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Authors: Michael Smith

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key-list
a list of keys, generally daily, for a cipher.
 
 
KGB
Komitet Gosudarstvennoi Bezopasnosti
, or Committee for State Security, the commonly understood title for the Russian state secret services. These had a variety of different titles throughout the period covered. The title KGB was not introduced until March 1954 and was abolished in October 1991, but for ease of understanding it is used throughout.
 
 
Kriegsmarine
the German Navy in the Second World War.
 
 
Luftwaffe
the German Air Force in the Second World War.
 
 
MI1b
the department of British military intelligence dealing with Sigint during the First World War.
 
 
MI5
the Security Service, title dates from the First World War and the immediate aftermath of the Armistice when it was part of Army intelligence and in theory its only role was to root out subversion within the armed forces.
 
 
MI6
common wartime name for the British Secret Intelligence Service, technically the Army intelligence branch that liaised with SIS. It was not introduced until 1940, but for ease of understanding it is used throughout.
 
 
MI8
the department of British military intelligence dealing with Sigint during the Second World War.
 
 
MND
Marinenachrichtendienst (Kriegsmarine
Communications Service).
 
 
M3
the
Kriegsmarine
three-rotor Enigma machine.
 
 
M4
the
Kriegsmarine
four-rotor Enigma machine.
 
 
menu
a series of linked plain-text/cipher text letters used for giving instructions to bombe operators on setting up the bombes.
 
 
message key
(Enigma) the rotor starting positions for a specific Enigma signal.
 
 
message setting
the message key (q.v.).
 
 
NID25
Naval Intelligence Department 25. The Royal Navy’s Sigint branch during the First World War, better known as Room 40 from the room in the Old Admiralty Buildings in Whitehall that it occupied.
 
 
NSA
National Security Agency.
 
 
Offizier
a system for doubly enciphering naval Enigma signals, which ensured that only officers could read their substantive text.
 
 
OKH
Oberkommando des Heeres
(High Command of the German Army).
 
 
OKW
Oberkommando der Wehrmacht
(High Command of the
Wehrmacht
).
 
 
OKW/Chi
OKW’s
Amtsgruppe Wehrmachtnachrichtenverbindungswesen Chiffrierabteilung
the section responsible for cipher security.
 
 
OTP
one-time pad. A series of random additives intended for use once only. If used correctly, the system is unbreakable.
 
 
perforated sheets
see
Zygalski sheets.
 
 
psilli
psychological cilli. An Enigma message setting which is so closely related to the message
Grundstellung
that it can be guessed (e.g.,
Grund
‘HIT’ might give message setting ‘LER’). Also a guessable keyboard sequence, such as ‘QWE’.
 
 
Purple
the Japanese diplomatic cipher machine,
angoo-ki taipu b
(Type B machine), codenamed Purple by the US Army.
 
 
RAF
Royal Air Force.
 
 
Red
the principal
Luftwaffe
Enigma cipher (codename assigned by Hut 6).
 
 
Red (Japanese)
the Japanese diplomatic cipher machine,
angoo-ki taipu a
(Type A machine), codenamed Red by the Americans.
 
 
re-encipherment
the encipherment of the same plain-text in two or more ciphers.
 
 
Ringstellung
ring setting. The setting of the ring (or tyre) on an Enigma rotor.
 
 
romaji
system of transliteration allowing
kana
to be spelt out in Roman letters.
 
 
rotor
(Enigma) rotating disc (or wheel) with randomly wired electric contacts used for encipherment in Enigma.
 
 
rotor order
(Enigma) the order in which rotors were inserted in Enigma (e.g., III, I, IV), looking at the machine from the front.
 
 
R/T
radio telephone.
 
 
Schlüsselkenngruppe
(naval Enigma)
see
cipher indicator group.
 
 
Schlüsselzusatz
cipher attachment.
 
 
SD
the
Sicherheitsdienst
(the intelligence service of the Nazi party).
 
