Re: [openpgp] Expected client behaviour ambiguity in signature verification

[Justus Winter <[e-mail]>]

Daniel Huigens <d.huigens=[e-mail]> writes:

> FWIW, OpenPGP.js does this check as well. I agree it would be nice to
> unify the behavior here. In my opinion, doing the check makes more
> sense than not doing it, because as you said, otherwise why have those
> bytes in the signature; we might as well remove them from v5 signatures.

Sequoia uses the digest prefix as when canonicalizing certificates.  If
we encounter a third party certification for which we don't have the
issuers certificate, we use the digest prefix as a heuristic to check if
a signature is associated with the right component, and if not, use it
to find the right component (with a chance of 2^16 of getting it wrong,
in which case we duplicate the signature).

Therefore, I'd like to keep the digest prefix.  If anything, I'd suggest
to include the full digest instead.

Best,
Justus