|Air Section||Non-Enigma enemy codes and ciphers. There was also a sub-section of Hut 3, referred to as the Hut 3 Air Section or Air Intelligence Section, producing intelligence from Luftwaffe Enigma signals.|
|Cover, Traffic and Records (CTR), later CoverManagement Y (CMY)||Controlled Y service interception of diplomatic and commercial wireless networks|
|Central Signal Registry(CSR)||Subsection of Communications Section, handled all incoming and outgoing signal traffic.|
Distribution and Reference
|Mechanism for distributing intelligence reporting.|
|Intelligence Exchange (IE)||Formed in 1941 to replace Distribution and Reference for intelligence reporting on naval, army andair force matters.|
|Hut 3 German Army and Air Force Enigma Reporting Section.||Produced intelligence reports from signals
deciphered by Hut 6. This section continued to be referred to as “Hut 3” after moving to Block D inFebruary 1943.
|Hut 4||See Naval Section.|
|Hut 6||Location of German Army and Air Force Enigma Processing and Decryption Section. This section
continued to be referred to as “Hut 6” after moving to Block D in February 1943.
|Hut 8||Location of German Navy Enigma Processing and Decryption Section from February 1940. This
section continued to be referred to as “Hut 8” after moving to Block D in February 1943.
|Illicit Signals Knox (ISK)||Deciphering of Abwehr (German Intelligence Service) Enigma coded signals. Initially headed by Dilly
|Illicit Signals Oliver Strachey (ISOS)||Deciphering of Abwehr (German Intelligence Service) manually coded signals. Initially headed byOliver Strachey.|
|Inter-Service Special Intelligence School ISSIS)||Training school in Bedford for cryptographers, from 1941. Also provided Japanese language courses
|JAFO Japanese Forces.||Team formed in 1944 to work on Japanese army and air targets.
Military Section Later Military Wing.
|Naval Section||Sometimes referred to as “Hut 4”. Responsible for intelligence from naval Enigma messages deciphered in Hut 8 and also for deciphering and exploiting non-Enigma naval ciphers. Located in Hut 4 from 1940 to mid 1942, then in Blocks A and B.|
|No 4 Intelligence School(4 IS or IV IS)||Cover name given by the War Office to the Military Section or Wing of BP.|
|SIXTA||Responsible for Traffic analysis - the study of communications links, call-signs, frequencies and timings and lengths of transmissions, to build up a picture of the enemy's organisation, routine and dispositions. Name formed from No 6 Intelligence School and Traffic Analysis.|
|Wireless Telegraphy Coordination (WTC)||Controlled Y Service cover of enemy, naval and air force wireless networks|