Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site duke.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!mcnc!duke!bet 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 UUCP - bet@ecsvax, bet@duke, ...{decvax,ihnp4,akgua}!mcnc!ecsvax!bet