Hut 4 was a wartime section of the

Government Code and Cypher School (GC&CS) Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...

Bletchley Park Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years followin ...

tasked with the translation, interpretation and distribution of '' Kriegsmarine'' (German navy) messages deciphered by

Hut 8 Hut 8 was a section in the Government Code and Cypher School (GC&CS) at Bletchley Park (the British World War II codebreaking station, located in Buckinghamshire) tasked with solving German naval ( Kriegsmarine) Enigma messages. The section was ...

. The messages were largely encrypted by Enigma machines. As the Kriegsmarine operated Enigma more securely, Hut 8 had less information for

Ultra adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. ' ...

than

Hut 6 Hut 6 was a wartime section of the Government Code and Cypher School (GC&CS) at Bletchley Park, Buckinghamshire, Britain, tasked with the solution of German Army and Air Force Enigma machine cyphers. Hut 8, by contrast, attacked Naval Enigma. ...

which handled Army and Air Force messages. Hut 4 also broke various hand cyphers and some Italian naval traffic.

Location

Located initially in one of the original single-story wooden huts, the name "Hut 4" was retained when the section moved to a new brick building, Block A, in 1941.

Operation

Naval Ultra was handled differently from Army and Air Force Ultra because the Admiralty was an operational HQ and could give orders during a battle; while the Imperial General Staff (Army) and Air Staff would give directives to theatre commanders general orders say to "clear the enemy out of Africa" with discretion over how to do it. Verbatim translations of naval decodes were sent to the Naval Intelligence Division (NID) of the Admiralty's Operational Intelligence Centre (OIC) in London and nowhere else (except for some naval intelligence sent directly from Bletchley to Commanders-in-Chief in the Mediterranean). Hut 4 also decoded a manual system known as the "dockyard cipher". This sometimes carried messages that were also sent on an Enigma network. Feeding these back to Hut 8 provided excellent '' cribs'' for breaking the current naval Enigma key.

People

* M. M. G. Jennings (Margaret Allan), racing driver * J. W. B. Barns, later Professor of Egyptology at Oxford *

Sarah Baring Sarah Kathleen Elinor Baring (''née'' Norton; 20 January 1920 – 4 February 2013) was an English socialite and memoirist, who worked for three years as a Linguistics, linguist at Bletchley Park, the principal centre of Allies of World War II, A ...

, later Viscountess Astor * Osla Benning,

Prince Philip Prince Philip, Duke of Edinburgh (born Prince Philip of Greece and Denmark, later Philip Mountbatten; 10 June 1921 – 9 April 2021) was the husband of Queen Elizabeth II. As such, he served as the consort of the British monarch from E ...

's first girlfriend * Jocelyn Bostock from Lady Margaret Hall (LMH) Oxford, assistant to Hinsley * Alec Naylor Dakin * Pamela Rose * Leonard R. Palmer, later Professor of Comparative Philology at Oxford.Briggs (2011) p 148 * Bernard Willson Note: Frank Birch and

Harry Hinsley Sir Francis Harry Hinsley, (26 November 1918 – 16 February 1998) was an English historian and cryptanalyst. He worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Int ...

were both associated with the naval section (Huts 4 & 8).

References

Sources

* Asa Briggs ''Secret Days: Code-breaking in Bletchley Park'' (2011, Frontline Books, London) *

Peter Calvocoressi Peter John Ambrose Calvocoressi (17 November 1912 – 5 February 2010) was a British lawyer, Liberal politician, historian, and publisher. He served as an intelligence officer at Bletchley Park during World War II. Early years Calvocoressi w ...

''Top Secret Ultra'' (1980, Cassell Ltd, London) {{DEFAULTSORT:Hut 04 Cryptography organizations Bletchley Park Buildings and structures in Milton Keynes