X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=src%2Fchain%2Fkeysinterface.rs;h=4e35e6764d246ced9b431ad473bfe84bf13ecb7f;hb=a2df43d525322812a6081e5ae0a666ce79efc20b;hp=bab21fd2b0bf656b62161270aa123c40efc90435;hpb=8c235d9e28da0bcdb1d68166fc771e0c83a7b2fc;p=rust-lightning diff --git a/src/chain/keysinterface.rs b/src/chain/keysinterface.rs index bab21fd2..4e35e676 100644 --- a/src/chain/keysinterface.rs +++ b/src/chain/keysinterface.rs @@ -3,9 +3,27 @@ //! on-chain output which is theirs. use bitcoin::blockdata::transaction::{OutPoint, TxOut}; -use bitcoin::blockdata::script::Script; +use bitcoin::blockdata::script::{Script, Builder}; +use bitcoin::blockdata::opcodes; +use bitcoin::network::constants::Network; +use bitcoin::util::hash::Hash160; +use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber}; -use secp256k1::key::SecretKey; +use secp256k1::key::{SecretKey, PublicKey}; +use secp256k1::Secp256k1; +use secp256k1; + +use crypto::hkdf::{hkdf_extract,hkdf_expand}; +use crypto::digest::Digest; + +use util::sha2::Sha256; +use util::logger::Logger; +use util::rng; +use util::byte_utils; + +use std::time::{SystemTime, UNIX_EPOCH}; +use std::sync::Arc; +use std::sync::atomic::{AtomicUsize, Ordering}; /// When on-chain outputs are created by rust-lightning an event is generated which informs the /// user thereof. This enum describes the format of the output and provides the OutPoint. @@ -19,18 +37,224 @@ pub enum SpendableOutputDescriptor { /// The output which is referenced by the given outpoint output: TxOut, }, - /// Outpoint commits to a P2WSH, should be spend by the following witness : + /// Outpoint commits to a P2WSH + /// P2WSH should be spend by the following witness : /// 0 /// With input nSequence set to_self_delay. - /// Outputs from a HTLC-Success/Timeout tx - DynamicOutput { + /// Outputs from a HTLC-Success/Timeout tx/commitment tx + DynamicOutputP2WSH { /// Outpoint spendable by user wallet outpoint: OutPoint, - /// local_delayedkey = delayed_payment_basepoint_secret + SHA256(per_commitment_point || delayed_payment_basepoint - local_delayedkey: SecretKey, - /// witness redeemScript encumbering output + /// local_delayedkey = delayed_payment_basepoint_secret + SHA256(per_commitment_point || delayed_payment_basepoint) OR + key: SecretKey, + /// witness redeemScript encumbering output. witness_script: Script, /// nSequence input must commit to self_delay to satisfy script's OP_CSV to_self_delay: u16, + /// The output which is referenced by the given outpoint + output: TxOut, + }, + /// Outpoint commits to a P2WPKH + /// P2WPKH should be spend by the following witness : + /// + /// Outputs to_remote from a commitment tx + DynamicOutputP2WPKH { + /// Outpoint spendable by user wallet + outpoint: OutPoint, + /// localkey = payment_basepoint_secret + SHA256(per_commitment_point || payment_basepoint + key: SecretKey, + /// The output which is reference by the given outpoint + output: TxOut, + } +} + +/// A trait to describe an object which can get user secrets and key material. +pub trait KeysInterface: Send + Sync { + /// 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) -> ChannelKeys; + /// Get a secret for construting an onion packet + fn get_session_key(&self) -> SecretKey; +} + +/// Set of lightning keys needed to operate a channel as described in BOLT 3 +#[derive(Clone)] +pub struct ChannelKeys { + /// Private key of anchor tx + 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 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], +} + +impl_writeable!(ChannelKeys, 0, { + funding_key, + revocation_base_key, + payment_base_key, + delayed_payment_base_key, + htlc_base_key, + commitment_seed +}); + +impl ChannelKeys { + /// Generate a set of lightning keys needed to operate a channel by HKDF-expanding a given + /// random 32-byte seed + pub fn new_from_seed(seed: &[u8; 32]) -> ChannelKeys { + let mut prk = [0; 32]; + hkdf_extract(Sha256::new(), b"rust-lightning key gen salt", seed, &mut prk); + let secp_ctx = Secp256k1::without_caps(); + + let mut okm = [0; 32]; + hkdf_expand(Sha256::new(), &prk, b"rust-lightning funding key info", &mut okm); + let funding_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken"); + + hkdf_expand(Sha256::new(), &prk, b"rust-lightning revocation base key info", &mut okm); + let