accepted_htlcs = Readable::read(reader)?;
 		let minimum_depth = Readable::read(reader)?;
 
-		let their_pubkeys = Readable::read(reader)?;
-		let their_cur_commitment_point = Readable::read(reader)?;
+		let channel_parameters = Readable::read(reader)?;
+		let counterparty_cur_commitment_point = Readable::read(reader)?;
 
-		let their_prev_commitment_point = Readable::read(reader)?;
-		let their_node_id = Readable::read(reader)?;
+		let counterparty_prev_commitment_point = Readable::read(reader)?;
+		let counterparty_node_id = Readable::read(reader)?;
 
-		let their_shutdown_scriptpubkey = Readable::read(reader)?;
+		let counterparty_shutdown_scriptpubkey = Readable::read(reader)?;
 		let commitment_secrets = Readable::read(reader)?;
 
-		let (monitor_last_block, channel_monitor) = Readable::read(reader)?;
-		// We drop the ChannelMonitor's last block connected hash cause we don't actually bother
-		// doing full block connection operations on the internal ChannelMonitor copies
-		if monitor_last_block != last_block_connected {
-			return Err(DecodeError::InvalidValue);
-		}
-
 		Ok(Channel {
 			user_id,
 
 			config,
 			channel_id,
 			channel_state,
-			channel_outbound,
 			secp_ctx: Secp256k1::new(),
 			channel_value_satoshis,
 
 			latest_monitor_update_id,
 
-			local_keys,
+			holder_keys,
 			shutdown_pubkey,
 			destination_script,
 
-			cur_local_commitment_transaction_number,
-			cur_remote_commitment_transaction_number,
+			cur_holder_commitment_transaction_number,
+			cur_counterparty_commitment_transaction_number,
 			value_to_self_msat,
 
 			pending_inbound_htlcs,
@@ -4406,75 +4634,75 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for Channel<ChanSigner> {
 
 			pending_update_fee,
 			holding_cell_update_fee,
-			next_local_htlc_id,
-			next_remote_htlc_id,
+			next_holder_htlc_id,
+			next_counterparty_htlc_id,
 			update_time_counter,
 			feerate_per_kw,
 
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_local: ::std::sync::Mutex::new((0, 0)),
+			holder_max_commitment_tx_output: ::std::sync::Mutex::new((0, 0)),
 			#[cfg(debug_assertions)]
-			max_commitment_tx_output_remote: ::std::sync::Mutex::new((0, 0)),
+			counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((0, 0)),
 
 			last_sent_closing_fee,
 
-			funding_txo,
 			funding_tx_confirmed_in,
 			short_channel_id,
 			last_block_connected,
 			funding_tx_confirmations,
 
-			their_dust_limit_satoshis,
-			our_dust_limit_satoshis,
-			their_max_htlc_value_in_flight_msat,
-			local_channel_reserve_satoshis,
-			their_htlc_minimum_msat,
-			our_htlc_minimum_msat,
-			their_to_self_delay,
-			our_to_self_delay,
-			their_max_accepted_htlcs,
+			counterparty_dust_limit_satoshis,
+			holder_dust_limit_satoshis,
+			counterparty_max_htlc_value_in_flight_msat,
+			counterparty_selected_channel_reserve_satoshis,
+			counterparty_htlc_minimum_msat,
+			holder_htlc_minimum_msat,
+			counterparty_max_accepted_htlcs,
 			minimum_depth,
 
-			their_pubkeys,
-			their_cur_commitment_point,
+			channel_transaction_parameters: channel_parameters,
+			counterparty_cur_commitment_point,
 
-			their_prev_commitment_point,
-			their_node_id,
+			counterparty_prev_commitment_point,
+			counterparty_node_id,
 
-			their_shutdown_scriptpubkey,
+			counterparty_shutdown_scriptpubkey,
 
-			channel_monitor: Some(channel_monitor),
 			commitment_secrets,
 
 			network_sync: UpdateStatus::Fresh,
+
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+			#[cfg(any(test, feature = "fuzztarget"))]
+			next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
 		})
 	}
 }
 
