Re: [openpgp] details of 4880bis work

On 16/04/2015 10:39 am, Christoph Anton Mitterer wrote:
> On Wed, 2015-04-15 at 14:01 -0700, Jon Callas wrote:
> > There was also a mention somewhere of removing the timestamp from the
> > fingerprint, and that's what I really want to comment on.
> > When 2440 started, removing the timestamp was one of the things I
> > wanted to do. However, it's not such a bad thing. If you make a
> > fingerprint merely be a function of the key (it has no variable data),
> > then you lose the ability to alias the key, which is actually useful.
> I think the main problem with the valid from/through dates not being a
> part of the fingerprint is the following:
>
> A user may intentionally want to limit his key for security reasons,
> e.g. he makes a 1024 bit and wants to make sure that no one is
> using/trusting it after two years anymore.
>
> AFAIU, if the dates are not part of the fingerprint this would also mean
> that they could be changed any time with a new self sig (including at a
> time when the key owner may deem the 1024 bit RSA already no longer
> secure enough to be trusted).
> Of course one can make a revocation cert, but an attacker could always
> try a blocking attack at the keyserver level.
>
> That's why I think, that creation and expiration times should be
> immutable once the key has been created; at least not without
> invalidating all signatures (i.e. those from other users).
While I can certainly see where you're coming from with this proposal,
the problem is that it is completely the opposite of the current
function of all key and subkey types.  There are quite a lot of
existing users out there who set expiration dates on their keys and
then keep changing them as the expiration date approaches.  So this
would be a nasty shock at the very least and may break some other
things, depending on what they're doing with all those keys.

To put it another way; that's a *lot* of old dogs we'd need to teach
new tricks to (and it's so often hard enough to teach the current
tricks to puppies already).


Regards,
Ben

signature.asc
Description: OpenPGP digital signature

_______________________________________________
openpgp mailing list
openpgp(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/openpgp