Refimprove date July 2010 Image Hash table 4 1 1 0 0 1 0 LL.svg thumb 240px right A hashfunction that maps ... . A hashfunction is any algorithm or subroutine that maps large data set data sets , called keys, to smaller ... returned by a hashfunction are called hash values , hash codes , hash sums , checksums or simply hashes ... hashfunction s. Although these concepts overlap to some extent, each has its own uses and requirements ... the headword . Specifically, the hashfunction is used to map the search key to the hash. The index ... for it. Still, in a half full table, a good hashfunction will typically narrow the search down to only ... When storing records in a large unsorted file, one may use a hashfunction to map each record to an index ... which have similar keys. For that purpose, one needs a hashfunction that maps similar keys to hash ... record numbers, using such a hashfunction, then similar records will end up in the same bucket ..., the hashfunction must be as insensitive as possible to data capture or transmission ... pieces, and a hashfunction is used to detect potentially equal pieces, as above. The Rabin Karp ... , and the hashfunction returns an index tuple. This special case of hashing is known as geometric ... concepts cryptographic hashfunction s, checksums, etc. . Low cost The cost of computing a hash ... binary tree if the number of items is large and the hashfunction produces few collisions and less efficient if the number of items is small and the hashfunction is complex. Determinism A hash ... it must always generate the same hash value. In other words, it must be a function mathematics function ... is possible . Uniformity A good hashfunction should map the expected inputs as evenly as possible over ... choice as a hashfunction, but the converse need not be true. Hash tables often contain only a small .... In an ideal perfect hashfunction , no bucket should have more than one record but a small number ... . When testing a hashfunction, the uniformity of the distribution of hash values can be evaluated ... more details
The Jenkins hash functions are a collection of non cryptographic hashfunction cryptographic hash functions for multi byte keys designed by Robert John Jenkins Junior Bob Jenkins . They can be used also as checksum s to detect accidental data corruption or detect identical records in a database . The first one was formally published in 1997. The hash functions one at a time Jenkins s one at a time hash is adapted here from a WWW page by Bob Jenkins, ref name dobbsx cite web first Bob last Jenkins year ca. 2006 url http www.burtleburtle.net bob hash doobs.html title A hashfunction for hash Table lookup accessdate April 16, 2009 ref which is an expanded version of his Dr. Dobbs Journal Dr. Dobbs article. ref name dobbs cite journal first Bob last Jenkins year 1997 title Hash functions journal Dr. Dobbs Journal date September 1997 ref source lang c uint32 t jenkins one at a time hash char key, size t len uint32 t hash, i for hash i 0 i len i hash key i hashhash 10 hashhash 6 hashhash 3 hashhash 11 hashhash 15 return hash source Image JenkinsOneAtATime 3.svg thumb 255px right Avalanche behavior of Jenkins One at a time hash over 3 byte keys The avalanche effect avalanche behavior of this hash is shown on the right. Each of the 24 rows corresponds to a single bit in the 3 byte input key, and each of the 32 columns corresponds to a bit in the output hash. Colors are chosen by how well the input key bit affects the given output hash bit a green square indicates good mixing behavior ... consequences such as preventing an optimizing compiler from inlining the hashfunction. See also Fowler Noll Vo hash MurmurHash References Reflist Category Hash functions ru ... byte of the input key are weakly mixed to a minority of bits in the output hash. lookup2 The lookup2 function was an interim successor to one at a time. lookup3 The lookup3 function consumes input ... is more important than simplicity. Note, though, that any speed improvement from the use of this hash ... more details
refimprove date December 2008 Lane is a cryptographic hashfunction submitted to the NIST hashfunction competition it was designed by Sebastiaan Indesteege with contributions by Elena Andreeva, Christophe De Canni re, Orr Dunkelman, Emilia K sper, Svetla Nikova, Bart Preneel and Elmar Tischhauser. It re uses many components from Advanced Encryption Standard AES in a custom construction. The authors claim performance of up to 25.66 cycles per byte on an Intel Core 2 Duo. External links http www.cosic.esat.kuleuven.be lane The Lane web site Crypto navbox hash Category NIST hashfunction competition crypto stub ... more details
