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Alberti Cipher
The Alberti Cipher, created in 1467 by Italian architect Leon Battista Alberti, was one of the first polyalphabetic ciphers. In the opening pages of his treatise ' he explained how his conversation with the papal secretary Leonardo Dati about a recently developed movable type printing press led to the development of his cipher wheel. Cipher disk Alberti's cipher disk embodies the first example of polyalphabetic substitution with mixed alphabets and variable period. This device, called ''Formula'', was made up of two concentric disks, attached by a common pin, which could rotate one with respect to the other. The larger one is called ''Stabilis'' [stationary or fixed], the smaller one is called ''Mobilis'' [movable]. The circumference of each disk is divided into 24 equal cells. The outer ring contains one uppercase alphabet for plaintext and the inner ring has a lowercase mixed alphabet for ciphertext. The outer ring also includes the numbers 1 to 4 for the superencipherment of a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alberti Cipher Disk
The Alberti Cipher, created in 1467 by Italian architect Leon Battista Alberti, was one of the first polyalphabetic ciphers. In the opening pages of his treatise ' he explained how his conversation with the papal secretary Leonardo Dati about a recently developed movable type printing press led to the development of his cipher wheel. Cipher disk Alberti's cipher disk embodies the first example of polyalphabetic substitution with mixed alphabets and variable period. This device, called ''Formula'', was made up of two concentric disks, attached by a common pin, which could rotate one with respect to the other. The larger one is called ''Stabilis'' tationary or fixed the smaller one is called ''Mobilis'' ovable The circumference of each disk is divided into 24 equal cells. The outer ring contains one uppercase alphabet for plaintext and the inner ring has a lowercase mixed alphabet for ciphertext. The outer ring also includes the numbers 1 to 4 for the superencipherment of a code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cipher
In cryptography, a cipher (or cypher) 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''. To encipher or encode is to convert information into cipher or code. In common parlance, "cipher" is synonymous with "code", as they are both a set of steps that encrypt a message; however, the concepts are distinct in cryptography, especially classical cryptography. Codes generally substitute different length strings of characters in the output, while ciphers generally substitute the same number of characters as are input. There are exceptions and some cipher systems may use slightly more, or fewer, characters when output versus the number that were input. Codes operated by substituting according to a large codebook which linked a random string of characters or numbers to a word or phrase. For example, "UQJHSE" could be the code for "Proceed to the following ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Kahn (writer)
David Kahn (b. February 7, 1930* ) is an American historian, journalist, and writer. He has written extensively on the history of cryptography and military intelligence. Kahn's first published book, '' The Codebreakers - The Story of Secret Writing'' (1967), has been widely considered to be a definitive account of the history of cryptography. Biography David Kahn was born in New York City to Florence Abraham Kahn, a glass manufacturer, and Jesse Kahn, a lawyer. Kahn has said he traces his interest in cryptography to reading Fletcher Pratt's ''Secret and Urgent'' as a boy. Kahn is a founding editor of the '' Cryptologia'' journal. In 1969, Kahn married Susanne Fiedler; they are now divorced. They have two sons, Oliver and Michael. He attended Bucknell University. After graduation, he worked as a reporter at ''Newsday''. He also served as an editor at the ''International Herald Tribune'' in Paris in the 1960s. It was during this period that he wrote an article for the ''New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpen-Adria-Universität Klagenfurt
The University of Klagenfurt (german: Universität Klagenfurt or ''Alpen-Adria-Universität Klagenfurt'', AAU) is a federal Austrian research university and the largest research and higher education institution in the States of Austria, state of Carinthia. It has its campus in Klagenfurt. Originally founded in 1970 and relaunched in 1993, the university today holds faculties of arts, humanities & education, management, economics & law, social sciences, and Technology, technical sciences. It is listed in the Academic Ranking of World Universities, ARWU, Times Higher Education World University Rankings, THE, and QS World University Rankings, QS global rankings and held rank 48 worldwide in THE's ''Young University Rankings'' 2021. The university has defined three research priority areas, ''Social Ecology'' (until 2018, transferred to University of Natural Resources and Life Sciences, Vienna, BOKU Vienna), ''Networked and Autonomous Systems'', and ''Multiple Perspectives in Optimizat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Analysis
In cryptanalysis, frequency analysis (also known as counting letters) is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers. Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters occur with varying frequencies. Moreover, there is a characteristic distribution of letters that is roughly the same for almost all samples of that language. For instance, given a section of English language, , , and are the most common, while , , and are rare. Likewise, , , , and are the most common pairs of letters (termed ''bigrams'' or ''digraphs''), and , , , and are the most common repeats. The nonsense phrase " ETAOIN SHRDLU" represents the 12 most frequent letters in typical English language text. In some ciphers, such properties of the natural language plaintext are preserved in the ciphertext, and these patterns have the pote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Distribution
In statistics, the frequency (or absolute frequency) of an event i is the number n_i of times the observation has occurred/recorded in an experiment or study. These frequencies are often depicted graphically or in tabular form. Types The cumulative frequency is the total of the absolute frequencies of all events at or below a certain point in an ordered list of events. The (or empirical probability) of an event is the absolute frequency normalized by the total number of events: : f_i = \frac = \frac. The values of f_i for all events i can be plotted to produce a frequency distribution. In the case when n_i = 0 for certain i, pseudocounts can be added. Depicting frequency distributions A frequency distribution shows us a summarized grouping of data divided into mutually exclusive classes and the number of occurrences in a class. It is a way of showing unorganized data notably to show results of an election, income of people for a certain region, sales of a product within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kasiski
