From: "Perry E. Metzger" <pmetzger@lehman.com>
Date: Fri, 12 Nov 93 16:33:45 PST
To: Matthew J Ghio <mg5n+@andrew.cmu.edu>
Subject: Re: Fractal cryptography
In-Reply-To: <ggt2OaK00awKAjSUYi@andrew.cmu.edu>
Message-ID: <9311130031.AA03966@snark.lehman.com>
MIME-Version: 1.0
Content-Type: text/plain



Matthew J Ghio says:
> hfinney@shell.portal.com (Hal Finney) wrote:
> 
> > There have been some discussions on sci.crypt within the past few months
> > on nonlinear/chaotic algorithms and their use in cryptography.  Fractal
> > cryptography sounds like it might be related.  The problem is that unless
> > an algorithm was SPECIFICALLY DESIGNED to prevent an intelligent
> > adversary from defeating it, the chances of it being an effective
> > cryptosystem are limited.  Just because nonlinear systems produce
> > complex-looking results does not mean that these results are unpredictable
> > given enough data.
> 
> Yeah, but how much data?  Just because something can be solved given
> enough data doesn't help me break it if I need 10^37643254 bytes of data
> to do it.

Amateurs regularly develop systems and claim fantastic things for
them. They then turn out to be trivial to break. This has made people
who are even semi-pro like some of the folks on this list shake their
heads and say "oh no, not another one" every time someone who hasn't
read the literature claims to have come up with "the new great
cryptosystem". This is the reason that people tend to be so skeptical
of the constant stream of new proposals from such individuals. Its
nothing personal -- its just the sort of jaded attitude you get when
this sort of thing happens repeatedly.

Perry