Fish (cryptography)
Encyclopedia
Fish was the Allied codename for any of several German teleprinter
stream cipher
s used during World War II
. Enciphered teleprinter traffic was used between German High Command and Army Group commanders in the field, so its intelligence value (Ultra) was of the highest strategic value to the Allies. This traffic normally passed over landlines, but as German forces extended their reach out of western Europe, they had to resort to wireless transmission.
, as well as receiving Enigma
-enciphered
Morse code
traffic, started to receive non-Morse traffic which was initially called NoMo. NoMo1 was a German army link between Berlin and Athens, and NoMo2 a temporary air force link between Berlin and Königsberg. The parallel Enigma-enciphered link to NoMo2, which was being read by Government Code and Cypher School at Bletchley Park
, revealed that the Germans called the wireless teleprinter transmission systems "Sägefisch" (sawfish), so the name "Fish" was adopted for this traffic. The enciphering/deciphering equipment was called a Geheimschreiber (secret writer) which, like Enigma, used a symmetrical substitution alphabet. The teleprinter code used was the International Telegraph Alphabet No. 2 (ITA2)—Murray's modification of the 5-bit Baudot code. The NoMo1 link was initially named Tunny, a name which later went on to be used both for the Lorenz SZ40/42 Geheimschreiber machines, and also for the Bletchley Park analogues of them. The NoMo1 link was subsequently re-named Codfish.
A large number of links were monitored by the Y-station
at Knockholt
and given names of fish. These included Bream (Berlin-Rome), Herring (Rome-Tunis), Jellyfish (Berlin-Paris), Grilse (Berlin-La Roche), Mullet (Berlin-Oslo), Turbot (Berlin-Copenhagen), Dace (Berlin-Königsberg), Whiting (Königsberg-Riga), Perch (Königsberg-Central Belarusse), Squid (Königsberg-N Ukraine), Octopus (Königsberg-E Ukraine), Stickleback (Königsberg-S Ukraine), Smelt (E Ukraine-S Ukraine), Grayling (Königsberg-Belgrade), Tarpon (Berlin-Bucharest), Gurnard (Berlin-Belgrade), Chubb (Belgrade-Salonica), Flounder (Salonika-Rhodes) and Codfish (Berlin-Salonika).
Geheimschreiber. In May 1940, after the German invasion of Norway, the Swedish mathematician
and cryptographer Arne Beurling
used traffic intercepted from telegraph lines that passed through Sweden to break this cipher. Although Bletchley Park eventually diagnosed and broke Sturgeon, the relatively low value of the intelligence gained, compared to the effort involved, meant that they did not read much of its traffic.
Thrasher was the name used for traffic enciphered on a Geheimschreiber that was probably the Siemens T43 one-time tape
machine. This was used only on a few circuits, in the later stages of the war and was diagnosed at Bletchley Park, but considered to be unbreakable.
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
stream cipher
Stream cipher
In cryptography, a stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream . In a stream cipher the plaintext digits are encrypted one at a time, and the transformation of successive digits varies during the encryption...
s used during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Enciphered teleprinter traffic was used between German High Command and Army Group commanders in the field, so its intelligence value (Ultra) was of the highest strategic value to the Allies. This traffic normally passed over landlines, but as German forces extended their reach out of western Europe, they had to resort to wireless transmission.
History
In June 1941, the "Y" wireless intercept stationsY-stations
Y-stations were British Signals Intelligence collection sites initially established during World War I and later used during World War II. These sites were operated by a range of agencies including the Army, Navy and RAF plus the Foreign Office , General Post Office and Marconi Company receiving...
, as well as receiving Enigma
Enigma machine
An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...
-enciphered
Cipher
In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...
Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
traffic, started to receive non-Morse traffic which was initially called NoMo. NoMo1 was a German army link between Berlin and Athens, and NoMo2 a temporary air force link between Berlin and Königsberg. The parallel Enigma-enciphered link to NoMo2, which was being read by Government Code and Cypher School at Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
, revealed that the Germans called the wireless teleprinter transmission systems "Sägefisch" (sawfish), so the name "Fish" was adopted for this traffic. The enciphering/deciphering equipment was called a Geheimschreiber (secret writer) which, like Enigma, used a symmetrical substitution alphabet. The teleprinter code used was the International Telegraph Alphabet No. 2 (ITA2)—Murray's modification of the 5-bit Baudot code. The NoMo1 link was initially named Tunny, a name which later went on to be used both for the Lorenz SZ40/42 Geheimschreiber machines, and also for the Bletchley Park analogues of them. The NoMo1 link was subsequently re-named Codfish.
