Antoine Poinsot fa7c46b503 descriptor: introduce a method to get the satisfaction size ...

In the wallet code, we are currently estimating the size of a signed
input by doing a dry run of the signing logic. This is unnecessary as
all outputs we are able to sign for can be represented by a descriptor,
and we can derive the size of a satisfaction ("signature") from the
descriptor itself directly.
In addition, this approach does not scale: getting the size of a
satisfaction through a dry run of the signing logic is only possible for
the most basic scripts.

This commit introduces the computation of the size of satisfaction per
descriptor. It's a bit intricate for 2 main reasons:
- We want to conserve the behaviour of the current dry-run logic used by
  the wallet that sometimes assumes ECDSA signatures will be low-r,
  sometimes not (when we don't create them).
- We need to account for the witness discount. A single descriptor may
  sometimes benefit of it, sometimes not (for instance `pk()` if used as
  top-level versus if used inside `wsh()`).

2023-08-25 12:40:11 +02:00

86 KiB

Raw Blame History

View Raw