[Edu-sig] Re: Cryptonomicon
Mon, 27 Nov 2000 09:52:48 -0800
Bruce Schneier, who wrote the Solitaire algorithm (called Pontifex in
Cryptonomicon) has an excellent page describing how and why it works:
One of the cool things about it is that it's designed to use playing
cards, so you can have students encrypt and decrypt messages with cards,
getting a tactile feel for encryption, then implement the code. There's
python code up on the site, too, though they make no claims about its
Anyway, it's much more realistic from an encryption point of view,
without being much more complicated than a clubhouse algorithm. Win-win.
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> 1. Re: Cryptonomicon (Kirby Urner)
> Message: 1
> Date: Sat, 25 Nov 2000 10:09:40 -0800
> To: email@example.com
> From: Kirby Urner <firstname.lastname@example.org>
> Subject: Re: [Edu-sig] Cryptonomicon
> I've added some links to my Python-based
> including to an URL where Windows users can
> download GUI simulators of Enigma machines.
> The Sale essay on deciphering the Enigma mentions
> how "no letter my encipher to itself" was actually
> a weakness of the German system, along with its
> bidirectionality, i.e. if A enciphered to J, then
> J enciphered to A.
> The difference between simple random substitution
> ala my clubhouse code algorithm (which allows
> self-substitution) and something like Enigma, is
> the latter changes the substitution key with each
> press of a letter (in the Enigma using a complicate
> system of rotors which, like a car odometer,
> knocked successive wheels one notch with each
> complete revolution of the one before).
> Here's some example plaintext and corresponding
> ciphertext, from one of the Enigma simulators:
> Input (note 5-letter chunking):
> AQUIC KBROW NFOXJ UMPED OVERT HELAZ YDOGW WWWWW
> WWWWW WWWWW WWWWW WWWWW WWWWW WWWWW WW
> Output (note how repeated Ws in the input
> nevertheless enciphers to different letters
> UVWFP ALDFF FMNML SHZLI GTMXM CISQU EIYED FJORN
> OMNRA CZVXL MRBAO JRGRO ZKCAJ NMMLP AO
> Also in the news: an Enigma machine stolen from
> the Bletchy Park museum was recently recovered,
> along with the internal rotors (found separately,
> according to newspaper accounts).
> Another link shows contains some scans of Turing's
> original typed manuscript re the Enigma, plus
> there's a virtual tour of Bletchy Park -- all
> very reinforcing of the storyline developed by
> Neal Stephenson's 'Cryptonomicon', the novel which
> originally inspired me to launch this thread.
> It's be high feasible to write an Enigma simulator
> in Python of course, including with a GUI front
> end. But in accordance with my "cave painting"
> analogy, I think what's important from a pedagogical
> point of view is, on first pass, to give just the
> flavor, the essential gist, and then move on to
> linked topics (e.g. digital circuit design and
> the evolution of computing hardware).
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