This one has significant problems with historical accuracy. I will get to that later.
The opening scene shows Cambridge mathematician Alan Turing (Benedict Cumberbatch) arrested for homosexuality in Manchester, England, in 1951. The story is told as a flashback from Turing’s interview with police Detective Nock (Rory Kinnear). Following Turing’s arrest, Detective Nock attempts to obtain a dossier on Turing, but his war record comes up empty. It has been purged. Nock wants to know what Turing did during the war. He suspects espionage.
By way of explaining, Turing challenges Nock to play the imitation game. It’s the movie’s version of a test originally proposed by Turing. If you exchange typewritten messages with a correspondent, can you tell whether your correspondent is a person or a computer?
And that’s the name of the movie. It’s The Imitation Game, and it’s from 2014, distributed by The Weinstein Company in the United States. The movie is loosely based on Alan Turing: The Enigma by Andrew Hodges.
England and France have gone to war with Germany. It’s 1939, and the Germans are in communication with their U-boats and far-flung command centers by radio telegraph. Operators using hand keys send dots and dashes over the air, and if the British can decode these messages they are going to be able to put the screws to the Germans.
The problem is that prior to the war the Germans developed a machine to encrypt messages. The machine employs a keyboard, and whenever a key is depressed the machine substitutes a different letter for the one pressed. Diabolically, the machine then changes the substitution table before the next key is pressed. The substitution table is constantly changing as the message is being entered.
Bad news for the Germans. A copy of the machine has been smuggled out by a spy, and the Brits have it. They call it Enigma. Now they know how it works. How do code breakers defeat Enigma? The War Office hires a bunch of mathematicians and code breakers to team up and solve the Enigma problem. Turing is one of them.
Immediately Turing reveals himself to be arrogantly self-confident (as he has a right to be) and also to be the large part of a horse’s rear end. He refuses to work with his teammates. He has a way of defeating Enigma, and he figures the others will only slow him down. There is not much love lost.
When Turing’s requests for £100,000 to build a machine to defeat Enigma, the request is ridiculed and turned down. Turing sends a letter directly to Winston Churchill, who responds by putting Turing in charge of the operation. His first act is to fire two of the team members pictured above. His popularity with his co-workers hits rock bottom.
Another flashback reveals Turing’s history of unpopularity. At school he is the butt of vicious practical jokes and bullying. His one friend is Christopher Morcom (Jack Bannon), with whom he has a homosexual relationship.
The team needs people adept at breaking codes. People good at solving crossword puzzles are also good at this kind of work. Turing devises an employment ad in the form of a crossword puzzle. Respondents with successful solutions are invited to participate in a tryout for open positions. Here we see Turing biking through bombed out London streets to monitor the test of applicants.
One of the applicants is sharp-looking Joan Clarke (Keira Knightley). Applicants are given six minutes to complete the puzzle. Nobody is expected to complete the puzzle. It took Turing eight. She completes it in less than six, the only one to complete the puzzle.
Commander Alastair Denniston (Charles Dance) has been opposed to Turing’s approach from the beginning and seeks to terminate the project. Lack of cooperation from Turing’s team members is not helping his case.
Joan recognizes the problem and suggests Turing show some humanity. It works. He hands out apples to all the crew. There is a thaw. One of the team members suggests a modification that will result in a three-times speedup in operation. Turing appreciates the idea and incorporates the improvement. Still, it’s a daunting task.
Without reviewing the story behind Turing’s approach, I’m going to attempt to relate the audience’s view. It goes like this. Enigma employs a system of gears to change the substitution table with each keystroke. Turing’s device emulates the operation of Enigma.
The permutation process produced by the gears remains constant for one day. At midnight (supposedly German time) the Germans change the permutation process. Starting each morning, the code breakers must begin to gather German messages scooped from the air by a team of radio listeners. They must take a message and determine what substitution sequence will convert the gibberish copied from the air into something meaningful. Turing’s device tries different substitution sequences, searching for one that makes sense of a message. There are 159,000,000,000,000,000, 000 (159 million million million) possible settings. Trying them all to find the correct one would take millions of years. The team has only a few hours each day.
They set the Enigma emulator to work. It chugs along. Time runs out. Another day wasted. Commander Denniston arrives with a team to dismantle the device and to get rid of it. Turing’s co-workers threaten to quit the project. Denniston gives them one month to show results.
Of course, they do. At a pub gathering that includes Joan and her sexy friend Helen (Tuppence Middleton), Turing is baffled by the social interaction going on. Helen is flirting with one of the team members, and a discussion ensues. Helen intercepts and transcribes German messages. She is so familiar with a certain German key operator she has figured out things about his personal life, even though she cannot read his transmissions. It becomes obvious that certain words and even whole phrases are repeated every day, some in every message (Heil Hitler).