Major Friedrich Wilhelm Kasiski (29 November 1805 – 22 May 1881) was a German infantry officer, cryptographer and archeologist. Kasiski was born in Schlochau, Kingdom of Prussia (now Człuchów, Poland). Military service Kasiski enlisted in East Prussia's 33rd Infantry Regiment on 20 March 1823 at the age of 17. In May 1824, he was promoted to the rank of Master Sergeant, and eight months later was commissioned as a Second Lieutenant in February 1825. It took fourteen years to earn his next promotion when, in May 1839, he advanced to the rank of First Lieutenant. His next advancement was quicker, promoted to Captain in November 1842. Kasiski finally retired from active service with the rank of Major on 17 February 1852. Between 1860 and 1868 he was the commander of a National Guard battalion. Cryptography In 1863, Kasiski published a 95-page book on cryptography, ''Die Geheimschriften und die Dechiffrir-Kunst'' (German, "Secret writing and the Art of Deciphering"). This w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vigenère Cipher
The Vigenère cipher () is a method of encryption, encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It employs a form of polyalphabetic cipher, polyalphabetic substitution. First described by Giovan Battista Bellaso in 1553, the cipher is easy to understand and implement, but it resisted all attempts to break it until 1863, three centuries later. This earned it the description le chiffrage indéchiffrable (French language, French for 'the indecipherable cipher'). Many people have tried to implement encryption schemes that are essentially Vigenère ciphers. In 1863, Friedrich Kasiski was the first to publish a general method of deciphering Vigenère ciphers. In the 19th century, the scheme was misattributed to Blaise de Vigenère (1523–1596) and so acquired its present name. History The very first well-documented description of a polyalphabetic cipher was by Leon Battista Alberti around 1467 and used a metal cipher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plaintext
In cryptography, plaintext usually means unencrypted information pending input into cryptographic algorithms, usually encryption algorithms. This usually refers to data that is transmitted or stored unencrypted. Overview With the advent of computing, the term ''plaintext'' expanded beyond human-readable documents to mean any data, including binary files, in a form that can be viewed or used without requiring a key or other decryption device. Information—a message, document, file, etc.—if to be communicated or stored in an unencrypted form is referred to as plaintext. Plaintext is used as input to an encryption algorithm; the output is usually termed ciphertext, particularly when the algorithm is a cipher. Codetext is less often used, and almost always only when the algorithm involved is actually a code. Some systems use multiple layers of encryption, with the output of one encryption algorithm becoming "plaintext" input for the next. Secure handling Insecure handling of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leon Battista Alberti
Leon Battista Alberti (; 14 February 1404 – 25 April 1472) was an Italian Renaissance humanist author, artist, architect, poet, priest, linguist, philosopher, and cryptographer; he epitomised the nature of those identified now as polymaths. He is considered the founder of Western cryptography, a claim he shares with Johannes Trithemius. Although he often is characterized exclusively as an architect, as James Beck has observed, "to single out one of Leon Battista's 'fields' over others as somehow functionally independent and self-sufficient is of no help at all to any effort to characterize Alberti's extensive explorations in the fine arts". Although Alberti is known mostly for being an artist, he was also a mathematician of many sorts and made great advances to this field during the fifteenth century. The two most important buildings he designed are the churches of San Sebastiano (1460) and Sant'Andrea (1472), both in Mantua. Alberti's life was described in Giorgio Vasari's ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Connecticut State University
Western Connecticut State University (WCSU and WestConn) is a public university in Danbury, Connecticut. It was founded in 1903 as a teacher's college and is part of the Connecticut State University System. WCSU consists of four schools: the Ancell School of Business, the Macricostas School of Arts and Sciences, the School of Professional Studies, and the School of Visual and Performing Arts. The university offers 38 Bachelor's and one associate degree programs, 15 Master's degree programs, and two doctoral programs. WCSU is accredited by the New England Commission of Higher Education (NECHE). WCSU is home to the Jane Goodall Center for Excellence in Environmental Studies, which is the result of a partnership between WCSU and the Jane Goodall Institute (a private non-profit organization that promotes research, education and wildlife conservation). The university's Westside campus houses the Ives Concert Park, one of the premier performance venues in the area. Western Connecticut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printing Press
A printing press is a mechanical device for applying pressure to an inked surface resting upon a printing, print medium (such as paper or cloth), thereby transferring the ink. It marked a dramatic improvement on earlier printing methods in which the cloth, paper or other medium was brushed or rubbed repeatedly to achieve the transfer of ink, and accelerated the process. Typically used for texts, the invention and global spread of the printing press was one of the most influential events in the second millennium. In Germany, around 1440, goldsmith Johannes Gutenberg invented the movable-type printing press, which started the Printing Revolution. Modelled on the design of existing screw presses, a single Renaissance movable-type printing press could produce up to 3,600 pages per workday, compared to forty by History of typography in East Asia, hand-printing and a few by scribe, hand-copying. Gutenberg's newly devised matrix (printing), hand mould made possible the precise and ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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