Both sides elect a commitment fee, and the lowest is chosen. That means
you can't game the other side (but if you offer too low, then can error
out of course).
Fees are split 50-50 if possible: originally the whole fee has to be
paid by the (single) funder. Neither side can withdraw funds which
would make them unable to pay fees.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Most complex change was gather_updates(), which handles all the "what
is the current state of the channel" logic for our dumb test utils.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Alpha has segregated witnesses, so txid doesn't include the inputs.
That means we can create the first commit transaction before we sign
the anchor tx.
Bitcoin will need to do this differently: presumbly via new sipops
(a OP_CHECKSIG2VERIFY I imagine).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I had each side using the other side's hash secret. That's a very
dumb idea, since it means you can steal from a unilateral close!
A's secret applies to A's commit transaction: it needs the
secret and B's final signature to steal funds, and that should
never happen (since A doesn't have the B's final signature, and
once A has given B the secret, they never broadcast the commit tx).
This makes the update a 4 step dance, since you need the new
revocation hash to make the other side's TX to sign.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We need to pay to this from two places: on their side, it's a simple
payment, on our side, it's a complex timeout-or-mutual-or-hval script,
which doesn't lend itself to arbitrary scripts.
Use P2SH, of course.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
DER encoding introduces problems for non-canonical encodings; we should
do that only at the lightning<->bitcoin interface.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell