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Make payment_key derivation deterministic #3391

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6dfe913
Drop `InMemorySigner` `Writeable` impl
tnull Sep 23, 2024
75c2b0a
Rename `payment_key` to `payment_basepoint` in `chan_utils`
tnull Sep 25, 2024
611c1a3
Rename `params` to `channel_keys_id` and take it by value
tnull Sep 25, 2024
6be731e
Rename `keys_id` to `channel_keys_id`
tnull Sep 28, 2024
ed2d63e
Rename `payment_point` to `payment_basepoint`
tnull Oct 31, 2024
aea8e5e
Make `payment_key` derivation deterministic
tnull Nov 6, 2024
a781d23
f Adjust test cases to accommodate new derivation scheme
tnull Oct 31, 2024
bf14ec8
f Allow legacy keys derivation for `test_restored_packages_retry`
tnull Nov 6, 2024
c70f7ec
Have `SignerProvider::get_shutdown_scriptpubkey` take `channel_keys_id`
tnull Nov 6, 2024
8991d74
Drop outdated comment
tnull Nov 11, 2024
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10 changes: 5 additions & 5 deletions lightning/src/chain/channelmonitor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1347,7 +1347,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {

assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
let counterparty_payment_script = chan_utils::get_counterparty_payment_script(
&channel_parameters.channel_type_features, &keys.pubkeys().payment_point
&channel_parameters.channel_type_features, &keys.pubkeys().payment_basepoint
);

let counterparty_channel_parameters = channel_parameters.counterparty_parameters.as_ref().unwrap();
Expand Down Expand Up @@ -4971,9 +4971,9 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
if onchain_tx_handler.channel_type_features().supports_anchors_zero_fee_htlc_tx() &&
counterparty_payment_script.is_p2wpkh()
{
let payment_point = onchain_tx_handler.channel_transaction_parameters.holder_pubkeys.payment_point;
let payment_basepoint = onchain_tx_handler.channel_transaction_parameters.holder_pubkeys.payment_basepoint;
counterparty_payment_script =
chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point).to_p2wsh();
chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_basepoint).to_p2wsh();
}

Ok((best_block.block_hash, ChannelMonitor::from_impl(ChannelMonitorImpl {
Expand Down Expand Up @@ -5243,7 +5243,7 @@ mod tests {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
revocation_basepoint: RevocationBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap())),
payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
payment_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
delayed_payment_basepoint: DelayedPaymentBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap())),
htlc_basepoint: HtlcBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap()))
};
Expand Down Expand Up @@ -5495,7 +5495,7 @@ mod tests {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
revocation_basepoint: RevocationBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap())),
payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
payment_basepoint: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
delayed_payment_basepoint: DelayedPaymentBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap())),
htlc_basepoint: HtlcBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap())),
};
Expand Down
24 changes: 12 additions & 12 deletions lightning/src/ln/chan_utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -478,7 +478,7 @@ pub struct ChannelPublicKeys {
/// The public key on which the non-broadcaster (ie the countersignatory) receives an immediately
/// spendable primary channel balance on the broadcaster's commitment transaction. This key is
/// static across every commitment transaction.
pub payment_point: PublicKey,
pub payment_basepoint: PublicKey,
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@TheBlueMatt TheBlueMatt Nov 25, 2024

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I think we discussed this elsewhere but IMO we should fix this in the spec, not here. The "base" in the "basepoint"s refer to the fact that its extended with the per_commitment_point to build a new point for each state. Since static_remotekey (which is now "ASSUMED" in the spec, and not described) its no longer used to derive a key but rather simply a key used as-is. The spec needs updating to remove references to its use as a base key.

/// The base point which is used (with derive_public_key) to derive a per-commitment payment
/// public key which receives non-HTLC-encumbered funds which are only available for spending
/// after some delay (or can be claimed via the revocation path).
Expand All @@ -491,7 +491,7 @@ pub struct ChannelPublicKeys {
impl_writeable_tlv_based!(ChannelPublicKeys, {
(0, funding_pubkey, required),
(2, revocation_basepoint, required),
(4, payment_point, required),
(4, payment_basepoint, required),
(6, delayed_payment_basepoint, required),
(8, htlc_basepoint, required),
});
Expand Down Expand Up @@ -816,9 +816,9 @@ pub(crate) fn legacy_deserialization_prevention_marker_for_channel_type_features

