Extending the key expiration date

Florian Weimer Florian.Weimer@RUS.Uni-Stuttgart.DE
Thu Sep 6 16:08:02 2001

"Janusz A. Urbanowicz" <alex@bofh.torun.pl> writes:

> > If an attacker obtains your secret key, he can arbitrarily increase
> > the lifetime of the key, thus increasing its value.
> It is no more flaw that the one lately announced about not-signing
> date, originator and recipients of the message.
But it's clearly a regression! The V3 key format does not show this kind of problem.
> By definition if an attacker have your secret key, he can do
> anything. You may call it a flaw in whole pulic key cryptography
> concept.
This is certainly wrong. For example, the attacker cannot override already distributed revocation certificates. Reliable expiration of keys is required to be able to cut down the length of certification revocation lists for most applications. Otherwise, large-scale CAs might become unusable after a few years of operation. -- Florian Weimer Florian.Weimer@RUS.Uni-Stuttgart.DE University of Stuttgart http://cert.uni-stuttgart.de/ RUS-CERT +49-711-685-5973/fax +49-711-685-5898