From: dlv@bwalk.dm.com (Dr.Dimitri Vulis KOTM)
Date: Fri, 8 Aug 1997 21:01:39 +0800
To: cypherpunks@toad.com
Subject: Re: REPOST : Un-forgeable Cancels
In-Reply-To: <12867.9708080920@misun2.mi.leeds.ac.uk>
Message-ID: <5R04ae64w165w@bwalk.dm.com>
MIME-Version: 1.0
Content-Type: text/plain



jbaber@mi.leeds.ac.uk writes:

> Any comments/glareing weaknesses that I have missed?

Well, you missed credited guys named Franz and Huusinen with proposing this
exact scheme a couple of years ago. You also missed my discussion on how to
allow the local admin to issue cancels as well.

I used to think this scheme is very cool.  Later I realized it had a serious
problem with forgeries in one's name.

Suppose X forges an article in Y's name, and specifies a cancel lock; then
Y can't cancel this forgery.

The retraction server which David is reported to be working on doesn't
rely on passwords on authenticate Y; if Y can demonstrate the ability
to receive a cookie sent to Y, then the server can issue a signed 'hide'
NoCeM for an article that purports to be from Y.  Works for forgeries too.

---

Dr.Dimitri Vulis KOTM
Brighton Beach Boardwalk BBS, Forest Hills, N.Y.: +1-718-261-2013, 14.4Kbps