Web Key Directory (WKD) server.

Serves OpenPGP public keys for any address at the parent domain.

Lookup with GnuPG:

  gpg --locate-external-key --auto-key-locate clear,wkd ADDRESS

Direct path:

  /.well-known/openpgpkey/[domain]/hu/[hash]

  where [hash] = z-base-32(SHA1(lowercase(localpart)))

Protocol: https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/