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ALAN TURING WARTIME RESEARCH PAPERS RELEASED BY GCHQ'Paper on Statistics of Repetitions'...
Catalogue reference: HW 25/38
What’s it about?
This record is about the ALAN TURING WARTIME RESEARCH PAPERS RELEASED BY GCHQ'Paper on Statistics of Repetitions'... dating from 1945 Jan 01 - 1946 Dec 31 in the series Government Code and Cypher School: Cryptographic Studies. It is held at The National Archives, Kew.
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Full description and record details
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Reference (The unique identifier to the record described, used to order and refer to it)
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HW 25/38
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Date (When the record was created)
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1945 Jan 01 - 1946 Dec 31
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Description (What the record is about)
- ALAN TURING WARTIME RESEARCH PAPERS RELEASED BY GCHQ'Paper on Statistics of Repetitions' As the country marks the centenary of Alan Turing's birth, two of his mathematical research papers, believed to have been written whilst he was at Bletchley Park during World War II, have been released by GCHQ to The National Archives.Because of continuing sensitivity the papers had been retained at GCHQ, but they have now been reassessed as suitable for release. The papers, called 'Paper on Statistics of Repetitions' and 'The Applications of Probability to Crypt', were written in an era when typographical errors would be corrected by hand and mathematical notation handwritten.The first, 'Paper on 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. This was very important in the exploitation of such messages at Bletchley Park.The second, longer, paper titled 'The Applications of Probability to Cryptography', 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. The associated example, 'Hitler is now of 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.
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Related material (A cross-reference to other related records)
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For Turing's second longer paper 'The Applications of Probability to Cryptography' please see: HW 25/37
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Held by (Who holds the record)
- The National Archives, Kew
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Former department reference (Former identifier given by the originating creator)
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CCR 151
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Legal status (A note as to whether the record being described is a Public Record or not)
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Public Record(s)
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Access conditions (Information on conditions that restrict or affect access to the record)
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Retained Until 2012
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Closure status (Whether the record is ‘open’ (available to the public) or ‘closed’ (not available due to a legal exemption))
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Open Document, Open Description
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Subjects (Categories and themes found in our collection (our subject list is under development, and some records may have no subjects or fewer than expected))
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Record URL
- https://beta.nationalarchives.gov.uk/catalogue/id/C11510466/
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Series information
HW 25
Government Code and Cypher School: Cryptographic Studies
See the series level description for more information about this record.
Catalogue hierarchy
Over 27 million records
This record is held at The National Archives, Kew
17,110 records
Within the department: HW
Records created or inherited by Government Communications Headquarters (GCHQ)
42 records
Within the series: HW 25
Government Code and Cypher School: Cryptographic Studies
You are currently looking at the piece: HW 25/38
ALAN TURING WARTIME RESEARCH PAPERS RELEASED BY GCHQ'Paper on Statistics of Repetitions'...
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