gpg: Remove support for PKA.
* g10/gpg.c (oPrintPKARecords): Remove. (opts): Remove --print-pka-records. (main): Remove "pka-lookups","pka-trust-increase" and other PKA stuff. * g10/options.h (EXPORT_DANE_FORMAT): Remove. (VERIFY_PKA_LOOKUPS, VERIFY_PKA_TRUST_INCREASE): Remove. (KEYSERVER_HONOR_PKA_RECORD): Remove. * g10/packet.h (pka_info_t): Remove. (PKT_signature): Remove flags.pka_tried and pka_info. * g10/parse-packet.c (register_known_notation): Remove "email@example.com". * g10/pkclist.c (check_signatures_trust): Remove PKA stuff. * g10/call-dirmngr.c (gpg_dirmngr_get_pka): Remove. * g10/export.c (parse_export_options): Remove "export-pka". (do_export): Adjust for this. (write_keyblock_to_output): Ditto. (do_export_stream): Ditto. (print_pka_or_dane_records): Rename to ... (print_dane_records): this and remove two args. Remove PKA printing. * g10/free-packet.c (free_seckey_enc, cp_pka_info): Adjust for removed pka_info field. * g10/getkey.c (get_pubkey_byname): Make AKL_PKA a dummy. * g10/keyserver.c: Remove "honor-pka-record". (keyserver_import_pka): Remove. * g10/mainproc.c (get_pka_address): Remove. (pka_uri_from_sig): Remove. (check_sig_and_print): Remove code for PKA.
PKA (Public Key Association) was a DNS based key discovery method
which looked up fingerprint by mail addresses in the DNS. This goes
back to the conference where DKIM was suggested to show that we
already had a better method for this available with PGP/MIME. PKA was
was later superseded by an experimental DANE method and is today not
anymore relevant. It is anyway doubtful whether PKA was ever widely
- Signed-off-by: Werner Koch <firstname.lastname@example.org>