X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=e564fa7ca186e5fae392404bd7a5b00dd3b7477c;hb=af69fae97bcfeb3d9b3b4b84d37240f45e37bb85;hp=f5a919bc22528c76caa9603e10ceec6ba42abb1a;hpb=af4738b778d08b728c69a8b3f27d721f7444938e;p=rust-lightning diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs index f5a919bc..e564fa7c 100644 --- a/lightning/src/chain/keysinterface.rs +++ b/lightning/src/chain/keysinterface.rs @@ -1,3 +1,12 @@ +// This file is Copyright its original authors, visible in version control +// history. +// +// This file is licensed under the Apache License, Version 2.0 or the MIT license +// , at your option. +// You may not use this file except in accordance with one or both of these +// licenses. + //! keysinterface provides keys into rust-lightning and defines some useful enums which describe //! spendable on-chain outputs which the user owns and is responsible for using just as any other //! on-chain output which is theirs. @@ -9,32 +18,33 @@ use bitcoin::network::constants::Network; use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber}; use bitcoin::util::bip143; -use bitcoin_hashes::{Hash, HashEngine}; -use bitcoin_hashes::sha256::HashEngine as Sha256State; -use bitcoin_hashes::sha256::Hash as Sha256; -use bitcoin_hashes::sha256d::Hash as Sha256dHash; -use bitcoin_hashes::hash160::Hash as Hash160; +use bitcoin::hashes::{Hash, HashEngine}; +use bitcoin::hashes::sha256::HashEngine as Sha256State; +use bitcoin::hashes::sha256::Hash as Sha256; +use bitcoin::hashes::sha256d::Hash as Sha256dHash; +use bitcoin::hash_types::WPubkeyHash; -use secp256k1::key::{SecretKey, PublicKey}; -use secp256k1::{Secp256k1, Signature}; -use secp256k1; +use bitcoin::secp256k1::key::{SecretKey, PublicKey}; +use bitcoin::secp256k1::{Secp256k1, Signature, Signing}; +use bitcoin::secp256k1; use util::byte_utils; -use util::logger::Logger; -use util::ser::Writeable; +use util::ser::{Writeable, Writer, Readable}; use ln::chan_utils; -use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys}; +use ln::chan_utils::{HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction, PreCalculatedTxCreationKeys}; use ln::msgs; -use std::sync::Arc; use std::sync::atomic::{AtomicUsize, Ordering}; +use std::io::Error; +use ln::msgs::DecodeError; /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to /// claim at any point in the future) an event is generated which you must track and be able to /// spend on-chain. The information needed to do this is provided in this enum, including the /// outpoint describing which txid and output index is available, the full output which exists at /// that txid/index, and any keys or other information required to sign. +#[derive(Clone, PartialEq)] pub enum SpendableOutputDescriptor { /// An output to a script which was provided via KeysInterface, thus you should already know /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the @@ -48,64 +58,122 @@ 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: - /// - /// - /// 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::on_accept) 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 }, - /// 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), } } -/// 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; +impl Writeable for SpendableOutputDescriptor { + fn write(&self, writer: &mut W) -> Result<(), ::std::io::Error> { + match self { + &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => { + 0u8.write(writer)?; + outpoint.write(writer)?; + output.write(writer)?; + }, + &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)?; + 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::StaticOutputRemotePayment { ref outpoint, ref output, ref key_derivation_params } => { + 2u8.write(writer)?; + outpoint.write(writer)?; + output.write(writer)?; + key_derivation_params.0.write(writer)?; + key_derivation_params.1.write(writer)?; + }, + } + Ok(()) + } +} - /// 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]; +impl Readable for SpendableOutputDescriptor { + fn read(reader: &mut R) -> Result { + match Readable::read(reader)? { + 0u8 => Ok(SpendableOutputDescriptor::StaticOutput { + outpoint: Readable::read(reader)?, + output: Readable::read(reader)?, + }), + 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH { + outpoint: 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::StaticOutputRemotePayment { + outpoint: Readable::read(reader)?, + output: Readable::read(reader)?, + key_derivation_params: (Readable::read(reader)?, Readable::read(reader)?), + }), + _ => Err(DecodeError::InvalidValue), + } + } } /// Set