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Alan Turing's Enigma Treatise online
uzada writes "Bruce Schneier's CRYPTOGRAM mailing list had a link off to three chapters of Alan Turing's treatise on the Enigma, retyped
from the only known paper copy. It may be a chance to see if Neal Stephenson knew what he was talking about in _Cryptonomicon_... "
It's only three chapters, but I'm looking forward to reading it, as Turing has been referenced in almost every CS class I've taken.
Anyone who is in England, or finds themselves there at some point, might like to take a train up to Bletchley Park and view the Museum of Cryptography there. They have Enigmas, Lorentz machines, materials used by the Poles to figure out the beginnings of an Enigma crack, and one of the most wonderful contraptions I've ever had the privilege of viewing: a working Colossus.
Tony Sale has taken photographs of the old Colossus, together with surviving notes, and built a new one. Colossus was a machine for figuring combinatorics for cracking cyphers generated by the Lorentz cypher machine, a more complex follow-on to the Enigma. Colossus fills a room, and is Britain's entry in the 'first digital computer' race. It's a late entrant because its details were classified until recently...long past any reasonable period for it, given that UNIX v6 used a modified Enigma algorithm for its passwords. (I hear that details of the Japanese Purple machine, however, are still classified in the U.S.)
The Turing paper discussed in this article talks about machines used to help in the decryption process of the Lorentz machine, such as the Bombe. Colossus is the height of such technology.
Colossus is a vacuum tube machine. Its reconstruction was possible only because the original was built with parts scrounged from British Telecom, and BT being what it is, those parts are still available for scrounging today. The machine is built on two six-foot rack assemblies, each about fifteen feet long, and about five or six feet apart. It runs on 400 volts. Input is a hand-built high-speed paper tape assembly. The machine clock comes from the smaller center sprocket holes on the tape. The input tape is an endless loop consisting of the cypher to be analyzed. Output is to a mechanical typewriter fitted with solenoids on the number, space and return mechanisms.
I had the peak experience of standing in the middle of Colossus while Tony turned it on around me. Tubes glowing, decade counters climbing, tape spinning like mad (5000 CPS and the mechanism is six feet high, full of eight-inch-wide tension wheels)...THIS is computing!
Don't miss seeing this thing in action. It'll make your week.
**** The PDF input file uses encryption and cannot be processed.s ec.ps
**** Please get and install the patch available from
**** http://www.ozemail.com.au/~geoffk/pdfencrypt/pdf_