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Round (cryptography)
In cryptography, a round or round function is a basic transformation that is repeated (iteration, iterated) multiple times inside the algorithm. Splitting a large algorithmic function into rounds simplifies both implementation and cryptanalysis. For example, encryption using an oversimplified three-round cipher can be written as C = R_3(R_2(R_1(P))), where is the ciphertext and is the plaintext. Typically, rounds R_1, R_2, ... are implemented using the same function, parameterized by the round constant and, for block ciphers, the ''round key'' from the key schedule. Parameterization is essential to reduce the self-similarity of the cipher, which could lead to slide attacks. Increasing the number of rounds "almost always" protects against differential cryptanalysis, differential and linear cryptanalysis, as for these tools the effort grows exponentially with the number of rounds. However, increasing the number of rounds does not ''always'' make weak ciphers into strong ones, as s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), adversarial behavior. More generally, cryptography is about constructing and analyzing Communication protocol, 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 (confidentiality, data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, Smart card#EMV, chip-based payment cards, digital currencies, password, computer passwords, and military communications. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Hash
A cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with a fixed size of n bits) that has special properties desirable for a cryptographic application: * the probability of a particular n-bit output result (hash value) for a random input string ("message") is 2^ (as for any good hash), so the hash value can be used as a representative of the message; * finding an input string that matches a given hash value (a ''pre-image'') is infeasible, ''assuming all input strings are equally likely.'' The ''resistance'' to such search is quantified as security strength: a cryptographic hash with n bits of hash value is expected to have a ''preimage resistance'' strength of n bits, unless the space of possible input values is significantly smaller than 2^ (a practical example can be found in ); * a ''second preimage'' resistance strength, with the same expectations, refers to a similar problem of finding a second message that m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Optimization
Global optimization is a branch of operations research, applied mathematics, and numerical analysis that attempts to find the global minimum or maximum of a function or a set of functions on a given set. It is usually described as a minimization problem because the maximization of the real-valued function g(x) is equivalent to the minimization of the function f(x):=(-1)\cdot g(x). Given a possibly nonlinear and non-convex continuous function f:\Omega\subset\mathbb^n\to\mathbb with the global minimum f^* and the set of all global minimizers X^* in \Omega, the standard minimization problem can be given as :\min_f(x), that is, finding f^* and a global minimizer in X^*; where \Omega is a (not necessarily convex) compact set defined by inequalities g_i(x)\geqslant0, i=1,\ldots,r. Global optimization is distinguished from local optimization by its focus on finding the minimum or maximum over the given set, as opposed to finding ''local'' minima or maxima. Finding an arbitrary local m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vincent Rijmen
Vincent Rijmen (; born 16 October 1970) is a Belgium, Belgian cryptographer and one of the two designers of the Rijndael, the Advanced Encryption Standard. Rijmen is also the co-designer of the WHIRLPOOL cryptographic hash function, and the block ciphers Anubis (cipher), Anubis, KHAZAD, Square (cipher), Square, NOEKEON and SHARK. In 1993, Rijmen obtained a degree in electronics engineering at the Katholieke Universiteit Leuven. Afterwards, he was a PhD student at the ESAT/COSIC lab of the K.U.Leuven. In 1997, Rijmen finished his doctoral dissertation titled ''Cryptanalysis and design of iterated block ciphers''. After his PhD he did postdoctoral work at the COSIC lab, on several occasions collaborating with Joan Daemen. One of their joint projects resulted in the algorithm Rijndael, which in October 2000 was selected by the National Institute for Standards and Technology (NIST) to become the Advanced Encryption Standard (AES). Since 1 August 2001, Rijmen has been working as chie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joan Daemen
