World War II cryptography
Encyclopedia
Cryptography
was used extensively during World War II
, with a plethora of code
and cipher
systems fielded by the nations involved. In addition, the theoretical and practical aspects of cryptanalysis
, or codebreaking, was much advanced.
Probably the most important cryptographic event of the war was the successful decryption by the Allies of the German "Enigma" Cipher
. The first complete break
into Enigma was accomplished by Poland
around 1932; the techniques and insights used were passed to the French and British Allies just before the outbreak of the War in 1939. They were substantially improved by British efforts at the Bletchley Park
research station during the War. Decryption of the Enigma Cipher
allowed the Allies to read important parts of German radio traffic on important networks and was an invaluable source of military intelligence
throughout the War. Intelligence from this source (and other high level sources, including the Fish
cyphers) was eventually called Ultra.
A similar break into an important Japanese cypher (PURPLE
) by the US Army Signals Intelligence Service started before the US entered the War. Product from this source was called MAGIC
. It was the highest security Japanese diplomatic cypher. For Japanese Naval cyphers see JN-25
. See also Attack on Pearl Harbor
.
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
was used extensively 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...
, with a plethora of code
Code (cryptography)
In cryptography, a code is a method used to transform a message into an obscured form, preventing those who do not possess special information, or key, required to apply the transform from understanding what is actually transmitted. The usual method is to use a codebook with a list of common...
and cipher
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...
systems fielded by the nations involved. In addition, the theoretical and practical aspects of cryptanalysis
Cryptanalysis
Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information that is normally required to do so. Typically, this involves knowing how the system works and finding a secret key...
, or codebreaking, was much advanced.
Probably the most important cryptographic event of the war was the successful decryption by the Allies of the German "Enigma" Cipher
Cryptanalysis of the Enigma
Cryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
. The first complete break
Cryptanalysis
Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information that is normally required to do so. Typically, this involves knowing how the system works and finding a secret key...
into Enigma was accomplished by Poland
Cryptanalysis of the Enigma
Cryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
around 1932; the techniques and insights used were passed to the French and British Allies just before the outbreak of the War in 1939. They were substantially improved by British efforts at the 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...
research station during the War. Decryption of the Enigma Cipher
Cryptanalysis of the Enigma
Cryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
allowed the Allies to read important parts of German radio traffic on important networks and was an invaluable source of military intelligence
Military intelligence
Military intelligence is a military discipline that exploits a number of information collection and analysis approaches to provide guidance and direction to commanders in support of their decisions....
throughout the War. Intelligence from this source (and other high level sources, including the Fish
Fish (cryptography)
Fish was the Allied codename for any of several German teleprinter stream ciphers 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 was of the highest strategic value to the Allies...
cyphers) was eventually called Ultra.
A similar break into an important Japanese cypher (PURPLE
PURPLE
In the history of cryptography, 97-shiki ōbun inji-ki or Angōki Taipu-B , codenamed Purple by the United States, was a diplomatic cryptographic machine used by the Japanese Foreign Office just before and during World War II...
) by the US Army Signals Intelligence Service started before the US entered the War. Product from this source was called MAGIC
Magic (cryptography)
Magic was an Allied cryptanalysis project during World War II. It involved the United States Army's Signals Intelligence Section and the United States Navy's Communication Special Unit. -Codebreaking:...
. It was the highest security Japanese diplomatic cypher. For Japanese Naval cyphers see JN-25
JN-25
The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well...
. See also Attack on Pearl Harbor
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...
.
Australia
- Central BureauCentral BureauThe Central Bureau was one of two Allied Sigint organisations in the South West Pacific area during World War II. Central Bureau was attached to the HQ of the Allied Commander of the South West Pacific area, Douglas MacArthur. The other unit was the joint RAN/USN Fleet Radio Unit, Melbourne ,...
- FRUMELFRUMELFleet Radio Unit, Melbourne was a United States-Australian-British signals intelligence unit, based in Melbourne, Australia during World War II. It was one of two major Allied signals intelligence units, called Fleet Radio Units, in the Pacific theatres, the other being FRUPAC , in Hawaii...
: Fleet Radio UnitFleet Radio UnitFleet Radio Units were the major centers for Allied cryptological and signals intelligence during the Pacific Campaign of World War II. Initially two FRUs were established in the Pacific, one at Pearl Harbor, Hawaii, called Station HYPO or FRUPAC , and the other, called Station CAST or Belconnen,...
, Melbourne - Secret Intelligence AustraliaSecret Intelligence AustraliaSecret Intelligence Australia was a British World War II intelligence unit commanded by Captain Roy Kendall who reported directly to MI6 in London. SIA was known as Section B of the Allied Intelligence Bureau but was not accountable in any way to the Australians or the Americans.SIA had two main...
