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Haval Xiaolong 002
HAVAL is a cryptographic hash function. Unlike MD5, but like most modern cryptographic hash functions, HAVAL can produce hashes of different lengths – 128 bits, 160 bits, 192 bits, 224 bits, and 256 bits. HAVAL also allows users to specify the number of rounds (3, 4, or 5) to be used to generate the hash. HAVAL was broken in 2004. HAVAL was invented by Yuliang Zheng, Josef Pieprzyk, and Jennifer Seberry in 1992. HAVAL hashes The HAVAL hashes (also termed ''fingerprints'') are typically represented as 32-, 40-, 48-, 56- or 64-digit hexadecimal numbers. The following demonstrates a 43-byte ASCII input and the corresponding HAVAL hash (256 bits, 5 passes): HAVAL("The quick brown fox jumps over the lazy og", 256, 5) = b89c551cdfe2e06dbd4cea2be1bc7d557416c58ebb4d07cbc94e49f710c55be4 Even a small change in the message will (with overwhelming probability) result in a completely different hash, e.g. changing the letter to a produces the following hash value: HAVAL("The quick b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Hash Function
A cryptographic hash function (CHF) is a hash algorithm (a map (mathematics), map of an arbitrary binary string to a binary string with a fixed size of n bits) that has special properties desirable for a cryptography, 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yuliang Zheng
Yuliang Zheng, Ph.D., is Professor and Chair of thDepartment of Computer Scienceat the University of Alabama at Birmingham. He is best known for inventing the signcryption In cryptography, signcryption is a public-key primitive that simultaneously performs the functions of both digital signature and encryption. Background Encryption and digital signature are two fundamental cryptographic tools that can guarantee ... cryptographic primitive that combines the digital signature and encryption operations into one single step. He also invented the HAVAL hash function, SPEED cipher, and STRANDOM pseudo-random number generator. Zheng is Chief Technology Officer oCalyptix Security a company he co-founded in 2002. External linksHomepage of Yuliang Zheng [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Josef Pieprzyk
Josef Pieprzyk (born 1949 in Poland) is currently a professor at Queensland University of Technology in Brisbane, Australia. He has worked on cryptography, in particular the XSL attack. He collaborated in the invention of the LOKI and LOKI97 block ciphers and the HAVAL cryptographic hash function A cryptographic hash function (CHF) is a hash algorithm (a map (mathematics), map of an arbitrary binary string to a binary string with a fixed size of n bits) that has special properties desirable for a cryptography, cryptographic application: .... External linksHome page 1949 births Living people Modern cryptographers 20th-century Polish mathematicians 21st-century Polish mathematicians Academic staff of Macquarie University Academic staff of Queensland University of Technology {{Poland-mathematician-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jennifer Seberry
Jennifer Roma Seberry (also published as Jennifer Seberry Wallis; born 13 February 1944 in Sydney) is an Australian cryptographer, mathematician, and computer scientist, currently a professor at the University of Wollongong, Australia. She was formerly the head of the Department of Computer Science and director of the Centre for Computer Security Research at the university. Education and career Seberry attended Parramatta High School and got her BSc at University of New South Wales, 1966; MSc at La Trobe University, 1969; PhD at La Trobe University, 1971 (Computational Mathematics); B.Ec. with two years completed at University of Sydney. Her doctoral advisor was Bertram Mond. Seberry was the first person to teach cryptology at an Australian University (University of Sydney). She was also the first woman Professor of Computer Science in Australia. She was the first woman Reader in Combinatorial Mathematics in Australia. she had supervised 30 doctorates and had 71 academic desc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen. Software developers and system designers widely use hexadecimal numbers because they provide a convenient representation of binary code, binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte is two hexadecimal digits and its value can be written as to in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, several notations denote hexadecimal numbers, usually involving a prefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control characters a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers; for example, the first 128 code points of Unicode are the same as ASCII. ASCII encodes each code-point as a value from 0 to 127 storable as a seven-bit integer. Ninety-five code-points are printable, including digits ''0'' to ''9'', lowercase letters ''a'' to ''z'', uppercase letters ''A'' to ''Z'', and commonly used punctuation symbols. For example, the letter is represented as 105 (decimal). Also, ASCII specifies 33 non-printing control codes which originated with ; most of which are now obsolete. The control cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Collision
In computer science, a hash collision or hash clash is when two distinct pieces of data in a hash table share the same hash value. The hash value in this case is derived from a hash function which takes a data input and returns a fixed length of bits. Although hash algorithms, especially cryptographic hash algorithms, have been created with the intent of being Collision resistance, collision resistant, they can still sometimes map different data to the same hash (by virtue of the pigeonhole principle). Malicious users can take advantage of this to mimic, access, or alter data. Due to the possible negative applications of hash collisions in data management and computer security (in particular, cryptographic hash functions), collision avoidance has become an important topic in computer security. Background Hash collisions can be unavoidable depending on the number of objects in a set and whether or not the bit string they are mapped to is long enough in length. When there is a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiaoyun Wang
Wang Xiaoyun (; born 1966) is a Chinese cryptographer, mathematician, and computer scientist. She is a professor in the Department of Mathematics and System Science of Shandong University and an academician of the Chinese Academy of Sciences. Early life and education Wang was born in Zhucheng, Shandong Province. She gained bachelor's (1987), master's (1990) and doctorate (1993) degrees at Shandong University, and subsequently lectured in the mathematics department from 1993. Her doctoral advisor was Pan Chengdong. Wang was appointed assistant professor in 1995, and full professor in 2001. She became the Chen Ning Yang Professor of the Center for Advanced Study, Tsinghua University in 2005. Career and research At the rump session of CRYPTO 2004, she and co-authors demonstrated collision attacks against MD5, SHA-0 and other related hash functions (a collision occurs when two distinct messages result in the same hash function output). They received a standing ovation for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xuejia Lai
Xuejia Lai () is a cryptographer, currently a professor at Shanghai Jiao Tong University. His notable work includes the design of the block cipher IDEA based on the Lai-Massey scheme, the theory of Markov ciphers, and the cryptanalysis of a number of cryptographic hash functions. His book ''On the Design and Security of Block Ciphers'' () is frequently cited in cryptography papers. Lai received a B.Sc. in electrical engineering in 1982 and an M.Sc. in mathematics in 1984 at Xidian University (then known as ''Northwest Institute of Telecommunication Engineering''). About 1982 he met James Massey, who was visiting the university to give lectures in cryptography. Lai served as interpreter for these lectures. He later became one of Massey's doctoral students at ETH Zurich ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, enginee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Function Security Summary
This article summarizes publicly known attacks against cryptographic hash functions. Note that not all entries may be up to date. For a summary of other hash function parameters, see comparison of cryptographic hash functions. Table color key Common hash functions Collision resistance Chosen prefix collision attack Preimage resistance Length extension *Vulnerable: MD5, SHA1, SHA256, SHA512 *Not vulnerable: SHA384, SHA-3, BLAKE2 Less-common hash functions Collision resistance Preimage resistance Attacks on hashed passwords Hashes described here are designed for fast computation and have roughly similar speeds. Because most users typically choose short passwords formed in predictable ways, passwords can often be recovered from their hashed value if a fast hash is used. Searches on the order of 100 billion tests per second are possible with high-end graphics processors. Special hashes called key derivation functions have been created to slow brute for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