Joan Daemen (; born 1965) is a Belgians, Belgian cryptographer who is currently professor of digital security (symmetric encryption) at Radboud University. He co-designed with Vincent Rijmen the Rijndael cipher, which was selected as the Advanced Encryption Standard (AES) in 2001. More recently, he co-designed the Keccak cryptographic hash, which was NIST hash function competition, selected as the new SHA-3 hash by NIST in October 2012. He has also designed or co-designed the MMB (cipher), MMB, Square (cipher), Square, SHARK (cipher), SHARK, NOEKEON, 3-Way, and BaseKing block ciphers. In 2017 he won the Levchin Prize for Real World Cryptography "for the development of AES and SHA3". He describes his development of encryption algorithms as creating the bricks which are needed to build the secure foundations online. In 1988, Daemen graduated in electro-mechanical engineering at the Katholieke Universiteit Leuven. He subsequently joined the COSIC research group, and has worked on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCREAM (cipher)
Scream may refer to: *Screaming, a loud vocalization Amusement rides * Scream (Heide Park), a gyro drop tower in Soltau, Germany * Scream (Six Flags drop tower), at Six Flags Fiesta Texas and Six Flags New England * Scream (roller coaster), at Six Flags Magic Mountain in California Arts, entertainment, and media Comics * Scream (comics), a fictional character in the ''Spider-Man'' comic book series * Angar the Screamer or Scream, a fictional character in the Marvel Comics universe * Scream! (comics), a British horror comic Films and television * ''Scream'', a 1964 Greek noir film directed by Kostas Andritsos * ''Scream'' (1981 film), a slasher film * ''Scream'' (franchise), a series of American horror films ** ''Scream'' (1996 film), the first of the series of horror films ** '' Scream 2'', the second of the series of horror films, 1997 ** '' Scream 3'', third movie in the horror films series, 2000 ** '' Scream 4'', fourth installment of the film series, 2011 ** ''Sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invariant Attack
Invariant and invariance may refer to: Computer science * Invariant (computer science), an expression whose value doesn't change during program execution ** Loop invariant, a property of a program loop that is true before (and after) each iteration * A data type in method overriding that is neither covariant nor contravariant * Class invariant, an invariant used to constrain objects of a class Physics, mathematics, and statistics * Invariant (mathematics), a property of a mathematical object that is not changed by a specific operation or transformation ** Rotational invariance, the property of function whose value does not change when arbitrary rotations are applied to its argument ** Scale invariance, a property of objects or laws that do not change if scales of length, energy, or other variables, are multiplied by a common factor ** Topological invariant * Invariant (physics), something does not change under a transformation, such as from one reference frame to another * In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption Key
A key in cryptography is a piece of information, usually a string of numbers or letters that are stored in a file, which, when processed through a cryptographic algorithm, can encode or decode cryptographic data. Based on the used method, the key can be different sizes and varieties, but in all cases, the strength of the encryption relies on the security of the key being maintained. A key's security strength is dependent on its algorithm, the size of the key, the generation of the key, and the process of key exchange. Scope The key is what is used to encrypt data from plaintext to ciphertext. There are different methods for utilizing keys and encryption. Symmetric cryptography Symmetric cryptography refers to the practice of the same key being used for both encryption and decryption. Asymmetric cryptography Asymmetric cryptography has separate keys for encrypting and decrypting. These keys are known as the public and private keys, respectively. Purpose Since the key ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round Constant
In cryptography, a round or round function is a basic transformation that is repeated ( iterated) multiple times inside the algorithm. Splitting a large algorithmic function into rounds simplifies both implementation and cryptanalysis. For example, encryption using an oversimplified three-round cipher can be written as C = R_3(R_2(R_1(P))), where is the ciphertext and is the plaintext. Typically, rounds R_1, R_2, ... are implemented using the same function, parameterized by the round constant and, for block ciphers, the ''round key'' from the key schedule. Parameterization is essential to reduce the self-similarity of the cipher, which could lead to slide attacks. Increasing the number of rounds "almost always" protects against differential and linear cryptanalysis, as for these tools the effort grows exponentially with the number of rounds. However, increasing the number of rounds does not ''always'' make weak ciphers into strong ones, as some attacks do not depend on the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightweight Cipher
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 r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