Germany
- Enigma (machine)
- Fish (cryptography)Fish (cryptography)Fish was the Allied codename for any of several German teleprinter stream ciphers 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 was of the highest strategic value to the Allies...
British codename for high level German teleprinter ciphers. - Lorenz cipherLorenz cipherThe Lorenz SZ40, SZ42A and SZ42B were German rotor cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. They implemented a Vernam stream cipher...
one of the Fish ciphers - Geheimfernschreiber
- B-DienstB-DienstThe B-Dienst was a German naval codebreaking organisation. During World War II, B-Dienst solved British Naval Cypher No. 3, providing intelligence for the Battle of the Atlantic, until the British Admiralty introduced Naval Cypher No. 5 on 10 June 1943. B-Dienst also solved a number of merchant...
- ReservehandverfahrenReservehandverfahren' was a German Naval World War II hand-cipher system used as a backup method when no working Enigma machine was available.The cipher had two stages: a transposition followed by bigram substitution. In the transposition stage, the cipher clerk would write out the plaintext into a "cage" — a shape...
Poland
- Cryptanalysis of the EnigmaCryptanalysis of the EnigmaCryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
- Biuro SzyfrówBiuro SzyfrówThe Biuro Szyfrów was the interwar Polish General Staff's agency charged with both cryptography and cryptology ....
(Cipher Bureau) - Marian RejewskiMarian RejewskiMarian Adam Rejewski was a Polish mathematician and cryptologist who in 1932 solved the plugboard-equipped Enigma machine, the main cipher device used by Germany...
- Jerzy RóżyckiJerzy RózyckiJerzy Witold Różycki was a Polish mathematician and cryptologist who worked at breaking German Enigma-machine ciphers.-Life:Różycki was born in what is now Ukraine, the fourth and youngest child of Zygmunt Różycki, a pharmacist and graduate of Saint Petersburg University, and Wanda, née Benita. ...
- Henryk ZygalskiHenryk ZygalskiHenryk Zygalski was a Polish mathematician and cryptologist who worked at breaking German Enigma ciphers before and during World War II.-Life:...
- bombaBomba (cryptography)The bomba, or bomba kryptologiczna was a special-purpose machine designed about October 1938 by Polish Cipher Bureau cryptologist Marian Rejewski to break German Enigma-machine ciphers....
- Lacida MachineLacidaThe Lacida was a Polish rotor cipher machine. It was designed and produced before World War II by Poland's Cipher Bureau for prospective wartime use by Polish military higher commands.-History:...
Soviet Union
As is common with World War II discussions of cryptology, there is a curious absence of information on Soviet efforts and accomplishments. Given the Red Army offenses on the Eastern Front, they must have obtained Enigma machines. What they did with them seems to be an unanswered question.United Kingdom
- Bletchley ParkBletchley ParkBletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
- Cryptanalysis of the EnigmaCryptanalysis of the EnigmaCryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
- Far East Combined BureauFar East Combined BureauThe Far East Combined Bureau, an outstation of the British Government Code and Cypher School, was set up in Hong Kong in March 1935, to monitor Japanese, and also Chinese and Russian intelligence and radio traffic...
(FECB) - Wireless Experimental CentreWireless Experimental CentreThe Wireless Experimental Centre was one of two overseas outposts of Station X, Bletchley Park, the British signals analysis centre during World War II. The other outpost was the Far East Combined Bureau....
(WEC) - BombeBombeThe bombe was an electromechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted signals during World War II...
- Colossus computerColossus computerNot to be confused with the fictional computer of the same name in the movie Colossus: The Forbin Project.Colossus was the world's first electronic, digital, programmable computer. Colossus and its successors were used by British codebreakers to help read encrypted German messages during World War II...
- TypexTypexIn the history of cryptography, Typex machines were British cipher machines used from 1937. It was an adaptation of the commercial German Enigma with a number of enhancements that greatly increased its security....
- Ultra
- 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...
- W. T. TutteW. T. TutteWilliam Thomas Tutte, OC, FRS, known as Bill Tutte, was a British, later Canadian, codebreaker and mathematician. During World War II he made a brilliant and fundamental advance in Cryptanalysis of the Lorenz cipher, a major German code system, which had a significant impact on the Allied...
- John Tiltman
- 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...
- Tommy FlowersTommy FlowersThomas "Tommy" Harold Flowers, MBE was an English engineer. During World War II, Flowers designed Colossus, the world's first programmable electronic computer, to help solve encrypted German messages.-Early life:...
- I. J. GoodI. J. GoodIrving John Good was a British mathematician who worked as a cryptologist at Bletchley Park with Alan Turing. After World War II, Good continued to work with Turing on the design of computers and Bayesian statistics at the University of Manchester...
