- 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::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);