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From: bet@duke.UUCP (Bennett E. Todd III)
Newsgroups: net.crypt
Subject: Encryption using compression
Message-ID: <5992@duke.UUCP>
Date: Wed, 3-Jul-85 21:01:05 EDT
Article-I.D.: duke.5992
Posted: Wed Jul  3 21:01:05 1985
Date-Received: Fri, 5-Jul-85 06:38:28 EDT
Reply-To: bet@ecsvax.UUCP (Bennett E. Todd III)
Distribution: net
Organization: Duke University Computation Center
Lines: 14


Trivial encryption algorithms are attacked by analysis of frequency
distributions, more or less. Wouldn't a simpleminded substitution or
transposition algorithm be beefed up to the point of requiring search
of the key space by applying a good compression program to the
plaintext first? The whole point to data compression is the redundancy
of tokens, and removing it by recoding the data to make all tokens
equally likely. If I were to use a simple substitution cypher with an
arbitrary premutation of bytes on the output of a good compression
program how could the resulting file be attacked?

-Bennett-- 

Bennett Todd -- Duke Computation Center, Durham, NC 27706 -- +1 919 684 3695
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