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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.
Doh, bad link! this one will work better.
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**** 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_
"Horizon"'s accuracy is often questionable, but they don't usually indulge in conspiracy theories. That the producer regarded the question as open is, in itself, very interesting.
Whilst that, in itself, hardly makes a convincing case, it does make me believe that the cause of Turing's death isn't as certain as the textbooks would have you believe.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Very true. It's still not certain whether he took his own life, or was "assisted", but the price he payed ended up being the highest possible.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The inventor of the Digital Computer, at Cambridge University
The inventor of the Stored Program Digital Computer, at Manchester University
The inventor of the cypher-breaking computer "Colossus"
The breaker of the Enigma cypher
The inventor of the science of Artificial Intelligence (hence the "Turing Test", which he devised)
An expert in mathematics
An expert in biology
A pioneer in software design theory (eg: the "halting" problem)
A pioneer in "computable" problems (eg: the Turing Machine)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The biography _Alan Turin: The Enigma_ gives a good description of the Enigma machine.
There's a typewriter keyboard with 26 keys and bulbs. When you strike a key a bulb lights up encrypting the letter. Then the machine changes state.
The state of the machine is defined by a series of rotors. Each rotor has 26 contacts and effectively swaps two letters. When the machine changes state, one or more rotors advances one position (out of 26) like an odometer. Typically, one wheel was fixed and three rotated with each letter encrypted.
As an additional complication, there was a plugboard at the back that swapped additional pairs of letters. (stecklered in the Turing paper).
Since the entire mechanism swapped letters, you only had to reproduce the initial state of the other machine and type in the cyphertext to extract the plaintext. Effectively, each letter in the plaintext was encripted with a different substitution cipher. Each substitution cipher was related to the subsequent ones by a complicated transformation.
IIRC, the order of the rotors and plugboard were sent out in codebooks and changed once a day. The initial position of the rotors was given in the first few characters of the ciphertext. At midnight every day, the codebreakers had an entirely new problem to solve -- determine that day's rotor position and plugboard settings. Once that was done, the entire day's communications could be read.
Their efforts were aided by the fact that German communiques often started identically. If you can guess what the first 15 letters of the plaintext are, you can make a lot of progress
The Polish mathematicians made a lot of progress with Enigma before Poland was overrun. They deduced the wiring of the wheels without having access to an actual machine. In a classic example of the failure of Security Through Obscurity, Enigma was thoroughly cracked fairly early in the war and the German command never believed that it had been broken. Late in the war they added additional rotors to the supply that kept the Bletchley group on their toes, but didn't significantly impede their ability to crack Enigma.
I have discovered a truly marvelous sig, unfortunately the sig limit is too small to contain i
Dr. Turing was a genius of integrity. He was more responsible than any other single person for saving England during the war. This fact could have gotten him out of jail and stopped the barbaric treatment of his homosexuality. Instead he honored his promise to keep secret things secret and paid a high personal price.
If tits were wings it'd be flying around.
I uhh *cough*, don't know how these files showed up in my directory, but they're here. There's only the index page and the 3 chapters there, nothing else. Please only access it if the main site borks under the slashdot effect...
lastly, what's going on with all the "nt rulez" stuff? Is somebody trying to suck moderator points?
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It's very clear the trolls aren't part of regular slashdot readers. There can't be many (if any) regulars here who don't know Alan Turing (the inventor of the Digital Computer, and the builder of the Manchester Mark 1, also known as the Baby, which had the first-ever optical memory). They're most likely bored web-surfers who are touring the net for online boards to wreck.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
...but can we port Linux to it? :)
/* This is humor. I'm making fun of posters who always ask if Linux can be ported to xxx. Please don't respond with reasons why or why not. If you do, I'll ask you if we can make a beowulf cluster of these machines. */
Save the whales. Feed the hungry. Free the mallocs.
The death of Alan Turing has been attributed to so many things (suicide, illness, MI5/MI6, etc) that I don't think anyone really knows (or cares) any more. Whatever works for them is what matters.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
But then, AC's can afford to attack, insult and abuse others for recognising a person's achievements, if it threatens those they idolise. Problem with idols is that they are rarely as idylic as the worshiper would like to believe.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)