Wireless sensor networks (WSN) are typically deployed in an unattended environment, where the legitimate users can login to the network and access data as and when demanded. Efficiency of WSN depends on the correctness of the information which has been collected. Consequently, verifying authenticity and integrity of delivered data is indispensable for security-sensitive WSNs. At the same time, security is most important to prevent outsiders (illegitimate party) from retrieving the correct information. However, traditional security methods are not suited for WSN because they are not efficient from the perspective of energy, while energy conservation is a pivotal issue in WSN. This paper proposes a user authentication mechanism to countermeasure the outside attacks. The salient feature of the proposed technique is that it establishes shared values and transmits a clue message during a single authentication process without using the public key cryptography. Therefore, our proposed clue authentication scheme for WSN, provides strong authentication and shared value establishment. Our protocol is well-suited in the resource-constrained sensor nodes; furthermore, it is more secure and efficient compared to related security protocols in sensor networks. To standardize the evaluation, this paper implements the authentication protocol in the platforms of SmartDust, Strong Arm chips and Xscale. Finally, the paper analyzes its resource usage and proves its feasibility.

Keywords