Re: #22

On Tue, 2005-02-08 at 16:24, Sam Hartman wrote:
> >>>>> "Michael" == Michael Thomas <[email protected]> writes:
> 
>     Michael> Well, it's pretty simple really: when you get tickets
>     Michael> from the KDC, they aren't protected by PFS so using PFS
>     Michael> later is pretty questionable. It's not useless, but it's
>     Michael> not any huge win either. Until Kerberos itself supports
>     Michael> PFS, people deploying KINK really ought not get worked up
>     Michael> into a lather about turning on PFS to improve security
>     Michael> since it's doesn't to any great degree.
> 
> I'm confused.  I thought the point of PFS was to make it impossible to
> recover session data .  How does the fact that the KDC does not do PFS
> decrease the value of PFS for Kink?

I'm also confused by Michael's remarks, but, as I recall, one of the 
motivations for KINK was to do IPsec SA setup with lower CPU overhead
by avoiding public key operations.   If you add in a D-H exchange for PFS, 
you blow away that motivation and this winds up looking like a strange
way to build a GSS-authenticated IKE..

						- Bill