of lightning keys needed to operate a channel as described in BOLT 3. @@ -130,32 +198,111 @@ pub trait KeysInterface: Send + Sync { /// Readable/Writable to serialize out a unique reference to this set of keys so /// that you can serialize the full ChannelManager object. /// -/// (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly -/// to the possibility of reentrancy issues by calling the user's code during our deserialization -/// routine). -pub trait ChannelKeys : Send { - /// 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 to_remote output of remote commitment tx - /// (and also as part of obscured commitment number) - fn payment_base_key<'a>(&'a self) -> &'a SecretKey; - /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output - fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey; - /// Gets the local htlc secret key used in commitment tx htlc outputs - fn htlc_base_key<'a>(&'a self) -> &'a SecretKey; - /// Gets the commitment seed - fn commitment_seed<'a>(&'a self) -> &'a [u8; 32]; +// (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly +// to the possibility of reentrancy issues by calling the user's code during our deserialization +// routine). +// 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 per-commitment point for a specific commitment number + /// + /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards. + fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey; + /// Gets the commitment secret for a specific commitment number as part of the revocation process + /// + /// An external signer implementation should error here if the commitment was already signed + /// and should refuse to sign it in the future. + /// + /// May be called more than once for the same index. + /// + /// Note that the commitment number starts at (1 << 48) - 1 and counts backwards. + /// TODO: return a Result so we can signal a validation error + fn release_commitment_secret(&self, idx: u64) -> [u8; 32]; + /// Gets the local channel public keys and basepoints + fn pubkeys(&self) -> &ChannelPublicKeys; + /// Gets arbitrary identifiers describing the set of keys which are provided back to you in + /// some SpendableOutputDescriptor types. These should be sufficient to identify this + /// ChannelKeys object uniquely and lookup or re-derive its keys. + fn key_derivation_params(&self) -> (u64, u64); /// Create a signature for a remote commitment transaction and associated HTLC transactions. /// /// Note that if signing fails or is rejected, the channel will be force-closed. + // + // TODO: Document the things someone using this interface should enforce before signing. + // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and + // making the callee generate it via some util function we expose)! + fn sign_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, keys: &PreCalculatedTxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + + /// Create a signature for a local commitment transaction. This will only ever be called with + /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees + /// that it will not be called multiple times. + /// An external signer implementation should check that the commitment has not been revoked. + // + // TODO: Document the things someone using this interface should enforce before signing. + // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and + fn sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; + + /// Same as sign_local_commitment, but exists only for tests to get access to local commitment + /// transactions which will be broadcasted later, after the channel has moved on to a newer + /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever + /// get called once. + #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))] + fn unsafe_sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result; + + /// Create a signature for each HTLC transaction spending a local commitment transaction. + /// + /// Unlike sign_local_commitment, this may be called multiple times with *different* + /// local_commitment_tx values. While this will never be called with a revoked + /// local_commitment_tx, it is possible that it is called with the second-latest + /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary + /// ChannelMonitor decided to broadcast before it had been updated to the latest. + /// + /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in + /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None + /// (implying they were considered dust at the time the commitment transaction was negotiated), + /// a corresponding None should