“The Imitation Game”, starring Benedict Cumberbatch, is one of the most popular movies that features cryptography. Unfortunately, it contains many historical errors.
There’s many a film that involves cryptography. Most readers of this blog certainly have heard of U-571 (2000), Enigma (2001), Windtalkers (2002), and Crypto (2019). In addition, there are films such as Sneakers, Mercury Rising, The Prestige, as well as several movies about the Zodiac Killer. Not to forget the marvellous The David Kahn Story, which is my all-time favorite.
The Imitation Game
The most popular crypto-related movie, however, is The Imitation Game, a 2014 production with Bendict Cumberbatch playing Alan Turing. The plot is about the work of Turing and his team on breaking the Enigma during the Second World War.
There’s no doubt that The Imitation Game is an entertaining and thrilling film about one of the most fascinating episodes in technology history. However, the content of the movie is to a large part historically incorrect. There are hundreds of scenes, quotes, and plot details that differ from what really happened. Many of these errors give a completely wrong impression of Turings life and work as well as of how the Enigma was broken. Here are some of the ones I noticed immediatley when I saw the movie:
Movie: Bletchley Park is a contemplative land estate where a few scientists work on their secret project. Not much else appears to be happening there.
Correct: Bletchley Park was an industry facility with over 10,000 employees.
Movie: Alan Turing and his men build one copy of the deciphering machine known today as the Turing-Welchman Bombe. They operate it themselves.
Correct: Over 200 copies of the Turing-Welchman Bombe were built. These devices were operated by hundreds of (mostly female) workers.
Movie: Alan Turing and his team not only break Enigma messages but also evaluate the plaintexts and decide how to use the evidence. Among other things, they choose the German U-boats that are to be attacked as well as the ones that are to be spared in order to keep the British codebreaking successes secret.
Correct: Turing and his men were not involved in evaluating the evidence gathered from deciphered messages, let alone did they take strategic decisions.
Mark Baldwin’s list
The many inaccuracies in The Imitation Game were recently discussed on the Crypto Collectors mailing list. Mark Baldwin from Birmingham, UK, posted a list of errors in this movie, along with an interesting diagram provided by the website Information is Beautiful. The diagram shows that 41.4% of the scenes in The Imitation Game are incorrect:
And here’s the error list Mark provided (he thankfully allowed me to publish it here). Some of the errors are already mentioned above:
Movie: Alan Turing’s group assessed what action should be taken on the information from Enigma decrypts, using ‘statistics’.
Correct: Bletchley Park didn’t make tactical or strategic decisions; these were left to Whitehall/military. Bletchley Park digested the Intelligence for Air Force and Army; RNID insisted on receiving ‘raw’ decrypts.
Movie: Christopher Morcom and Alan Turing are in same class when young teens.
Correct: Alan Turing was one year younger – not in same class. No contact until early 1927 (Alan Turing then 14).
Movie: Bletchley Park’s identity disguised as a ‘Radio Factory’
Correct: No evidence – it was first called ‘The Government Code & Cipher School’, then ‘Government Communication Headquarters’
Movie: Denniston amazed by Alan Turing’s mentioning Enigma in Sep 39. Correct: Denniston had selected Alan Turing for a crypto course in 1938, and had introduced Alan Turing to Enigma by 4 Jan 1939
Movie: ‘There are only five divisions of Military Intelligence’.
Correct: MI6, MI7 and MI8 had been created in WW1.
Movie: Menzies plants Cairncross at BP Sep 39 to give information to Russians.
Correct: Russians were UKs enemies until Op Barbarossa (June 1941). Cairncross didn’t join BP until 1942.
Movie: Alastair Denniston determined to get rid of Alan Turing.
Correct: No evidence – and thus the film blackens Denniston’s reputation
Movie: Four-rotor Enigma is shown as being in use early in the war.
Correct: Four-rotor Enigma was not introduced until 1 Feb 1942.
Movie: Alan Turing builds Bombe in shed at Bletchley Park.
Correct: Alan Turing invented the Bombe, but it was built by BTM at Letchworth.
Movie: Hugh Alexander invents the diagonal board.
Correct: Gordon Welchman invented the diagonal board.
Movie: John Cairncross worked in Alan Turing’s team.
Correct: ‘I never met some of the most important’.
Movie: Message to Russians intercepted, revealing ‘a spy in Bletchley Park’.
Correct: Cairncross’s treachery was never detected.
Movie: Alan Turing calls the Bombe ‘Christopher’.
Correct: No evidence
Movie: Alan Turing speaks of ‘digital computer’.
Correct: This term was not used until much later.
Movie: One group (Alan Turing, Cairncross, Good, Alexander, Hilton, Clarke) operated the ONLY Bombe, and thus were the sole providers of Enigma Intelligence.
Correct: There were over 200 Bombes, operated by three shifts a day, thus over 1000 operators were involved.
Movie: Helen works at Bletchley Park as a radio interceptor.
Correct: No interception was done at Bletchley Park – all in Y stations – so no interceptor would be stationed at Bletchley Park.
Movie: Only after Helen’s revelation does Alan Turing realise that the Bombe should search for a predicted or probable word, not search through all possibilities.
Correct: Alan Turing’s design was based on searching for a probable word.
Movie: Alan Turing’s homosexuality was kept secret.
Correct: It was known, but disregarded.
Movie: By refusing to report Cairncross, Alan Turing acts as an accessory to treachery.
Correct: No evidence that he would have acted thus.
Movie: Few women are shown at Bletchley Park.
Correct: 75% were women.
Movie: Alan Turing was a ‘Professor at Kings’.
Correct: Alan Turing was a graduate of King’s College, Cambridge, but was a Reader at Manchester University. Although called ‘Prof’’ at BP, he never had a chair.
Movie: Neighbour reported a break-in at Alan Turing’s house.
Correct: Alan Turing reported the break-in.
Movie: A policeman learned about Alan Turing’s homosexual activities from a young man involved.
Correct: Alan Turing told the police himself.
Movie: Joan Clarke visits Alan Turing after his conviction.
Correct: No evidence
Movie: Alan Turing calls his [home] computer ‘Christopher’.
Correct: No evidence – and he didn’t have a home computer.
Movie: Towards the end of his life, Alan Turing exhibits ill-effects of hormone therapy.
Correct: No evidence – and the therapy only lasted a year after the trial (March 1952), and Alan Turing died in June 1954.