ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS 3A Air Section within Hut 3 at Bletchley Park 3G Research Section within Hut 3 at Bletchley Park 3L Liaison Section within Hut 3 at Bletchley Park, responsible for links to external customers 3M Military Section within Hut 3 at Bletchley Park 3N Naval Section within Hut 3 at Bletchley Park 6IS No. 6 Intelligence School, based at Beaumanor Abwehr Amt Auslandsnachrichten und Abwehr – the German military intelligence service ANCXF Allied Naval Commander Expeditionary Force – the commander of the naval elements of the invasion force, post held on D-Day by Admiral Ramsay Ast Abwehrstellung – a regional office of the Abwehr in Germany or occupied countries xvi ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS BEETLE Bletchley Park codename for Enigma key used by Luftwaffe Command on the Eastern Front BODYGUARD The overall Allied codename for deception operations prior to the invasion Bombe The key-finding machine devised by Alan Turing and Gordon Welchman, fundamental to the successful decryption of Enigma messages BP Common wartime nickname for Bletchley Park BREAM Bletchley codename for the Lorenz teleprinter link between Berlin and O.B. Südwest (q.v.) in Rome C The head of the Secret Intelligence Service (SIS/MI6), post occupied by Hugh Sinclair and Stewart Menzies during the Second World War CIS Combined Intelligence Section – joint group of British army and naval intelligence Colossus Codename for the key-finding machine developed to assist in decrypting German teleprinter traffic (see FISH) COMINT See SIGINT CORAL Allied codename for cipher used by Japanese naval attaches COSSAC Chief of Staff to Supreme Allied Commander – organisation led by Lt Gen. F.E. Morgan, tasked with planning the Allied invasion during 1943 xvii ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS Crib A portion of the plaintext (q.v.) of an encrypted message which could be guessed, and used to assist in the decryption process CX/MSS File prefix allocated to high-level (q.v.) intercepts (see also ULTRA) DAFFODIL Bletchley codename for Enigma key used by Luftgau XI (Westfront) (q.v.) D-Day 6 June 1944, the day on which the invasion of Normandy began. The ‘D’ has no significance other than as the initial letter of ‘Day’ (similarly ‘H-Hour’, etc.). Dates before and after the invasion were expressed in days, for example ‘D-20’ or ‘D+10’ – twenty days before or ten days after the invasion, respectively Depth In codebreaking several messages composed using the same cipher key D/F Direction finding – identification of the location of enemy wireless transmitters by use of bearings taken at intercept stations DOLPHIN Bletchley codename for Enigma key used by Kriegsmarine (q.v.) surface vessels and by U-boats in ‘home waters’ DTN Defence Teleprinter Network – a military cable network which connected Bletchley Park with its outstations and customers via telephone and teleprinter E-boat Allied designation for German fast attack craft Enigma A family of rotor-based electro-mechanical encryption machines used by Axis forces xviii ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS FALCON Bletchley codename for Enigma key used by the German military administrative districts (Wehrkreis) FHO Fremde Heere Ost – the German intelligence organisation tasked with the study of Allied armies in the eastern (Soviet) theatre FHW Fremde Heere West – the German intelligence organisation tasked with the study of Allied armies in the western theatre FISH Codename given at Bletchley to German teleprinter traffic encrypted using the Lorenz SZ40/42 cipher machines Flivo Fliegerverbindungsoffizier – air liaison officer FORTITUDE Allied codename for the deception operations mounted prior to D-Day in 1944 FUSAG First US Army Group – the title given to the fictional force created as part of the Operation FORTITUDE deception operation GADFLY Bletchley codename for Enigma key used by X. Fliegerkorps in the Mediterranean GAF German Air Force (Luftwaffe) GANNET Bletchley codename for Enigma key used by German High Command in Norway GC&CS Government Code and Cipher School – the codebreaking organisation at Bletchley Park during the Second World War GCHQ Cover name applied to GC&CS, latterly adopted post-war as the formal name of the organisation Gold Codename for British invasion beach on D-Day xix ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS GPO General Post Office GRAMPUS Bletchley codename for the Enigma key used in the Black Sea GRILSE Bletchley codename for the Lorenz teleprinter link between Berlin and Heeresgruppe B (Army Group B) in France (grilse is a type of young salmon) GURNARD Bletchley codename for the Lorenz teleprinter link between Berlin and O.B. Südost (q.v.) in Greece Heer German army High-level machine-enciphered Hollerith