/// Gets the witnessScript for the to_remote output when anchors are enabled.
#[inline]
pub fn get_to_countersignatory_with_anchors_redeemscript(payment_point: &PublicKey) -> ScriptBuf {
pub fn get_to_countersignatory_with_anchors_redeemscript(payment_basepoint: &PublicKey) -> ScriptBuf {
Builder::new()
.push_slice(payment_point.serialize())
.push_slice(payment_basepoint.serialize())
.push_opcode(opcodes::all::OP_CHECKSIGVERIFY)
.push_int(1)
.push_opcode(opcodes::all::OP_CSV)
Expand Down Expand Up @@ -933,7 +933,7 @@ impl ChannelTransactionParameters {
let dummy_keys = ChannelPublicKeys {
funding_pubkey: PublicKey::from_slice(&[2; 33]).unwrap(),
revocation_basepoint: PublicKey::from_slice(&[2; 33]).unwrap().into(),
payment_point: PublicKey::from_slice(&[2; 33]).unwrap(),
payment_basepoint: PublicKey::from_slice(&[2; 33]).unwrap(),
delayed_payment_basepoint: PublicKey::from_slice(&[2; 33]).unwrap().into(),
htlc_basepoint: PublicKey::from_slice(&[2; 33]).unwrap().into(),
};
Expand Down Expand Up @@ -1119,7 +1119,7 @@ impl HolderCommitmentTransaction {
let channel_pubkeys = ChannelPublicKeys {
funding_pubkey: dummy_key.clone(),
revocation_basepoint: RevocationBasepoint::from(dummy_key),
payment_point: dummy_key.clone(),
payment_basepoint: dummy_key.clone(),
delayed_payment_basepoint: DelayedPaymentBasepoint::from(dummy_key.clone()),
htlc_basepoint: HtlcBasepoint::from(dummy_key.clone())
};
Expand Down Expand Up @@ -1515,9 +1515,9 @@ impl CommitmentTransaction {

if to_countersignatory_value_sat > Amount::ZERO {
let script = if channel_parameters.channel_type_features().supports_anchors_zero_fee_htlc_tx() {
get_to_countersignatory_with_anchors_redeemscript(&countersignatory_pubkeys.payment_point).to_p2wsh()
get_to_countersignatory_with_anchors_redeemscript(&countersignatory_pubkeys.payment_basepoint).to_p2wsh()
} else {
ScriptBuf::new_p2wpkh(&Hash160::hash(&countersignatory_pubkeys.payment_point.serialize()).into())
ScriptBuf::new_p2wpkh(&Hash160::hash(&countersignatory_pubkeys.payment_basepoint.serialize()).into())
};
txouts.push((
TxOut {
Expand Down Expand Up @@ -1608,8 +1608,8 @@ impl CommitmentTransaction {
let broadcaster_pubkeys = channel_parameters.broadcaster_pubkeys();
let countersignatory_pubkeys = channel_parameters.countersignatory_pubkeys();
let commitment_transaction_number_obscure_factor = get_commitment_transaction_number_obscure_factor(
&broadcaster_pubkeys.payment_point,
&countersignatory_pubkeys.payment_point,
&broadcaster_pubkeys.payment_basepoint,
&countersignatory_pubkeys.payment_basepoint,
channel_parameters.is_outbound(),
);

Expand Down Expand Up @@ -1974,13 +1974,13 @@ mod tests {
// Generate broadcaster and counterparty outputs
let tx = builder.build(1000, 2000);
assert_eq!(tx.built.transaction.output.len(), 2);
assert_eq!(tx.built.transaction.output[1].script_pubkey, bitcoin::address::Address::p2wpkh(&CompressedPublicKey(builder.counterparty_pubkeys.payment_point), Network::Testnet).script_pubkey());
assert_eq!(tx.built.transaction.output[1].script_pubkey, bitcoin::address::Address::p2wpkh(&CompressedPublicKey(builder.counterparty_pubkeys.payment_basepoint), Network::Testnet).script_pubkey());

// Generate broadcaster and counterparty outputs as well as two anchors
builder.channel_parameters.channel_type_features = ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies();
let tx = builder.build(1000, 2000);
assert_eq!(tx.built.transaction.output.len(), 4);
assert_eq!(tx.built.transaction.output[3].script_pubkey, get_to_countersignatory_with_anchors_redeemscript(&builder.counterparty_pubkeys.payment_point).to_p2wsh());
assert_eq!(tx.built.transaction.output[3].script_pubkey, get_to_countersignatory_with_anchors_redeemscript(&builder.counterparty_pubkeys.payment_basepoint).to_p2wsh());

