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World War II Cryptography
Cryptography was used extensively during World War II because of the importance of radio communication and the ease of radio interception. The nations involved fielded a plethora of code and cipher systems, many of the latter using rotor machines. As a result, the theoretical and practical aspects of ''cryptanalysis'', or ''codebreaking'', were much advanced. Possibly the most important codebreaking event of the war was the successful decryption by the Allies of the German "Enigma" Cipher. The first break into Enigma was accomplished by Polish Cipher Bureau 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 Bletchley Park 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. Intelligenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Listening Station
A radio listening station (also: listening post, radio intercept station or wireless intercept station, W/T station for wireless telegraphy) is a facility used for military reconnaissance, especially telecommunications reconnaissance (also known as ''signals intelligence SIGINT'') by "intercepting" radio transmitter communications. In contrast to the original eavesdropping on an acoustic speech conversation, radio eavesdropping stations are used to eavesdrop on the information transmitted wirelessly using radio technology. For this purpose, highly sensitive radio receivers and suitable receiving antennas are used (see images). First World War After Heinrich Hertz (1857–1894) succeeded in 1886 as the first to generate electromagnetic waves in the ultra-short wave range, and Guglielmo Marconi (1874–1937) around 1900 was able to increase the range of his radio transmissions to hundreds of kilometers, thus radiotelegraphy technology was used in the First World War (1914–19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fleet Radio Unit
Fleet Radio Units (FRU) 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 (Fleet Radio Unit, Pacific), and the other, called Station CAST or Belconnen, at Cavite Naval Yard, then Corregidor, Philippines. With the fall of the Philippines to Imperial Japanese forces in April and May 1942, CAST personnel were evacuated to a newly established FRU at Melbourne, Australia, called FRUMEL (Fleet Radio Unit, Melbourne). HYPO and FRUMEL supervised detached field units scattered at various locations and aboard ships throughout the south, central, and north Pacific areas until the end of World War II. A third center, NEGAT, was based at OP-20-G headquarters in Washington DC. The entire cryptanalysis effort conducted by the units was called ''Operation Magic''. Liaison between the units and with the Far East Combined Bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gisbert Hasenjaeger
Gisbert F. R. Hasenjaeger (June 1, 1919 – September 2, 2006) was a German mathematical logician. Independently and simultaneously with Leon Henkin in 1949, he developed a new proof of the completeness theorem of Kurt Gödel for predicate logic. He worked as an assistant to Heinrich Scholz at Section IVa of Oberkommando der Wehrmacht Chiffrierabteilung, and was responsible for the security of the Enigma machine. Personal life Gisbert Hasenjaeger went to high school in Mülheim, where his father was a lawyer and local politician. After completing school in 1936, Gisbert volunteered for labor service. He was drafted for military service in World War II, and fought as an artillerist in the Russian campaign, where he was badly wounded in January 1942. After his recovery, in October 1942, Heinrich Scholz got him employment in the Cipher Department of the High Command of the Wehrmacht (OKW/Chi), where he was the youngest member at 24. He attended a cryptography training c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cipher Department Of The High Command Of The Wehrmacht
The Cipher Department of the High Command of the Wehrmacht (german: Amtsgruppe Wehrmachtnachrichtenverbindungen, Abteilung Chiffrierwesen) (also ''Oberkommando der Wehrmacht Chiffrierabteilung'' or ''Chiffrierabteilung of the High Command of the Wehrmacht'' or ''Chiffrierabteilung of the OKW'' or ''OKW/Chi'' or ''Chi'') was the Signal Intelligence Agency of the Supreme Command of the Armed Forces of the German Armed Forces before and during World War II. OKW/Chi, within the formal order of battle hierarchy OKW/WFsT/Ag WNV/Chi, dealt with the cryptanalysis and deciphering of enemy and neutral states' message traffic and security control of its own key processes and machinery, such as the rotor cipher machine ENIGMA machine. It was the successor to the former Chi bureau (german: Chiffrierstelle) of the Reichswehr Ministry. Short name The letter "Chi" for the ''Chiffrierabteilung'' ("cipher department") is, contrary to what one might expect, not the Greek letter Chi , nor anythin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reservehandverfahren
( en, Reserve Hand Procedure) 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 on a piece of paper. Pairs of letters were then substituted using a set of bigram tables.Hugh Sebag-Montefiore, ''Enigma: Battle for the Code'', 2000, pp. 213–214. The cipher was first solved at Bletchley Park in June 1941 by means of documents captured from U-boat the previous month. Thereafter it was solved using cryptanalysis for over three years. Some 1,400 signals were read during that period. The section working on RHV was headed by historian Sir John H. Plumb. The decrypts were sometimes useful in themselves for the intelligence that they contained, but were more important as a source for cribs for solving Naval Enigma. A Mediterrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-Dienst