 #[cfg(test)]
 mod tests {
-	use bitcoin::BitcoinHash;
 	use bitcoin::util::bip143;
 	use bitcoin::consensus::encode::serialize;
 	use bitcoin::blockdata::script::{Script, Builder};
-	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::blockdata::transaction::{Transaction, TxOut, SigHashType};
 	use bitcoin::blockdata::constants::genesis_block;
 	use bitcoin::blockdata::opcodes;
 	use bitcoin::network::constants::Network;
 	use bitcoin::hashes::hex::FromHex;
 	use hex;
 	use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash};
-	use ln::channel::{Channel,ChannelKeys,InboundHTLCOutput,OutboundHTLCOutput,InboundHTLCState,OutboundHTLCState,HTLCOutputInCommitment,TxCreationKeys};
+	use ln::channel::{Channel,Sign,InboundHTLCOutput,OutboundHTLCOutput,InboundHTLCState,OutboundHTLCState,HTLCOutputInCommitment,HTLCCandidate,HTLCInitiator,TxCreationKeys};
 	use ln::channel::MAX_FUNDING_SATOSHIS;
 	use ln::features::InitFeatures;
-	use ln::msgs::{OptionalField, DataLossProtect};
+	use ln::msgs::{OptionalField, DataLossProtect, DecodeError};
 	use ln::chan_utils;
-	use ln::chan_utils::{LocalCommitmentTransaction, ChannelPublicKeys};
+	use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT};
 	use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
-	use chain::keysinterface::{InMemoryChannelKeys, KeysInterface};
+	use chain::keysinterface::{InMemorySigner, KeysInterface};
 	use chain::transaction::OutPoint;
 	use util::config::UserConfig;
-	use util::enforcing_trait_impls::EnforcingChannelKeys;
+	use util::enforcing_trait_impls::EnforcingSigner;
 	use util::test_utils;
 	use util::logger::Logger;
 	use bitcoin::secp256k1::{Secp256k1, Message, Signature, All};
@@ -4500,17 +4728,17 @@ mod tests {
 	}
 
 	struct Keys {
-		chan_keys: InMemoryChannelKeys,
+		chan_keys: InMemorySigner,
 	}
 	impl KeysInterface for Keys {
-		type ChanKeySigner = InMemoryChannelKeys;
+		type Signer = InMemorySigner;
 
 		fn get_node_secret(&self) -> SecretKey { panic!(); }
 		fn get_destination_script(&self) -> Script {
 			let secp_ctx = Secp256k1::signing_only();
 			let channel_monitor_claim_key = SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap();
-			let our_channel_monitor_claim_key_hash = WPubkeyHash::hash(&PublicKey::from_secret_key(&secp_ctx, &channel_monitor_claim_key).serialize());
-			Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&our_channel_monitor_claim_key_hash[..]).into_script()
+			let channel_monitor_claim_key_hash = WPubkeyHash::hash(&PublicKey::from_secret_key(&secp_ctx, &channel_monitor_claim_key).serialize());
+			Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_monitor_claim_key_hash[..]).into_script()
 		}
 
 		fn get_shutdown_pubkey(&self) -> PublicKey {
@@ -4519,11 +4747,11 @@ mod tests {
 			PublicKey::from_secret_key(&secp_ctx, &channel_close_key)
 		}
 
-		fn get_channel_keys(&self, _inbound: bool, _channel_value_satoshis: u64) -> InMemoryChannelKeys {
+		fn get_channel_signer(&self, _inbound: bool, _channel_value_satoshis: u64) -> InMemorySigner {
 			self.chan_keys.clone()
 		}
-		fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) { panic!(); }
-		fn get_channel_id(&self) -> [u8; 32] { [0; 32] }
+		fn get_secure_random_bytes(&self) -> [u8; 32] { [0; 32] }
+		fn read_chan_signer(&self, _data: &[u8]) -> Result<Self::Signer, DecodeError> { panic!(); }
 	}
 
 	fn public_from_secret_hex(secp_ctx: &Secp256k1<All>, hex: &str) -> PublicKey {
@@ -4543,15 +4771,131 @@ mod tests {
 
 		let node_a_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 		let config = UserConfig::default();
-		let node_a_chan = Channel::<EnforcingChannelKeys>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, 10000000, 100000, 42, &config).unwrap();
+		let node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, 10000000, 100000, 42, &config).unwrap();
 
 		// Now change the fee so we can check that the fee in the open_channel message is the
 		// same as the old fee.
 		fee_est.fee_est = 500;
-		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.bitcoin_hash());
+		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
 		assert_eq!(open_channel_msg.feerate_per_kw, original_fee);
 	}
 