- Leo MarksLeo MarksLeopold Samuel Marks was an English cryptographer, screenwriter and playwright.-Early life:Born the son of an antiquarian bookseller in London, he was first introduced to cryptography when his father showed him a copy of Edgar Allan Poe's story, "The Gold-Bug"...
- poem codePoem codeThe poem code is a simple, and insecure, cryptographic method.The method works by the sender and receiver pre-arranging a poem to use. The sender chooses a set number of words at random from the poem and gives each letter in the chosen words a number. The numbers are then used as a key for some...
United States
- Magic (cryptography)Magic (cryptography)Magic was an Allied cryptanalysis project during World War II. It involved the United States Army's Signals Intelligence Section and the United States Navy's Communication Special Unit. -Codebreaking:...
- Signals Intelligence ServiceSignals Intelligence ServiceThe Signals Intelligence Service was the United States Army codebreaking division, headquartered at Arlington Hall. It was a part of the Signal Corps so secret that outside the office of the Chief Signal officer, it did not officially exist. William Friedman began the division with three "junior...
US Army, see also Arlington HallArlington HallArlington Hall was a former girl's school and the headquarters of the US Army's Signal Intelligence Service cryptography effort during World War II. The site presently houses the George P. Shultz National Foreign Affairs Training Center, and the United States National Guard Readiness Center. It... - OP-20-GOP-20-GOP-20-G or "Office of Chief Of Naval Operations , 20th Division of the Office of Naval Communications, G Section / Communications Security", was the US Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications...
US Navy - William Friedman
- Frank RowlettFrank RowlettFrank Byron Rowlett was an American cryptologist.Rowlett was born in Rose Hill, Virginia and attended Emory & Henry College in Emory, Virginia, where he was a member of the Beta Lambda Zeta fraternity. In 1929 he received a bachelor's degree in mathematics and chemistry...
- Abraham SinkovAbraham SinkovDr. Abraham Sinkov was a US cryptanalyst.-Biography:Sinkov, the son of immigrants from Russia, was born in Philadelphia, but grew up in Brooklyn. After graduating from Boys High School—what today would be called a "magnet school" -- he took his B.S. in mathematics from City College of New York...
- Joseph RochefortJoseph RochefortJoseph John Rochefort was an American Naval officer and cryptanalyst. His contributions and those of his team were pivotal to victory in the Pacific War....
- Joseph MauborgneJoseph MauborgneIn the history of cryptography, Joseph Oswald Mauborgne co-invented the one-time pad with Gilbert Vernam of Bell Labs. In 1914 he published the first recorded solution of the Playfair cipher...
- Agnes Meyer DriscollAgnes Meyer DriscollAgnes Meyer Driscoll was, known as Miss Aggie or Madame X, an Americancryptanalyst during both World War I and World War II.-Early years:...
- SIGABASIGABAIn the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s...
- Codetalkers
- SIGSALYSIGSALYIn cryptography, SIGSALY was a secure speech system used in World War II for the highest-level Allied communications....
- M-209M-209In cryptography, the M-209, designated CSP-1500 by the Navy is a portable, mechanical cipher machine used by the US military primarily in World War II, though it remained in active use through the Korean War...
- Station HYPOStation HYPOStation HYPO, also known as Fleet Radio Unit Pacific was the United States Navy signals monitoring and cryptographic intelligence unit in Hawaii during World War II. It was one of two major Allied signals intelligence units, called Fleet Radio Units in the Pacific theaters, along with FRUMEL in...
- Station CASTStation CASTStation CAST was the United States Navy signals monitoring and cryptographic intelligence fleet radio unit at Cavite Navy Yard in the Philippines, until Cavite was captured by the Japanese forces in 1942, during World War II. It was an important part of the Allied intelligence effort, addressing...
- Station NEGAT
See also
- CryptographyCryptographyCryptography is the practice and study of techniques for secure communication in the presence of third parties...
- History of cryptographyHistory of cryptographyThe history of cryptography begins thousands of years ago. Until recent decades, it has been the story of what might be called classic cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids...
- World War I cryptographyWorld War I cryptographyCodes and ciphers were used extensively in World War I. The decoding by British Naval intelligence of the Zimmermann telegram helped bring the United States into the war....
- Ultra (cryptography)
- Magic (cryptography)Magic (cryptography)Magic was an Allied cryptanalysis project during World War II. It involved the United States Army's Signals Intelligence Section and the United States Navy's Communication Special Unit. -Codebreaking:...
- Cryptanalysis of the EnigmaCryptanalysis of the EnigmaCryptanalysis of the Enigma enabled the western Allies in World War II to read substantial amounts of secret Morse-coded radio communications of the Axis powers that had been enciphered using Enigma machines. This yielded military intelligence which, along with that from other decrypted Axis radio...