The room erupts. The team realizes they have broken the back of the German encryption system. The war is won.
Everybody rushes back to the lab. The machine is set to search for some known words. The dials start rotating. The machine stops. It has found the substitution sequence for the day. The correct substitution sequence is fed into Enigma, and it decodes a message.
Next comes the awful realization that they must not make full use of all intercepts. To do so would tip their hand. The Germans would realize their system has been compromised, and they would stop using Enigma. It’s the classic case of killing the goose that lays the golden eggs.
The Allies defeat the Axis powers and win the war. People move on to other jobs.
In the movie Alan Turing is convicted of “indecency” and sentenced to two years in jail. An alternative is chemical castration. Joan, now married, meets with him and reminds him of his enormous contribution to the war effort and to the advancement of computer science.
Turing killed himself in 1954.
As I said up front, this production suffers from a sever lack of historical accuracy. Something that struck me immediately as I was watching the video was the scene in the London street above. The time frame is is supposed to be prior to the German Blitz. Much of what remains also caused me discomfort. A lot did not ring true. It turns out my impressions are shared by others:
British historian Alex von Tunzelmann, writing for The Guardian in November 2014, pointed out many historical inaccuracies in the film, saying in conclusion: “Historically, The Imitation Game is as much of a garbled mess as a heap of unbroken code”. Journalist Christian Caryl also found numerous historical inaccuracies, describing the film as constituting “a bizarre departure from the historical record” that changed Turing’s rich life to be “multiplex-friendly”. L.V. Anderson of Slate magazine compared the film’s account of Turing’s life and work to the biography it was based on, writing, “I discovered that The Imitation Game takes major liberties with its source material, injecting conflict where none existed, inventing entirely fictional characters, rearranging the chronology of events, and misrepresenting the very nature of Turing’s work at Bletchley Park”. Andrew Grant of Science News wrote, “… like so many other Hollywood biopics, it takes some major artistic license – which is disappointing, because Turing’s actual story is so compelling.”
Not mentioned in the foregoing are my concerns with the way code breaking and issues of security are handled in the movie:
- Searching for known words in a message is, if not Code Breaking 101, is at least Code Breaking 102. Too much is made of it in the movie.
- Also, to much is made of the filtering of Ultra (decrypted intercepts). The movie treats this as a novelty. Major intelligence has always been treated in this manner. For example, one way to expose a spy is to feed him information and then see if the enemy acts on it. The Americans cracked the Japanese naval codes prior to Pearl Harbor and used intercepted communications to track down and kill Admiral Yamamoto. Great care was exercised to make the attack appear to be the result of an ordinary mission.
- In the movie we see people sitting at a table in a pub or a coffee shop, throwing words like Enigma around. Also the pub scene above has Turing shouting for all to hear that Germany has just lost the war. Never going to happen. I held a security clearance in the past, and in no case was anything sensitive ever allowed to to be discussed outside a closed and secure area.
- A footnote at the end of the movie states that breaking Enigma remained a British state secret for 50 years. It is difficult to reconcile this with the following excerpt (and others) from the David Kahn book The Codebreakers, which came out in 1967:
A truth he never suspected may lurk in his apothegm. For the Russians may have done as well in solving German cryptograms as in protecting their own. By 1942 they had cracked messages in the Enigma, a rotor machine. And the Germans themselves paid a left-handed tribute to Soviet cryptanalytic perspicacity when a 1943 conference of signal officers ruefully ordered : “It is forbidden to mark the Fuhrer’s radio messages in any special way.”
David Kahn, The Codebreakers, 1968. p. 649
Somehow tales regarding the secrecy of World War Two cryptanalytic work have become overinflated. This may be one manifestation.
Turing’s work to automate cryptanalysis spurred the development of machine computation. Pioneering work was accomplished by English mathematician Charles Babbage, who developed a mechanical device to perform calculations. Ada, Countess of Lovelace, worked with Babbage and is credited with being the world’s first computer programmer. She was the daughter of English poet George Lord Byron, and more recently a modern computer programming language was named Ada, after her.
The canonic Turing Machine was never an actual machine. It existed only as a mathematical construct, and no practical computer is based on the concept. Alan Turing collaborated with Hungarian refugee mathematician John von Neumann, and it’s von Neumann’s architecture that is the basis for most modern computers. Interestingly, von Neumann survived Turing by less than three years, dying of natural causes.