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John Herivel
John William Jamieson Herivel (29 August 1918 – 18 January 2011) was a British science historian and World War II codebreaker at Bletchley Park. As a codebreaker concerned with Cryptanalysis of the Enigma, Herivel is remembered chiefly for the discovery of what was soon dubbed the Herivel tip or Herivelismus. Herivelismus consisted of the idea, the Herivel tip and the method of establishing whether it applied using the Herivel square. It was based on Herivel's insight into the habits of German operators of the Enigma cipher machine that allowed Bletchley Park to easily deduce part of the daily key. For a brief but critical period after May 1940, the Herivel tip in conjunction with " cillies" (another class of operator error) was the main technique used to solve Enigma. After the war, Herivel became an academic, studying the history and philosophy of science at Queen's University Belfast, particularly Isaac Newton, Joseph Fourier, Christiaan Huygens. In 1956, he took a bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Historian
The history of science and technology (HST) is a field of history that examines the development of the understanding of the natural world (science) and humans' ability to manipulate it (technology) at different points in time. This academic discipline also examines the cultural, economic, and political context and impacts of scientific practices; it likewise may study the consequences of new technologies on existing scientific fields. Academic study of history of science History of science is an academic discipline with an international community of specialists. Main professional organizations for this field include the History of Science Society, the British Society for the History of Science, and the European Society for the History of Science. Much of the study of the history of science has been devoted to answering questions about what science ''is'', how it ''functions'', and whether it exhibits large-scale patterns and trends. History of the academic study of history of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Government Code And Cypher School
The Government Code and Cypher School (GC&CS) was a British signals intelligence agency set up in 1919. During the First World War, the British Army and Royal Navy had separate signals intelligence agencies, MI1b and NID25 (initially known as Room 40) respectively. It was particularly known for its work on codebreaking at Bletchley Park and after the war became the Government Communications Headquarters (GCHQ). Interwar period In 1919, the Cabinet's Secret Service Committee, chaired by Lord Curzon, recommended that a peacetime codebreaking agency should be created, a task which was given to the Director of Naval Intelligence, Hugh Sinclair.Johnson, 1997, p. 44 Sinclair merged staff from NID25 and MI1b into the new organisation, which initially consisted of around 25–30 officers and a similar number of clerical staff. It was titled the "Government Code and Cypher School" (GC&CS), a cover-name which was chosen by Victor Forbes of the Foreign Office. Alastair Denniston, who h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bombe
The bombe () was an Electromechanics, electro-mechanical device used by British cryptologists to help decipher German Enigma machine, Enigma-machine-encrypted secret messages during World War II. The United States Navy, US Navy and United States Army, US Army later produced their own machines to the same functional specification, albeit engineered differently both from each other and from Polish and British bombes. The British bombe was developed from a device known as the "Bomba (cryptography), bomba" (), which had been designed in Poland at the Biuro Szyfrów (Cipher Bureau) by cryptologist Marian Rejewski, who had been breaking German Enigma machine, Enigma messages for the previous seven years, using it and earlier machines. The initial design of the British bombe was produced in 1939 at the UK Government Code and Cypher School (GC&CS) at Bletchley Park by Alan Turing, with an important refinement devised in 1940 by Gordon Welchman. The engineering design and construction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygalski Sheets
The method of Zygalski sheets was a cryptologic technique used by the Polish Cipher Bureau before and during World War II, and during the war also by British cryptologists at Bletchley Park, to decrypt messages enciphered on German Enigma machines. The Zygalski-sheet apparatus takes its name from Polish Cipher Bureau mathematician–cryptologist Henryk Zygalski, who invented it about October 1938. Method Zygalski's device comprised a set of 26 perforated sheets for each of the, initially, six possible sequences for inserting the three rotors into the Enigma machine's scrambler. Each sheet related to the starting position of the left (slowest-moving) rotor. The 26 × 26 matrix represented the 676 possible starting positions of the middle and right rotors and was duplicated horizontally and vertically: ''a–z, a–y''. The sheets were punched with holes in the positions that would allow a "female" to occur. Polish mathematician–cryptologist Marian Rejewski writes about ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enigma Rotors And Spindle Showing Contacts Rachet And Notch
Enigma may refer to: *Riddle, someone or something that is mysterious or puzzling Biology *ENIGMA, a class of gene in the LIM domain Computing and technology * Enigma (company), a New York–based data-technology startup *Enigma machine, a family of German electro-mechanical encryption machines *Enigma, the codename for Red Hat Linux 7.2 * Enigma (DVB), the second generation of Enigma software Film * ''Enigma'' (1982 film), a film starring Martin Sheen and Sam Neill * ''Enigma'' (2001 film), a film adapted from the Robert Harris novel * ''Enigma'' (2009 film), a short film by the Shumway Brothers * ''Enigma'' (2025 film), a documentary directed by Zackary Drucker Literature * ''Enigma'' (novel), a 1995 novel by Robert Harris *Enigma (DC Comics), a DC Comics character * Enigma (Marvel Comics), a Marvel Comics character * ''Enigma'' (Vertigo), a title published by DC's imprint Vertigo * ''Enigma'' (manga), a 2010 manga published in ''Weekly Shōnen Jump'' *''Enigma Cipher'', a ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enigma Rotor Details