be included in the return value. All other positions in the + /// return value must contain a signature. + fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result>, ()>; + + /// Create a signature for the given input in a transaction spending an HTLC or commitment + /// transaction output when our counterparty broadcasts an old state. /// - /// TODO: Document the things someone using this interface should enforce before signing. - /// TODO: Add more input vars to enable better checking (preferably removing commitment_tx and - /// making the callee generate it via some util function we expose)! - fn sign_remote_commitment(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()>; + /// 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. + /// + /// Amount is value of the output spent by this input, committed to in the BIP 143 signature. + /// + /// per_commitment_key is revocation secret which was provided by our counterparty when they + /// revoked the state which they eventually broadcast. It's not a _local_ secret key and does + /// not allow the spending of any funds by itself (you need our local revocation_secret to do + /// so). + /// + /// 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). + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, secp_ctx: &Secp256k1) -> Result; + + /// Create a signature for a claiming transaction for a HTLC output on a remote commitment + /// transaction, either offered or received. + /// + /// Such a transaction may claim multiples offered outputs at same time if we know the + /// preimage for each when we create it, but only the input at index `input` should be + /// signed for here. It may be called multiple times for same output(s) if a fee-bump is + /// needed with regards to an upcoming timelock expiration. + /// + /// Witness_script is either a offered or received script as defined in BOLT3 for HTLC + /// outputs. + /// + /// Amount is value of the output spent by this input, committed to in the BIP 143 signature. + /// + /// Per_commitment_point is the dynamic point corresponding to the channel state + /// detected onchain. It has been generated by our counterparty and is used to derive + /// channel state keys, which are then included in the witness script and committed to in the + /// BIP 143 signature. + fn sign_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. /// @@ -171,11 +318,52 @@ pub trait ChannelKeys : Send { /// protocol. fn sign_channel_announcement(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1) -> Result; - /// Set the remote channel basepoints. This is done immediately on incoming channels - /// and as soon as the channel is accepted on outgoing channels. + /// Set the remote channel basepoints and remote/local to_self_delay. + /// This is done immediately on incoming channels and as soon as the channel is accepted on outgoing channels. + /// + /// We bind local_to_self_delay late here for API convenience. /// /// Will be called before any signatures are applied. - fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys); + fn on_accept(&mut self, channel_points: &ChannelPublicKeys, remote_to_self_delay: u16, local_to_self_delay: u16); +} + +/// 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; + /// Gets a unique, cryptographically-secure, random 32 byte value. This is used for encrypting + /// onion packets and for temporary channel IDs. There is no requirement that these be + /// persisted anywhere, though they must be unique across restarts. + fn get_secure_random_bytes(&self) -> [u8; 32]; +} + +#[derive(Clone)] +/// Holds late-bound channel data. +/// This data is available after the channel is known to be accepted, either +/// when receiving an open_channel for an inbound channel or when +/// receiving accept_channel for an outbound channel. +struct AcceptedChannelData { + /// Remote public keys and base points + remote_channel_pubkeys: ChannelPublicKeys, + /// The to_self_delay value specified by our counterparty and applied on locally-broadcastable + /// transactions, ie the amount of time that we have to wait to recover our funds if we + /// broadcast a transaction. You'll likely want to pass this to the + /// ln::chan_utils::build*_transaction functions when signing local transactions. + remote_to_self_delay: u16, + /// The to_self_delay value specified by us and applied on transactions broadcastable + /// by our counterparty, ie the amount of time that they have to wait to recover their funds + /// if they broadcast a transaction. + local_to_self_delay: u16, } #[derive(Clone)] @@ -185,34 +373,108 @@ pub