// Generate broadcaster output and anchor
let tx = builder.build(3000, 0);
Expand Down
22 changes: 11 additions & 11 deletions lightning/src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1588,7 +1588,7 @@ trait InitialRemoteCommitmentReceiver<SP: Deref> where SP::Target: SignerProvide
let funding_redeemscript = context.get_funding_redeemscript();
let funding_txo = context.get_funding_txo().unwrap();
let funding_txo_script = funding_redeemscript.to_p2wsh();
let obscure_factor = get_commitment_transaction_number_obscure_factor(&context.get_holder_pubkeys().payment_point, &context.get_counterparty_pubkeys().payment_point, context.is_outbound());
let obscure_factor = get_commitment_transaction_number_obscure_factor(&context.get_holder_pubkeys().payment_basepoint, &context.get_counterparty_pubkeys().payment_basepoint, context.is_outbound());
let shutdown_script = context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
let mut monitor_signer = signer_provider.derive_channel_signer(context.channel_value_satoshis, context.channel_keys_id);
monitor_signer.provide_channel_parameters(&context.channel_transaction_parameters);
Expand Down Expand Up @@ -2483,7 +2483,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: common_fields.funding_pubkey,
revocation_basepoint: RevocationBasepoint::from(common_fields.revocation_basepoint),
payment_point: common_fields.payment_basepoint,
payment_basepoint: common_fields.payment_basepoint,
delayed_payment_basepoint: DelayedPaymentBasepoint::from(common_fields.delayed_payment_basepoint),
htlc_basepoint: HtlcBasepoint::from(common_fields.htlc_basepoint)
};
Expand Down Expand Up @@ -2749,7 +2749,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider {

log_trace!(logger, "Building commitment transaction number {} (really {} xor {}) for channel {} 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()),
get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_basepoint, &self.get_counterparty_pubkeys().payment_basepoint, self.is_outbound()),
&self.channel_id,
if local { "us" } else { "remote" }, if generated_by_local { "us" } else { "remote" }, feerate_per_kw);

Expand Down Expand Up @@ -7975,7 +7975,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
funding_pubkey: keys.funding_pubkey,
revocation_basepoint: keys.revocation_basepoint.to_public_key(),
payment_basepoint: keys.payment_point,
payment_basepoint: keys.payment_basepoint,
delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
htlc_basepoint: keys.htlc_basepoint.to_public_key(),
first_per_commitment_point,
Expand Down Expand Up @@ -8116,7 +8116,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: msg.common_fields.funding_pubkey,
revocation_basepoint: RevocationBasepoint::from(msg.common_fields.revocation_basepoint),
payment_point: msg.common_fields.payment_basepoint,
payment_basepoint: msg.common_fields.payment_basepoint,
delayed_payment_basepoint: DelayedPaymentBasepoint::from(msg.common_fields.delayed_payment_basepoint),
htlc_basepoint: HtlcBasepoint::from(msg.common_fields.htlc_basepoint)
};
Expand Down Expand Up @@ -8189,7 +8189,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
funding_pubkey: keys.funding_pubkey,
revocation_basepoint: keys.revocation_basepoint.to_public_key(),
payment_basepoint: keys.payment_point,
payment_basepoint: keys.payment_basepoint,
delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
htlc_basepoint: keys.htlc_basepoint.to_public_key(),
first_per_commitment_point,
Expand Down Expand Up @@ -8381,7 +8381,7 @@ impl<SP: Deref> OutboundV2Channel<SP> where SP::Target: SignerProvider {
max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
funding_pubkey: keys.funding_pubkey,
revocation_basepoint: keys.revocation_basepoint.to_public_key(),
payment_basepoint: keys.payment_point,
payment_basepoint: keys.payment_basepoint,
delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
htlc_basepoint: keys.htlc_basepoint.to_public_key(),
first_per_commitment_point,
Expand Down Expand Up @@ -8439,7 +8439,7 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: msg.common_fields.funding_pubkey,
revocation_basepoint: RevocationBasepoint(msg.common_fields.revocation_basepoint),
payment_point: msg.common_fields.payment_basepoint,
payment_basepoint: msg.common_fields.payment_basepoint,
delayed_payment_basepoint: DelayedPaymentBasepoint(msg.common_fields.delayed_payment_basepoint),
htlc_basepoint: HtlcBasepoint(msg.common_fields.htlc_basepoint)
};
Expand Down Expand Up @@ -8530,7 +8530,7 @@ impl<SP: Deref> InboundV2Channel<SP> where SP::Target: SignerProvider {
max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
funding_pubkey: keys.funding_pubkey,
revocation_basepoint: keys.revocation_basepoint.to_public_key(),
payment_basepoint: keys.payment_point,
payment_basepoint: keys.payment_basepoint,
delayed_payment_basepoint: keys.delayed_payment_basepoint.to_public_key(),
htlc_basepoint: keys.htlc_basepoint.to_public_key(),
first_per_commitment_point,
Expand Down Expand Up @@ -10367,7 +10367,7 @@ mod tests {
let counterparty_pubkeys = ChannelPublicKeys {
funding_pubkey: public_from_secret_hex(&secp_ctx, "1552dfba4f6cf29a62a0af13c8d6981d36d0ef8d61ba10fb0fe90da7634d7e13"),
revocation_basepoint: RevocationBasepoint::from(PublicKey::from_slice(&<Vec<u8>>::from_hex("02466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f27").unwrap()[..]).unwrap()),
payment_point: public_from_secret_hex(&secp_ctx, "4444444444444444444444444444444444444444444444444444444444444444"),
payment_basepoint: public_from_secret_hex(&secp_ctx, "4444444444444444444444444444444444444444444444444444444444444444"),
delayed_payment_basepoint: DelayedPaymentBasepoint::from(public_from_secret_hex(&secp_ctx, "1552dfba4f6cf29a62a0af13c8d6981d36d0ef8d61ba10fb0fe90da7634d7e13")),
htlc_basepoint: HtlcBasepoint::from(public_from_secret_hex(&secp_ctx, "4444444444444444444444444444444444444444444444444444444444444444"))
};
Expand All @@ -10379,7 +10379,7 @@ mod tests {
chan.context.channel_transaction_parameters.funding_outpoint = Some(funding_info);
signer.provide_channel_parameters(&chan.context.channel_transaction_parameters);

