use bitcoin::util::hash::Hash160;
use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
+use bitcoin_hashes::{Hash, HashEngine};
+use bitcoin_hashes::sha256::Hash as Sha256;
+
use secp256k1::key::{SecretKey, PublicKey};
use secp256k1::Secp256k1;
use secp256k1;
-use crypto::hkdf::{hkdf_extract,hkdf_expand};
-
-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.
/// 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 :
/// <local_delayedsig> 0 <witnessScript>
/// 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 :
+ /// <local_sig> <local_pubkey>
+ /// 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,
}
}
/// 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
pub commitment_seed: [u8; 32],
}
-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
- }
- }
-}
+impl_writeable!(ChannelKeys, 0, {
+ funding_key,
+ revocation_base_key,
+ payment_base_key,
+ delayed_payment_base_key,
+ htlc_base_key,
+ commitment_seed
+});
/// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
/// and derives keys from that.
destination_script: Script,
shutdown_pubkey: PublicKey,
channel_master_key: ExtendedPrivKey,
+ channel_child_index: AtomicUsize,
+ session_master_key: ExtendedPrivKey,
+ session_child_index: AtomicUsize,
logger: Arc<Logger>,
}
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,
}
}
fn get_channel_keys(&self, _inbound: bool) -> ChannelKeys {
- let channel_pubkey = ExtendedPubKey::from_private(&self.secp_ctx, &self. channel_master_key);
- let mut seed = [0; 32];
- for (arr, slice) in seed.iter_mut().zip((&channel_pubkey.public_key.serialize()[0..32]).iter()) {
- *arr = *slice;
+ // 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::engine();
+
+ 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[..]);
+
+ seed = Sha256::from_engine(sha).into_inner();
+
+ let commitment_seed = {
+ let mut sha = Sha256::engine();
+ sha.input(&seed);
+ sha.input(&b"commitment seed"[..]);
+ Sha256::from_engine(sha).into_inner()
+ };
+ macro_rules! key_step {
+ ($info: expr, $prev_key: expr) => {{
+ let mut sha = Sha256::engine();
+ sha.input(&seed);
+ sha.input(&$prev_key[..]);
+ sha.input(&$info[..]);
+ SecretKey::from_slice(&self.secp_ctx, &Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
+ }}
}
- ChannelKeys::new_from_seed(&seed)
+ 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 htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
+
+ ChannelKeys {
+ funding_key,
+ revocation_base_key,
+ payment_base_key,
+ delayed_payment_base_key,
+ htlc_base_key,
+ commitment_seed,
+ }
+ }
+
+ fn get_session_key(&self) -> SecretKey {
+ let mut sha = Sha256::engine();
+
+ 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[..]);
+ SecretKey::from_slice(&self.secp_ctx, &Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted")
}
}