A perfect hashfunction for a set S is a hashfunction that maps distinct elements in S to a set of integers, with no hash collision collisions . A perfect hashfunction has many of the same Hashfunction Applications applications as other hash functions, but with the advantage that no collision resolution has to be implemented. Properties and uses A perfect hashfunction for a specific set S that can ... 2010 . The minimal size of the description of a perfect hashfunction depends on the range of its function ... perfect hash functions suitable for use with a hash table require at least a number of bits that is proportional to the size of S. A perfect hashfunction with values in a limited range mathematics ... in a lookup table table indexed by the output of the function. Using a perfect hashfunction is best ... updates, is cuckoo hashing . Minimal perfect hashfunction A minimal perfect hashfunction is a perfect hashfunction that maps n keys to n consecutive integers usually 0..n 1 or 1..n . A more formal way of expressing this is Let j and k be elements of some finite set K . F is a minimal perfect hashfunction iff F j F k implies j k and there exists an integer a such that the range of F is a .. a K 1. It has been proved that a general purpose minimal perfect hash scheme requires at least 1.44 bits key. ref Cite journal author Djamal Belazzougui, Fabiano C. Botelho, Martin Dietzfelbinger title Hash ... 2.5 bits key. Citation needed date December 2011 A minimal perfect hashfunction F is order preserving ... Perfect HashFunction Category Hashing Category Hash functions Category Search algorithms ... k sub , j < k implies F a sub j sub < F a sub k sub . Order preserving minimal perfect hash functions require necessarily n log n bits to be represented. A minimal perfect hashfunction F is monotone if it preserves the lexicographical order of the keys. Monotone minimal perfect hash functions ... reading Richard J. Cichelli. Minimal Perfect Hash Functions Made Simple , Communications of the ACM ... more details
for the computer hardware feature SIMD SIMD is a cryptographic hashfunction based on the Merkle Damg rd construction submitted to the NIST hashfunction competition by Ga tan Leurent. It is one of fourteen entries to be accepted into round two of the competition, ref name round2 Cite web url http csrc.nist.gov groups ST hash sha 3 Round2 submissions rnd2.html title Second Round Candidates publisher Computer Security Resource Center, National Institute of Standards and Technology accessdate 2009 07 25 ref but was not shortlisted for the third and final round. ref name round3 Cite web url http csrc.nist.gov groups ST hash sha 3 Round3 submissions rnd3.html title Third Final Round Candidates publisher Computer Security Resource Center, National Institute of Standards and Technology accessdate 2011 05 04 ref The designer states that the most important component of SIMD is its message expansion, which is designed to give a high minimal distance . The algorithm s speed is claimed to be 11 13 cycles per byte . ref name important cite web url http www.di.ens.fr leurent simd.html title The SIMD HashFunction last Leurent first Ga tan accessdate 2009 07 25 ref References Reflist Crypto hash Category NIST hashfunction competition ... more details
Image Cryptographic Hash Function.svg thumb 375px right A cryptographic hashfunction specifically, SHA ... the resulting output, by the so called avalanche effect . A cryptographic hashfunction is a algorithm ... called the message digest or simply digest. The ideal cryptographic hashfunction has four main ... forms of authentication . They can also be used as ordinary hashfunction s, to index data in hash ... of any length as input and produce a fixed length hash value. A cryptographic hashfunction must be able ... hashfunction should behave as much as possible like a random function while still being deterministic ... cryptographic hashfunction s but do not usually have a strong connection to practical security. For example ... benefits. One of the main applications of a hashfunction is to allow the fast look up of a data in a hash ... a cryptographic hashfunction, specifically a one way compression function . The methods resemble ..., with feedback to ensure that the resulting function is not bijective . NIST hashfunction competition SHA 3 finalists include functions with block cipher like components e.g., Skein hashfunction Skein , BLAKE and functions based on other designs e.g., JH hashfunction JH , Keccak . A standard ... in a hashfunction than for encryption. Merkle Damg rd construction Main Merkle Damg rd construction ... construction A hashfunction must be able to process an arbitrary length message into a fixed length ... be specially designed for hashing or be built from a block cipher. A hashfunction built with the Merkle ... for the full hashfunction can be traced back to a collision in the compression function. The last .... As a result, many entrants in the current NIST hashfunction competition are built on different ... constructions using hash functions can be provably secure if the underlying hashfunction is secure ... a secret random seed with a counter and hashing it. Some hash functions, such as Skein hashfunction .... For Merkle Damg rd hash functions, the concatenated function is as collision resistant as its strongest ... more details