struct InMemoryChannelKeys { pub funding_key: SecretKey, /// Local secret key for blinded revocation pubkey pub revocation_base_key: SecretKey, - /// Local secret key used in commitment tx htlc outputs - pub payment_base_key: SecretKey, + /// Local secret key used for our balance in remote-broadcasted commitment transactions + pub payment_key: SecretKey, /// Local secret key used in HTLC tx pub delayed_payment_base_key: SecretKey, /// Local htlc secret key used in commitment tx htlc outputs pub htlc_base_key: SecretKey, /// Commitment seed pub commitment_seed: [u8; 32], - /// Remote public keys and base points - pub remote_channel_pubkeys: Option, + /// Local public keys and basepoints + pub(crate) local_channel_pubkeys: ChannelPublicKeys, + /// Remote public keys and remote/local to_self_delay, populated on channel acceptance + accepted_channel_data: Option, /// The total value of this channel - pub channel_value_satoshis: u64, + channel_value_satoshis: u64, + /// Key derivation parameters + key_derivation_params: (u64, u64), +} + +impl InMemoryChannelKeys { + /// Create a new InMemoryChannelKeys + pub fn new( + secp_ctx: &Secp256k1, + funding_key: SecretKey, + revocation_base_key: SecretKey, + payment_key: SecretKey, + delayed_payment_base_key: SecretKey, + htlc_base_key: SecretKey, + commitment_seed: [u8; 32], + channel_value_satoshis: u64, + key_derivation_params: (u64, u64)) -> InMemoryChannelKeys { + let local_channel_pubkeys = + InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key, + &payment_key, &delayed_payment_base_key, + &htlc_base_key); + InMemoryChannelKeys { + funding_key, + revocation_base_key, + payment_key, + delayed_payment_base_key, + htlc_base_key, + commitment_seed, + channel_value_satoshis, + local_channel_pubkeys, + accepted_channel_data: None, + key_derivation_params, + } + } + + fn make_local_keys(secp_ctx: &Secp256k1, + funding_key: &SecretKey, + revocation_base_key: &SecretKey, + payment_key: &SecretKey, + delayed_payment_base_key: &SecretKey, + htlc_base_key: &SecretKey) -> ChannelPublicKeys { + let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s); + ChannelPublicKeys { + funding_pubkey: from_secret(&funding_key), + revocation_basepoint: from_secret(&revocation_base_key), + payment_point: from_secret(&payment_key), + delayed_payment_basepoint: from_secret(&delayed_payment_base_key), + htlc_basepoint: from_secret(&htlc_base_key), + } + } + + /// Remote pubkeys. + /// Will panic if on_accept wasn't called. + pub fn remote_pubkeys(&self) -> &ChannelPublicKeys { &self.accepted_channel_data.as_ref().unwrap().remote_channel_pubkeys } + + /// The to_self_delay value specified by our counterparty and applied on locally-broadcastable + /// transactions, ie the amount of time that we have to wait to recover our funds if we + /// broadcast a transaction. You'll likely want to pass this to the + /// ln::chan_utils::build*_transaction functions when signing local transactions. + /// Will panic if on_accept wasn't called. + pub fn remote_to_self_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().remote_to_self_delay } + + /// The to_self_delay value specified by us and applied on transactions broadcastable + /// by our counterparty, ie the amount of time that they have to wait to recover their funds + /// if they broadcast a transaction. + /// Will panic if on_accept wasn't called. + pub fn local_to_self_delay(&self) -> u16 { self.accepted_channel_data.as_ref().unwrap().local_to_self_delay } } impl ChannelKeys for InMemoryChannelKeys { - fn funding_key(&self) -> &SecretKey { &self.funding_key } - fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key } - fn payment_base_key(&self) -> &SecretKey { &self.payment_base_key } - fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key } - fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key } - fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed } - - fn sign_remote_commitment(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { + fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1) -> PublicKey { + let commitment_secret = SecretKey::from_slice(&chan_utils::build_commitment_secret(&self.commitment_seed, idx)).unwrap(); + PublicKey::from_secret_key(secp_ctx, &commitment_secret) + } + + fn release_commitment_secret(&self, idx: u64) -> [u8; 32] { + chan_utils::build_commitment_secret(&self.commitment_seed, idx) + } + + fn pubkeys(&self) -> &ChannelPublicKeys { &self.local_channel_pubkeys } + fn key_derivation_params(&self) -> (u64, u64) { self.key_derivation_params } + + fn sign_remote_commitment(&self, feerate_per_kw: u32, commitment_tx: &Transaction, pre_keys: &PreCalculatedTxCreationKeys, htlcs: &[&HTLCOutputInCommitment], secp_ctx: &Secp256k1) -> Result<(Signature, Vec), ()> { if commitment_tx.input.len() != 1 { return Err(()); } + let keys = pre_keys.trust_key_derivation(); let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + let accepted_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &accepted_data.remote_channel_pubkeys.funding_pubkey); let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]); let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key); @@ -222,7 +484,7 @@ impl ChannelKeys for InMemoryChannelKeys { let mut htlc_sigs = Vec::with_capacity(htlcs.len()); for ref htlc in htlcs { if let Some(_) = htlc.transaction_output_index { - let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key); + let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, accepted_data.local_to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key); let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]); let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) { @@ -236,14 +498,84 @@ impl ChannelKeys for InMemoryChannelKeys { Ok((commitment_sig, htlc_sigs)) } + fn sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { + let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); + let remote_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_data.remote_channel_pubkeys.funding_pubkey); + + Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) + } + + #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))] + fn unsafe_sign_local_commitment(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result { + let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); + let remote_channel_pubkeys = &self.accepted_channel_data.as_ref().expect("must accept before signing").remote_channel_pubkeys; + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + + Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx)) + } + + fn sign_local_commitment_htlc_transactions(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1) -> Result>, ()> { + let local_csv = self.accepted_channel_data.as_ref().unwrap().remote_to_self_delay; + local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx) + } + + fn sign_justice_transaction(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &Option, 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, self.local_to_self_delay(), &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, 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)) + } + Err(()) + } + fn sign_closing_transaction(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1) -> Result { if closing_tx.input.len() != 1 { return Err(()); } if closing_tx.input[0].witness.len() != 0 { return Err(()); } if closing_tx.output.len() > 2 { return Err(()); } - let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing"); let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key); - let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey); + let remote_channel_data = self.accepted_channel_data.as_ref().expect("must accept before signing"); + let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_data.remote_channel_pubkeys.funding_pubkey); let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx) .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]); @@ -255,22 +587,68 @@ impl ChannelKeys for InMemoryChannelKeys { Ok(secp_ctx.sign(&msghash, &self.funding_key)) } - fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) { - assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys"); - self.remote_channel_pubkeys = Some(channel_pubkeys.clone()); + fn on_accept(&mut self, channel_pubkeys: &ChannelPublicKeys, remote_to_self_delay: u16, local_to_self_delay: u16) { + assert!(self.accepted_channel_data.is_none(), "Already accepted"); + self.accepted_channel_data = Some(AcceptedChannelData { + remote_channel_pubkeys: channel_pubkeys.clone(), + remote_to_self_delay, + local_to_self_delay, + }); + } +} + +impl_writeable!(AcceptedChannelData, 0, + { remote_channel_pubkeys, remote_to_self_delay, local_to_self_delay }); + +impl Writeable for InMemoryChannelKeys { + fn write(&self, writer: &mut W) -> Result<(), Error> { + self.funding_key.write(writer)?; + self.revocation_base_key.write(writer)?; + self.payment_key.write(writer)?; + self.delayed_payment_base_key.write(writer)?; + self.htlc_base_key.write(writer)?; + self.commitment_seed.write(writer)?; + self.accepted_channel_data.write(writer)?; + self.channel_value_satoshis.write(writer)?; + self.key_derivation_params.0.write(writer)?; + self.key_derivation_params.1.write(writer)?; + + Ok(()) } } -impl_writeable!