[openpgp] Embedded TPK subpacket

[Justus Winter <[e-mail]>]

Hello,

I'd like to propose a new signature subpacket that contains a TPK,
let's call it the Embedded TPK subpacket.

I see two immediate use cases:

  - If a designated revoker creates a revocation signature, she can
    embed her TPK in the signature, so that it is easy to verify the
    revocation without having to hunt for her TPK.

  - Some MUAs attach TPKs to emails, pEp does so too, and Autocrypt
    includes TPKs in mail headers.  Instead of doing that, one could
    then transmit ones TPK (and those of others in the conversation)
    in-band.  This has the advantage of requiring no cooperation of
    the MUAs, and the PGP implementations can gather the TPKs when
    parsing the signatures.


Thanks,
Justus