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From: tli@oberon.UUCP (Tony Li)
Newsgroups: net.crypt
Subject: Re: Encryption using compression
Message-ID: <78@oberon.UUCP>
Date: Tue, 9-Jul-85 03:47:40 EDT
Article-I.D.: oberon.78
Posted: Tue Jul  9 03:47:40 1985
Date-Received: Mon, 15-Jul-85 06:51:16 EDT
References: <5992@duke.UUCP> <11379@brl-tgr.ARPA> <5993@duke.UUCP>
Reply-To: tli@oberon.UUCP (Tony Li)
Distribution: net
Organization: U. of So. Calif., Los Angeles
Lines: 19
Summary: 

The problem with your beautiful theory is that you haven't changed the
frequency of the characters in your text.  By running compress on the
plaintext, you've simply inserted a substitution cipher before your shuffle
cipher.  Once the natural language of the plaintext becomes known, it should
quickly become obvious to the cryptographer that your character frequencies
are incorrect.  This leads immediately to the idea of a substitution.

May I suggest Gaines as an excellent place to begin your reading?  Even the
introductory chapters and a pocket calculator are useful for simple
cryptograms.

Cheers, 
Tony ;-)
-- 
Tony Li ;-)		Usc Computer Science
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