X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=5859385d9fbc09655f6c52eeb1f5237f4348aa03;hb=9f7bcfb1ede0ecd8cd635c2bacf1774cc65487b7;hp=fea11367eca56cb4fc6732ed1aa8c497b1e5b621;hpb=2f4f0aa7660d5f72d0bcbdea7fa3ab3f9ff35d2d;p=rust-lightning diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index fea11367..5859385d 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -25,7 +25,6 @@ use util::ser::{Writeable, Writer, Readable}; use ln::chan_utils; use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction}; use ln::msgs; -use ln::channelmanager::PaymentPreimage; use std::sync::atomic::{AtomicUsize, Ordering}; use std::io::Error; @@ -50,43 +49,66 @@ pub enum SpendableOutputDescriptor { output: TxOut, }, /// An output to a P2WSH script which can be spent with a single signature after a CSV delay. - /// The private key which should be used to sign the transaction is provided, as well as the - /// full witness redeemScript which is hashed in the output script_pubkey. + /// /// The witness in the spending input should be: - /// (MINIMALIF standard rule) - /// - /// Note that the nSequence field in the input must be set to_self_delay (which corresponds to - /// the transaction not being broadcastable until at least to_self_delay blocks after the input - /// confirms). + /// (MINIMALIF standard rule) + /// + /// Note that the nSequence field in the spending input must be set to to_self_delay + /// (which means the transaction is not broadcastable until at least to_self_delay + /// blocks after the outpoint confirms). + /// /// These are generally the result of a "revocable" output to us, spendable only by us unless - /// it is an output from us having broadcast an old state (which should never happen). + /// it is an output from an old state which we broadcast (which should never happen). + /// + /// To derive the delayed_payment key which is used to sign for this input, you must pass the + /// local delayed_payment_base_key (ie the private key which corresponds to the pubkey in + /// ChannelKeys::pubkeys().delayed_payment_basepoint) and the provided per_commitment_point to + /// chan_utils::derive_private_key. The public key can be generated without the secret key + /// using chan_utils::derive_public_key and only the delayed_payment_basepoint which appears in + /// ChannelKeys::pubkeys(). + /// + /// To derive the remote_revocation_pubkey provided here (which is used in the witness + /// script generation), you must pass the remote revocation_basepoint (which appears in the + /// call to ChannelKeys::set_remote_channel_pubkeys) and the provided per_commitment point + /// to chan_utils::derive_public_revocation_key. + /// + /// The witness script which is hashed and included in the output script_pubkey may be + /// regenerated by passing the revocation_pubkey (derived as above), our delayed_payment pubkey + /// (derived as above), and the to_self_delay contained here to + /// chan_utils::get_revokeable_redeemscript. + // + // TODO: we need to expose utility methods in KeyManager to do all the relevant derivation. DynamicOutputP2WSH { /// The outpoint which is spendable outpoint: OutPoint, - /// The secret key which must be used to sign the spending transaction - key: SecretKey, - /// The witness redeemScript which is hashed to create the script_pubkey in the given output - witness_script: Script, + /// Per commitment point to derive delayed_payment_key by key holder + per_commitment_point: PublicKey, /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in /// the witness_script. to_self_delay: u16, /// The output which is referenced by the given outpoint output: TxOut, + /// The channel keys state used to proceed to derivation of signing key. Must + /// be pass to KeysInterface::derive_channel_keys. + key_derivation_params: (u64, u64), + /// The remote_revocation_pubkey used to derive witnessScript + remote_revocation_pubkey: PublicKey }, - // TODO: Note that because key is now static and exactly what is provided by us, we should drop - // this in favor of StaticOutput: - /// An output to a P2WPKH, spendable exclusively by the given private key. + /// An output to a P2WPKH, spendable exclusively by our payment key (ie the private key which + /// corresponds to the public key in ChannelKeys::pubkeys().payment_point). /// The witness in the spending input, is, thus, simply: - /// + /// + /// /// These are generally the result of our counterparty having broadcast the current state, /// allowing us to claim the non-HTLC-encumbered outputs immediately. - DynamicOutputP2WPKH { + StaticOutputRemotePayment { /// The outpoint which is spendable outpoint: OutPoint, - /// The secret key which must be used to sign the spending transaction - key: SecretKey, /// The output which is reference by the given outpoint output: TxOut, + /// The channel keys state used to proceed to derivation of signing key. Must + /// be pass to KeysInterface::derive_channel_keys. + key_derivation_params: (u64, u64), } } @@ -98,19 +120,22 @@ impl Writeable for SpendableOutputDescriptor { outpoint.write(writer)?; output.write(writer)?; }, - &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref key, ref witness_script, ref to_self_delay, ref output } => { + &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref per_commitment_point, ref to_self_delay, ref output, ref key_derivation_params, ref remote_revocation_pubkey } => { 1u8.write(writer)?; outpoint.write(writer)?; - key.write(writer)?; - witness_script.write(writer)?; + per_commitment_point.write(writer)?; to_self_delay.write(writer)?; output.write(writer)?; + key_derivation_params.0.write(writer)?; + key_derivation_params.1.write(writer)?; + remote_revocation_pubkey.write(writer)?; }, - &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref key, ref output } => { + &SpendableOutputDescriptor::StaticOutputRemotePayment { ref outpoint, ref output, ref key_derivation_params } => { 2u8.write(writer)?; outpoint.write(writer)?; - key.write(writer)?; output.write(writer)?; + key_derivation_params.0.write(writer)?; + key_derivation_params.1.write(writer)?; }, } Ok(()) @@ -126,43 +151,22 @@ impl Readable for SpendableOutputDescriptor { }), 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH { outpoint: Readable::read(reader)?, - key: Readable::read(reader)?, - witness_script: Readable::read(reader)?, + per_commitment_point: Readable::read(reader)?, to_self_delay: Readable::read(reader)?, output: Readable::read(reader)?, + key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?), + remote_revocation_pubkey: Readable::read(reader)?, }), - 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH { + 2u8 => Ok(SpendableOutputDescriptor::StaticOutputRemotePayment { outpoint: Readable::read(reader)?, - key: Readable::read(reader)?, output: Readable::read(reader)?, + key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?), }), _ => Err(DecodeError::InvalidValue), } } } -/// A trait to describe an object which can get user secrets and key material. -pub trait KeysInterface: Send + Sync { - /// A type which implements ChannelKeys which will be returned by get_channel_keys. - type ChanKeySigner : ChannelKeys; - - /// Get node secret key (aka node_id or network_key) - fn get_node_secret(&self) -> SecretKey; - /// Get destination redeemScript to encumber static protocol exit points. - fn get_destination_script(&self) -> Script; - /// Get shutdown_pubkey to use as PublicKey at channel closure - fn get_shutdown_pubkey(&self) -> PublicKey; - /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you - /// restarted with some stale data! - fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner; - /// Get a secret and PRNG seed for construting an onion packet - fn get_onion_rand(&self) -> (SecretKey, [u8; 32]); - /// Get a unique temporary channel id. Channels will be referred to by this until the funding - /// transaction is created, at which point they will use the outpoint in the funding - /// transaction. - fn get_channel_id(&self) -> [u8; 32]; -} - /// Set of lightning keys needed to operate a channel as described in BOLT 3. /// /// Signing services could be implemented on a hardware wallet. In this case, @@ -191,8 +195,6 @@ pub trait KeysInterface: Send + Sync { // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors. pub trait ChannelKeys : Send+Clone { - /// Gets the private key for the anchor tx - fn funding_key<'a>(&'a self) -> &'a SecretKey; /// Gets the local secret key for blinded revocation pubkey fn revocation_base_key<'a>(&'a self) -> &'a SecretKey; /// Gets the local secret key used in the to_remote output of remote commitment tx (ie the @@ -251,45 +253,48 @@ pub trait ChannelKeys : Send+Clone { /// return value must contain a signature. fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1) -> Result>, ()>; - /// Create a signature for a transaction spending an HTLC or commitment transaction output - /// when our counterparty broadcast an old state. + /// Create a signature for the given input in a transaction spending an HTLC or commitment + /// transaction output when our counterparty broadcasts an old state. /// - /// Justice transaction may claim multiples outputs at same time if timelock are similar. + /// A justice transaction may claim multiples outputs at the same time if timelocks are + /// similar, but only a signature for the input at index `input` should be signed for here. /// It may be called multiples time for same output(s) if a fee-bump is needed with regards /// to an upcoming timelock expiration. /// - /// Witness_script is a revokable witness script as defined in BOLT3 for `to_local`/HTLC - /// outputs. + /// Amount is value of the output spent by this input, committed to in the BIP 143 signature. /// - /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143). + /// per_commitment_key is revocation secret which was provided by our counterparty when