Other uses Skein disambiguation Skein Infobox cryptographic hashfunction name Skein image File Skein permutation.png thumb Skein permutation caption General designers Niels Ferguson , Bruce Schneier publish date series derived from Threefish derived to related to certification SHA 3 finalist Detail digest size arbitrary structure rounds 72 256 & 512 block size , 80 1024 block size speed 6.1 cycles per byte cpb on Core 2 . ref name skein cite paper date 2010 10 01 author Ferguson et al. title The Skein HashFunction Family url http www.skein hash.info sites default files skein1.3.pdf ref cryptanalysis Skein is a cryptographic hashfunction and one out of five finalists in the NIST hashfunction competition to design what will become the SHA 3 standard, the intended successor of SHA 1 and SHA 2 . According to Stefan Lucks , the name Skein refers to how the Skein function intertwines the input ..., the Skein HashFunction first 2008 10 31 publisher Slashdot accessdate 2008 10 31 ref The authors ... hash.info sites default files skein1.3.pdf Paper describing the hashfunction, Version 1.3 2010 10 01 ref gallery File Skein Mix Function.png Skein Mix Function gallery Skein s nonlinearity comes ... of the NIST hashfunction competition, to make this attack less effective, even though they believe the hash would be secure even without these tweaks. ref name skein References reflist External links ... Research Group CERG at George Mason University Crypto navbox hash Category NIST hashfunction competition ... S box es. The function is optimized for 64 bit processors, and the Skein paper defines optional features such as randomized Hashfunction hashing , parallelizable Hash tree tree hashing , a stream cipher , personalization, and a key derivation function . Cryptanalysis In October 2010, an attack that combines ... www.skein hash.info node 30 An implementation of Skein in Ada https github.com basho skerl Skein hashfunction for Erlang, via NIFs http sourceforge.net p skeinbash home Home Skein 512 512 implemented ... more details
Infobox cryptographic hashfunction name JH image caption General designers Hongjun Wu publish date series derived from derived to related to certification SHA 3 finalist Detail digest size 224, 256, 384, 512 structure rounds speed 16.1 cycles per byte cpb on Core 2 in 64 bit mode using SSE2 37.3 cpb using ANSI C. cryptanalysis JH is a cryptographic hashfunction submitted to the NIST hashfunction competition by Hongjun Wu. JH was chosen as one of the five finalists of the competition. JH has a 1024 bit state, and works on 512 bit input blocks. Processing an input block consists of three steps XOR the input block into the left half of the state. Apply a 42 round unkeyed permutation encryption function to the state. This consists of 42 repetitions of Break the input into 256 4 bit blocks, and map each through one of two 4 bit S boxes, the choice being made by a 256 bit round dependent key schedule. Equivalently, combine each input block with a key bit, and map the result through a 5 4 bit S box. Mix adjacent 4 bit blocks using a maximum distance separable code over Finite field GF 2 sup 4 sup . Permute 4 bit blocks so that they will be adjacent to different blocks in following rounds. The final half round consists of an S box substitution without a following MDS or permutation step. XOR the input block into the right half of the state. The resulting digest is the first 224, 256, 384 or 512 bits from the 1024 bit final value. It is well suited to a bit slicing implementation using the SSE2 instruction set, giving speeds of 16.8 Cycles per byte . External links http www3.ntu.edu.sg home wuhj research jh index.html The JH web site http ehash.iaik.tugraz.at wiki JH JH page on the SHA 3 Zoo http cryptography.gmu.edu athena index.php?id source codes A VHDL source codes developed in the Cryptographic Engineering Research Group CERG at George Mason University Crypto navbox hash Category NIST hashfunction competition crypto stub ru JH ... more details
Fugue is a cryptographic hashfunction submitted by IBM to the NIST hashfunction competition . It was designed by Shai Halevi, William E. Hall, and Charanjit S. Jutla. Fugue takes an arbitrary length message and compresses it down to a fixed bit length either 224, 256, 384 or 512 bits . The hash functions for the different output lengths are called Fugue 224, Fugue 256, Fugue 384 and Fugue 512. The authors also describe a parametrized version of Fugue. A weak version of Fugue 256 is also described using this parameterized version. The selling point of Fugue is the authors claimed proof that a wide range of current attack strategies based on differential cryptanalysis cannot be efficient against Fugue. It is also claimed to be competitive with the NIST hashfunction SHA hash functions SHA 256 in both software and hardware efficiency, achieving up to 36.2 cycles per byte on an