The most significant byte of the locktime in a commitment transaction
must be set to 0x20. This is to make sure that the locktime value
is always higher than 500,000,000, making it interpreted as a Unix
epoch timestamp, and not a block height. It also makes sure that the
locktime is below the current time, allowing the commitment transaction
to be included in a block.
Since the sequence field in the input of the commitment transaction is
used for the other half of the obscured commitment transaction number,
it will never assume the maxInt value (0xFFFFFFFF) which would disable
locktime checking.
From BIP 68:
If bit (1 << 31) of the sequence number is set, then no consensus
meaning is applied to the sequence number and can be included in any
block under all currently possible circumstances.
Which is what we want.
Reported-by: Olaoluwa Osuntokun <laolu32@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Now using `<>` on inline code only when part of a script and extra
emphasis is warranted. Outside of scripts the variable names are
already highlighted, so no need to add further emphasis.
There was talk of using a simple increment, but it was removed after
Tadge educated me. Somehow this didn't get updated.
Reported-by: Tadge Dryja <tdryja@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Inspired by Andrew Shvv's work, this expands the HTLC weight calculation
and fixes the gross errors (the witness program itself wasn't counted in
the weights!).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Commit a0c4f7cfd1 "BOLT 3: add more detailed commitment transaction
estimation (#26)" simplified the weight formula to assume there was a
to-remote output.
This worst-case 18% error, but it's simple. Document it.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
1. Add a short paragraph on P2WSH (the witness script is omitted for brevity in all descriptions) and fix witness scripts for spending the different tx outputs.
2. use CHECK(MULTI)SIG instead of CHECK(MULTI)SIGVERIFY
3. Fix order and nulldummy for witness in HTLC transactions
4. Fix a minor typo (if -> it)
(Commits rebased and squashed together by Rusty)
Make the fee amount by kiloweight, not by kilobyte, and spell out how
to calculate it. Note that we have to trim HTLCs outputs whose second-stage
would also fall below dust limit, and we also make some reasonable
approximations on transaction size (which is unknowable before signatures
anyway).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
After much discussion with Tadge and Laolu, I think we have something
which is nicely outsourcable, and yetnot insanely complex.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit modifies BOLT 3 slightly to use a code block for the multi-sig script. Without this change, the script doesn't display correctly, as the angle brackets are interpreted as markdown syntax.