+	#[test]
+	fn test_holder_vs_counterparty_dust_limit() {
+		// Test that when calculating the local and remote commitment transaction fees, the correct
+		// dust limits are used.
+		let feeest = TestFeeEstimator{fee_est: 15000};
+		let secp_ctx = Secp256k1::new();
+		let seed = [42; 32];
+		let network = Network::Testnet;
+		let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
+
+		// Go through the flow of opening a channel between two nodes, making sure
+		// they have different dust limits.
+
+		// Create Node A's channel pointing to Node B's pubkey
+		let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		let config = UserConfig::default();
+		let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+
+		// Create Node B's channel by receiving Node A's open_channel message
+		// Make sure A's dust limit is as we expect.
+		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
+		assert_eq!(open_channel_msg.dust_limit_satoshis, 1560);
+		let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
+		let node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+
+		// Node B --> Node A: accept channel, explicitly setting B's dust limit.
+		let mut accept_channel_msg = node_b_chan.get_accept_channel();
+		accept_channel_msg.dust_limit_satoshis = 546;
+		node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap();
+
+		// Put some inbound and outbound HTLCs in A's channel.
+		let htlc_amount_msat = 11_092_000; // put an amount below A's effective dust limit but above B's.
+		node_a_chan.pending_inbound_htlcs.push(InboundHTLCOutput {
+			htlc_id: 0,
+			amount_msat: htlc_amount_msat,
+			payment_hash: PaymentHash(Sha256::hash(&[42; 32]).into_inner()),
+			cltv_expiry: 300000000,
+			state: InboundHTLCState::Committed,
+		});
+
+		node_a_chan.pending_outbound_htlcs.push(OutboundHTLCOutput {
+			htlc_id: 1,
+			amount_msat: htlc_amount_msat, // put an amount below A's dust amount but above B's.
+			payment_hash: PaymentHash(Sha256::hash(&[43; 32]).into_inner()),
+			cltv_expiry: 200000000,
+			state: OutboundHTLCState::Committed,
+			source: HTLCSource::OutboundRoute {
+				path: Vec::new(),
+				session_priv: SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap(),
+				first_hop_htlc_msat: 548,
+			}
+		});
+
+		// Make sure when Node A calculates their local commitment transaction, none of the HTLCs pass
+		// the dust limit check.
+		let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered);
+		let local_commit_tx_fee = node_a_chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
+		let local_commit_fee_0_htlcs = node_a_chan.commit_tx_fee_msat(0);
+		assert_eq!(local_commit_tx_fee, local_commit_fee_0_htlcs);
+
+		// Finally, make sure that when Node A calculates the remote's commitment transaction fees, all
+		// of the HTLCs are seen to be above the dust limit.
+		node_a_chan.channel_transaction_parameters.is_outbound_from_holder = false;
+		let remote_commit_fee_3_htlcs = node_a_chan.commit_tx_fee_msat(3);
+		let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered);
+		let remote_commit_tx_fee = node_a_chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+		assert_eq!(remote_commit_tx_fee, remote_commit_fee_3_htlcs);
+	}
+
+	#[test]
+	fn test_timeout_vs_success_htlc_dust_limit() {
+		// Make sure that when `next_remote_commit_tx_fee_msat` and `next_local_commit_tx_fee_msat`
+		// calculate the real dust limits for HTLCs (i.e. the dust limit given by the counterparty
+		// *plus* the fees paid for the HTLC) they don't swap `HTLC_SUCCESS_TX_WEIGHT` for
+		// `HTLC_TIMEOUT_TX_WEIGHT`, and vice versa.
+		let fee_est = TestFeeEstimator{fee_est: 253 };
+		let secp_ctx = Secp256k1::new();
+		let seed = [42; 32];
+		let network = Network::Testnet;
+		let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
+
+		let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		let config = UserConfig::default();
+		let mut chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_id, 10000000, 100000, 42, &config).unwrap();
+
+		let commitment_tx_fee_0_htlcs = chan.commit_tx_fee_msat(0);
+		let commitment_tx_fee_1_htlc = chan.commit_tx_fee_msat(1);
+
+		// If HTLC_SUCCESS_TX_WEIGHT and HTLC_TIMEOUT_TX_WEIGHT were swapped: then this HTLC would be
+		// counted as dust when it shouldn't be.
+		let htlc_amt_above_timeout = ((253 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + chan.holder_dust_limit_satoshis + 1) * 1000;
+		let htlc_candidate = HTLCCandidate::new(htlc_amt_above_timeout, HTLCInitiator::LocalOffered);
+		let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
+
+		// If swapped: this HTLC would be counted as non-dust when it shouldn't be.
+		let dust_htlc_amt_below_success = ((253 * HTLC_SUCCESS_TX_WEIGHT / 1000) + chan.holder_dust_limit_satoshis - 1) * 1000;
+		let htlc_candidate = HTLCCandidate::new(dust_htlc_amt_below_success, HTLCInitiator::RemoteOffered);
+		let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
+
+		chan.channel_transaction_parameters.is_outbound_from_holder = false;
+
+		// If swapped: this HTLC would be counted as non-dust when it shouldn't be.
+		let dust_htlc_amt_above_timeout = ((253 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + chan.counterparty_dust_limit_satoshis + 1) * 1000;
+		let htlc_candidate = HTLCCandidate::new(dust_htlc_amt_above_timeout, HTLCInitiator::LocalOffered);
+		let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
+
+		// If swapped: this HTLC would be counted as dust when it shouldn't be.
+		let htlc_amt_below_success = ((253 * HTLC_SUCCESS_TX_WEIGHT / 1000) + chan.counterparty_dust_limit_satoshis - 1) * 1000;
+		let htlc_candidate = HTLCCandidate::new(htlc_amt_below_success, HTLCInitiator::RemoteOffered);
+		let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
+	}
+
 	#[test]
 	fn channel_reestablish_no_updates() {
 		let feeest = TestFeeEstimator{fee_est: 15000};
@@ -4563,15 +4907,15 @@ mod tests {
 
 		// Go through the flow of opening a channel between two nodes.
 
-		// Create Node A's channel
-		let node_a_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		// Create Node A's channel pointing to Node B's pubkey
+		let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 		let config = UserConfig::default();
-		let mut node_a_chan = Channel::<EnforcingChannelKeys>::new_outbound(&&feeest, &&keys_provider, node_a_node_id, 10000000, 100000, 42, &config).unwrap();
+		let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
 
 		// Create Node B's channel by receiving Node A's open_channel message
-		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.bitcoin_hash());
+		let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
 		let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
-		let mut node_b_chan = Channel::<EnforcingChannelKeys>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+		let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
 
 		// Node B --> Node A: accept channel
 		let accept_channel_msg = node_b_chan.get_accept_channel();
@@ -4623,7 +4967,7 @@ mod tests {
 		let logger : Arc<Logger> = Arc::new(test_utils::TestLogger::new());
 		let secp_ctx = Secp256k1::new();
 
-		let mut chan_keys = InMemoryChannelKeys::new(
+		let mut chan_keys = InMemorySigner::new(
 			&secp_ctx,
 			SecretKey::from_slice(&hex::decode("30ff4956bbdd3222d44cc5e8a1261dab1e07957bdac5ae88fe3261ef321f3749").unwrap()[..]).unwrap(),
 			SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap(),
@@ -4634,97 +4978,109 @@ mod tests {
 			// These aren't set in the test vectors:
 			[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff],
 			10_000_000,
-			(0, 0)
+			[0; 32]
 		);
 
 		assert_eq!(chan_keys.pubkeys().funding_pubkey.serialize()[..],
 				hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]);
 		let keys_provider = Keys { chan_keys: chan_keys.clone() };
 
-		let their_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		let counterparty_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 		let mut config = UserConfig::default();
 		config.channel_options.announced_channel = false;
-		let mut chan = Channel::<InMemoryChannelKeys>::new_outbound(&&feeest, &&keys_provider, their_node_id, 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
-		chan.their_to_self_delay = 144;
-		chan.our_dust_limit_satoshis = 546;
+		let mut chan = Channel::<InMemorySigner>::new_outbound(&&feeest, &&keys_provider, counterparty_node_id, 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
+		chan.holder_dust_limit_satoshis = 546;
 
 		let funding_info = OutPoint{ txid: Txid::from_hex("8984484a580b825b9972d7adb15050b3ab624ccd731946b3eeddb92f4e7ef6be").unwrap(), index: 0 };
-		chan.funding_txo = Some(funding_info);
 
