Applying Message Authentication Code (MAC) in text chatting system

Abstract The use of Cryptography of text Authentication has become a standard approach in many applications, particularly in Internet Security Protocols. This research describes a new approach of authentication text and can be applied to text chatting system. This work presents simple and practical constructions Message Authentication Code (MAC) based on a cryptographic hash function. The proposed MAC Code provides security and authenticity for any length of messages, furthermore it is fast and easy to implement. .