hash function


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hash function

(programming)
A hash coding function which assigns a data item distinguished by some "key" into one of a number of possible "hash buckets" in a hash table. The hash function is usually combined with another more precise function.

For example a program might take a string of letters and put it in one of twenty six lists depending on its first letter. Ideally, a hash function should distribute items evenly between the buckets to reduce the number of hash collisions. If, for example, the strings were names beginning with "Mr.", "Miss" or "Mrs." then taking the first letter would be a very poor hash function because all names would hash the same.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

hash function

An algorithm that turns a variable amount of text into a small, fixed-length value called a "hash value," "hash code" or "digest." Hash functions are widely used to create codes for digital signatures and message authentication (see cryptographic hash function). Hash functions are also employed to create lookup tables (see hash table) as well as spam analysis (see hash buster).
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References in periodicals archive ?
Choose a hash function H(*):{0,1}* [right arrow] [Z.sup.n.sub.q].
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The protocol adapts both of the symmetric and asymmetric cryptography techniques as well as hash functions. The protocol includes two main sub protocols: The Registration protocol which is executed between the authentication server and mobiles; and Authentication protocol which is executed between the Mobile (U1) and Authentication Center (AuC) through Mobile (U2).
I could write a similarly simple hash function for images.
Suppose we want to learn K hash functions that leading to a X-digit representation B of X.
A novel digital watermarking scheme for medical images which offers robustness to the watermark information and fragility to the host medical image based on chaotic key, hash function, product codes, and RNS is proposed.
Regarding the hash function selected, to the best of our knowledge, the basic implementation of spongent-88 has the smallest results reported for both ASIC [35] and FPGA [31].
A 160 bit hash function that is related to previous algorithm but more conservative.
Where mapping function [??]: [G.sub.1] x [G.sub.1] [right arrow] [G.sub.2] Primitive Generator P: P [member of] [G.sub.1] Random integer s: s [member of] [Z.sup.*.sub.q] Public Key [P.sub.pub] =sP Hash function H: [Z.sup.*.sub.q] [right arrow] [G.sub.1]
A random hash function [f.sub.R] from [F.sup.n.sub.2] to [F.sup.m.sub.2] is called [delta]-almost [universal.sub.2] when
a hash function. For example, a function g(x)=[ x/2], divides x by 2,
At the same time, the system effectively integrates a lightweight RFID authentication protocol based on Hash function to achieve secure access and privacy protection.