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Friedrich Kasiski | A Wisdom Archive on Friedrich Kasiski | | Friedrich Kasiski A selection of articles related to Friedrich Kasiski | |
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| ARTICLES RELATED TO Friedrich Kasiski | | | |  Friedrich Kasiski: Encyclopedia II - Substitution cipher - Homophonic substitutionAn early attempt to increase the difficulty of frequency analysis attacks on substitution ciphers was to disguise plaintext letter frequencies by homophony. In these ciphers, plaintext letters map to more than one ciphertext symbol. Usually, the highest-frequency plaintext symbols are given more equivalents than lower frequency letters. In this way, the frequency distribution is flattened, making analysis more difficult.
Since more than 26 characters will be required in the ciphertext alphabet, various solutions are employed to ...
See also:Substitution cipher, Substitution cipher - Simple substitution, Substitution cipher - Examples, Substitution cipher - Security for simple substitution ciphers, Substitution cipher - Homophonic substitution, Substitution cipher - Polyalphabetic substitution, Substitution cipher - Polygraphic substitution, Substitution cipher - Mechanical substitution ciphers, Substitution cipher - The one-time pad, Substitution cipher - Substitution in modern cryptography Read more here: » Substitution cipher: Encyclopedia II - Substitution cipher - Homophonic substitution |
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| | | | | Friedrich Kasiski: Encyclopedia II - History of cryptography - Cryptography from 1800 to World War II Although cryptography has a long and complex history, it wasn't until the 19th century that it developed anything more than ad hoc approaches to either encryption or cryptanalysis (the science of finding weaknesses in crypto systems). Examples of the latter include Charles Babbage's Crimean War era work on mathematical cryptanalysis of polyalphabetic ciphers, rediscovered and published somewhat later by the Prussian Friedrich Kasiski. Understanding of cryptography at this time typically consisted of hard-won rules of thumb; see, for example, ...
See also:History of cryptography, History of cryptography - Classical cryptography, History of cryptography - Medieval cryptography, History of cryptography - Cryptography from 1800 to World War II, History of cryptography - World War II cryptography, History of cryptography - Modern cryptography, History of cryptography - Shannon, History of cryptography - An encryption standard, History of cryptography - Public key, History of cryptography - Cryptography politics, History of cryptography - Modern cryptanalysis Read more here: » History of cryptography: Encyclopedia II - History of cryptography - Cryptography from 1800 to World War II |
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| | | | | Friedrich Kasiski: Encyclopedia II - History of cryptography - Medieval cryptography It was probably religiously motivated textual analysis of the Qur'an which led to the invention of the frequency analysis technique for breaking monoalphabetic substitution ciphers sometime around 1000 CE. It was the most fundamental cryptanalytic advance until WWII. Essentially all ciphers remained vulnerable to this cryptanalytic technique until the invention of the polyalphabetic cipher by Alberti (ca 1465), and many remained so thereafter.
Cryptography became (secretly) still more important as a consequence of political competitio ...
See also:History of cryptography, History of cryptography - Classical cryptography, History of cryptography - Medieval cryptography, History of cryptography - Cryptography from 1800 to World War II, History of cryptography - World War II cryptography, History of cryptography - Modern cryptography, History of cryptography - Shannon, History of cryptography - An encryption standard, History of cryptography - Public key, History of cryptography - Cryptography politics, History of cryptography - Modern cryptanalysis Read more here: » History of cryptography: Encyclopedia II - History of cryptography - Medieval cryptography |
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| | | | | Friedrich Kasiski: Encyclopedia II - History of cryptography - Classical cryptography The earliest known use of cryptography is found in non-standard hieroglyphs carved into monuments from Egypt's Old Kingdom (ca 4500+ years ago). These are not thought to be serious attempts at secret communications, however, but rather to have been attempts at mystery, intrigue, or even amusement for literate onlookers. These are examples of still other uses of cryptography, or of something that looks (impressively if misleadingly) like it. Later, Hebrew scholars made use of simple monoalphabetic substitution ciphers (such as the Atbash ciph ...
