[openpgp] Deterministic generation of (symmetric) public key params from private key params

[Daniel Huigens <[e-mail]>]

Hi folks,

In the meeting last week, Justus noted that folks might want to
deterministically generate key pairs from the private key material
(presumably by storing some metadata like the key generation time).

And, the change in draft-ietf-openpgp-persistent-symmetric-keys-00
complicates this, by no longer storing the hash seed in the private
key material.

So, you'd have to store some additional algorithm-specific metadata
from the public key material, namely the fingerprint seed.

Since we didn't have much time for discussion last week, I thought I'd
ask the wider WG here whether this is a use case people care about,
and whether this workaround would be sufficient?

Best,
Daniel