-		let their_pubkeys = ChannelPublicKeys {
+		let counterparty_pubkeys = ChannelPublicKeys {
 			funding_pubkey: public_from_secret_hex(&secp_ctx, "1552dfba4f6cf29a62a0af13c8d6981d36d0ef8d61ba10fb0fe90da7634d7e13"),
 			revocation_basepoint: PublicKey::from_slice(&hex::decode("02466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f27").unwrap()[..]).unwrap(),
 			payment_point: public_from_secret_hex(&secp_ctx, "4444444444444444444444444444444444444444444444444444444444444444"),
 			delayed_payment_basepoint: public_from_secret_hex(&secp_ctx, "1552dfba4f6cf29a62a0af13c8d6981d36d0ef8d61ba10fb0fe90da7634d7e13"),
 			htlc_basepoint: public_from_secret_hex(&secp_ctx, "4444444444444444444444444444444444444444444444444444444444444444")
 		};
-		chan_keys.set_remote_channel_pubkeys(&their_pubkeys);
+		chan.channel_transaction_parameters.counterparty_parameters = Some(
+			CounterpartyChannelTransactionParameters {
+				pubkeys: counterparty_pubkeys.clone(),
+				selected_contest_delay: 144
+			});
+		chan.channel_transaction_parameters.funding_outpoint = Some(funding_info);
+		chan_keys.ready_channel(&chan.channel_transaction_parameters);
 
-		assert_eq!(their_pubkeys.payment_point.serialize()[..],
+		assert_eq!(counterparty_pubkeys.payment_point.serialize()[..],
 		           hex::decode("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]);
 
-		assert_eq!(their_pubkeys.funding_pubkey.serialize()[..],
+		assert_eq!(counterparty_pubkeys.funding_pubkey.serialize()[..],
 		           hex::decode("030e9f7b623d2ccc7c9bd44d66d5ce21ce504c0acf6385a132cec6d3c39fa711c1").unwrap()[..]);
 
-		assert_eq!(their_pubkeys.htlc_basepoint.serialize()[..],
+		assert_eq!(counterparty_pubkeys.htlc_basepoint.serialize()[..],
 		           hex::decode("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]);
 
-		// We can't just use build_local_transaction_keys here as the per_commitment_secret is not
+		// We can't just use build_holder_transaction_keys here as the per_commitment_secret is not
 		// derived from a commitment_seed, so instead we copy it here and call
 		// build_commitment_transaction.
-		let delayed_payment_base = &chan.local_keys.pubkeys().delayed_payment_basepoint;
+		let delayed_payment_base = &chan.holder_keys.pubkeys().delayed_payment_basepoint;
 		let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap();
 		let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
-		let htlc_basepoint = &chan.local_keys.pubkeys().htlc_basepoint;
-		let keys = TxCreationKeys::new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &their_pubkeys.revocation_basepoint, &their_pubkeys.htlc_basepoint).unwrap();
-
-		chan.their_pubkeys = Some(their_pubkeys);
+		let htlc_basepoint = &chan.holder_keys.pubkeys().htlc_basepoint;
+		let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap();
 
-		let mut unsigned_tx: (Transaction, Vec<HTLCOutputInCommitment>);
-
-		let mut localtx;
 		macro_rules! test_commitment {
-			( $their_sig_hex: expr, $our_sig_hex: expr, $tx_hex: expr, {
-				$( { $htlc_idx: expr, $their_htlc_sig_hex: expr, $our_htlc_sig_hex: expr, $htlc_tx_hex: expr } ), *
+			( $counterparty_sig_hex: expr, $sig_hex: expr, $tx_hex: expr, {
+				$( { $htlc_idx: expr, $counterparty_htlc_sig_hex: expr, $htlc_sig_hex: expr, $htlc_tx_hex: expr } ), *
 			} ) => { {
-				unsigned_tx = {
+				let (commitment_tx, htlcs): (_, Vec<HTLCOutputInCommitment>) = {
 					let mut res = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, chan.feerate_per_kw, &logger);
+
 					let htlcs = res.2.drain(..)
 						.filter_map(|(htlc, _)| if htlc.transaction_output_index.is_some() { Some(htlc) } else { None })
 						.collect();
 					(res.0, htlcs)
 				};
+				let trusted_tx = commitment_tx.trust();
+				let unsigned_tx = trusted_tx.built_transaction();
 				let redeemscript = chan.get_funding_redeemscript();
-				let their_signature = Signature::from_der(&hex::decode($their_sig_hex).unwrap()[..]).unwrap();
-				let sighash = Message::from_slice(&bip143::SighashComponents::new(&unsigned_tx.0).sighash_all(&unsigned_tx.0.input[0], &redeemscript, chan.channel_value_satoshis)[..]).unwrap();
-				secp_ctx.verify(&sighash, &their_signature, chan.their_funding_pubkey()).unwrap();
+				let counterparty_signature = Signature::from_der(&hex::decode($counterparty_sig_hex).unwrap()[..]).unwrap();
+				let sighash = unsigned_tx.get_sighash_all(&redeemscript, chan.channel_value_satoshis);
+				secp_ctx.verify(&sighash, &counterparty_signature, chan.counterparty_funding_pubkey()).unwrap();
 
