Variations on Enigma

Verifying secret information is a challenge.  After enjoying the movie Imitation Game, I went to the library for books on Bletchley Park and Enigma. I found Enigma by Wladislaw Kozaczuk. Kozaczuk tells a story completely different from the one offered by F. W Winterbotham in The Ultra Secret.

I had read Andrew Hodges’ biography, Alan Turing: the Enigma back in the early nineties.  I am pretty sure that I read F. W. Winterbotham’s The Ultra Secret fifteen years earlier because it was sold by Loompanics Unlimited, who paid me to write The Code Book: All About Unbreakable Codes and How to Use Them. (On NecessaryFacts here.)

Discussing Imitation Game online, I read from others several twice-told tales that just were not so. I wrote several myself before I read Kozaczuk’s book.  I now regard it as the correct version – if the truth can have “versions.”

It is true that the Polish device for mechanically attacking the Enigma ciphers was called a “bomba.”  It was named for a large spheroid chocolate cake.  It was not shaped like the cake at all.  According to their story, it was only what they were having for dessert at a restaurant when they discussed the code name for their project.

 “The bomb was an electro-mechanical aggregate based on six Polish Enigmas, combined with additional devices and transmissions.  An electrically driven system of rotors revolved automatically, creating in each bomb, successively, over a period of about two hours (100-120 minutes), 17,576 different combinations. When the rotors aligned with the sought-for position, a light went on, the motors stopped automatically, and the cryptologist read the indications.   Thus, by setting in motion the bombs (six were built at once in November 1938), the daily keys could be recovered within two hours. “ (page 53)

 Mathematicians working for Polish intelligence had been attacking Enigma with some success for over ten years.  They had their own Enigma machines.  Built by reverse-engineering, they were variations on the commercial model. That was essentially the same foundation as the German devices that had been modified for military use.

Mathematician Marian Rejewski developed a theoretical model of the German Enigma. His work achieved realization in the construction of the Bomba.  That device depended on electronic elements created by AVA Radio Manufacturing, a small firm in Warsaw which had been working for their government since the firm was launched in the winter 1929/1930.

The story of AVA in particular and the Polish cryptanalysis project in general should be familiar to Americans today.  One of the founders of AVA never completed school beyond the fourth grade, but started out as an apprentice locksmith.  The company’s key to government work came via another founder who worked in the Cipher Bureau.  At heart, AVA was a small shop run by two brothers who were amateur radio operators.  After high school (“gymnasium” in Europe) they built and sold cheap little radio receivers.  But they were pretty good at their craft.

Also diligent were the young mathematicians from Poznan University: Marian Rejewsky, Henryk Zygalski, and Jerzy Rozycki.  (The book has a pronunciation guide up front:  Rejewski is “Rey EF ski”.)  Recruited specifically to work on German communications, Rejewski spent a year in Göttingen studying advanced statistics.  It was his judgment that Germany’s mathematics programs had fallen behind, and were not producing leading edge ideas.  Moreover, as would be borne out later, the German military did not trust mathematicians because they would get lost in theory instead of producing immediate results.  From our viewpoint today, that choice was evidence of the failure of their philosophical assumptions. 

By 1934, the Polish mathematicians and radio hams had collaborated to build four Enigma duplicates.

None of that appeared in Winterbotham’s book. Neither did Alan Turing have a place in the book.  In the movie, Imitation Game, Commander Alastair Denniston was portrayed as a martinet of limited vision.  Unfair as that may well have been, it is recorded independently (or at least repeated often), that Denniston considered Enigma to be unbreakable.  It is hard to find success at something you regard as impossible.  Nonetheless, Winterbotham gave Commander Denniston full credit for running the group—headed by Alfred Dillwyn “Dilly” Knox, who received one mention only—that broke Enigma.   

In fact, Winterbotham said of Knox that he was “quite young” when working at Bletchley Park.  Knox was born in 1884. He had been with the UK’s “black chamber” in World War I; and he is credited with delivering the decryption of the Zimmerman Telegram.

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“Sometimes it is the people no one imagines anything of who do the things that no one can imagine.”  The take-away line from The Imitation Game states the theme.  The plot is the quest to build a computer that can decipher enemy communications and win a war.

 

Even with the Bombe, much work was done manually and brainually.
This grid shown in the movie is not the Banburismus of Turing.

Scholars complain about the historical inaccuracies. It is easy to do.  This is not a documentary. The film is a drama about one man’s achievement of what experts considered impossible.  That much is absolutely true. Commander Alistair Denniston held neither expectation nor hope for success.  The film dramatizes his disdain for the codebreakers. And it is drama, rather than the unemotional grinding out of intellectually difficult, yet ultimately routine, work. 

 

10,000 people worked there,
80% of them women.

Contrary to the movie, Joan Clarke’s team working on the Naval Enigma had early successes.  In the movie, by mid-1941 Denniston was not the only one enraged by Turing’s lack of progress.  In real life, by then, decipherment of Naval Enigma traffic allowed fleets to be redirected around U-boat packs. Lost tonnage shrank. But it is true that not all intercepts could be acted on. The Ultra Secret by F. W. Winterbotham (Harper & Row, 1974) broke that story long ago. 