- BombeBombeThe bombe was an electromechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted signals during World War II...
- Enigma (machine)
- SIGABASIGABAIn the history of cryptography, the ECM Mark II was a cipher machine used by the United States for message encryption from World War II until the 1950s...
- TypeXTypexIn the history of cryptography, Typex machines were British cipher machines used from 1937. It was an adaptation of the commercial German Enigma with a number of enhancements that greatly increased its security....
- Lorenz cipherLorenz cipherThe Lorenz SZ40, SZ42A and SZ42B were German rotor cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. They implemented a Vernam stream cipher...
- Geheimfernschreiber
- Codetalkers
- PURPLEPURPLEIn the history of cryptography, 97-shiki ōbun inji-ki or Angōki Taipu-B , codenamed Purple by the United States, was a diplomatic cryptographic machine used by the Japanese Foreign Office just before and during World War II...
- SIGSALYSIGSALYIn cryptography, SIGSALY was a secure speech system used in World War II for the highest-level Allied communications....
- JN-25JN-25The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well...
- Bletchley ParkBletchley ParkBletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
- Biuro SzyfrówBiuro SzyfrówThe Biuro Szyfrów was the interwar Polish General Staff's agency charged with both cryptography and cryptology ....
- PC BrunoPC BrunoPC Bruno was a Polish-French intelligence station that operated outside Paris during World War II, from October 1939 until June 9, 1940. It decrypted German ciphers, most notably messages enciphered on the Enigma machine.-History:...
- SISSignals Intelligence ServiceThe Signals Intelligence Service was the United States Army codebreaking division, headquartered at Arlington Hall. It was a part of the Signal Corps so secret that outside the office of the Chief Signal officer, it did not officially exist. William Friedman began the division with three "junior...
US Army, later moved to Arlington Hall - OP-20-GOP-20-GOP-20-G or "Office of Chief Of Naval Operations , 20th Division of the Office of Naval Communications, G Section / Communications Security", was the US Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications...
US Navy
- Marian RejewskiMarian RejewskiMarian Adam Rejewski was a Polish mathematician and cryptologist who in 1932 solved the plugboard-equipped Enigma machine, the main cipher device used by Germany...
- Jerzy RóżyckiJerzy RózyckiJerzy Witold Różycki was a Polish mathematician and cryptologist who worked at breaking German Enigma-machine ciphers.-Life:Różycki was born in what is now Ukraine, the fourth and youngest child of Zygmunt Różycki, a pharmacist and graduate of Saint Petersburg University, and Wanda, née Benita. ...
- Henryk ZygalskiHenryk ZygalskiHenryk Zygalski was a Polish mathematician and cryptologist who worked at breaking German Enigma ciphers before and during World War II.-Life:...
- 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...
- W. T. TutteW. T. TutteWilliam Thomas Tutte, OC, FRS, known as Bill Tutte, was a British, later Canadian, codebreaker and mathematician. During World War II he made a brilliant and fundamental advance in Cryptanalysis of the Lorenz cipher, a major German code system, which had a significant impact on the Allied...
- John Tiltman
- 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...
- Tommy FlowersTommy FlowersThomas "Tommy" Harold Flowers, MBE was an English engineer. During World War II, Flowers designed Colossus, the world's first programmable electronic computer, to help solve encrypted German messages.-Early life:...
- I. J. GoodI. J. GoodIrving John Good was a British mathematician who worked as a cryptologist at Bletchley Park with Alan Turing. After World War II, Good continued to work with Turing on the design of computers and Bayesian statistics at the University of Manchester...
- William Friedman
- Frank RowlettFrank RowlettFrank Byron Rowlett was an American cryptologist.Rowlett was born in Rose Hill, Virginia and attended Emory & Henry College in Emory, Virginia, where he was a member of the Beta Lambda Zeta fraternity. In 1929 he received a bachelor's degree in mathematics and chemistry...
- Abraham SinkovAbraham SinkovDr. Abraham Sinkov was a US cryptanalyst.-Biography:Sinkov, the son of immigrants from Russia, was born in Philadelphia, but grew up in Brooklyn. After graduating from Boys High School—what today would be called a "magnet school" -- he took his B.S. in mathematics from City College of New York...
- Joseph RochefortJoseph RochefortJoseph John Rochefort was an American Naval officer and cryptanalyst. His contributions and those of his team were pivotal to victory in the Pacific War....
- Agnes Meyer DriscollAgnes Meyer DriscollAgnes Meyer Driscoll was, known as Miss Aggie or Madame X, an Americancryptanalyst during both World War I and World War II.-Early years:...
- Hans Thilo-Schmidt