-				let mut per_htlc = Vec::new();
+				let mut per_htlc: Vec<(HTLCOutputInCommitment, Option<Signature>)> = Vec::new();
 				per_htlc.clear(); // Don't warn about excess mut for no-HTLC calls
+				let mut counterparty_htlc_sigs = Vec::new();
+				counterparty_htlc_sigs.clear(); // Don't warn about excess mut for no-HTLC calls
 				$({
-					let remote_signature = Signature::from_der(&hex::decode($their_htlc_sig_hex).unwrap()[..]).unwrap();
-					per_htlc.push((unsigned_tx.1[$htlc_idx].clone(), Some(remote_signature)));
+					let remote_signature = Signature::from_der(&hex::decode($counterparty_htlc_sig_hex).unwrap()[..]).unwrap();
+					per_htlc.push((htlcs[$htlc_idx].clone(), Some(remote_signature)));
+					counterparty_htlc_sigs.push(remote_signature);
 				})*
-				assert_eq!(unsigned_tx.1.len(), per_htlc.len());
+				assert_eq!(htlcs.len(), per_htlc.len());
 
-				localtx = LocalCommitmentTransaction::new_missing_local_sig(unsigned_tx.0.clone(), their_signature.clone(), &chan_keys.pubkeys().funding_pubkey, chan.their_funding_pubkey(), keys.clone(), chan.feerate_per_kw, per_htlc);
-				let local_sig = chan_keys.sign_local_commitment(&localtx, &chan.secp_ctx).unwrap();
-				assert_eq!(Signature::from_der(&hex::decode($our_sig_hex).unwrap()[..]).unwrap(), local_sig);
+				let holder_commitment_tx = HolderCommitmentTransaction::new(
+					commitment_tx.clone(),
+					counterparty_signature,
+					counterparty_htlc_sigs,
+					&chan.holder_keys.pubkeys().funding_pubkey,
+					chan.counterparty_funding_pubkey()
+				);
+				let (holder_sig, htlc_sigs) = chan_keys.sign_holder_commitment_and_htlcs(&holder_commitment_tx, &secp_ctx).unwrap();
+				assert_eq!(Signature::from_der(&hex::decode($sig_hex).unwrap()[..]).unwrap(), holder_sig, "holder_sig");
 
-				assert_eq!(serialize(&localtx.add_local_sig(&redeemscript, local_sig))[..],
-						hex::decode($tx_hex).unwrap()[..]);
+				let funding_redeemscript = chan.get_funding_redeemscript();
+				let tx = holder_commitment_tx.add_holder_sig(&funding_redeemscript, holder_sig);
+				assert_eq!(serialize(&tx)[..], hex::decode($tx_hex).unwrap()[..], "tx");
 
-				let htlc_sigs = chan_keys.sign_local_commitment_htlc_transactions(&localtx, chan.their_to_self_delay, &chan.secp_ctx).unwrap();
-				let mut htlc_sig_iter = localtx.per_htlc.iter().zip(htlc_sigs.iter().enumerate());
+				// ((htlc, counterparty_sig), (index, holder_sig))
+				let mut htlc_sig_iter = holder_commitment_tx.htlcs().iter().zip(&holder_commitment_tx.counterparty_htlc_sigs).zip(htlc_sigs.iter().enumerate());
 
 				$({
-					let remote_signature = Signature::from_der(&hex::decode($their_htlc_sig_hex).unwrap()[..]).unwrap();
+					let remote_signature = Signature::from_der(&hex::decode($counterparty_htlc_sig_hex).unwrap()[..]).unwrap();
 
