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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 ...
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Reservehandverfahren Allgemein (MDvNr 929-1) Booklet
( 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 Mediterranean ...
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U-boat
U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role (commerce raiding) and enforcing a naval blockade against enemy shipping. The primary targets of the U-boat campaigns in both wars were the merchant convoys bringing supplies from Canada and other parts of the British Empire, and from the United States, to the United Kingdom and (during the Second World War) to the Soviet Union and the Allied territories in the Mediterranean. German submarines also destroyed Brazilian merchant ships during World War II, causing Brazil to declare war on both Germany and Italy on 22 August 1942. The term is an anglicised version of the German word ''U-Boot'' , a shortening of ''Unterseeboot'' ('under-sea-boat'), though the German term refers to any submarine. Austro-Hungarian Navy submarines were also kno ...
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History Of Telecommunications In Germany
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well as the memory, discovery, collection, organization, presentation, and interpretation of these events. Historians seek knowledge of the past using historical sources such as written documents, oral accounts, art and material artifacts, and ecological markers. History is not complete and still has debatable mysteries. History is also an academic discipline which uses narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. Historians often debate which narrative best explains an event, as well as the significance of different causes and effects. Historians also debate the nature of history as an end in itself, as well as its usefulness to give perspective on the problems of the p ...
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Classical Ciphers
Classical may refer to: European antiquity *Classical antiquity, a period of history from roughly the 7th or 8th century B.C.E. to the 5th century C.E. centered on the Mediterranean Sea *Classical architecture, architecture derived from Greek and Roman architecture of classical antiquity *Classical mythology, the body of myths from the ancient Greeks and Romans *Classical tradition, the reception of classical Greco-Roman antiquity by later cultures *Classics, study of the language and culture of classical antiquity, particularly its literature *Classicism, a high regard for classical antiquity in the arts Music and arts *Classical ballet, the most formal of the ballet styles *Classical music, a variety of Western musical styles from the 9th century to the present *Classical guitar, a common type of acoustic guitar *Classical Hollywood cinema, a visual and sound style in the American film industry between 1927 and 1963 * Classical Indian dance, various codified art forms whose theo ...
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Mykonos
Mykonos (, ; el, Μύκονος ) is a Greek island, part of the Cyclades, lying between Tinos, Syros, Paros and Naxos. The island has an area of and rises to an elevation of at its highest point. There are 10,134 inhabitants according to the 2011 census, most of whom live in the largest town, Mykonos, which lies on the west coast. The town is also known as ''Chora'' (i.e. 'Town' in Greek, following the common practice in Greece when the name of the island itself is the same as the name of the principal town). Mykonos's nickname is "The Island of the Winds", due to the very strong winds that usually blow on the island. Tourism is a major industry and Mykonos is known for its vibrant nightlife and for being a gay-friendly destination with many establishments catering for the LGBT community. History Herodotus mentions Carians as the original inhabitants of the island. Ionians from Athens seem to have followed next in the early 11th century BC. There were many people living on t ...
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Crib (cryptanalysis)
The known-plaintext attack (KPA) is an attack model for cryptanalysis where the attacker has access to both the plaintext (called a crib), and its encrypted version (ciphertext). These can be used to reveal further secret information such as secret keys and code books. The term "crib" originated at Bletchley Park, the British World War II decryption operation, where it was defined as: History The usage "crib" was adapted from a slang term referring to cheating (e.g., "I cribbed my answer from your test paper"). A "crib" originally was a literal or interlinear translation of a foreign-language text—usually a Latin or Greek text—that students might be assigned to translate from the original language. The idea behind a crib is that cryptologists were looking at incomprehensible ciphertext, but if they had a clue about some word or phrase that might be expected to be in the ciphertext, they would have a "wedge," a test to break into it. If their otherwise random attacks on the c ...
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John H
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died c. AD 30), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (lived c. AD 30), one of the twelve apostles of Jesus * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope Jo ...
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Cryptanalysis
Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown. In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation. Even though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematically advanced comput ...
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Bletchley Park
Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following 1883 for the financier and politician Sir Herbert Leon in the Victorian Gothic, Tudor, and Dutch Baroque styles, on the site of older buildings of the same name. During World War II, the estate housed the Government Code and Cypher School (GC&CS), which regularly penetrated the secret communications of the Axis Powersmost importantly the German Enigma and Lorenz ciphers. The GC&CS team of codebreakers included Alan Turing, Gordon Welchman, Hugh Alexander, Bill Tutte, and Stuart Milner-Barry. The nature of the work at Bletchley remained secret until many years after the war. According to the official historian of British Intelligence, the "Ultra" intelligence produced at Bletchley shortened the war by two to four years, and without it th ...
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Kriegsmarine
The (, ) was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war (1919–1935) of the Weimar Republic. The was one of three official branches, along with the and the , of the , the German armed forces from 1935 to 1945. In violation of the Treaty of Versailles, the grew rapidly during German naval rearmament in the 1930s. The 1919 treaty had limited the size of the German navy and prohibited the building of submarines. ships were deployed to the waters around Spain during the Spanish Civil War (1936–1939) under the guise of enforcing non-intervention, but in reality supported the Nationalists against the Spanish Republicans. In January 1939, Plan Z, a massive shipbuilding program, was ordered, calling for surface naval parity with the British Royal Navy by 1944. When World War II broke out in September 1939, Plan Z was shelved in favour of a crash building program for submarines (U-boat ...
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Hugh Sebag-Montefiore
Nicholas Hugh Sebag-Montefiore (born 5 March 1955) is a British writer. He trained as a barrister before becoming a journalist and then a non-fiction writer. His second book ''Dunkirk: Fight to the Last Man'' was published in 2006. His previous book is ''Enigma: The Battle for the Code'', the story of breaking the German Enigma machine code at Bletchley Park during the Second World War (Weidenfeld & Nicolson, 2000). His family owned Bletchley Park until they sold it to the British government in 1938. In 2016, ''Somme: Into the Breach'' appeared in time for the 100th anniversary of the Somme Offensive. Cecil Sebag-Montefiore, the author's great-grandfather, took his own life after serving with the Royal Engineers on the Western Front. He has been married since 1989 to Aviva Burnstock, the head of the Department of Art Conservation & Technology at the Courtauld Institute in London. His brother Simon Sebag Montefiore is also a writer, besides being an historian. His cousin Denzil ...
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