TWO 70-year-old papers written by Alan Turing have been released by the government’s communication headquarters.
The papers were believed to have been written by the war hero, who would have celebrated his 100th birthday this year, while he was working at the home of codebreaking during Second World War.
The papers, called “Paper on Statistics of Repetitions” and “The Applications of Probability to Crypt” were kept at GCHQ because of their sensitivity but have since been reassessed as suitable for release.
The first paper 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.
The second, longer paper, showed that Turing was determined to apply rigorous probability analysis to a wide range of cryptanalytic problems of the day.
One highlight sees Turing use life expectancy to look at conditional probability. The associated example “Hitler is now of age 52” suggests the paper was written between April 1941 and April 1942. Bletchley Park’s output of decrypts was certainly aided by the paper’s techniques.
A spokesman for GCHQ said: “We are delighted to release these papers showing more of Alan Turing’s pioneering research during his time at Bletchley Park.
“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.”