Author : Surya Prakash Dwivedi

Message Digestion is a popular technique for representing a full length message in to short form i.e. Shorter form of message in coded form but have full information about the message after decoding that text. This is popular and novel approach of public key cryptography .Using a specific cryptographic hashed formula we convert the full length message into a strings of digits and protect the integrity of a text or media and check the alternatives of all part of information. In this proposed paper I introduce various comparative message digestion technique. They typically consist of two main components: a compression function that operates in fixed-length part of input message text, and a unique mode of operation that predomination, how apply the flatten function again and again on the pieces in order to permit for random-length text inputs. Crypto-graphic hash operations are next to needs to sustain some important and draconian security features along with (but not limited to) first-premise resistance, second-preimiage resistance, collision resistance, pseudo randomness, and unpredictability.

Keywords: Hash function, SHA-1,2,3,4, Message Digest, compressed function, collision resistance, cryptography security, Collision, Bruit force, Salt.