On Thu, Aug 17, 2017 at 9:30 PM, John Levine <johnl@xxxxxxxxx> wrote:
In article <7877.1502972732@obiwan.sandelman.ca > you write:
>This is an interesting idea. For those of us who deal with many emails,
>(particularly upon return from vacation), not having to deal with lunch plans
>that have expired would in fact be nice.
See RFC 2156 and RFC 4021, section 2.1.50. To me the interesting
question is why, since we've had Expires: for 20 years, nobody uses it
outside of netnews.
> That's a job for good-old-Usenet Supersedes:,
>but that's one email overcoming another, and the whole thing needs
>some cryptographic support. Note that a merkle hash (a la s/key) would
>probably suffice.
Seems like overkill. How about you pay attention to the Supersedes:
(see RFC 2156 and RFC 4021, section 2.1.46) if old and new messages
both have DKIM signatures from the same domain? Same question about
why after 20 years nobody uses it outside of netnews.
DKIM almost helps but this is a data level feature and it really does not work well with a presentation layer authentication scheme like DKIM.
And to make it work well, you have to start from a messaging infrastructure where every message and sender can authenticate themselves cryptographically from the beginning...