Date Added: Jan 2012
User Authentication is defined as 'Provision of Assurance that the message is originated from authorized user'. Message Authentication is defined as 'Provision of assurance that the message is not altered'. Former is provided by Message Authentication Codes (MAC) and later is provided by Hash functions. When MAC uses Hash function to generate authentication code it is called Hash based MAC (HMAC). In this paper a new algorithm is proposed for HMAC which uses MD5 algorithm as hash function and based on parallel processing. The algorithm is implemented using GUI based controls in MATLAB toolbox called GUIDE which enables the algorithm to be friendly with the user.