(InMemoryChannelKeys, 0, { - funding_key, - revocation_base_key, - payment_base_key, - delayed_payment_base_key, - htlc_base_key, - commitment_seed, - remote_channel_pubkeys, - channel_value_satoshis -}); +impl Readable for InMemoryChannelKeys { + fn read(reader: &mut R) -> Result { + let funding_key = Readable::read(reader)?; + let revocation_base_key = Readable::read(reader)?; + let payment_key = Readable::read(reader)?; + let delayed_payment_base_key = Readable::read(reader)?; + let htlc_base_key = Readable::read(reader)?; + let commitment_seed = Readable::read(reader)?; + let remote_channel_data = Readable::read(reader)?; + let channel_value_satoshis = Readable::read(reader)?; + let secp_ctx = Secp256k1::signing_only(); + let local_channel_pubkeys = + InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key, + &payment_key, &delayed_payment_base_key, + &htlc_base_key); + let params_1 = Readable::read(reader)?; + let params_2 = Readable::read(reader)?; + + Ok(InMemoryChannelKeys { + funding_key, + revocation_base_key, + payment_key, + delayed_payment_base_key, + htlc_base_key, + commitment_seed, + channel_value_satoshis, + local_channel_pubkeys, + accepted_channel_data: remote_channel_data, + key_derivation_params: (params_1, params_2), + }) + } +} /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key /// and derives keys from that. @@ -286,18 +664,17 @@ pub struct KeysManager { shutdown_pubkey: PublicKey, channel_master_key: ExtendedPrivKey, channel_child_index: AtomicUsize, - session_master_key: ExtendedPrivKey, - session_child_index: AtomicUsize, - channel_id_master_key: ExtendedPrivKey, - channel_id_child_index: AtomicUsize, + rand_bytes_master_key: ExtendedPrivKey, + rand_bytes_child_index: AtomicUsize, - unique_start: Sha256State, - logger: Arc, + seed: [u8; 32], + starting_time_secs: u64, + starting_time_nanos: u32, } impl KeysManager { /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your - /// RNG is busted) this may panic (but more importantly, you will possibly lose funds). + /// CSRNG is busted) this may panic (but more importantly, you will possibly lose funds). /// starting_time isn't strictly required to actually be a time, but it must absolutely, /// without a doubt, be unique to this instance. ie if you start multiple times with the same /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to @@ -315,16 +692,16 @@ 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, logger: Arc, 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) => { let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key; let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) { Ok(destination_key) => { - let pubkey_hash160 = Hash160::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.key.serialize()[..]); + let wpubkey_hash = WPubkeyHash::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.to_bytes()); Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0) - .push_slice(&pubkey_hash160.into_inner()) + .push_slice(&wpubkey_hash.into_inner()) .into_script() }, Err(_) => panic!("Your RNG is busted"), @@ -334,13 +711,7 @@ impl KeysManager { Err(_) => panic!("Your RNG is busted"), }; let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted"); - let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted"); - let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted"); - - let mut unique_start = Sha256::engine(); - unique_start.input(&byte_utils::be64_to_array(starting_time_secs)); - unique_start.input(&byte_utils::be32_to_array(starting_time_nanos)); - unique_start.input(seed); + let rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted"); KeysManager { secp_ctx, @@ -349,46 +720,43 @@ impl KeysManager { shutdown_pubkey, channel_master_key, channel_child_index: AtomicUsize::new(0), - session_master_key, - session_child_index: AtomicUsize::new(0), - channel_id_master_key, - channel_id_child_index: AtomicUsize::new(0), + rand_bytes_master_key, + rand_bytes_child_index: AtomicUsize::new(0), - unique_start, - logger, + seed: *seed, + starting_time_secs, + starting_time_nanos, } }, Err(_) => panic!