Writing in Turing: Pioneer of the Information Age (Oxford, 2012),  B. Jack Copeland acknowledges that Cmdr. Denniston built Bletchley in the early years 1937-1939, though he proved unsuited to the task of managing 10,000 and getting their needs met by arguing for more money and more people. Also, it was late in 1941 when Turing and many others wrote to Prime Minister Winston Churchill, not Turing alone in mid-year. Such quibbles satisfy historians, but do not change the impact of the story.

You can buy a real one.
Some fetch a 6-figure price.
(They also sell replicas - and are not alone in that.)
http://enigmamuseum.com/

In real life, although the Turing-Welchman “Bombe” could and did reveal the settings of the Enigma machines, much of its output had to be checked by hand. In fact, Clarke and Turing spent long hours working together in Hut 8. They continued to do so after they broke off their engagement. And they met each other's parents after they announced their engagement. Turing apparently did not meet them before, as in the movie. 

Moreover, different than the portrayal, it was common for all of the cryptanalysts to continue work on the previous day’s cipher traffic until the next round of communiqués arrived.  They knew of stock phrases - such as ending each message with "Heil Hitler" - because that was long since a basic tool of diplomatic and military cryptanalysis: date at the top; "Your Excellency"; etc.

Turing called his manual labor “Banburismus” after the long sheets of paper made in Banbury.  But Turing called Clarke’s method “Dillyismus” after Dillwin Knox, the World War One cryptologist who revealed the Zimmerman Telegram.

 

Soon to be an eBook from
http://www.bletchleyparkresearch.co.uk

Before going to the theater, I intended to watch the film as a story in the abstract, not as a documentary.  That was very hard to do.  I read Andrew Hodges’s booklet biography of Turing when it came out in 1999.  (The film is based on his recent and greatly expanded biography, Turing: The Enigma; Princeton, 2014). Ahead of seeing the film, I researched Joan Clarke and wrote about her for the E-Sylum maillist of the Numismatic Bibilomania Society.  My research into her work continues. Having her numismatic bibliography, from an obituary in the BNJ, I submitted a proposal to the ANA.

http://www.bletchleypark.org.uk

From Wired, “How Designers Recreated Alan Turing’s Code-Breaking Computer for Imitation Game,” by Angela Watercutter, November 21, 2014 here. 

"Turing produced the design for the Bombe, building on the design of the original Polish Bomba which had been produced by Marian Rejewski in 1938. The Bletchley Park Bombe designed by Turing, was refined by another Bletchley Park codebreaker Gordon Welchman and actually built by engineer Harold Keen who was based at the British Tabulating Company, not at Bletchley Park."

 

A snippet of what displays on
the devices given to visitors to
perhaps the most computerized park in the UK.

Among those who complain about the film is Dr. Sue Black whose blog is "Cheeky Geek" here.

In a scene stolen from the future,
a tank crushes an (empty) Tommy helmet.

A biography of Joan Clarke's work is this article by Lynsey Ann Lord which is extracted from a University of St Andrews honours project. (Clarke finished all three triposes examinations and qualified for an M. Sc. in addition to her B.A. in mathematics.  She received neither because Cambridge did not grant degrees to women back then.)

      

Joan Elisabeth Lowther Murray [nee Clarke] (1917—1996) cryptanalyst and numismatist is listed in the Oxford Dictionary of National Biography here. 

Lord Stewartby (Bernard Harold Ian Halley Stewart), one of her collaborators in the coinage of Scotland, wrote the obituary for the British Numismatic Journal Vol. 67 No. 13, pg 162-167. (Online here.)  In 1986, Joan E. L. Murray was granted a BNS Sanford Saltus Medal for her research. 

He is not really Turing and it is not really his Bombe
but it was still a good movie.

The Secret Lives of Codebreakers: The Men and Women Who Cracked the Enigma Code at Bletchley Park by Sinclair McKay. New York: Plume (Penguin Group), 2012. (Originally published in the UK as The Secret Life of Bletchley Park (Aurum Press).) This retelling of the capture of Enigma wheels from the U-110 has some inaccuracies. The book says very little about Joan Clarke, though quite a bit about Mavis Lever (later Batey), who also worked on the Naval Enigma.

The Ultra Secret: the first account of the most astounding cryptanalysis coup of World War II – how the British broke the German code and read most of the signals between Hitler and his generals throughout the war by F. W. Winterbotham, New York: Harper and Rowe, 1974. This book broke the story. It is not from the viewpoint of Bletchley Park, and has no mention of Turing.

Engima: How the German Machine Cipher was Broken, and How it was Read by the Allies in World War II  by Wladyslaw Kozaczuk, edited and translated by Christopher Kasparek, University Publications of America, 1984 (Warsaw: Ksiazka I Wiedza, 1979).  Polish mathematicians had begun a theoretical analysis as early as 1932. The Turing-Welchman Bombe was an extension of the Polish Bomba; it was not Turing's universal machine.

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