International Journal of Computer Applications
The main purpose of message authentication is to prevent manipulation of the message which is sent. MAC stands for Message Authentication Code which is also known as "Integrity check value" or "Cryptographic checksum". The basic objectives of a hash function are to: prevent finding a message from a given hash value (inversion) prevents finding two messages with the same hash value (collision). On the other hand, message authentication codes are mainly to prevent forgery. Thus, using hash functions for message authentication may get a bit complex as hash functions do not have the in-built functionality of a key.