The ''B-Dienst'' (german: Beobachtungsdienst, observation service), also called x''B-Dienst'', X-''B-Dienst'' and χ''B-Dienst'', was a Department of the German Naval Intelligence Service (german: Marinenachrichtendienst, MND III) of the OKM, that dealt with the interception and recording, decoding and analysis of the enemy, in particular British radio communications before and during World War II. B-Dienst worked on cryptanalysis and deciphering (decrypting) of enemy and neutral states' message traffic and security control of ''Kriegsmarine'' key processes and machinery. :"The ultimate goal of all evaluation was recognizing the opponent's goal by pro-active identification of data." B-Dienst was instrumental in moulding Wehrmacht operations during the Battles of Norway and France in spring 1940, primarily due to the cryptanalysis successes it had achieved against early and less secure British Naval cyphers. B-Dienst broke British Naval Combined Cypher No. 3 in October 1941, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Weather Cipher
The Short Weather Cipher (german: Wetterkurzschlüssel, abbreviated ''WKS''), also known as the weather short signal book, was a cipher, presented as a codebook, that was used by the radio telegraphists aboard U-boats of the German Navy (Kriegsmarine) during World War II. It was used to condense weather reports into a short 7-letter message, which was enciphered by using the naval Enigma and transmitted by radiomen to intercept stations on shore, where it was deciphered by Enigma and the 7-letter weather report was reconstructed. History During World War II, during various times, different versions of the cipher were in operation. The first issue carried the codename ''Weimar''. It was replaced by the edition ''Eisenach'' on 20 January 1942. On 10 March 1943, the third edition of the weather key, bearing the codename ''Naumburg'', entered into force. On May 9, 1941, during Operation Primrose, the operation to occupy Åndalsnes and create a diversion south of Trondheim in Norway as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens And Halske T52
The Siemens & Halske T52, also known as the Geheimschreiber ("secret teleprinter"), or ''Schlüsselfernschreibmaschine'' (SFM), was a World War II German cipher machine and teleprinter produced by the electrical engineering firm Siemens & Halske. The instrument and its traffic were codenamed ''Sturgeon'' by British cryptanalysts. While the Enigma machine was generally used by field units, the T52 was an online machine used by Luftwaffe and German Navy units, which could support the heavy machine, teletypewriter and attendant fixed circuits. It fulfilled a similar role to the Lorenz cipher machines in the German Army. The British cryptanalysts of Bletchley Park codenamed the German teleprinter ciphers Fish, with individual cipher-systems being given further codenames: just as the T52 was called ''Sturgeon'', the Lorenz machine was codenamed ''Tunny''. Operation The teleprinters of the day emitted each character as five parallel bits on five lines, typically encoded in the Baudo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorenz Cipher
The Lorenz SZ40, SZ42a and SZ42b were German rotor stream cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. The model name ''SZ'' was derived from ''Schlüssel-Zusatz'', meaning ''cipher attachment''. The instruments implemented a Vernam stream cipher. British cryptanalysts, who referred to encrypted German teleprinter traffic as ''Fish'', dubbed the machine and its traffic ''Tunny'' (meaning tunafish) and deduced its logical structure three years before they saw such a machine. The SZ machines were in-line attachments to standard teleprinters. An experimental link using SZ40 machines was started in June 1941. The enhanced SZ42 machines were brought into substantial use from mid-1942 onwards for high-level communications between the German High Command in Wünsdorf close to Berlin, and Army Commands throughout occupied Europe. The more advanced SZ42A came into routine use in February 1943 and the SZ42B in June 1944. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish (cryptography)
Fish (sometimes FISH) was the UK's GC&CS Bletchley Park 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 (Ultra) was of the highest strategic value to the Allies. This traffic normally passed over landlines, but as German forces extended their geographic reach beyond western Europe, they had to resort to wireless transmission. Bletchley Park decrypts of messages enciphered with the Enigma machines revealed that the Germans called one of their wireless teleprinter transmission systems ''"Sägefisch"'' (sawfish) which led British cryptographers to refer to encrypted German radiotelegraphic traffic as Fish. The code Tunny (tunafish) was the name given to the first non-Morse link, and it was subsequently used for the Lorenz SZ machines and the traffic enciphered by them. History In June 1941, the British ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans-Thilo Schmidt
Hans-Thilo Schmidt (13 May 1888 – 19 September 1943) codenamed Asché or Source D, was a spy who, during the 1930s, sold secrets about the Germans' Enigma machine to the French. The materials he provided facilitated Polish mathematician Marian Rejewski's reconstruction of the wiring in the Enigma's rotors and reflector; thereafter the Poles were able to read a large proportion of Enigma-enciphered traffic. Selling Enigma secrets A former officer, Schmidt had been forced to leave the army having suffered from gas during the First World War.May, Ernest ''Strange Victory'', New York: Hill & Wang, 2000 page 135. However, his brother, Rudolf Schmidt, secured him a civilian post at the German Armed Forces' cryptographic headquarters, the Cipher Office. Shortly after the military version of the Enigma machine was introduced, he contacted French intelligence and offered to supply information about the new machine. His offer was accepted by Captain Gustave Bertrand of French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