("Your rng is busted"), } } -} - -impl KeysInterface for KeysManager { - type ChanKeySigner = InMemoryChannelKeys; - - fn get_node_secret(&self) -> SecretKey { - self.node_secret.clone() - } - - fn get_destination_script(&self) -> Script { - self.destination_script.clone() - } - - fn get_shutdown_pubkey(&self) -> PublicKey { - self.shutdown_pubkey.clone() + fn derive_unique_start(&self) -> Sha256State { + let mut unique_start = Sha256::engine(); + unique_start.input(&byte_utils::be64_to_array(self.starting_time_secs)); + unique_start.input(&byte_utils::be32_to_array(self.starting_time_nanos)); + unique_start.input(&self.seed); + unique_start } + /// Derive an old set of ChannelKeys for per-channel secrets based on a key derivation + /// parameters. + /// Key derivation parameters are accessible through a per-channel secrets + /// ChannelKeys::key_derivation_params and is provided inside DynamicOuputP2WSH in case of + /// onchain output detection for which a corresponding delayed_payment_key must be derived. + pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params_1: u64, params_2: u64) -> InMemoryChannelKeys { + let chan_id = ((params_1 & 0xFFFF_FFFF_0000_0000) >> 32) as u32; + let mut unique_start = Sha256::engine(); + unique_start.input(&byte_utils::be64_to_array(params_2)); + unique_start.input(&byte_utils::be32_to_array(params_1 as u32)); + unique_start.input(&self.seed); - fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys { // We only seriously intend to rely on the channel_master_key for true secure // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie // starting_time provided in the constructor) to be unique. - let mut sha = self.unique_start.clone(); - - let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel); - let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted"); - sha.input(&child_privkey.private_key.key[..]); + let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(chan_id).expect("key space exhausted")).expect("Your RNG is busted"); + unique_start.input(&child_privkey.private_key.key[..]); - let seed = Sha256::from_engine(sha).into_inner(); + let seed = Sha256::from_engine(unique_start).into_inner(); let commitment_seed = { let mut sha = Sha256::engine(); @@ -407,45 +775,53 @@ impl KeysInterface for KeysManager { } let funding_key = key_step!(b"funding key", commitment_seed); let revocation_base_key = key_step!(b"revocation base key", funding_key); - let payment_base_key = key_step!(b"payment base key", revocation_base_key); - let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_base_key); + let payment_key = key_step!(b"payment key", revocation_base_key); + let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_key); let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key); - InMemoryChannelKeys { + InMemoryChannelKeys::new( + &self.secp_ctx, funding_key, revocation_base_key, - payment_base_key, + payment_key, delayed_payment_base_key, htlc_base_key, commitment_seed, - remote_channel_pubkeys: None, channel_value_satoshis, - } + (params_1, params_2), + ) } +} - fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) { - let mut sha = self.unique_start.clone(); +impl KeysInterface for KeysManager { + type ChanKeySigner = InMemoryChannelKeys; - let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel); - let child_privkey = self.session_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted"); - sha.input(&child_privkey.private_key.key[..]); + fn get_node_secret(&self) -> SecretKey { + self.node_secret.clone() + } - let mut rng_seed = sha.clone(); - // Not exactly the most ideal construction, but the second value will get fed into - // ChaCha so it is another step harder to break. - rng_seed.input(b"RNG Seed Salt"); - sha.input(b"Session Key Salt"); - (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"), - Sha256::from_engine(rng_seed).into_inner()) + fn get_destination_script(&self) -> Script { + self.destination_script.clone() + } + + fn get_shutdown_pubkey(&self) -> PublicKey { + self.shutdown_pubkey.clone() + } + + fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys { + let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel); + let ix_and_nanos: u64 = (child_ix as u64) << 32 | (self.starting_time_nanos as u64); + self.derive_channel_keys(channel_value_satoshis, ix_and_nanos, self.starting_time_secs) } - fn get_channel_id(&self) -> [u8; 32] { - let mut sha = self.unique_start.clone(); + fn get_secure_random_bytes(&self) -> [u8; 32] { + let mut sha = self.derive_unique_start(); - let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel); - let child_privkey = self.channel_id_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted"); + let child_ix = self.rand_bytes_child_index.fetch_add(1, Ordering::AcqRel); + let child_privkey = self.rand_bytes_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted"); sha.input(&child_privkey.private_key.key[..]); - (Sha256::from_engine(sha).into_inner()) + sha.input(b"Unique Secure Random Bytes Salt"); + Sha256::from_engine(sha).into_inner() } }