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Substitution Box
In cryptography, an S-box (substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically used to obscure the relationship between the key and the ciphertext, thus ensuring Shannon's property of confusion. Mathematically, an S-box is a vectorial Boolean function. In general, an S-box takes some number of input bits, ''m'', and transforms them into some number of output bits, ''n'', where ''n'' is not necessarily equal to ''m''. An ''m''×''n'' S-box can be implemented as a lookup table with 2''m'' words of ''n'' bits each. Fixed tables are normally used, as in the Data Encryption Standard (DES), but in some ciphers the tables are generated dynamically from the key (e.g. the Blowfish and the Twofish encryption algorithms). Example One good example of a fixed table is the S-box from DES (S5), mapping 6-bit input into a 4-bit output: Given a 6-bit input, the 4-bit output is found by selecting the row using th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "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 synonymo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Cryptanalysis
In cryptography, linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. Attacks have been developed for block ciphers and stream ciphers. Linear cryptanalysis is one of the two most widely used attacks on block ciphers; the other being differential cryptanalysis. The discovery is attributed to Mitsuru Matsui, who first applied the technique to the FEAL cipher (Matsui and Yamagishi, 1992). Subsequently, Matsui published an attack on the Data Encryption Standard (DES), eventually leading to the first experimental cryptanalysis of the cipher reported in the open community (Matsui, 1993; 1994). The attack on DES is not generally practical, requiring 247 known plaintexts. A variety of refinements to the attack have been suggested, including using multiple linear approximations or incorporating non-linear expressions, leading to a generalized partitioning cryptanalysis. Evidence of security against linear cryptanalysis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Wiley & Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New Je ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queen's University At Kingston
Queen's University at Kingston, commonly known as Queen's University or simply Queen's, is a public research university in Kingston, Ontario, Canada. Queen's holds more than of land throughout Ontario and owns Herstmonceux Castle in East Sussex, England. Queen's is organized into eight faculties and schools. The Church of Scotland established Queen's College in October 1841 via a royal charter from Queen Victoria. The first classes, intended to prepare students for the ministry, were held 7 March 1842 with 13 students and two professors. In 1869, Queen's was the first Canadian university west of the Maritime provinces to admit women. In 1883, a women's college for medical education affiliated with Queen's University was established after male staff and students reacted with hostility to the admission of women to the university's medical classes. In 1912, Queen's ended its affiliation with the Presbyterian Church, and adopted its present name. During the mid-20th century, the u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selected Areas In Cryptography
Selected Areas in Cryptography (SAC) is an international cryptography conference (originally a workshop) held every August in Canada since 1994. The first workshop was organized by Carlisle Adams, Henk Meijer, Stafford Tavares and Paul van Oorschot. Through 1999, SAC was hosted at either Queen's University or Carleton University, but starting in 2000, locations have ranged across Canada. SAC has featured research presentations on many cryptographic topics, with a traditional focus on the design and analysis of block ciphers. SAC is regarded as a high-quality venue for presenting cryptographic results, and is the only cryptography conference held annually in Canada. Since 2003, SAC has included an invited lecture called the Stafford Tavares Lecture, in honor of one of its original organizers and strongest supporters. Each year, SAC features four topics: # Design and analysis of symmetric key primitives and cryptosystems including block and stream ciphers, hash functions, MAC alg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlisle Adams
Carlisle M. Adams is a Canadian cryptographer and computer security researcher. Formerly senior cryptographer at Entrust, he is currently a professor at the University of Ottawa. His notable work includes the design (with Stafford Tavares) of the block ciphers CAST-128 and CAST-256, whose S-boxes are based on the non-linear properties of bent functions. He also helped organize the first Selected Areas in Cryptography (SAC) workshop in 1994. He is also the security advisor of the Ottawa-based electronic signature An electronic signature, or e-signature, is data that is logically associated with other data and which is used by the signatory to sign the associated data. This type of signature has the same legal standing as a handwritten signature as long as i ... company Signority. References External links Carlisle Adams's page at uOttawa Living people Modern cryptographers Public-key cryptographers Canadian computer scientists Computer security academics Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brighton