Intel Family 6 Model 15 Xeon 5150, and up to 25 cycles per byte on an Intel Core 2 processor T7700. On 45nm Core2 processors, e.g. T9400, Fugue 256 runs at 16 cycles per byte using SSE4.1 instructions. On the newer Westmere architectures 32nm , e.g. Core i5, Fugue 256 runs at 14 cycles byte. Fugue s design starts from the hashfunction Grindahl , and like Grindahl uses the S box from Advanced Encryption Standard AES , but it replaces the 4x4 column mixing matrix with a 16x16 super mix operation which greatly improves diffusion. The super mix operation is however, only slightly more computationally expensive to implement than the AES mixing strategy. SuperMix The 224 and 256 bit variants of Fugue work with a state which can be represented in 4 by 30 matrix of unsigned bytes, whereas the 384 and 512 bit ... comm research projects.nsf pages fugue.index.html The HashFunction Fugue Crypto navbox hash Category NIST hashfunction competition ... at the head of the state . The SuperMix function can be defined as math text SuperMix U text ROL left ... more details
Portal Cryptography The NIST hashfunction competition is an open competition held by the US National ... CANDIDATES Retrieved 9 Nov 2011 ref BLAKE hashfunction BLAKE Gr stl Lars Knudsen Knudsen et al. JH hashfunction JH Keccak Keccak team, Joan Daemen Daemen et al. Skein hashfunction Skein Bruce ... to Final Round The following hashfunction submissions were accepted for Round Two, but did not make ... Robshaw, Yannick Seurin date October 29, 2008 accessdate 11 December 2008 ref Fugue hashfunction Fugue IBM Hamsi ref cite web url http ehash.iaik.tugraz.at uploads 9 95 Hamsi.pdf title The HashFunction ... ref cite web url http ehash.iaik.tugraz.at uploads e ea Luffa Specification.pdf title HashFunction ... uploads f f5 Shavite.pdf title The SHAvite 3 HashFunction format PDF author Eli Biham coauthors Orr Dunkelman accessdate 11 December 2008 ref SIMD hashfunction SIMD colend Did not pass to Round Two The following hashfunction submissions were accepted for Round One but did not pass to Round ... FSB Lane hashfunction Lane Lesamnta ref cite web url http ehash.iaik.tugraz.at uploads 5 5c Lesamnta.pdf ... hash.html title The Sarmal HashFunction accessdate 12 October 2010 author Kerem Var c coauthors ... uploads c ca Cheetah.pdf title The HashFunction Cheetah Speci cation and Supporting Documentation ... extension.txt title Danilo Gligoroski Cheetah hashfunction is not resistant against length extension ... November 2008 coauthors Jean Philippe Aumasson and Mar a Naya Plasencia ref NaSHA hashfunction NaSHA ... title The Sg il Cryptographic HashFunction accessdate 9 11 2008 date September 2008 author Peter ... web url http ehash.iaik.tugraz.at uploads 3 39 Twister.pdf title The Twister HashFunction Family ... dch.pdf title The DCH HashFunction format PDF author David A. Wilson date October 23, 2008 accessdate ...&sid 601&pid 547 title SHAMATA hashfunction A candidate algorithm for NIST competition accessdate 10 ... uploads 4 40 Tangle.pdf title The Tangle HashFunction format PDF author Rafael Alvarez ... more details
Infobox cryptographic hashfunction name GOST R 34.11 94 image caption General designers FAPSI and VNIIstandart ... rounds 32 cryptanalysis A 2008 attack breaks the full round hashfunction. The paper presents a collision ... and Janusz Szmidt title Cryptanalysis of the GOST HashFunction url http www.springerlink.com content 2514122231284103 ref The GOST hashfunction , defined in the standards GOST R 34.11 94 and GOST 34.311 95 , is a 256 bit cryptographic hashfunction . It was initially defined in the Russian national standard GOST R 34.11 94 Information Technology Cryptographic Information Security HashFunction ... CIS is GOST 34.311 95. The hashfunction is based on the GOST block cipher GOST block cipher . Algorithm ... hashfunction math H out f H in , m math , where math H out math , math H in math , math m math are a 256 bit blocks. Each message block, starting the first one, is processed by the step hashfunction math f math , to calculate intermediate hash value br math H i 1 f H i , m i math br The math H ... function of the message M. File GOST hash calculation.gif So, the algorithm works as follows. Initialization math h initial math Initial 256 bit value of the hashfunction, determined by user. math ... 1 n 1 do the following while math M 256 math math h f h, m i math apply step hashfunction math ... value is math h math . The step hashfunction The step hashfunction math f math maps two ... that breaks the full round GOST hashfunction. The paper presents a collision attack in 2 sup ... Szmidt title Cryptanalysis of the GOST HashFunction url http www.springerlink.com content ... cite web date 2010 03 url http tools.ietf.org html rfc5831 title GOST R 34.11 94 HashFunction ... gosthash.tar.gz C implementation and test vectors for GOST hashfunction from Markku Juhani Saarinen ... wiki GOST The GOST HashFunction Ecrypt page Crypto navbox hash DEFAULTSORT Gost HashFunction Category Broken hash functions Category Cryptographic hash functions Category GOST standards ... more details
