SHA – a brief

The Secure Hash Algorithms are a group of cryptographic hash functions proposed by the National Institute of Standards and Technology (NIST) and include:

• SHA-0: A word applied to the first form of the 160-bit hash function produced in 1993 under the name “SHA”. It was pulled back soon after production because of an undisclosed “noteworthy blemish” and supplanted by the marginally overhauled variant SHA-1.
• SHA-1: A 160-bit hash function which looks like the prior MD5. This was planned by the National Security Agency (NSA) to be essential for the Digital Signature Algorithm. Cryptographic shortcomings were found in SHA-1, and the standard was not, at this point endorsed for most cryptographic uses after 2010.
• SHA-2: A group of two comparative hash functions, with various block sizes, known as SHA-256 and SHA-512, they contrast in the word size; SHA-256 utilizations are of 32-byte words where SHA-512’s are of 64-byte words.
• SHA-3: A hash function, once in the past called Keccak, picked in 2012 after a public rivalry among non-NSA originators. It underpins similar hash lengths as SHA-2, and its inside structure varies altogether from the remainder of the SHA family.

A cryptographic hash function is an exceptional class of hash function that has certain properties that make it appropriate for use in cryptography. It is a numerical algorithm that maps information of self-assertive size to a piece line of a fixed size (a hash function) which is intended to likewise be a one-way output function, that is, a function which is infeasible to revert.