Why isn't there a defined protocol to retrieve PGP keys from a destination mail server? Or am I just not searching with the right parameters?
I imagine a quite simple process like other established processes (AutoDiscovery, etc.):
- Sender enters recipients e-mail into the mail client (thunderbird/outlook/whatever)
- Mail client resolves the PGP discovery service of that domain via a defined SRV record
- If the intended recipient has added a pubkey to his profile the service will answer the request accordingly (otherwise nothing really happens)
- The mail client uses the pub key and intransparent to the sender encrypts the message before sending
I mean a database and a very simple web service that takes an e-mail address as a parameter and eventually replies with the corresponding database entry isn't that sophisticated.
Why hasn't this been done? Or am I missing a crucial point (except politics)?
This protocol actually already exists and is part of GnuPG since v2.1.12: WKD. The protocol was submitted to the IETF in 2016 by [Werner Koch] of the GnuPG e.V..