A large number of links were monitored by the Y-station
Y-stations
Y-stations were British Signals Intelligence collection sites initially established during World War I and later used during World War II. These sites were operated by a range of agencies including the Army, Navy and RAF plus the Foreign Office , General Post Office and Marconi Company receiving...
at Knockholt
Knockholt
Knockholt is a village and civil parish in Kent, England, lying approximately 5 miles south of Orpington and 3 miles northwest of Sevenoaks. It is part of the Sevenoaks district and according to the 2001 census it had a population of 1,166...
and given names of fish. These included Bream (Berlin-Rome), Herring (Rome-Tunis), Jellyfish (Berlin-Paris), Grilse (Berlin-La Roche), Mullet (Berlin-Oslo), Turbot (Berlin-Copenhagen), Dace (Berlin-Königsberg), Whiting (Königsberg-Riga), Perch (Königsberg-Central Belarusse), Squid (Königsberg-N Ukraine), Octopus (Königsberg-E Ukraine), Stickleback (Königsberg-S Ukraine), Smelt (E Ukraine-S Ukraine), Grayling (Königsberg-Belgrade), Tarpon (Berlin-Bucharest), Gurnard (Berlin-Belgrade), Chubb (Belgrade-Salonica), Flounder (Salonika-Rhodes) and Codfish (Berlin-Salonika).
Traffic Code names
Sturgeon was the name given to traffic encoded with the Siemens and Halske T52Siemens and Halske T52
The Siemens and Halske T52, also known as the Geheimfernschreiber , or Schlüsselfernschreibmaschine , was a World War II German teleprinter cipher machine...
Geheimschreiber. In May 1940, after the German invasion of Norway, the Swedish mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
and cryptographer Arne Beurling
Arne Beurling
Arne Carl-August Beurling was a Swedish mathematician and professor of mathematics at Uppsala University and later at the Institute for Advanced Study in Princeton, New Jersey....
used traffic intercepted from telegraph lines that passed through Sweden to break this cipher. Although Bletchley Park eventually diagnosed and broke Sturgeon, the relatively low value of the intelligence gained, compared to the effort involved, meant that they did not read much of its traffic.
Thrasher was the name used for traffic enciphered on a Geheimschreiber that was probably the Siemens T43 one-time tape
One-time pad
In cryptography, the one-time pad is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key of the same length as the plaintext, resulting...
machine. This was used only on a few circuits, in the later stages of the war and was diagnosed at Bletchley Park, but considered to be unbreakable.
List of senior involved staff at Bletchley Park
Including both executives and cryptographers on FISH (Tunny) in the Testery.- Ralph TesterRalph TesterRalph P. Tester was an administrator at Bletchley Park, the British codebreaking station during World War II. He founded and supervised a section named the Testery for breaking TUNNY .-Background:...
— linguist and head of TesteryTesteryThe Testery was a section at Bletchley Park, the British codebreaking station during World War II. It was set up in July 1942 under Major Ralph Tester to achieve Cryptanalysis of the Lorenz cipher. The three original founding members, cryptographers, and linguists were Captain Jerry Roberts,... - Max NewmanMax NewmanMaxwell Herman Alexander "Max" Newman, FRS was a British mathematician and codebreaker.-Pre–World War II:Max Newman was born Maxwell Neumann in Chelsea, London, England, on 7 February 1897...
— mathematician and codebreaker who later set up the NewmanryNewmanryThe Newmanry was a section at Bletchley Park, the British codebreaking station during World War II. Its job was to develop and employ machine methods in Cryptanalysis of the Lorenz cipher. The Newmanry was named after its founder and head, Max Newman... - Jerry RobertsJerry RobertsCaptain Jerry Roberts was born at Wembley, London in November 1920. His father was a pharmacist and his mother an organist who played in the local chapel....
— shift-leader, linguist and senior codebreaker - Peter Ericsson — shift-leader, linguist and senior codebreaker
- Victor Masters — shift-leader
- Denis Oswald — linguist and senior codebreaker
- Peter HiltonPeter HiltonPeter John Hilton was a British mathematician, noted for his contributions to homotopy theory and for code-breaking during the Second World War.-Life:Hilton was born in London, and educated at St Paul's School...
— codebreaker and mathematician - Peter BenensonPeter BenensonPeter Benenson was an English lawyer and the founder of human rights group Amnesty International . In 2001, Benenson received the Pride of Britain Award for Lifetime Achievement.-Biography:...
— codebreaker - Peter Edgerley — codebreaker
- John Christie — codebreaker
- John Thompson — codebreaker
- Roy JenkinsRoy JenkinsRoy Harris Jenkins, Baron Jenkins of Hillhead OM, PC was a British politician.The son of a Welsh coal miner who later became a union official and Labour MP, Roy Jenkins served with distinction in World War II. Elected to Parliament as a Labour member in 1948, he served in several major posts in...
— codebreaker - Tom Colvill — general manager
See also
- Alan TuringAlan TuringAlan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
- Colossus (computer)
- Heath Robinson (codebreaking machine)Heath Robinson (codebreaking machine)Heath Robinson was a machine used by British codebreakers at Bletchley Park during World War II to solve messages in the German teleprinter cipher used by the Lorenz SZ40/42 cipher machine; the cipher and machine were called "Tunny" by the codebreakers, who named different German teleprinter...
- TuringeryTuringeryTuringery or Turing's Method was a hand codebreaking method devised by the mathematician and cryptanalyst Alan Turing at the British Government Code and Cypher School at Bletchley Park during World War II...