they + /// revoked the state which they eventually broadcast. It's not a _local_ secret key and does + /// not allow the spending of any funds by itself (you need our local revocation_secret to do + /// so). /// - /// Amount is value of the output spent by this input, committed by sigs (BIP 143). + /// htlc holds HTLC elements (hash, timelock) if the output being spent is a HTLC output, thus + /// changing the format of the witness script (which is committed to in the BIP 143 + /// signatures). /// - /// Per_commitment key is revocation secret such as provided by remote party while - /// revocating detected onchain transaction. It's not a _local_ secret key, therefore - /// it may cross interfaces, a node compromise won't allow to spend revoked output without - /// also compromissing revocation key. - //TODO: dry-up witness_script and pass pubkeys - fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_key: &SecretKey, revocation_pubkey: &PublicKey, is_htlc: bool, secp_ctx: &Secp256k1) -> Result; + /// on_remote_tx_csv is the relative lock-time that that our counterparty would have to set on + /// their transaction were they to spend the same output. It is included in the witness script + /// and thus committed to in the BIP 143 signature. + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, on_remote_tx_csv: u16, secp_ctx: &Secp256k1) -> Result; /// Create a signature for a claiming transaction for a HTLC output on a remote commitment /// transaction, either offered or received. /// - /// HTLC transaction may claim multiples offered outputs at same time if we know preimage - /// for each at detection. It may be called multtiples time for same output(s) if a fee-bump - /// is needed with regards to an upcoming timelock expiration. + /// Such a transaction may claim multiples offered outputs at same time if we know the + /// preimage for each when we create it, but only the input at index `input` should be + /// signed for here. It may be called multiple times for same output(s) if a fee-bump is + /// needed with regards to an upcoming timelock expiration. /// /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC /// outputs. /// - /// Input index is a pointer towards outpoint spent, commited by sigs (BIP 143). - /// - /// Amount is value of the output spent by this input, committed by sigs (BIP 143). + /// Amount is value of the output spent by this input, committed to in the BIP 143 signature. /// - /// Preimage is solution for an offered HTLC haslock. A preimage sets to None hints this - /// htlc_tx as timing-out funds back to us on a received output. - //TODO: dry-up witness_script and pass pubkeys - fn sign_remote_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_point: &PublicKey, preimage: &Option, secp_ctx: &Secp256k1) -> Result; + /// Per_commitment_point is the dynamic point corresponding to the channel state + /// detected onchain. It has been generated by our counterparty and is used to derive + /// channel state keys, which are then included in the witness script and committed to in the + /// BIP 143 signature. + fn sign_remote_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result; /// Create a signature for a (proposed) closing transaction. /// @@ -312,21 +317,43 @@ pub trait ChannelKeys : Send+Clone { fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys); } +/// A trait to describe an object which can get user secrets and key material. +pub trait KeysInterface: Send + Sync { + /// A type which implements ChannelKeys which will be returned by get_channel_keys. + type ChanKeySigner : ChannelKeys; + + /// Get node secret key (aka node_id or network_key) + fn get_node_secret(&self) -> SecretKey; + /// Get destination redeemScript to encumber static protocol exit points. + fn get_destination_script(&self) -> Script; + /// Get shutdown_pubkey to use as PublicKey at channel closure + fn get_shutdown_pubkey(&self) -> PublicKey; + /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you + /// restarted with some stale data! + fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner; + /// Get a secret and PRNG seed for constructing an onion packet + fn get_onion_rand(&self) -> (SecretKey, [u8; 32]); + /// Get a unique temporary channel id. Channels will be referred to by this until the funding + /// transaction is created, at which point they will use the outpoint in the funding + /// transaction. + fn get_channel_id(&self) -> [u8; 32]; +} + #[derive(Clone)] /// A simple implementation of ChannelKeys that just keeps the private keys in memory. pub struct InMemoryChannelKeys { /// Private key of anchor tx - funding_key: SecretKey, + pub funding_key: SecretKey, /// Local secret key for blinded revocation pubkey - revocation_base_key: SecretKey, + pub revocation_base_key: SecretKey, /// Local secret key used for our balance in remote-broadcasted commitment transactions - payment_key: SecretKey, + pub payment_key: SecretKey, /// Local