-					let ref htlc = unsigned_tx.1[$htlc_idx];
-					let htlc_tx = chan.build_htlc_transaction(&unsigned_tx.0.txid(), &htlc, true, &keys, chan.feerate_per_kw);
+					let ref htlc = htlcs[$htlc_idx];
+					let htlc_tx = chan.build_htlc_transaction(&unsigned_tx.txid, &htlc, true, &keys, chan.feerate_per_kw);
 					let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
-					let htlc_sighash = Message::from_slice(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]).unwrap();
-					secp_ctx.verify(&htlc_sighash, &remote_signature, &keys.b_htlc_key).unwrap();
+					let htlc_sighash = Message::from_slice(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]).unwrap();
+					secp_ctx.verify(&htlc_sighash, &remote_signature, &keys.countersignatory_htlc_key).unwrap();
 
 					let mut preimage: Option<PaymentPreimage> = None;
 					if !htlc.offered {
@@ -4738,20 +5094,18 @@ mod tests {
 						assert!(preimage.is_some());
 					}
 
-					let mut htlc_sig = htlc_sig_iter.next().unwrap();
-					while (htlc_sig.1).1.is_none() { htlc_sig = htlc_sig_iter.next().unwrap(); }
-					assert_eq!((htlc_sig.0).0.transaction_output_index, Some($htlc_idx));
+					let htlc_sig = htlc_sig_iter.next().unwrap();
+					assert_eq!((htlc_sig.0).0.transaction_output_index, Some($htlc_idx), "output index");
 
-					let our_signature = Signature::from_der(&hex::decode($our_htlc_sig_hex).unwrap()[..]).unwrap();
-					assert_eq!(Some(our_signature), *(htlc_sig.1).1);
-					assert_eq!(serialize(&localtx.get_signed_htlc_tx((htlc_sig.1).0, &(htlc_sig.1).1.unwrap(), &preimage, chan.their_to_self_delay))[..],
-							hex::decode($htlc_tx_hex).unwrap()[..]);
+					let signature = Signature::from_der(&hex::decode($htlc_sig_hex).unwrap()[..]).unwrap();
+					assert_eq!(signature, *(htlc_sig.1).1, "htlc sig");
+					let index = (htlc_sig.1).0;
+					let channel_parameters = chan.channel_transaction_parameters.as_holder_broadcastable();
+					let trusted_tx = holder_commitment_tx.trust();
+					assert_eq!(serialize(&trusted_tx.get_signed_htlc_tx(&channel_parameters, index, &(htlc_sig.0).1, (htlc_sig.1).1, &preimage))[..],
+							hex::decode($htlc_tx_hex).unwrap()[..], "htlc tx");
 				})*
-				loop {
-					let htlc_sig = htlc_sig_iter.next();
-					if htlc_sig.is_none() { break; }
-					assert!((htlc_sig.unwrap().1).1.is_none());
-				}
+				assert!(htlc_sig_iter.next().is_none());
 			} }
 		}
 
