Re: [openpgp] Possible to define a common key format for LibrePGP and OpenPGP-IETF?

[Andrew Gallagher <[e-mail]>]

On 15 Dec 2023, at 12:20, Kai Engert <[e-mail]> wrote:
> 
> However, if a common key format is possible, then I would like to suggest that both sides take a step back to think about this idea.
> 
> If both sides, LibrePGP and crypto-refresh, actively agreed to specify a common key format, that allows both sides to implement applications according to the divergent PGP specifications, then I think it would be a huge win for the ecosystem and users. The common keyformat would avoid the complexity of having to handle multiple keys in parallel - for those users who wish to have interoperability with all implementations.

Hi, Kai.

AIUI, the key format and the signature format are tightly linked (a v6 key MUST only create v6 sigs, etc). This effectively means that to have a common key format we would need to agree a common signature format. Message formats such as SEIPDv2 are less tightly bound to the key format, and we should in principle be able to manage them through existing preference mechanisms.

The two main points of difference between the signature formats are the random seed and the metadata hash. I don’t believe these are insuperable, but it would require some choreography to reconcile them without reopening the draft.

So I am cautiously hopeful that what you suggest is technically possible, perhaps via a “first amendment” type document that we could potentially have a draft of before the RFC is officially published? This could perhaps describe optional extensions that would bridge the gap between the functionality of the two signature formats.

A