secret key used in HTLC tx - delayed_payment_base_key: SecretKey, + pub delayed_payment_base_key: SecretKey, /// Local htlc secret key used in commitment tx htlc outputs - htlc_base_key: SecretKey, + pub htlc_base_key: SecretKey, /// Commitment seed - commitment_seed: [u8; 32], + pub commitment_seed: [u8; 32], /// Local public keys and basepoints pub(crate) local_channel_pubkeys: ChannelPublicKeys, /// Remote public keys and base points @@ -382,10 +409,11 @@ impl InMemoryChannelKeys { htlc_basepoint: from_secret(&htlc_base_key), } } + + fn remote_pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { self.remote_channel_pubkeys.as_ref().unwrap() } } impl ChannelKeys for InMemoryChannelKeys { - fn funding_key(&self) -> &SecretKey { &self.funding_key } fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key } fn payment_key(&self) -> &SecretKey { &self.payment_key } fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key } @@ -444,17 +472,47 @@ impl ChannelKeys for InMemoryChannelKeys { local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx) } - fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_key: &SecretKey, revocation_pubkey: &PublicKey, is_htlc: bool, secp_ctx: &Secp256k1) -> Result { - if let Ok(revocation_key) = chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) { - let sighash_parts = bip143::SighashComponents::new(&justice_tx); - let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]); - return Ok(secp_ctx.sign(&sighash, &revocation_key)) - } - Err(()) + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, on_remote_tx_csv: u16, secp_ctx: &Secp256k1) -> Result { + let revocation_key = match chan_utils::derive_private_revocation_key(&secp_ctx, &per_commitment_key, &self.revocation_base_key) { + Ok(revocation_key) => revocation_key, + Err(_) => return Err(()) + }; + let per_commitment_point = PublicKey::from_secret_key(secp_ctx, &per_commitment_key); + let revocation_pubkey = match chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) { + Ok(revocation_pubkey) => revocation_pubkey, + Err(_) => return Err(()) + }; + let witness_script = if let &Some(ref htlc) = htlc { + let remote_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().htlc_basepoint) { + Ok(remote_htlcpubkey) => remote_htlcpubkey, + Err(_) => return Err(()) + }; + let local_htlcpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) { + Ok(local_htlcpubkey) => local_htlcpubkey, + Err(_) => return Err(()) + }; + chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &remote_htlcpubkey, &local_htlcpubkey, &revocation_pubkey) + } else { + let remote_delayedpubkey = match chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().delayed_payment_basepoint) { + Ok(remote_delayedpubkey) => remote_delayedpubkey, + Err(_) => return Err(()) + }; + chan_utils::get_revokeable_redeemscript(&revocation_pubkey, on_remote_tx_csv, &remote_delayedpubkey) + }; + let sighash_parts = bip143::SighashComponents::new(&justice_tx); + let sighash = hash_to_message!(&sighash_parts.sighash_all(&justice_tx.input[input], &witness_script, amount)[..]); + return Ok(secp_ctx.sign(&sighash, &revocation_key)) } - fn sign_remote_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, witness_script: &Script, amount: u64, per_commitment_point: &PublicKey, preimage: &Option, secp_ctx: &Secp256k1) -> Result { + fn sign_remote_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { if let Ok(htlc_key) = chan_utils::derive_private_key(&secp_ctx, &per_commitment_point, &self.htlc_base_key) { + let witness_script = if let Ok(revocation_pubkey) = chan_utils::derive_public_revocation_key(&secp_ctx, &per_commitment_point, &self.pubkeys().revocation_basepoint) { + if let Ok(remote_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.remote_pubkeys().htlc_basepoint) { + if let Ok(local_htlcpubkey) = chan_utils::derive_public_key(&secp_ctx, &per_commitment_point, &self.pubkeys().htlc_basepoint) { + chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &remote_htlcpubkey, &local_htlcpubkey, &revocation_pubkey) + } else { return Err(()) } + } else { return Err(()) } + } else { return Err(()) }; let sighash_parts = bip143::SighashComponents::new(&htlc_tx); let sighash = hash_to_message!(&sighash_parts.sighash_all(&htlc_tx.input[input], &witness_script, amount)[..]); return Ok(secp_ctx.sign(&sighash, &htlc_key)) @@ -581,7 +639,7 @@ impl KeysManager { /// Note that until the 0.1 release there is no guarantee of backward compatibility between /// versions. Once the library is more fully supported, the docs will be updated to include a /// detailed description of the guarantee. - pub fn new(seed: &[u8; 32], network: Network, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager { + pub fn new(seed: &[u8; 32], network: Network, starting_time_secs: u64, starting_time_nanos: u32) -> Self { let secp_ctx = Secp256k1::signing_only(); match ExtendedPrivKey::new_master(network.clone(), seed) { Ok(master_key) => {