See also:History of cryptography, History of cryptography - Classical cryptography, History of cryptography - Medieval cryptography, History of cryptography - Cryptography from 1800 to World War II, History of cryptography - World War II cryptography, History of cryptography - Modern cryptography, History of cryptography - Shannon, History of cryptography - An encryption standard, History of cryptography - Public key, History of cryptography - Cryptography politics, History of cryptography - Modern cryptanalysis Read more here: » History of cryptography: Encyclopedia II - History of cryptography - Classical cryptography |
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| | | | | Friedrich Kasiski: Encyclopedia II - Charles Babbage - Other accomplishments In 1824 Babbage won the Gold Medal of the Royal Astronomical Society "for his invention of an engine for calculating mathematical and astronomical tables".
From 1828 to 1839 Babbage was Lucasian professor of mathematics at Cambridge. He contributed largely to several scientific periodicals, and was instrumental in founding the Astronomical Society in 1820 and the Statistical Society in 1834. However ...
See also:Charles Babbage, Charles Babbage - Life, Charles Babbage - Education, Charles Babbage - Marriage, Charles Babbage - Children, Charles Babbage - Design of computers, Charles Babbage - Difference engine, Charles Babbage - Printer, Charles Babbage - Analytical engine, Charles Babbage - Other accomplishments, Charles Babbage - Odd Read more here: » Charles Babbage: Encyclopedia II - Charles Babbage - Other accomplishments |
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| | | | | Friedrich Kasiski: Encyclopedia II - History of cryptography - World War II cryptography By World War II, mechanical and electromechanical cipher machines were in wide use, although — where such machines were impractical — manual systems continued in use. Great advances were made in cipher-breaking, all in secrecy. Information about this period has begun to be declassified as the official British 50-year secrecy period has come to an end, as U.S. archives have slowly opened, and as assorted memoirs and articles have appeared.
The Germans made heavy use, in several variants, of an electromechanical rotor machine known ...
See also:History of cryptography, History of cryptography - Classical cryptography, History of cryptography - Medieval cryptography, History of cryptography - Cryptography from 1800 to World War II, History of cryptography - World War II cryptography, History of cryptography - Modern cryptography, History of cryptography - Shannon, History of cryptography - An encryption standard, History of cryptography - Public key, History of cryptography - Cryptography politics, History of cryptography - Modern cryptanalysis Read more here: » History of cryptography: Encyclopedia II - History of cryptography - World War II cryptography |
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| | | | | Friedrich Kasiski: Encyclopedia II - Vigenère cipher - History Leone Battista Alberti (the inventor of polyalphabetic ciphers), Johannes Trithemius (in his works Poligraphia and Stegonographia) and Giovanni Battista Della Porta (in Magia Naturalis) all created important predecessors to the Vigenère cipher. Trithemius was the first person to introduce the tabula recta, but he provided no system for switching between cipher alphabets.
The Vigenère cipher was originally described by Giovan Batista Belaso in his 1553 book La cifra del. Sig. Giovan Batista Belaso. Blaise ...
See also:Vigenère cipher, Vigenère cipher - History, Vigenère cipher - Description, Vigenère cipher - Cryptanalysis, Vigenère cipher - Kasiski examination, Vigenère cipher - Friedman test, Vigenère cipher - The cipher of Blaise de Vigenère, Vigenère cipher - Variants, Vigenère cipher - Notes Read more here: » Vigenère cipher: Encyclopedia II - Vigenère cipher - History |
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| | | | | Friedrich Kasiski: Encyclopedia II - Substitution cipher - Polygraphic substitution In a polygraphic substitution cipher, plaintext letters are substituted for in larger groups (typically pairs, making a digraphic cipher), instead of substituting letters individually. The advantage of this is first that the frequency distribution of digraphs is much flatter than that of individual letters (though not actually flat in real languages; for example, 'TH' is much more common than 'XQ' in English). Second, the larger number of symbols requires correspondi ...