Infobox cryptographic hashfunction name BLAKE image caption General designers Jean Philippe Aumasson , Luca Henzen , Willi Meier , Raphael C. W. Phan publish date series derived from derived to related to certification SHA 3 finalist Detail digest size 256 or 512 bits structure rounds 14 or 16 speed 8.4 cycles per byte cpb on Core 2 for BLAKE 256 7.8 cpb for BLAKE 512 cryptanalysis BLAKE is a cryptographic hashfunction submitted to the NIST hashfunction competition by Jean Philippe Aumasson, Luca Henzen, Willi Meier, and Raphael C. W. Phan. It is based on Dan Bernstein s ChaCha cipher ChaCha stream cipher, but a permuted copy of the input block, XORed with some round constants, is added before each ChaCha round. BLAKE was chosen as one of the five finalists of the competition. Like SHA 2 , there are two variants differing in the word size. ChaCha operates on a 4 4 array of words. BLAKE repeatedly combines an 8 word hash value with 16 message words, truncating the ChaCha result to obtain the next hash value. BLAKE 256 uses 32 bit words, while BLAKE 512 uses 64 bit words. Algorithm Like SHA 2 , BLAKE comes in two variants one that uses 32 bit words, used for computing hashes up to 256 bits long, and one that uses 64 bit words, used for computing hashes up to 512 bits long. The core block transformation combines 16 words of input with 16 working variables, but only 8 words 256 or 512 bits are preserved between blocks. It uses a table of 16 constant words the leading 512 or 1024 bits of the fractional part of , and a table of 10 16 element permutations 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 14 10 4 8 9 15 13 6 1 12 0 2 11 7 5 3 2 11 8 12 0 5 2 15 13 10 14 3 6 7 1 ..., respectively, and the number of rounds is increased to 16. Tweaks Throughout the NIST hashfunction ... CERG at George Mason University Crypto navbox hash Category NIST hashfunction competition crypto stub ... i code varies from 0 to 7. The differences from the ChaCha quarter round function are The addition ... more details
This article summarizes publicly known cryptanalysis attacks against cryptographic hashfunction s. Note that not all entries may be up to date. class wikitable border 1 Table color key No known successful attacks style background ffff90 color black Theoretical break style background ff9090 color black Attack demonstrated in practice Common hash functions Collision resistance main Collision attack class wikitable border 1 Hashfunction Security claim Best attack Attack date Comment style background ff9090 color black MD5 2 sup 64 sup 2 sup 24.1 sup time 2007 07 ref cite paper author M.M.J. Stevens date 2007 07 title On Collisions for MD5 url http www.win.tue.nl hashclash On 20Collisions 20for 20MD5 20 20M.M.J. 20Stevens.pdf ref This attack takes seconds on a regular PC. style background ffff90 color black SHA 1 2 sup 80 sup 2 sup 51 sup 2010 ref cite paper author St phane Manuel date 2010 title Classification and Generation of Disturbance Vectors for Collision Attacks against SHA 1 url ... 2 sup 256 sup Preimage resistance main Preimage attack class wikitable border 1 Hashfunction Security ... Step SHA 512 url http eprint.iacr.org 2009 479.pdf ref Less common hash functions Collision resistance class wikitable border 1 Hashfunction Security claim Best attack Attack date Comment MD2 cryptography ... border 1 Hashfunction Security claim Best attack Attack date style background ffff90 color black ... leurent files MD4 FSE08.pdf ref See also Cryptographic hashfunction Collision attack Preimage attack Block cipher security summary References reflist crypto navbox hash Category Cryptographic hash functions Category Cryptography lists and comparisons ... sup 2008 11 25 ref name sha2 collision Chosen prefix collision attack class wikitable border 1 Hashfunction Security claim Best attack Attack date Comment style background ff9090 color black MD5 2 ... ftp E5 AF 86 E7 A0 81 E5 AD A6 HASH E5 87 BD E6 95 B0 Improved 20Collision 20Attacks 20on 20MD4 20and ... more details
naor PAPERS uowhf abs.html Universal One Way Hash Functions and their Cryptographic Applications , 1989. Category Cryptographic hash functions ... more details
