Subject: Re: [bitcoin-dev] CHECKSIGFROMSTACK/{Verify} BIP for Bitcoin

From: Jeremy <[email-masked]>
Date: Sun, 4 Jul 2021 10:30:18 -0700

I don't really see the point of CHECKSIGFROMSTACKADD since it's not bound
to the txdata? When might you use this?

And yes -- "Add OP_CHECKSIGFROMSTACK and OP_CHECKSIGFROMSTACKVERIFY to
follow the semantics from bip340-342 when witness program is v1." is a bit
light on detail for what the BIP would end up looking like. If you're able
to open up the design process a bit more on that it would be good as I
think there are some topics worth discussing at large before things proceed
with Elements (assuming feature compatibility remains a goal).

The non-prehashed argument seems OK (at the cost of an extra byte...) but
are there specific applications for !=32 arguments? I can't think of a
particular one beyond perhaps efficiency. Can we safely use 0-520 byte
arguments?

Also do you have thoughts on the other questions i posed above? E.g.
splitting R/S could be helpful w/o CAT.

--
@JeremyRubin <https://twitter.com/JeremyRubin>
<https://twitter.com/JeremyRubin>

On Sat, Jul 3, 2021 at 1:13 PM Russell O'Connor <[email-masked]>
wrote:

> There is one line written at
> https://github.com/ElementsProject/elements/pull/949/files#r660130155.
>