Call me crazy, but ...

[Andrew Gallagher]

> On 14 Jul 2021, at 23:52, Стефан Васильев via Gnupg-users <gnupg-users at gnupg.org> wrote:
> 
> It would tell me as 3rd party that for WoT puposes, if this is still used,
> Alice and her good friend Bob were able to sign their pub keys remotely,
> based on a free of charge verification method.

That’s what ordinary third-party sigs do. Adding medical data to a public key does not add anything to the process.

You should also beware that medical information is treated as sensitive personal data under GDPR, and this subject to stricter rules. Keyserver operators already have enough legal issues handling ordinary personal data (email addresses etc) without adding vaccination certificates to the dataset.

A