OpenPGP header

[Simon Josefsson <jas@extundo.com>]

There is an effort to standardize the features from X-PGP:, X-PGP-ID:
etc into OpenPGP:, see:

http://josefsson.org/openpgp-header/

While general comments are appreciated, what I'd like to ask here is
whether Gnus should try to generate this header automatically?

Note the key word 'try'.

Exactly how Gnus can determine whether the user has a working OpenPGP
installation isn't obvious.  Check whether ~/.gnupg/gpg.conf exists
and use the key id from the 'default-key' token in that file?

OTOH, even if that test succeed, it is not clear that the user wishes
to add the header to all messages she sends.

Perhaps it would be sufficient to make it easy to optionally ask Gnus
to set the header.  Right now I don't think it is simple enough,
here's what I'm using currently:

 '(message-send-hook (quote ((lambda nil (save-excursion (save-restriction (message-narrow-to-headers) (goto-char (point-max)) (insert "OpenPGP: id=B565716F; url=http://josefsson.org/key.txt
")))))))

Perhaps a variable message-insert-openpgp, that is nil by default, but
may contain a list with information to populate in that header?  An
example value would be:

(setq message-insert-openpgp
      '((id . "B565716F") (url . "http://josefsson.org/key.txt")))

What do you think?