Fowler Noll Vo is a non Cryptographic hashfunction cryptographic hashfunction created by Glenn Fowler, Landon Curt Noll , and Phong Vo. The basis of the FNV hash algorithm was taken from an idea sent ... hashfunction MurmurHash Notes reflist 2 External links http www.isthe.com chongo tech comp fnv index.html .... In a subsequent ballot round, Landon Curt Noll improved on their algorithm. Some people tried this hash ... Vo or FNV hash. ref http www.isthe.com chongo tech comp fnv index.html history FNV hash history ... xor fold Changing the FNV hash size xor folding ref ref http www.isthe.com chongo tech comp fnv index.html other folding Changing the FNV hash size non powers of 2 ref The FNV hash algorithms and http ... put into the public domain ref FNV is not a cryptographic hash . The hash One of FNV s key advantages is that it is very simple to implement. Start with an initial hash value of FNV offset basis . For each byte in the input, multiply hash by the FNV prime , then XOR it with the byte from the input. The alternate algorithm, FNV 1a, reverses the multiply and XOR steps. FNV 1 hash The FNV 1 hash algorithm ... hash ref hash FNV offset basis for each octet of data to be hashed hashhash math times math FNV prime hashhash XOR octet of data return hash In the above pseudocode , all variables are signedness unsigned ... hash. The variable, octet of data , is an 8 bit unsigned integer . As an example, consider the 64 bit FNV 1 hash All variables, except for octet of data , are 64 bit unsigned integers . The variable ... . The XOR is an 8 bit operation that modifies only the lower 8 bits of the hash value. The hash value ... 1 hash ref FNV 1a hash The FNV 1a hash differs from the FNV 1 hash by only the order in which the multiply ... alternate algorithm ref hash FNV offset basis for each octet of data to be hashed hashhash XOR octet of data hashhash math times math FNV prime return hash The above pseudocode has the same assumptions ... Hash functions de FNV Informatik ru FNV ... more details
function has thus become a hot topic. In other words, most of the hash functions in use nowadays ... Hash Functions In this approach, we base the security of hashfunction on some hard mathematical problem ... approach. A cryptographic hashfunction has provable security against collision attacks if finding .... Constructing a hashfunction with provable security is much more difficult than using a classical ... in the latest version. SWIFFT is an example of a hashfunction that circumvents these security problems ... FunctionHash m x sup m sup mod n where n is hard to factor composite number, and x is some prespecified ... Hashfunction a provably secure collision resistant hashfunction assuming the hardness of finding ... Only hashfunction based on the concept of Elliptic curves, Subset Sum Problem and summation of polynomials ... a second pre image attack was found. Fast Syndrome Based Hash FSB Fast Syndrome Based hashfunction ... hashfunction A compression function where finding collisions is as hard as solving the discrete ... A family of hash functions based on the Knapsack problem . The Z mor Tillich hashfunction ... hashfunction. As the attacks include a birthday search in a reduced set of size math 2n math they indeed ... Tillich hashfunction new Attacks and Reduced Variants with Equivalent Security contribution ...In cryptography , cryptographic hash functions can be divided into two main categories. In the first ... complexity formal reduction . These functions are called Provably Secure Cryptographic Hash Functions . However this does not mean that such a function could not be broken. To construct them ... the bits of the message are mixed to produce the hash. They are then believed to be hard to break, but no such formal proof is given. Almost all widely spread hash functions fall in this category. Some of these functions are already broken and are no longer in use. Types of Security of Hash Functions Generally, the basic security of cryptographic hash functions can be seen from three different angles ... more details
wiktionary hashHash may refer to Hash symbol , the glyph Hash mark disambiguation , one of various symbols Hash food , a coarse mixture of ingredients Hash chain , a method of producing many one time keys from a single key or password Hashfunction , a derivation of data Cryptographic hashfunctionHash table , a data structure hash Unix , an operating system command Hashish , a psychoactive drug Hash House Harriers , a running club Fragment identifier , in computer hypertext, a string of characters that refers to a subordinate resource Geohash , a spatial data structure which subdivides space into buckets of grid shape disambiguation cs Hash de Hash hu Hash egy rtelm s t lap nl Hash ja pl Hash ru sv Hash th ... more details
Summary Information Description Source self made Date 5 5 2008 Author User Wjwillia Wjwillia User talk Wjwillia talk other versions none Licensing self cc by 3.0 Orphan image Copy to Wikimedia Commons bot Fbot ... more details
In cryptography , N Hash is a cryptographic hashfunction based on the FEAL round function, and is now considered insecure. It was proposed in 1990 by Miyaguchi et al. weaknesses were published the following year. N Hash has a 128 bit hash size. A message is divided into 128 bit blocks, and each block is combined with the hash value computed so far using the g One way compression function compression function . g contains eight rounds, each of which uses an F function, similar to the one used by FEAL . Eli Biham and Adi Shamir 1991 applied the technique of differential cryptanalysis to N Hash, and showed that hash collision collision s could be generated faster than by a birthday attack for N Hash variants with even up to 12 rounds. References Eli Biham, Adi Shamir Differential Cryptanalysis of Feal and N Hash. EUROCRYPT 1991 1&ndash 16 S. Miyaguchi, K. Ohta, and M. Iwata 128 bit hashfunction N hash , NTT Review, 2 6 , November 1990, pp128&ndash 132. Crypto navbox hash Category Cryptographic hash functions crypto stub fr N hash it N Hash pl Funkcja N Hash ru N Hash ... more details