 
Sigint
signals intelligence. All intelligence derived from studying radio and other signals.
 
 
SIS
(American) Signal Intelligence Service – the US Army’s codebreaking unit (the name was changed on several occasions during the war).
 
 
SIS
(British) the Secret Intelligence Service (MI6).
 
 
SKL
Seekriegsleitung
(the German naval war staff).
 
 
SOE
Special Operations Executive
 
 
Spruchschlüssel
see
message key.
 
 
SS
Schutzstaffeln
. Protection squads formed in the 1920s, which became a powerful organization in the Nazi party, and Germany, with a military section, the
Waffen
SS.
 
 
SSA
Signal Security Agency. The codebreaking unit of the US Army (which had a variety of names during the war; cf. SIS (American)).
 
 
SSD
Signal Security Detachment. A codebreaking section in the US Army.
 
 
Stecker
short for
Steckerverbindungen
(plug connections).
 
 
Steckerverbindungen
the plug connections in Enigma’s plugboard.
 
 
Stichwort
(naval Enigma) cue word – a procedure modifying a daily key when a key-list had been compromised.
 
 
Stop
the position at which a bombe stopped, corresponding to a possible Enigma key.
 
 
Sturgeon
GC&CS codename for the Siemens and Halske T52 series of teleprinter cipher machines.
 
 
success rate
decrypts as a percentage of the signals intercepted.
 
 
superenciphered code
see
enciphered code.
 
 
SZ 40 or 42
the Lorenz
Schlüsselzusatz
(cipher attachment) for teleprinters.
 
 
TA
see
traffic analysis.
 
 
TJAO
Temporary Junior Administrative Officer
 
 
traffic
radio signals, generally encrypted, between two or more stations, or using a common code or cipher.
 
 
traffic analysis
the study of the external characteristics of signals (such as call signs and frequencies used) in order to derive intelligence.
 
 
trigram
a group of three figures or letters.
 
 
Tunny
GC&CS codename for the Lorenz SZ 40/42 teleprinter cipher attachment.
 
 
Typex
the British cipher machine, based on Enigma (but without an entry plugboard). Never broken by the German codebreakers.
 
 
Uhr
a device which made Enigma’s plugboard largely nonreciprocal (see Chapter 19).
 
 
UKD
see Umkehrwalze
D.
 
 
Ultra
‘special intelligence’ – intelligence derived from high-grade codes and ciphers, such as Enigma and Fish.
 
 
Umkehrwalze
(Enigma) reflector.
 
 
Umkehrwalze D
(Enigma) reflector Dora (UKD), which was rewirable in the field as part of an Enigma key (see Chapter 19). Used almost exclusively by the
Luftwaffe
.
 
 
Walzenlage
(Enigma) rotor order (e.g., II, V, III).
 
 
WEC
Wireless Experimental Centre. British signals intelligence site set up just outside Delhi in June 1942.
 
 
WED
Wireless Experimental Depot. British intercept and decryption site based at Abbottabad on the North West Frontier, set up in the 1920s.
 
 
Wehrmacht
all three branches of the German armed forces in the Second World War.
 
 
Werftschlüssel
dockyard cipher – a manual cipher system used by the
Kriegsmarine
.
 
 
wheel
see
rotor.
 
 
Wren
member of the WRNS (q.v.).
 
 
WRNS
Women’s Royal Naval Service.
 
 
Y service
the intercept and DF service (before October 1943, the service also dealt with traffic analysis and broke some lowgrade codes and ciphers).
 
 
Zählwerk
Enigma
see counter Enigma.
 
 
Zygalski
sheets
lettered sheets with holes punched in them, showing which combinations of rotor starting positions and wheel orders produced females. By suitably aligning the relevant sheets on top of each other, the
Ringstellungen
and rotor order were revealed by the coincidence of holes in some sheets.
BOOK: The Bletchley Park Codebreakers
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