Brighton () is a seaside resort and one of the two main areas of the City of Brighton and Hove in the county of East Sussex, England. It is located south of London. Archaeological evidence of settlement in the area dates back to the Bronze Age, Roman and Anglo-Saxon periods. The ancient settlement of "Brighthelmstone" was documented in the ''Domesday Book'' (1086). The town's importance grew in the Middle Ages as the Old Town developed, but it languished in the early modern period, affected by foreign attacks, storms, a suffering economy and a declining population. Brighton began to attract more visitors following improved road transport to London and becoming a boarding point for boats travelling to France. The town also developed in popularity as a health resort for sea bathing as a purported cure for illnesses. In the Georgian era, Brighton developed as a highly fashionable seaside resort, encouraged by the patronage of the Prince Regent, later King George IV, who spent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitution Cipher
In cryptography, a substitution cipher is a method of encrypting in which units of plaintext are replaced with the ciphertext, in a defined manner, with the help of a key; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing the inverse substitution process to extract the original message. Substitution ciphers can be compared with transposition ciphers. In a transposition cipher, the units of the plaintext are rearranged in a different and usually quite complex order, but the units themselves are left unchanged. By contrast, in a substitution cipher, the units of the plaintext are retained in the same sequence in the ciphertext, but the units themselves are altered. There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rijndael S-box
The Rijndael S-box is a substitution box (lookup table) used in the Rijndael cipher, on which the Advanced Encryption Standard (AES) cryptographic algorithm is based. Forward S-box The S-box maps an 8-bit input, , to an 8-bit output, . Both the input and output are interpreted as polynomials over GF(2). First, the input is mapped to its multiplicative inverse in , Rijndael's finite field. Zero, as the identity, is mapped to itself. This transformation is known as the ''Nyberg S-box'' after its inventor Kaisa Nyberg. The multiplicative inverse is then transformed using the following affine transformation: : \begins_0\\s_1\\s_2\\s_3\\s_4\\s_5\\s_6\\s_7\end = \begin 1 & 0 & 0 & 0 & 1 & 1 & 1 & 1 \\ 1 & 1 & 0 & 0 & 0 & 1 & 1 & 1 \\ 1 & 1 & 1 & 0 & 0 & 0 & 1 & 1 \\ 1 & 1 & 1 & 1 & 0 & 0 & 0 & 1 \\ 1 & 1 & 1 & 1 & 1 & 0 & 0 & 0 \\ 0 & 1 & 1 & 1 & 1 & 1 & 0 & 0 \\ 0 & 0 & 1 & 1 & 1 & 1 & 1 & 0 \\ 0 & 0 & 0 & 1 & 1 & 1 & 1 & 1 \end\begin b_0\\ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permutation Cipher
In cryptography, a transposition cipher is a method of encryption which scrambles the positions of characters (''transposition'') without changing the characters themselves. Transposition ciphers reorder units of plaintext (typically characters or groups of characters) according to a regular system to produce a ciphertext which is a permutation of the plaintext. They differ from substitution ciphers, which do not change the position of units of plaintext but instead change the units themselves. Despite the difference between transposition and substitution operations, they are often combined, as in historical ciphers like the ADFGVX cipher or complex high-quality encryption methods like the modern Advanced Encryption Standard (AES). General principle Plaintexts can be rearranged into a ciphertext using a key, scrambling the order of characters like the shuffled pieces of a jigsaw puzzle. The resulting message is hard to decipher without the key because there are many ways the char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permutation Box
In cryptography, a permutation box (or P-box) is a method of bit-shuffling used to permute or transpose bits across S-boxes inputs, retaining diffusion while transposing. In block ciphers, the S-boxes and P-boxes are used to make the relation between the plaintext and the ciphertext difficult to understand (see Shannon's property of confusion). P-boxes are typically classified as ''compression'', ''expansion'', and ''straight'', depending on whether the number of output bits is less than, greater than, or equal to the number of input bits, respectively. Only straight P-boxes are invertible. See also * Boolean function * Nothing-up-my-sleeve number * Substitution cipher In cryptography, a substitution cipher is a method of encrypting in which units of plaintext are replaced with the ciphertext, in a defined manner, with the help of a key; the "units" may be single letters (the most common), pairs of letters, trip ... References Symmetric-key cryptography Permutations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