See also:Substitution cipher, Substitution cipher - Simple substitution, Substitution cipher - Examples, Substitution cipher - Security for simple substitution ciphers, Substitution cipher - Homophonic substitution, Substitution cipher - Polyalphabetic substitution, Substitution cipher - Polygraphic substitution, Substitution cipher - Mechanical substitution ciphers, Substitution cipher - The one-time pad, Substitution cipher - Substitution in modern cryptography Read more here: » Substitution cipher: Encyclopedia II - Substitution cipher - Polygraphic substitution |
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| | | | | Friedrich Kasiski: Encyclopedia II - Substitution cipher - Polyalphabetic substitution Polyalphabetic substitution ciphers were first described in 1467 by Leone Battista Alberti in the form of disks. Johannes Trithemius, in his book Steganographia (Ancient Greek for "hidden writing") introduced the now more standard form of a tableau (see below; ca. 1500 but not published until much later). A more sophisticated version using mixed alphabets was described in 1563 by Giovanni Battista della Porta in his book, De Furtivis Literarum Notis (Latin for "On concealed characters in writing").
In a polyalphab ...
See also:Substitution cipher, Substitution cipher - Simple substitution, Substitution cipher - Examples, Substitution cipher - Security for simple substitution ciphers, Substitution cipher - Homophonic substitution, Substitution cipher - Polyalphabetic substitution, Substitution cipher - Polygraphic substitution, Substitution cipher - Mechanical substitution ciphers, Substitution cipher - The one-time pad, Substitution cipher - Substitution in modern cryptography Read more here: » Substitution cipher: Encyclopedia II - Substitution cipher - Polyalphabetic substitution |
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| | | | | | Friedrich Kasiski: Encyclopedia II - Substitution cipher - Mechanical substitution ciphers Between circa WWI and the widespread availability of computers (for some governments this was approximately the 1950s or 1960s; for other organizations it was a decade or more later; for individuals it was no earlier than 1975), mechanical implementations of polyalphabetic substitution ciphers were widely used. Several inventors had similar ideas about the same time, and rotor cipher machines were patented four times in 1919. The most important of the resulting machines was the Enigma, especially in the versions used by the German military from approximately 1930. Th ...
See also:Substitution cipher, Substitution cipher - Simple substitution, Substitution cipher - Examples, Substitution cipher - Security for simple substitution ciphers, Substitution cipher - Homophonic substitution, Substitution cipher - Polyalphabetic substitution, Substitution cipher - Polygraphic substitution, Substitution cipher - Mechanical substitution ciphers, Substitution cipher - The one-time pad, Substitution cipher - Substitution in modern cryptography Read more here: » Substitution cipher: Encyclopedia II - Substitution cipher - Mechanical substitution ciphers |
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| | | | | Friedrich Kasiski: Encyclopedia II - Vigenère cipher - Description In a Caesar cipher, each letter of the alphabet is shifted along some number of places; for example, in a Caesar cipher of shift 3, A would become D, B would become E and so on. The Vigenère cipher consists of using several Caesar ciphers in sequence with different shift values.
To encipher, a table of alphabets can be used, termed a tabula recta, Vigenère square, or Vigenère table. It consists of the alphabet written out 26 times in different rows, each alphabet shifted cycl ...
See also:Vigenère cipher, Vigenère cipher - History, Vigenère cipher - Description, Vigenère cipher - Cryptanalysis, Vigenère cipher - Kasiski examination, Vigenère cipher - Friedman test, Vigenère cipher - The cipher of Blaise de Vigenère, Vigenère cipher - Variants, Vigenère cipher - Notes Read more here: » Vigenère cipher: Encyclopedia II - Vigenère cipher - Description |
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