a cryptographic hashfunction such as SHA 1 is used for the hashing. If the hash list only needs to protect ... uses an MD4 top hash of an MD4 hash list to uniquely identify a file Cryptographic hashfunction ...Unreferenced date March 2009 In computer science , a hash list is typically a List computing list of Hashfunction hashes of the data blocks in a file or set of files. Lists of hashes are used for many different purposes, such as fast table lookup hash table s and distributed databases distributed hash table s . This article covers hash lists that are used to guarantee data integrity. Image Hash list.svg thumb 350px right A hash list with a top hash A hash list is an extension of the old concept of hashing an item for instance, a file . A hash list is usually sufficient for most needs, but a more advanced form of the concept is a hash tree . Hash lists can be used to protect any kind of data stored, handled and transferred in and between computers. An important use of hash lists is to make ... be used. Hash lists are better than a simple hash of the entire file since, in the case of a data block ... a hash of the file, many undamaged blocks would have to be redownloaded, and the file reconstructed and tested until the correct hash of the entire file is obtained. Hash lists also protect against nodes ... from some other source. Root hash Often, an additional hash of the hash list itself a top hash , also called root hash or master hash is used. Before downloading a file on a p2p network, in most cases the top hash is acquired from a trusted source, for instance a friend or a web site that is known to have good recommendations of files to download. When the top hash is available, the hash list can be received from any non trusted source, like any peer in the p2p network. Then the received hash list is checked against the trusted top hash, and if the hash list is damaged or fake, another hash list from another source will be tried until the program finds one that matches the top hash. In some ... more details
Hash key can have several meanings. For its use to describe the key on a telephone keypad, see number sign . For its use in data structure, database and cryptographic applications, see hashfunction or unique key . Disambig ... more details
Infobox cryptographic hashfunction name SANDstorm image caption General designers Mark Torgerson, Richard Schroeppel, Tim Draelos, Nathan Dautenhahn, Sean Malone, Andrea Walker, Michael Collins, Hilarie Orman, publish date 2008 series derived from derived to related to certification Detail digest size 224, 256, 384, 512 structure rounds cryptanalysis None The SANDstorm hash ref http www.sandia.gov scada documents SANDstorm Submission 2008 10 30.pdf SANDstorm Algorithm Specification ref is a cryptographic hashfunction designed in 2008 by Mark Torgerson, Richard Schroeppel , Tim Draelos, Nathan Dautenhahn, Sean Malone, Andrea Walker, Michael Collins, and Hilarie Orman for the NIST SHA 3 competition . The SANDstorm hash was accepted into the first round of the NIST hashfunction competition, but was not accepted into the second round ref http csrc.nist.gov groups ST hash sha 3 Round2 submissions rnd2.html NIST Information on Round 2 ref . References references External links http www.sandia.gov scada documents SANDstorm Submission 2008 10 30.pdf SANDstorm Algorithm Specification http csrc.nist.gov groups ST hash sha 3 Round1 documents SANDstorm.zip SANDStorm Submission Package Crypto navbox hash DEFAULTSORT Sandstorm Hash Category Cryptographic hash functions Category NIST hashfunction competition ... more details
A hash chain is the successive application of a cryptographic hashfunction to a piece of data. In computer security , a hash chain is a method to produce many One time password one time keys from a single Key cryptography key or password . For non repudiation a hashfunction can be applied successively to additional pieces of data in order to record the chronology of data s existence. Definition A hash chain is a successive application of a cryptographic hashfunction math h x math to a string. For example, math h h h h x math gives a hash chain of length 4, often denoted math h 4 x math Applications main S KEY Leslie Lamport Lamport ref name lamporthash L. Lamport, Password Authentication with Insecure Communication , Communications of the ACM 24.11 November 1981 , pp 770 772. http scholar.google.de scholar?num 100&hl de&lr &cluster 10450198314466995215 http citeseer.ist.psu.edu context 2064887 0 ref suggested