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Mini VMac
VMAC is a block cipher-based message authentication code (MAC) algorithm using a universal hash proposed by Ted Krovetz and Wei Dai Wei Dai ( zh, c=戴维 or zh, c=戴伟) is a computer engineer known for contributions to cryptography and cryptocurrencies. He developed the Crypto++ cryptographic library, created the b-money cryptocurrency system, and co-proposed the VMAC ... in April 2007. The algorithm was designed for high performance backed by a formal analysis. VMAC is designed to have exceptional performance in software on 64-bit CPU architectures while still performing well on 32-bit architectures. Measured speeds are as fast as one-half CPU cycle per byte (cpb) on 64-bit architectures, under five cpb on desktop 32-bit processors, and around ten cpb on embedded 32-bit architectures. A closely related variant of VMAC that is optimized for 32-bit architectures is given by UMAC. Overview VMAC is a MAC in the style of Wegman and Carter. A fast "universal" hash funct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block Cipher
In cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called ''blocks''. Block ciphers are the elementary building blocks of many cryptographic protocols. They are ubiquitous in the storage and exchange of data, where such data is secured and authenticated via encryption. A block cipher uses blocks as an unvarying transformation. Even a secure block cipher is suitable for the encryption of only a single block of data at a time, using a fixed key. A multitude of modes of operation have been designed to allow their repeated use in a secure way to achieve the security goals of confidentiality and authenticity. However, block ciphers may also feature as building blocks in other cryptographic protocols, such as universal hash functions and pseudorandom number generators. Definition A block cipher consists of two paired algorithms, one for encryption, , and the other for decryption, . Both algorithms accept two inputs: an input ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Authentication Code
In cryptography, a message authentication code (MAC), sometimes known as an authentication tag, is a short piece of information used for authentication, authenticating and Data integrity, integrity-checking a message. In other words, it is used to confirm that the message came from the stated sender (its authenticity) and has not been changed (its integrity). The MAC value allows verifiers (who also possess a secret key) to detect any changes to the message content. Terminology The term message integrity code (MIC) is frequently substituted for the term ''MAC'', especially in communications to distinguish it from the use of the latter as ''media access control address'' (''MAC address''). However, some authors use MIC to refer to a message digest, which aims only to uniquely but opaquely identify a single message. RFC 4949 recommends avoiding the term ''message integrity code'' (MIC), and instead using ''checksum'', ''error detection code'', ''hash function, hash'', ''keyed hash'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universal Hash
In mathematics and computing, universal hashing (in a randomized algorithm or data structure) refers to selecting a hash function at random from a family of hash functions with a certain mathematical property (see definition below). This guarantees a low number of collisions in expectation, even if the data is chosen by an adversary. Many universal families are known (for hashing integers, vectors, strings), and their evaluation is often very efficient. Universal hashing has numerous uses in computer science, for example in implementations of hash tables, randomized algorithms, and cryptography. Introduction Assume we want to map keys from some universe U into m bins (labelled = \). The algorithm will have to handle some data set S \subseteq U of , S, =n keys, which is not known in advance. Usually, the goal of hashing is to obtain a low number of collisions (keys from S that land in the same bin). A deterministic hash function cannot offer any guarantee in an adversarial sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wei Dai
Wei Dai ( zh, c=戴维 or zh, c=戴伟) is a computer engineer known for contributions to cryptography and cryptocurrencies. He developed the Crypto++ cryptographic library, created the b-money cryptocurrency system, and co-proposed the VMAC message authentication algorithm. Education and career Dai graduated from the University of Washington with a degree in computer science, just before creating b-money in 1998. He is described as an "intensely private computer engineer". Wei Dai was a member of the Cypherpunks, Extropians, and SL4 mailing lists in the 1990s. On SL4 he exchanged with people such as Eliezer Yudkowsky, Robin Hanson, Nick Bostrom, Aubrey de Grey, Anders Sandberg, Eric Drexler, David Pearce, Hal Finney, and others in a nascent rationalist community. Dai has contributed to the field of cryptography and has identified critical Cipher Block Chaining (CBC) vulnerabilities affecting SSH2 and the browser exploit against SSL/TLS known as BEAST (Browser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UMAC (cryptography)
In cryptography, a universal hashing message authentication code, or UMAC, is a message authentication code (MAC) calculated using universal hashing, which involves choosing a hash function from a class of hash functions according to some secret (random) process and applying it to the message. The resulting digest or fingerprint is then encrypted to hide the identity of the hash function that was used. A variation of the scheme was first published in 1999. As with any MAC, it may be used to simultaneously verify both the ''data integrity'' and the ''authenticity'' of a message. In contrast to traditional MACs, which are serializable, a UMAC can be executed in parallel. Thus, as machines continue to offer more parallel-processing capabilities, the speed of implementing UMAC can increase., Equation 1 and also section 4.2 "Definition of NH". A specific type of UMAC, also commonly referred to just as "UMAC", is described in an informational RFC published as RFC 4418 in March 2006 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
