Rusty Russell [ARCHIVE] on Nostr: 📅 Original date posted:2019-12-02 📝 Original message: Conner Fromknecht <conner ...
📅 Original date posted:2019-12-02
📝 Original message:
Conner Fromknecht <conner at lightning.engineering> writes:
> Hi all,
>
> I recently revisited the eltoo paper and noticed some things related
> watchtowers that might affect channel construction.
>
> Due to NOINPUT, any update transaction _can_ spend from any other, so
> in theory the tower only needs the most recent update txn to resolve
> any dispute.
>
> In order to spend, however, the tower must also produce a witness
> script which when hashed matches the witness program of the input. To
> ensure settlement txns can only spend from exactly one update txn,
> each update txn uses unique keys for the settlement clause, meaning
> that each state has a _unique_ witness program.
I didn't think this was the design. The update transaction can spend
any prior, with a fixed script, due to NOINPUT.
The settlement transaction does *not* use NOINPUT, and thus can only
spend the matching update.
Cheers,
Rusty.
📝 Original message:
Conner Fromknecht <conner at lightning.engineering> writes:
> Hi all,
>
> I recently revisited the eltoo paper and noticed some things related
> watchtowers that might affect channel construction.
>
> Due to NOINPUT, any update transaction _can_ spend from any other, so
> in theory the tower only needs the most recent update txn to resolve
> any dispute.
>
> In order to spend, however, the tower must also produce a witness
> script which when hashed matches the witness program of the input. To
> ensure settlement txns can only spend from exactly one update txn,
> each update txn uses unique keys for the settlement clause, meaning
> that each state has a _unique_ witness program.
I didn't think this was the design. The update transaction can spend
any prior, with a fixed script, due to NOINPUT.
The settlement transaction does *not* use NOINPUT, and thus can only
spend the matching update.
Cheers,
Rusty.