GCHQ releases two Turing papers

GCHQ has released two mathematical papers written by cryptographer Alan Turing after keeping the works secret for over half a century.GCHQ has released two mathematical papers written by cryptographer Alan Turing.

GCHQ has released two mathematical papers written by cryptographer Alan Turing after keeping the works secret for over half a century.

Alan Turing

GCHQ has released two mathematical papers written by cryptographer Alan Turing. Image credit: Wikipedia

The intelligence agency believes the handwritten papers were produced by Turing during his time at Bletchley Park, the World War Two code-breaking centre, GCHQ said in a press release on Thursday.

"We are delighted to release these papers showing more of Alan Turing’s pioneering research during his time at Bletchley Park," said a GCHQ spokesperson. "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."

GCHQ judged the papers 'sensitive' until recent reassessment. One of the papers, the informal 'Paper on Statistics of Repetitions', seeks a means to tell whether two enciphered messages with different plaintext and an overlap of characters used the same encipherment key during the overlap.

The second paper, 'The Applications of Probability to Cryptography', was possibly written between April 1941 and April 1942, as it contains the reference 'Hitler is now of age 52'. The paper uses probability analysis to look at four problems: 'Vigenère', 'A Letter Substitution Problem', 'Theory of Repeats', and 'Transposition Ciphers', said GCHQ.

The papers were kept at Bletchley Park until February, and were then transported to the National Archives at Kew, a National Archives spokesman told ZDNet UK on Thursday. The papers were released on Tuesday.

The two papers have not been digitised, and only currently exist in handwritten form. People wishing to read the papers need to travel to the National Archives at Kew with the reference numbers of the papers, and two forms of ID — a picture ID, and proof of address. People who do this will probably be given a reader ticket number, which will then allow them to request the papers for viewing.

2012 is the centenary of Alan Turing's birth. Turing, whose work heavily contributing to the Allied war effort, committed suicide in 1954 by taking cyanide. Turing had been convicted of homosexuality, which was then a crime, and was given the choice between prison or chemical castration. The UK government officially apologised over Turing's treatment in 2009, over 50 years after his death.