revocation_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken"); + + hkdf_expand(Sha256::new(), &prk, b"rust-lightning payment base key info", &mut okm); + let payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken"); + + hkdf_expand(Sha256::new(), &prk, b"rust-lightning delayed payment base key info", &mut okm); + let delayed_payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken"); + + hkdf_expand(Sha256::new(), &prk, b"rust-lightning htlc base key info", &mut okm); + let htlc_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken"); + + hkdf_expand(Sha256::new(), &prk, b"rust-lightning local commitment seed info", &mut okm); + + ChannelKeys { + funding_key: funding_key, + revocation_base_key: revocation_base_key, + payment_base_key: payment_base_key, + delayed_payment_base_key: delayed_payment_base_key, + htlc_base_key: htlc_base_key, + commitment_seed: okm + } + } +} + +/// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key +/// and derives keys from that. +/// +/// Your node_id is seed/0' +/// ChannelMonitor closes may use seed/1' +/// Cooperative closes may use seed/2' +/// The two close keys may be needed to claim on-chain funds! +pub struct KeysManager { + secp_ctx: Secp256k1, + node_secret: SecretKey, + destination_script: Script, + shutdown_pubkey: PublicKey, + channel_master_key: ExtendedPrivKey, + channel_child_index: AtomicUsize, + session_master_key: ExtendedPrivKey, + session_child_index: AtomicUsize, + + logger: Arc, +} + +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. + pub fn new(seed: &[u8; 32], network: Network, logger: Arc) -> KeysManager { + let secp_ctx = Secp256k1::new(); + match ExtendedPrivKey::new_master(&secp_ctx, network.clone(), seed) { + Ok(master_key) => { + let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0)).expect("Your RNG is busted").secret_key; + let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1)) { + Ok(destination_key) => { + let pubkey_hash160 = Hash160::from_data(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.serialize()[..]); + Builder::new().push_opcode(opcodes::All::OP_PUSHBYTES_0) + .push_slice(pubkey_hash160.as_bytes()) + .into_script() + }, + Err(_) => panic!("Your RNG is busted"), + }; + let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2)) { + Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key, + Err(_) => panic!("Your RNG is busted"), + }; + let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3)).expect("Your RNG is busted"); + let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4)).expect("Your RNG is busted"); + KeysManager { + secp_ctx, + node_secret, + destination_script, + shutdown_pubkey, + channel_master_key, + channel_child_index: AtomicUsize::new(0), + session_master_key, + session_child_index: AtomicUsize::new(0), + + logger, + } + }, + Err(_) => panic!("Your rng is busted"), + } + } +} + +impl KeysInterface for KeysManager { + 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 get_channel_keys(&self, _inbound: bool) -> ChannelKeys { + // We only seriously intend to rely on the channel_master_key for true secure + // entropy, everything else just ensures uniqueness. We generally don't expect + // all clients to have non-broken RNGs here, so we also include the current + // time as a fallback to get uniqueness. + let mut sha = Sha256::new(); + + let mut seed = [0u8; 32]; + rng::fill_bytes(&mut seed[..]); + sha.input(&seed); + + let now = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time went backwards"); + sha.input(&byte_utils::be32_to_array(now.subsec_nanos())); + sha.input(&byte_utils::be64_to_array(now.as_secs())); + + 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("Your RNG is busted"); + sha.input(&child_privkey.secret_key[..]); + + sha.result(&mut seed); + ChannelKeys::new_from_seed(&seed) + } + + fn get_session_key(&self) -> SecretKey { + let mut sha = Sha256::new(); + let mut res = [0u8; 32]; + + let now = SystemTime::now().duration_since(UNIX_EPOCH).expect("Time went backwards"); + sha.input(&byte_utils::be32_to_array(now.subsec_nanos())); + sha.input(&byte_utils::be64_to_array(now.as_secs())); + + 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("Your RNG is busted"); + sha.input(&child_privkey.secret_key[..]); + sha.result(&mut res); + SecretKey::from_slice(&self.secp_ctx, &res).expect("Your RNG is busted") } }