@@ -5091,6 +5445,65 @@ mod tests {
 		test_commitment!("304402202ade0142008309eb376736575ad58d03e5b115499709c6db0b46e36ff394b492022037b63d78d66404d6504d4c4ac13be346f3d1802928a6d3ad95a6a944227161a2",
 		                 "304402207e8d51e0c570a5868a78414f4e0cbfaed1106b171b9581542c30718ee4eb95ba02203af84194c97adf98898c9afe2f2ed4a7f8dba05a2dfab28ac9d9c604aa49a379",
 		                 "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", {});
+
+		// commitment tx with 3 htlc outputs, 2 offered having the same amount and preimage
+		chan.value_to_self_msat = 7_000_000_000 - 2_000_000;
+		chan.feerate_per_kw = 253;
+		chan.pending_inbound_htlcs.clear();
+		chan.pending_inbound_htlcs.push({
+			let mut out = InboundHTLCOutput{
+				htlc_id: 1,
+				amount_msat: 2000000,
+				cltv_expiry: 501,
+				payment_hash: PaymentHash([0; 32]),
+				state: InboundHTLCState::Committed,
+			};
+			out.payment_hash.0 = Sha256::hash(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()).into_inner();
+			out
+		});
+		chan.pending_outbound_htlcs.clear();
+		chan.pending_outbound_htlcs.push({
+			let mut out = OutboundHTLCOutput{
+				htlc_id: 6,
+				amount_msat: 5000000,
+				cltv_expiry: 506,
+				payment_hash: PaymentHash([0; 32]),
+				state: OutboundHTLCState::Committed,
+				source: HTLCSource::dummy(),
+			};
+			out.payment_hash.0 = Sha256::hash(&hex::decode("0505050505050505050505050505050505050505050505050505050505050505").unwrap()).into_inner();
+			out
+		});
+		chan.pending_outbound_htlcs.push({
+			let mut out = OutboundHTLCOutput{
+				htlc_id: 5,
+				amount_msat: 5000000,
+				cltv_expiry: 505,
+				payment_hash: PaymentHash([0; 32]),
+				state: OutboundHTLCState::Committed,
+				source: HTLCSource::dummy(),
+			};
+			out.payment_hash.0 = Sha256::hash(&hex::decode("0505050505050505050505050505050505050505050505050505050505050505").unwrap()).into_inner();
+			out
+		});
+
+		test_commitment!("30440220048705bec5288d28b3f29344b8d124853b1af423a568664d2c6f02c8ea886525022060f998a461052a2476b912db426ea2a06700953a241135c7957f2e79bc222df9",
+		                 "3045022100c4f1d60b6fca9febc8b39de1a31e84c5f7c4b41c97239ef05f4350aa484c6b5e02200c5134ac8b20eb7a29d0dd4a501f6aa8fefb8489171f4cb408bd2a32324ab03f",
+		                 "02000000000101bef67e4e2fb9ddeeb3461973cd4c62abb35050b1add772995b820b584a488489000000000038b02b8005d007000000000000220020748eba944fedc8827f6b06bc44678f93c0f9e6078b35c6331ed31e75f8ce0c2d8813000000000000220020305c12e1a0bc21e283c131cea1c66d68857d28b7b2fce0a6fbc40c164852121b8813000000000000220020305c12e1a0bc21e283c131cea1c66d68857d28b7b2fce0a6fbc40c164852121bc0c62d0000000000160014cc1b07838e387deacd0e5232e1e8b49f4c29e484a79f6a00000000002200204adb4e2f00643db396dd120d4e7dc17625f5f2c11a40d857accc862d6b7dd80e0400483045022100c4f1d60b6fca9febc8b39de1a31e84c5f7c4b41c97239ef05f4350aa484c6b5e02200c5134ac8b20eb7a29d0dd4a501f6aa8fefb8489171f4cb408bd2a32324ab03f014730440220048705bec5288d28b3f29344b8d124853b1af423a568664d2c6f02c8ea886525022060f998a461052a2476b912db426ea2a06700953a241135c7957f2e79bc222df901475221023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb21030e9f7b623d2ccc7c9bd44d66d5ce21ce504c0acf6385a132cec6d3c39fa711c152ae3e195220", {
+
+		                  { 0,
+		                  "304502210081cbb94121761d34c189cd4e6a281feea6f585060ad0ba2632e8d6b3c6bb8a6c02201007981bbd16539d63df2805b5568f1f5688cd2a885d04706f50db9b77ba13c6",
+		                  "304502210090ed76aeb21b53236a598968abc66e2024691d07b62f53ddbeca8f93144af9c602205f873af5a0c10e62690e9aba09740550f194a9dc455ba4c1c23f6cde7704674c",
+		                  "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" },
+		                  { 1,
+		                  "304402201d0f09d2bf7bc245a4f17980e1e9164290df16c70c6a2ff1592f5030d6108581022061e744a7dc151b36bf0aff7a4f1812ba90b8b03633bb979a270d19858fd960c5",
+		                  "30450221009aef000d2e843a4202c1b1a2bf554abc9a7902bf49b2cb0759bc507456b7ebad02204e7c3d193ede2fd2b4cd6b39f51a920e581e35575e357e44d7b699c40ce61d39",
+		                  "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" },
+		                  { 2,
+		                  "30440220010bf035d5823596e50dce2076a4d9f942d8d28031c9c428b901a02b6b8140de02203250e8e4a08bc5b4ecdca4d0eedf98223e02e3ac1c0206b3a7ffdb374aa21e5f",
+		                  "30440220073de0067b88e425b3018b30366bfeda0ccb703118ccd3d02ead08c0f53511d002203fac50ac0e4cf8a3af0b4b1b12e801650591f748f8ddf1e089c160f10b69e511",
+		                  "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" }
+		} );
 	}
 
 	#[test]