GCHQ Releases Two Secret Alan Turing Papers


Britain’s top secret listening station, GCHQ, has released two mathematical papers written by codebreaker Alan Turing

Britain’s spy centre GCHQ has celebrated the centenary of Alan Turing by releasing two mathematical research papers relating to his wartime code-breaking work at GCHQ’s predecessor, Bletchley Park.

The two papers – namely ‘Statistics of Repetitions’ and ‘The Applications of Probability to Crypt’ – are thought to have been written whilst Turing was at Bletchley Park during the second World War, and have been kept in secret for 70 years, stored at GCHQ for protection.

The intelligence agency says that the first paper ‘Statistics of Repetitions’ is an informal report in which Turing works out the best statistical means of testing whether two cipher messages use the same key in parts of the message. It said that this was very important in the handling of such messages at Bletchley Park.

The second paper, ‘The Applications of Probability to Crypt’, is a longer document and reportedly demonstrates that Turing was determined to apply rigorous probability analysis to a wide range of cryptanalytic problems of the day.

“A particular highlight is where Turing uses life expectancy to examine conditional probability,” said GCHQ. “The associated example, ‘Hitler is now age 52’, adds piquancy and suggests that the paper was written between April 1941 and April 1942. Bletchley Park’s output of decrypts was almost certainly enabled by the techniques in this paper.”

“We are delighted to release these papers showing more of Alan Turing’s pioneering research during his time at Bletchley Park,” said an unnamed spokesperson for GCHQ. “It was this type of research that helped turn the tide of war and it is particularly pleasing that we are able to share these papers during this centenary year.”

Tragic Life

Alan Turing of course is world famous as one of a number of genius codebreakers stationed at Bletchley Park during the Second World War. There he was part of the team that helped crack the Enigma code.

But besides being a formidable mathematician and cryptanalyst, Turing laid the foundations of computer science by thinking up a theoretical computer called the Turing Machine, and also helped create the world’s first modern computer, the Manchester Small-Scale Experimental Machine.

However Turing’s personal life had a tragic quality to it as well as he also homosexual, which was a criminal offence at that time.

In 1952 he was convicted of gross indecency with another man. As a result of this conviction, Turing was forced to choose between prison or chemical castration by taking female hormones. He chose the latter and, two years later aged 41, Turing took his own life.

Last December, an online petition was launched to request a pardon for his conviction of ‘gross indecency’. That official pardon was rejected in February this year, although former Prime Minister Gordon Brown had previously issued an unequivocal posthumous apology to Mr Turing on behalf of the Government back in 2009, and described the treatment of Turing as “appalling”.

Gordon Brown’s apology came after a previous a petition on the Number10.gov.uk Website in 2009, which was signed by thousands of people. That petition called for a posthumous government apology to Turing.

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