With today’s technology, several applications have faith in the existence of little devices that may exchange info and kind communication networks. During a good portion of such applications, the confidentiality and integrity of the communicated messages are of specific interest. During this paper, the authors tend to propose 2 novel techniques for authenticating short encrypted messages that square measure directed to meet the necessities of mobile and pervasive applications. By taking advantage of the actual fact that the message to be genuine must even be encrypted, they tend to propose incontrovertibly secure authentication codes that square measure additional economical than any message authentication code within the paper.