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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: sci.crypt
Subject: Re: New PubKey System Coming
Message-ID: <7506@utzoo.UUCP>
Date: Sat, 10-Jan-87 21:09:46 EST
Article-I.D.: utzoo.7506
Posted: Sat Jan 10 21:09:46 1987
Date-Received: Sat, 10-Jan-87 21:09:46 EST
References: <3859@utcsri.UUCP>, <5490@brl-smoke.ARPA>
Organization: U of Toronto Zoology
Lines: 19

> -		"It would take more than a billion years, working with the 
> -	fastest computers available, to break just one key," he said.
> 
> I hope it is obvious to most readers of this newsgroup that
> the above claim is bullshit...

It's a standard claim by the inventors of wonderful new cryptosystems, in
fact.  In one sense, you can claim that even solving a monoalphabetic
substitution would take 26! (about 400000000000000000000000000) trials.
In fact, a bright 12-year-old with an interest in the subject can break
one in an hour, given a reasonable amount of input text.  The fundamental
fallacy is the assumption that a cryptanalyst tries and discards one key
at a time, when in fact he discards entire classes of keys at a time.  A
minute's attention to a frequency chart of a text encrypted with a
monoalphabetic substitution will eliminate 99.999...% of those 26! possible
keys at once.  "Work smart, not hard."
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry