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Communication Theory Of Secrecy Systems
"Communication Theory of Secrecy Systems" is a paper published in 1949 by Claude Shannon discussing cryptography from the viewpoint of information theory Information theory is the mathematical study of the quantification (science), quantification, Data storage, storage, and telecommunications, communication of information. The field was established and formalized by Claude Shannon in the 1940s, .... It is one of the foundational treatments (arguably ''the'' foundational treatment) of modern cryptography. His work has been described as a "turning point, and marked the closure of classical cryptography and the beginning of modern cryptography." It has also been described as turning cryptography from an "art to a science". It is also a proof that all theoretically unbreakable ciphers must have the same requirements as the one-time pad. The paper serves as the foundation of secret-key cryptography, including the work of Horst Feistel, the Data Encryption Standard (DES), Adv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claude E
Claude may refer to: People and fictional characters * Claude (given name), a list of people and fictional characters * Claude (surname), a list of people * Claude Callegari (1962–2021), English Arsenal supporter * Claude Debussy (1862–1918), French composer * Claude Kiambe (born 2003), Congolese-born Dutch singer * Claude Lévi-Strauss (1908–2009), French anthropologist and ethnologist * Claude Lorrain (c. 1600–1682), French landscape painter, draughtsman and etcher traditionally called just "Claude" in English * Claude Makélélé (born 1973), French football manager * Claude McKay (1890–1948), Jamaican-American writer and poet * Claude Monet (1840–1926), French painter * Claude Rains (1889–1967), British-American actor * Claude Shannon (1916–2001), American mathematician, electrical engineer and computer scientist * Madame Claude (1923–2015), French brothel keeper Fernande Grudet Places * Claude, Texas, a city * Claude, West Virginia, an unincorporated commu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confusion And Diffusion
In cryptography, confusion and diffusion are two properties of a secure cipher identified by Claude Elwood Shannon, Claude Shannon in his 1945 classified report ''A Mathematical Theory of Cryptography''. These properties, when present, work together to thwart the application of statistics, and other methods of cryptanalysis. Confusion in a symmetric cipher is obscuring the local correlation between the input (plaintext), and output (ciphertext) by varying the application of the Key (cryptography), key to the data, while diffusion is hiding the plaintext statistics by spreading it over a larger area of ciphertext. Although ciphers can be confusion-only (substitution cipher, one-time pad) or diffusion-only (transposition cipher), any "reasonable" block cipher uses both confusion and diffusion. These concepts are also important in the design of cryptographic hash function, cryptographic hash functions, and pseudorandom number generators, where decorrelation of the generated values i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1949 In Science
The year 1949 in science and technology involved some significant events, listed below. Astronomy and space exploration * January 26 – The Hale Telescope at Palomar Observatory in California, the largest aperture optical telescope in the world for 28 years, sees first light. * June 14 – Albert II, a rhesus monkey, becomes the first mammal in space, in a U.S.-launched V-2 rocket, reaching an altitude of 83 miles (134 km) but dying on impact after a parachute failure. Chemistry * Radiocarbon dating technique discovered by Willard Libby and his colleagues at the University of Chicago—work for which Libby will receive the Nobel Prize in 1960. * A group including Dorothy Hodgkin publish the three-dimensional molecular structure of penicillin, demonstrating that it contains a β-lactam ring. Computer science * April – Manchester Mark 1 computer operable at the University of Manchester in England. * May 6 – EDSAC, the first practicable stored-program computer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1949 Documents
Events January * January 1 – A United Nations-sponsored ceasefire brings an end to the Indo-Pakistani War of 1947. The war results in a stalemate and the division of Kashmir, which still continues as of 2025 * January 2 – Luis Muñoz Marín becomes the first democratically elected Governor of Puerto Rico. * January 11 – The first "networked" television broadcasts take place, as KDKA-TV in Pittsburgh, Pennsylvania, goes on the air, connecting east coast and mid-west programming in the United States. * January 16 – Şemsettin Günaltay forms the new government of Turkey. It is the 18th government, last One-party state, single party government of the Republican People's Party. * January 17 – The first Volkswagen Beetle, VW Type 1 to arrive in the United States, a 1948 model, is brought to New York City, New York by Dutch businessman Ben Pon Sr., Ben Pon. Unable to interest dealers or importers in the Volkswagen, Pon sells the sample car to pay his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1945 In Science
The year 1945 in science and technology involved some significant events, listed below. Biology * Salvador Edward Luria and Alfred Day Hershey independently recognize that viruses undergo mutations. Chemistry * A team at Oak Ridge National Laboratory led by Charles Coryell discovers chemical element 61, the only one still missing between 1 and 96 on the periodic table, which they will name promethium. Found by analysis of fission products of irradiated uranium fuel, its discovery is not made public until 1947. * Dorothy Hodgkin and C. H. (Harry) Carlisle publish the first three-dimensional molecular structure of a steroid, cholesteryl iodide. In January, Hodgkin also discovers the structure of penicillin, not published until 1949. * A team at American Cyanamid's Lederle Laboratories, Pearl River, New York, led by Yellapragada Subbarow, obtain folic acid in a pure crystalline form. Computer science * June 30 – Distribution of John von Neumann's ''First Draft of a Report ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography Publications