assert_eq!(counterparty_pubkeys.payment_point.serialize()[..],
assert_eq!(counterparty_pubkeys.payment_basepoint.serialize()[..],
<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]);

assert_eq!(counterparty_pubkeys.funding_pubkey.serialize()[..],
Expand Down
12 changes: 7 additions & 5 deletions lightning/src/sign/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -178,8 +178,10 @@ impl StaticPaymentOutputDescriptor {
pub fn witness_script(&self) -> Option<ScriptBuf> {
self.channel_transaction_parameters.as_ref().and_then(|channel_params| {
if channel_params.supports_anchors() {
let payment_point = channel_params.holder_pubkeys.payment_point;
Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(&payment_point))
let payment_basepoint = channel_params.holder_pubkeys.payment_basepoint;
Some(chan_utils::get_to_countersignatory_with_anchors_redeemscript(
&payment_basepoint,
))
} else {
None
}
Expand Down Expand Up @@ -282,7 +284,7 @@ pub enum SpendableOutputDescriptor {
/// [`chan_utils::get_revokeable_redeemscript`].
DelayedPaymentOutput(DelayedPaymentOutputDescriptor),
/// An output spendable exclusively by our payment key (i.e., the private key that corresponds
/// to the `payment_point` in [`ChannelSigner::pubkeys`]). The output type depends on the
/// to the `payment_basepoint` in [`ChannelSigner::pubkeys`]). The output type depends on the
/// channel type negotiated.
///
/// On an anchor outputs channel, the witness in the spending input is:
Expand Down Expand Up @@ -1125,7 +1127,7 @@ impl InMemorySigner {
ChannelPublicKeys {
funding_pubkey: from_secret(&funding_key),
revocation_basepoint: RevocationBasepoint::from(from_secret(&revocation_base_key)),
payment_point: from_secret(&payment_key),
payment_basepoint: from_secret(&payment_key),
delayed_payment_basepoint: DelayedPaymentBasepoint::from(from_secret(
&delayed_payment_base_key,
)),
Expand Down Expand Up @@ -1226,7 +1228,7 @@ impl InMemorySigner {
return Err(());
}

let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_point);
let remotepubkey = bitcoin::PublicKey::new(self.pubkeys().payment_basepoint);
// We cannot always assume that `channel_parameters` is set, so can't just call
// `self.channel_parameters()` or anything that relies on it
let supports_anchors_zero_fee_htlc_tx = self
Expand Down