the use of hash chains as a password protection scheme in an insecure environment. A server which needs to provide authentication may store a hash chain rather than a plain text password and prevent theft of the password in transmission or theft from the server. For example ... to the One way function one way property of Cryptographic hashfunction cryptographically secure hashfunction s, it is infeasible for the eavesdropper to reverse the hashfunction and obtain an earlier piece of the hash chain. In this example, the user could authenticate 1000 times before the hash chain is exhausted. Each time the hash value is different, and thus cannot be duplicated by an attacker. See also Challenge response authentication Hash list In contrast to the recursive structure of hash chains, the elements of a hash list are independent of each other. One time password References ... h h 999 password h 1000 password math and verifies this matches the hash chain it has stored. It then stores ... seeing math h 999 password math communicated to the server will be unable to re transmit the same hash ... more details
be used to sign a single message. But combined with hash trees they can be used for many messages and then become a Merkle signature scheme fairly efficient digital signature scheme . How hash trees work A hash tree is a Binary tree tree of Hashfunction hashes in which the leaves are hashes of data ... nodes under each node. Usually, a cryptographic hashfunction such as SHA 1 , Whirlpool hash Whirlpool , or Tiger hash Tiger is used for the hashing. If the hash tree only needs to protect against ...Image Hash tree.png thumb 300px right A binary hash tree In cryptography and computer science Hash trees or Merkle trees are a type of data structure Cn reason How do hash trees fit WP s definition of data ... about a larger piece of data for instance a file used to verify its contents. Hash trees are a combination of hash list s and hash chain ing, which in turn are extensions of hashfunctionhash ing. Hash trees in which the underlying hashfunction is Tiger cryptography Tiger are often called Tiger trees or Tiger tree hashes . Uses Hash trees can be used to verify any kind of data stored, handled and transferred in and between computers. Currently the main use of hash trees is to make sure that data ... been made to use hash trees in trusted computing systems. Sun Microsystems has used Hash Trees in the ZFS ... End to End Data Integrity ref Hash Trees are used in Google Wave protocol, ref Google Wave Federation ... tree is a hierarchical hash verification if the hash over the entire keyspace is not the same ... replicas which contain mostly similar data. http www.aosabook.org en nosql.html ref Hash trees ... encryption function , Crypto 87 ref The original purpose was to make it possible to efficiently ... children. For example, in the picture hash 0 is the result of hashing hash 0 0 and then hash 0 1 . That is, hash 0 hashhash 0 0 hash 0 1 where denotes concatenation. Most hash tree .... In the top of a hash tree there is a top hash or root hash or master hash . Before downloading a file ... more details
Spectral Hash is a cryptographic hashfunction submitted to the NIST hashfunction competition by Gokay Saldaml , Cevahir Demirk ran, Megan Maguire, Carl Minden, Jacob Topper, Alex Troesch, Cody Walker, etin Kaya Ko . ref name NIST submission, 2009 cite web title Spectral Hash url http csrc.nist.gov groups ST hash sha 3 Round1 Feb2009 documents spectral koc.pdf author etin Kaya Ko publisher Computer Security Resource Center, NIST format pdf ref ref name NIST Conference, 2009 cite web title First SHA 3 Candidate Conference date 25 28 February 2009 url http csrc.nist.gov groups ST hash sha 3 Round1 Feb2009 program.html publisher Computer Security Resource Center, NIST ref ref name IEEE, 2009 cite journal title A High Performance Hardware Architecture for Spectral Hash Algorithm pages 215 218 journal 2009 20th IEEE International Conference on Application specific Systems, Architectures and Processors year 2009 url http www.computer.org portal web csdl doi 10.1109 ASAP.2009.31 doi 10.1109 ASAP.2009.31 author Ray C.C. Cheung, etin K. Ko , John D. Villasenor ref It uses a Merkle Damgard construction and employs several mathematical structures including Finite fields and Discrete Fourier transforms. The authors claims 512 bit hashes at 51.2 gigabits per second on a 100 MHz Virtex 4 FPGA. Spectral hash is insecure a method exists to generate arbitrary collisions in the hash state, and therefore in the final hash digest. ref cite web url http ehash.iaik.tugraz.at uploads 4 4b Spectralhash heilman.txt title Collision for Spectral Hash last Heilman first Ethan date 2009 03 12 accessdate 19 May 2009 ref References Reflist External links http cs.ucsb.edu koc shash index.html The Spectral Hash web site Crypto navbox hash Category NIST hashfunction competition crypto stub ... more details
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