[OpenAFS] why kerberos only works in monolithic organizations

Adam Megacz megacz@cs.berkeley.edu
Thu, 29 Dec 2005 20:35:35 -0800

Ken Hornstein <kenh@cmf.nrl.navy.mil> writes:
> Maybe it's me, but I've never really seen the difference between a junk
> certificate and a Kerberos ticket;

Somebody with no prior trust relationship can check the validity of a
junk certificate.

> I'm confused; do you know about some cryptosystem that I don't that
> doesn't require users to know some sort of key?

Asymmetric cryptography eliminates the need for the party verifying
the key to share a secret with the certificate issuer.

This is the problem with Kerberos when you try to expand beyond a
single administrative domain (or more than a few for whom it is
feasible to do N^2 cross-realm): you have to hunt down the KDC admin
and cajole him/her into doing you a favor.

This works fine for a certain set of organizations, which, as a
result, have been the only ones who use Kerberos (and hence AFS for
the most part).

Kerberos was designed in an era when computers were much slower and
the (much greater) computational burden of asymmetric cryptography was
a serious problem.  This is no longer the case.

  - a

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