Questions about some signature subpackets

Christoph Anton Mitterer <cam@mathematica.scientia.net> Sat, 25 February 2006 17:50 UTC

Message-ID: <44009247.5040707@mathematica.scientia.net>
Date: Sat, 25 Feb 2006 18:22:15 +0100
From: Christoph Anton Mitterer <cam@mathematica.scientia.net>
User-Agent: Debian Thunderbird 1.0.7 (X11/20051019)
MIME-Version: 1.0
To: ietf-openpgp@imc.org
Subject: Questions about some signature subpackets
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Sender: owner-ietf-openpgp@mail.imc.org
Precedence: bulk

Hi everybody.

I've got a question about some signature subpackets: Especially key
expiration time (9) and key flags (27). According to the standard
they're allowed on selfsigs (this includes the sigtypes 0x10-0x13, 0x1F
and the 0x18).
Ok most implementations (like gnupg) put this on a 0x13-type signature.

Why is it allowed to put key-expiration-time and key-flags on 0x10-0x13?
I think for the primary key only a 0x1F sig is suited.
When specifing things like features or preferred algorithms, one can
imagine that each user has different settings. But is there any case
where User IDs could/should specify different key-flags and/or
key-expiration-time? If so, could you tell me such an example?

Best wishes,
Christoph Anton Mitterer.

btw: Wouldn't it be good to introduce other User Attribute Image Formats
(especially PNG and JPEG2000)? Perhaps it would be even a good idea to
add new User Attribute Types, like one for XMPP (Jabber) addresses (this
has been standardized by the IETF...).

Questions about some signature subpackets Christoph Anton Mitterer