Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP 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