From: abostick@netcom.com (Alan Bostick)
Date: Sun, 10 Mar 1996 08:32:22 +0800
To: tcmay@got.net
Subject: Re: Fractals, Cellular Automata, and Encryption
In-Reply-To: <ad63bf5600021004e133@[205.199.118.202]>
Message-ID: <tWhQx8m9LsaQ085yn@netcom.com>
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In article <ad63bf5600021004e133@[205.199.118.202]>,
tcmay@got.net (Timothy C. May) wrote:

> Steven Wolfram had some speculations about using fractal or cellular
> automata-based systems for a new kind of cipher. His paper is in one of his
> books ("Theory and Application of Cellular Automata"), but it doesn't
> really get beyond just speculating. And, I recall that someone proved
> several years ago that Wolfram's CA-based encryption scheme was formally
> equivalent to a linear congruential generator.
> 
> I think I included a few paragraphs on this topic in my Cyphernomicon.

Schneier has a few words to say about cellular automata in the first edition
of APPLIED CRYPTOGRAPHY (I don't have the 2nd, shame on me).

Howard Gutowitz published and patented in 1992 a symmetric block cipher
algorithm, based on cellular automata, called CA-1.1 .  There are a
couple of CA-based hash algorithms.  CA-based PRNGs have been shown to
be isomorphic to linear feedback shift register RNGs (not linear
congruential generators, despite what Tim says) and so are subject to
the same security woes as LFSRs.

- -- 
Alan Bostick               | I'm laughing with, not laughing at.
mailto:abostick@netcom.com | The question is, laughing with WHAT?
news:alt.grelb             |      James "Kibo" Parry <kibo@world.std.com>
http://www.alumni.caltech.edu/~abostick

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