/// 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];
+ /// 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)]
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,
seed: [u8; 32],
starting_time_secs: u64,
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
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 rand_bytes_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
KeysManager {
secp_ctx,
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),
seed: *seed,
starting_time_secs,
self.derive_channel_keys(channel_value_satoshis, ix_and_nanos, self.starting_time_secs)
}
- fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
+ fn get_secure_random_bytes(&self) -> [u8; 32] {
let mut sha = self.derive_unique_start();
- 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[..]);
-
- 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_channel_id(&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[..]);
+ sha.input(b"Unique Secure Random Bytes Salt");
Sha256::from_engine(sha).into_inner()
}
}