Use a Real Enigma Encryption Machine and Bombe Decryption Device

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- Ian Watson, author of The Universal Machine

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Days to Centenary: 14

We’re nearing the finish line of the countdown to the Turing Centenary — just two weeks to go!

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If you’re a regular on this site you already know two ways to build your own Enigma machine.  Still, wouldn’t you love to encode something on a real Enigma machine and have it decoded on an actual Bombe?

Next week you can, at least if you’re in the vicinity of the Cheltenham Science Fair.

Military Enigma Machine

From June 12-17 the Fair will be borrowing a real Enigma machine, on loan from GCHQ.  You can have a Twitter message encoded and it will then be sent to Bletchley Park, where it will be decoded with a Bombe, the code-breaking device masterminded by Alan Turing to defeat the Enigma codes being used by the Nazis in World WarII.

Rebuilt Bombe Decryption Device

How that for a little historical role-playing?  Visit the Discover Zone to participate.

The Fair is also featuring an address by  Jack Copeland, Director of the Turing Archive, called Alan Turing: Pioneer Of The Information Age on June 12 at 8:30 pm.  General admission tickets are £9.

The Enigma Logo

The Desire for Enigma: The Mysterious Theft of the Code Machine

Days to Centenary: 234

On April 1, 2000 someone pulled a major April Fool’s prank, stealing one of only three Enigma code machines in the world from Bletchley Park. The Abwehr Enigma G312 machine was valued at £100,000.

Police believed that the machine had simply been carried out of the historic site, but don’t blame Bletchley Park. The enigma was secured in a glass cabinet which was not broken in the theft. An alarm system was in use and volunteers were watching over the site’s displays. Whoever carried out the theft was either very lucky or, more likely, very professional. All the more so because the theft happened just a week before a new infrared security system was to be installed.

Just what had happened to the machine was a mystery for several months. Then, in September 2000, police began receiving letters from a man who referred to himself as “the Master,” who claimed to be acting on behalf of a third party who had innocently purchased the machine, not knowing that it was stolen.

At one point police entertained the charmingly recursive theory that the letters from the Master contained coded clues as to the Enigma’s location and called in expert code breakers.

The Master’s letters demanded £25,000 for the machine’s return, to be paid by October 6, 2000. Bletchley Park announced that it would pay the ransom and had the money ready, but even as the deadline passed the Master failed to make contact to collect it.

Two weeks later Jeremy Paxman, a television presenter at the BBC, opened a parcel at his office and found the Enigma machine inside. It was missing a few parts, but these were later delivered as well.

Paxman and the purloined Enigma

Ultimately a dealer in World War Two memorabilia named Dennis Yates was charged with “handling” the stolen merchandise after admitting that he sent the letters and delivered the machine to Paxman. Yates was scheduled to stand trial at Aylesbury Crown Court, but decided at the last moment to plead guilty and was sentenced to ten months in jail.

In court, Yates said he had become involved in a scheme which soon passed out of his control and that his life had been threatened by persons involved in the theft. He never named the actual theives and they were never caught.

The title of this post is an allusion to a painting by Salvador Dali called The Enigma of Desire — My Mother, My Mother, My Mother (1929). Details of its creation and underlying psychology here.

Grokking the Enigma

Days to Centenary: 246

The term “grok” comes from the novel Stranger in a Strange Land by Robert A. Heinlein.  The novel’s own definition of grok is as follows:

Grok means to understand so thoroughly that the observer becomes a part of the observed—to merge, blend, intermarry, lose identity in group experience. It means almost everything that we mean by religion, philosophy, and science—and it means as little to us (because of our Earthling assumptions) as color means to a blind man.

It might be permissible to say that Alan Turing grokked the Enigma, the encoding/decoding device used by the German military during World War II.  Probably the closest any of us mortals will come to reproducing his experience will come from reading the Enigma web page mounted by Erik Vestergaard, a Danish mathematician and high school math teacher.

The Enigma plugboard

The site is full of useful information, but so is a corporate prospectus — that doesn’t make them a great read.

Luckily the site is also lively and well illustrated and provides clear explanations of how the Enigma worked and how its codes were broken by Turing and company.  And when an explanation isn’t enough, the page has vivid diagrams that help the reader understand what’s going on.

An encryption diagram from the page

And for those who are upset by the fact that Turing’s renown often means that his predecessors in Poland — who worked out early Enigma cracks — are overlooked, the page has an extensive section on Marian Rejewski and the Poles.  This includes links to pdfs of mathematical papers on the methods used by Rejewski and his compatriots.

Marian Rejewski

Finally, Vestergaard took his students on a trip to Bletchley Park in 2007 and his photographs not only provide a homelier view of the place than one gets on many other web sites, but it gives us a glipse at just how badly in need of repair this historic site is.  As I recently wrote, the site has just been awarded funds by the Heritage Lottery for a major reconstruction project, but the Bletchley Park Trust must raise over a million pounds on its own before it can access the lottery funds.  You might want to think about making a small donation so that the Trust can reach its fundraising goal and unlock the endowment it needs.

Hut 6 at Bletchley Park, photographed during Vestergaard's class trip

For a well rounded introduction to the historical role and the functioning of the Enigma machine that presented such a challenge to Allied codebreakers, I have found no better resource than this page.