machine A device for processing data via punched cards, used as part of the decryption process HUMINT Human intelligence – information gained by human agents behind enemy lines, either members of the Allied secret services or local inhabitants and members of resistance organisations, or by interrogation of prisoners of war Hut 3 German Army and Air Force Enigma Reporting Section responsible for processing and distributing decrypted German army and air force Enigma traffic Hut 6 German Army and Air Force Enigma Processing and Decryption Section responsible for breaking army and air force Enigma messages Hut 8 German Naval Enigma Processing and Decryption Section responsible for breaking naval Enigma messages xx ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS IMINT Imagery intelligence – aerial photography of enemy forces and installations Indoctrinated recipient An individual who had been let in on the secret of Bletchley Park ISK Illicit Signals Knox – section at Bletchley Park dealing with high-level (q.v.) communications using the Abwehr (q.v.) variants of Enigma ISOS Illicit Signals Oliver Strachey – section at Bletchley Park dealing with lower-level hand ciphers used by German intelligence agents JADE Allied codename for a Japanese diplomatic cipher system used particularly by Japanese attachés JELLYFISH Bletchley codename for the Lorenz teleprinter link between Berlin and O.B. West (q.v.) in Paris JMA Allied codename for code used by Japanese military attachés Juno Codename for Canadian invasion beach on D-Day Key The specific settings for a particular encryption machine KO Kriegsorganisation – Abwehr (q.v.) outstations in neutral countries Kriegsmarine German navy Lorenz SZ40/42 Cipher machine used by German forces to encrypt wireless teleprinter traffic (see FISH) Luftgau Luftwaffe regional command Luftwaffe German air force xxi ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS MAGIC Allied codename for traffic intercepted using the Japanese PURPLE cipher Martian Codename applied to reports from the Combined Intelligence Section (q.v.) concerning German defences in France MI14 Department of Military Intelligence at the War Office tasked with investigation of the German armed forces MULLET Bletchley codename for the Lorenz teleprinter link between Berlin and Norway NEPTUNE Allied codename for the naval part of the OVERLORD invasion operation Newmanry Machine Section – named after Max Newman, responsible for machine breaking of German Lorenz-enciphered teleprinter traffic NUTHATCH Bletchley codename for Enigma key connecting Berlin with Belgrade O.B. Südost Oberbefehlshaber Südost – the German commander-in-chief in Greece, a position held on D-Day by Generalfeldmarschall Maximilian von Weichs O.B. Südwest Oberbefehlshaber Südwest – the German commander-in-chief in Italy, a position held on D-Day by Generalfeldmarschall Albert Kesselring O.B. West Oberbefehlshaber West – the German commander-in-chief in France and the Low Countries, a position held on D-Day by Generalfeldmarschall Gerd von Rundstedt xxii ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS OIC Operational Intelligence Centre – the planning headquarters of the Royal Navy at the Admiralty in London OKH Oberkommando des Heeres – the Army High Command of Nazi Germany OKM Oberkommando der Marine – the Naval High Command of Nazi Germany OKW Oberkommando der Wehrmacht – the High Command of the armed forces of Nazi Germany Omaha Codename for US invasion beach on D-Day OCELOT Bletchley codename for Enigma key used by army–air liaison officers (known as a Flivo (q.v.) key after the Fliegerverbindungsoffizier, air liaison officer) ORANGE Bletchley codename for Enigma key used by Waffen SS OVERLORD Codename for the allied invasion of Europe in 1944 Plaintext The original text of a message prior to its encryption; or equally, the same text after decryption by the recipient PORPOISE Bletchley codename for Enigma key used by German Mediterranean shore installations PURPLE Allied codename for a Japanese diplomatic cipher system used particularly by the Japanese ambassador in Berlin QUINCE Bletchley codename for Enigma key used by the Waffen SS RED Bletchley codename for Enigma key used by the German air force xxiii ABBREVIATIONS, CODENAMES AND TECHNICAL TERMS RSS Initially the Radio Security Section (later the Radio Security Service) – body tasked with the interception of Abwehr wireless traffic SCU Special Communications Unit – unit attached to a field headquarters tasked with the reception of ULTRA messages from Bletchley Park SD Sicherheitsdienst – the security branch of the SS SHAEF Supreme Headquarters Allied Expeditionary Force – the headquarters led by Gen. Eisenhower responsible for planning and carrying out the invasion of north-west Europe in 1944 SHARK Bletchley codename