From: pgut001@cs.auckland.ac.nz
Date: Fri, 26 Jan 1996 16:17:02 +0800
To: cypherpunks@toad.com
Subject: Re: "Concryption" Prior Art
Message-ID: <199601260604.TAA27250@cs26.cs.auckland.ac.nz>
MIME-Version: 1.0
Content-Type: text/plain


Death rays from Mars made pcw@access.digex.net (Peter Wayner) write:

>I haven't read the supposed Concryption patent so I don't know
>what the claim structure is. But if they truly claim the right
>to do encryption and compression simultaneously, then I've got
>some prior art that should knock out such a broad claim. The
>paper is "A Redundancy Reducing Cipher" (Cryptologia, May 88).
>It's not very secure, but it does do some manner of encryption
>at the same time as compressing a file with a Huffman-like
>system. The journal is found in many university libraries so it
>should be easy to produce a solid counterclaim.

There's a much earlier paper by Frank Rubin in a 1979 Cryptologia which
covers encryption+compression with Huffman and arithmetic coding.
However the Con-cryption patent covers first compressing, then
encrypting.  Unless they've got very good lawyers, you can probably
ignore it.

Peter.