Hashing is the process of generating a value from a text or a list of numbers using a mathematical function known as a hash function.There are many hash functions that use numeric numeric or alphanumeric keys. Examples: I h(x) = x mod N is a hash function for integer keys I h((x;y)) = (5 x +7 y) mod N is a hash function for pairs of integers h(x) = x mod 5 key element 0 1 6 tea 2 coffee 3 4 14 chocolate A hash table consists of: Typically the block sizes are from 128 bits to 512 bits. Three versions of Whirlpool have been released; namely WHIRLPOOL-0, WHIRLPOOL-T, and WHIRLPOOL. Later in 1995, SHA-1 was designed to correct alleged weaknesses of SHA-0. An example of the Multiplication Method is as follows − Adapting Knuth’s suggestion, c to be fraction of the form s / 2^32. An example of the Mid Square Method is as follows −. The following illustration demonstrates hash function −. Hash functions provide protection to password storage. This is then multiplied with n to get the hash value. It is derived from the modified version of Advanced Encryption Standard (AES). This process is often referred to as hashing the data. Hashing algorithm involves rounds of above hash function like a block cipher. Hash functions are extremely useful and appear in almost all information security applications. This property means given an input and its hash, it should be hard to find a different input with the same hash. Though from same family, there are structurally different. So the concept of hashing arise. Schematic of hashing algorithm is depicted in the following illustration −. We call h(x) hash value of x. Here, h(k) is the hash value obtained by dividing the key value k by size of hash table n using the remainder. An analytical attack was reported to be successful only in an hour by using computer cluster. RACE Integrity Primitives Evaluation Message Digest (RIPEMD) 3. In general, the hash is much smaller than the input data, hence hash functions are sometimes called compression functions. Hashing Function Direct address table has various limitations. MD5 was most popular and widely used hash function for quite some years. Family of SHA comprise of four SHA algorithms; SHA-0, SHA-1, SHA-2, and SHA-3. Original RIPEMD (128 bit) is based upon the design principles used in MD4 and found to provide questionable security. Data integrity check is a most common application of the hash functions. This property means it should be hard to find two different inputs of any length that result in the same hash. This property protects against an attacker who only has a hash value and is trying to find the input. How to add/merge two hash tables in PowerShell? Hash function coverts data of arbitrary length to a fixed length. An example of the Division Method is as follows −. The 256 and 320-bit versions reduce the chance of accidental collision, but do not have higher levels of security as compared to RIPEMD-128 and RIPEMD-160 respectively. SHA-2 family has four further SHA variants, SHA-224, SHA-256, SHA-384, and SHA-512 depending up on number of bits in their hash value. One of the designer was Vincent Rijmen, a co-creator of the AES. For example, SHA-2 is a family of hash functions that includes SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256. Typically the block sizes are from 128 bits to 512 bits. It however, does not provide any assurance about originality. It is best that n is a prime number as that makes sure the keys are distributed with more uniformity. The MD family comprises of hash functions MD2, MD4, MD5 and MD6.