A novel dynamic user authentication scheme for wireless sensor networks

In 2006, Wong et al. proposed a dynamic user authentication scheme for WSNs that allows legitimate users to query and collect sensor readings from sensor nodes of the network. They presented analysis to show that their scheme is secure and efficient. Later, in 2007, Tseng et al. pointed out several weaknesses in Wong et al.¿s scheme and proposed an improved scheme to overcome the weaknesses. However, in this paper we show that Tseng et al.¿s scheme is still insecure under a reasonable attack model. Moreover, their scheme does not achieve mutual authentication, which is very important for many applications. We first discuss the weaknesses in Tseng et al.¿s scheme, and then propose a novel scheme, which overcomes the weaknesses in Tseng et al.¿s scheme and achieves mutual authentication. The proposed scheme not only inherits all the advantages of Tseng et al.¿s scheme but also improves its security strength.