Date Added: May 2012
A Wireless Sensor Network (WSN) consisting of a large number of tiny sensors can be an effective tool for gathering data in diverse kinds of environments. The data collected by each sensor node is communicated to the base station, which forwards the data to the end user. In wireless sensor network data security plays an important role where confidentiality, authentication, integrity, non repudiation are given importance. This paper synthesizes existing user authentication schemes in wireless sensor networks and highlights the challenges in user authentication.