This article contains technical details about the rotors of the Enigma machine The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the W .... Understanding the way the machine encrypts requires taking into account the current position of each rotor, the ring setting and its internal wiring. Physical design of rotors Image:Enigma-rotor-pin-contacts.jpg, The right side of a rotor, showing the pin electrical contacts. The Roman numeral V identifies the wiring of the rotor. Image:Enigma-rotor-flat-contacts.jpg, The left side of an Enigma rotor, showing the flat (plate) electrical contacts. A single turnover notch is visible on the left edge of the rotor. Rotor electrical view No letter can map to itself, a cryptographic weakness caused by the same wires being used for forwards and bac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyalphabetic Cipher
A polyalphabetic cipher is a substitution cipher, substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The Enigma machine is more complex but is still fundamentally a polyalphabetic substitution cipher. History The work of Al-Qalqashandi (1355–1418), based on the earlier work of Ibn al-Durayhim (1312–1359), contained the first published discussion of the substitution and transposition of ciphers, as well as the first description of a polyalphabetic cipher, in which each plaintext letter is assigned more than one substitute. However, it has been claimed that polyalphabetic ciphers may have been developed by the Arab cryptologist Al Kindi (801–873) centuries earlier. The Alberti cipher by Leon Battista Alberti around 1467 was an early polyalphabetic cipher. Alberti used a mixed alphabet to encrypt a message, but whenever he wanted to, he would switch to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotor Machine
In cryptography, a rotor machine is an electro-mechanical stream cipher device used for encrypting and decrypting messages. Rotor machines were the cryptographic state-of-the-art for much of the 20th century; they were in widespread use from the 1920s to the 1970s. The most famous example is the German Enigma machine, the output of which was deciphered by the Allies during World War II, producing intelligence code-named '' Ultra''. Description The primary component of a rotor machine is a set of ''rotors'', also termed ''wheels'' or ''drums'', which are rotating disks with an array of electrical contacts on either side. The wiring between the contacts implements a fixed substitution of letters, replacing them in some complex fashion. On its own, this would offer little security; however, before or after encrypting each letter, the rotors advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromechanics
Electromechanics combine processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focus on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each other. This process is especially prominent in systems such as those of DC or AC rotating electrical machines which can be designed and operated to generate power from a mechanical process (Electric generator, generator) or used to power a mechanical effect (Electric motor, motor). Electrical engineering in this context also encompasses electronic engineering, electronics engineering. Electromechanical devices are ones which have both electrical and mechanical processes. Strictly speaking, a manually operated switch is an electromechanical component due to the mechanical movement causing an electrical output. Though this is true, the term is usually understood to refer to devices which involve an electrical signal to create mechanical mov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy. International Morse code encodes the 26 ISO basic Latin alphabet, basic Latin letters to , one Diacritic, accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals (Prosigns for Morse code, prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration can vary for signal clarity and operator skill, but for any one message, once the rhythm is established, a beat (music), half-beat is the basic unit of time measurement in Morse code. The duration of a ''dah'' is three times the duration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Rees (mathematician)
David Rees FRS (29 May 1918 – 16 August 2013) was a British professor of pure mathematics at the University of Exeter, having been head of the Mathematics / Mathematical Sciences Department at Exeter from 1958 to 1983. During the Second World War, Rees was active on Enigma research in Hut 6 at Bletchley Park. Early life Rees was born in Abergavenny to David Rees (1881–), a corn merchant, and his wife Florence Gertrude (Gertie) née Powell (1884–1970), the 4th out of 5 children. Despite periods of ill health and absence, he successfully completed his early education at King Henry VIII Grammar School. Education and career Rees won a scholarship to Sidney Sussex College, Cambridge, supervised by Gordon Welchman and graduating in summer 1939. On completion of his education, he initially worked on semigroup theory; the Rees factor semigroup is named after him. He also characterised completely simple and completely 0-simple semigroups, in what is nowadays known as Rees ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luftwaffe
The Luftwaffe () was the aerial warfare, aerial-warfare branch of the before and during World War II. German Empire, Germany's military air arms during World War I, the of the Imperial German Army, Imperial Army and the of the Imperial German Navy, Imperial Navy, had been disbanded in May 1920 in accordance with the terms of the 1919 Treaty of Versailles, which banned Germany from having any air force. During the interwar period, German pilots were trained secretly in violation of the treaty at Lipetsk (air base), Lipetsk Air Base in the Soviet Union. With the rise of the Nazi Party and the repudiation of the Versailles Treaty, the Luftwaffe's existence was publicly acknowledged and officially established on 26 February 1935, just over two weeks before open defiance of the Versailles Treaty through German rearmament and conscription would be announced on 16 March. The Condor Legion, a Luftwaffe detachment sent to aid Nationalist faction (Spanish Civil War), Nationalist for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
