Date Added: Feb 2010
Designing a user authentication protocol for wireless sensor networks is a difficult task because wireless networks are susceptible to attacks and sensor node has limited energy, processing and storage resources. Recently, several authentication schemes have been proposed. This paper shows some security problems and design weaknesses in those schemes. Furthermore, an enhanced two-factor user authentication protocol is presented. The proposed scheme only uses hash function, and a successful user authentication just requires three message exchanges. Security and performance analyses demonstrate that compared to the well-known authentication schemes, the authors' proposal is more secure and efficient.