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security ( data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymous with encryption, converting re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Cryptography
Cryptography, the use of codes and ciphers, began thousands of years ago. Until recent decades, it has been the story of what might be called classical cryptography — that is, of methods of encryption that use pen and paper, or perhaps simple mechanical aids. In the early 20th century, the invention of complex mechanical and electromechanical machines, such as the Enigma rotor machine, provided more sophisticated and efficient means of encryption; and the subsequent introduction of electronics and computing has allowed elaborate schemes of still greater complexity, most of which are entirely unsuited to pen and paper. The development of cryptography has been paralleled by the development of cryptanalysis — the "breaking" of codes and ciphers. The discovery and application, early on, of frequency analysis to the reading of encrypted communications has, on occasion, altered the course of history. Thus the Zimmermann Telegram triggered the United States' entry into World War ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell System Technical Journal
The ''Bell Labs Technical Journal'' was the in-house scientific journal for scientists of Bell Labs, published yearly by the IEEE society. The journal was originally established as ''The Bell System Technical Journal'' (BSTJ) in New York by the American Telephone and Telegraph Company (AT&T) in 1922. It was published under this name until 1983, when the breakup of the Bell System placed various parts of the companies in the system into independent corporate entities. The journal was devoted to the scientific fields and engineering disciplines practiced in the Bell System for improvements in the wide field of electrical communication. After the restructuring of Bell Labs in 1984, the journal was renamed to ''AT&T Bell Laboratories Technical Journal''. In 1985, it was published as the ''AT&T Technical Journal'' until 1996, when it was renamed to ''Bell Labs Technical Journal''. The journal was discontinued in 2020. The last managing editor was Charles Bahr. History The Bell System ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicity Distance
In cryptography, unicity distance is the length of an original ciphertext needed to break the cipher by reducing the number of possible spurious keys to zero in a brute force attack. That is, after trying every possible key, there should be just one decipherment that makes sense, i.e. expected amount of ciphertext needed to determine the key completely, assuming the underlying message has redundancy. Claude Shannon defined the unicity distance in his 1949 paper " Communication Theory of Secrecy Systems". Consider an attack on the ciphertext string "WNAIW" encrypted using a Vigenère cipher with a five letter key. Conceivably, this string could be deciphered into any other string—RIVER and WATER are both possibilities for certain keys. This is a general rule of cryptanalysis: with no additional information it is impossible to decode this message. Of course, even in this case, only a certain number of five letter keys will result in English words. Trying all possible keys w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One-time Pad
The one-time pad (OTP) is an encryption technique that cannot be Cryptanalysis, cracked in cryptography. It requires the use of a single-use pre-shared key that is larger than or equal to the size of the message being sent. In this technique, a plaintext is paired with a random secret Key (cryptography), key (also referred to as a ''one-time pad''). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using Modular arithmetic, modular addition. The resulting ciphertext is impossible to decrypt or break if the following four conditions are met: # The key must be at least as long as the plaintext. # The key must be True random, truly random. # The key must never be reused in whole or in part. # The key must be kept completely secret by the communicating parties. These requirements make the OTP the only known encryption system that is mathematically proven to be unbreakable under the principles of informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Product Cipher
In cryptography, a product cipher combines two or more transformations in a manner intending that the resulting cipher is more secure than the individual components to make it resistant to cryptanalysis.Handbook of Applied Cryptography by Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone. Fifth Printing (August 2001) page 251. The product cipher combines a sequence of simple transformations such as substitution (S-box), permutation (P-box), and modular arithmetic. The concept of product ciphers is due to Claude Shannon, who presented the idea in his foundational paper, ''Communication Theory of Secrecy Systems''. A particular product cipher design where all the constituting transformation functions have the same structure is called an iterative cipher with the term " rounds" applied to the functions themselves. For transformation involving reasonable number of n message symbols, both of the foregoing cipher systems (the S-box and P-box) are by themselves wanting. Shannon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Mathematical Theory Of Communication
"A Mathematical Theory of Communication" is an article by mathematician Claude E. Shannon published in '' Bell System Technical Journal'' in 1948. It was renamed ''The Mathematical Theory of Communication'' in the 1949 book of the same name, a small but significant title change after realizing the generality of this work. It has tens of thousands of citations, being one of the most influential and cited scientific papers of all time, as it gave rise to the field of information theory, with ''Scientific American'' referring to the paper as the "Magna Carta of the Information Age", while the electrical engineer Robert G. Gallager called the paper a "blueprint for the digital era". Historian James Gleick rated the paper as the most important development of 1948, placing the transistor second in the same time period, with Gleick emphasizing that the paper by Shannon was "even more profound and more fundamental" than the transistor. It is also noted that "as did relativity and qua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
