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A universal hashing scheme is a randomized algorithm that selects a hash function h among a family of such functions, in such a way that the probability of a collision of any two distinct keys is 1/m, where m is the number of distinct hash values desired—independently of the two keys. Universal hashing ensures (in a probabilistic sense) that ...
Double hashing is a computer programming technique used in conjunction with open addressing in hash tables to resolve hash collisions, by using a secondary hash of the key as an offset when a collision occurs. Double hashing with open addressing is a classical data structure on a table .
Having two hash functions allows any key x to have up to two potential locations to be stored based on the values of the respective outputs, h 1 (x) and h 2 (x). It is important to note that, although there are two hash functions, there is only one table; both hash functions map to locations on that table.
[1] [2] It works by applying a hash function to the features and using their hash values as indices directly (after a modulo operation), rather than looking the indices up in an associative array. In addition to its use for encoding non-numeric values, feature hashing can also be used for dimensionality reduction. [2]
In computer science, a hash table is a data structure that implements an associative array, also called a dictionary or simply map; an associative array is an abstract data type that maps keys to values. [3] A hash table uses a hash function to compute an index, also called a hash code, into an array of buckets or slots, from which the desired ...
UMAC and Poly1305-AES and several other message authentication code algorithms are based on universal hashing. [4] [5] In such applications, the software chooses a new hash function for every message, based on a unique nonce for that message. Several hash table implementations are based on universal hashing.
The sponge construction for hash functions. P i are blocks of the input string, Z i are hashed output blocks.. In cryptography, a sponge function or sponge construction is any of a class of algorithms with finite internal state that take an input bit stream of any length and produce an output bit stream of any desired length.
hash HAS-160: 160 bits hash HAVAL: 128 to 256 bits hash JH: 224 to 512 bits hash LSH [19] 256 to 512 bits wide-pipe Merkle–Damgård construction: MD2: 128 bits hash MD4: 128 bits hash MD5: 128 bits Merkle–Damgård construction: MD6: up to 512 bits Merkle tree NLFSR (it is also a keyed hash function) RadioGatún: arbitrary ideal mangling ...