An Improved Authentication Protocol for Hierarchical Wireless Sensor Networks using ECC

User authentication in case of wireless sensor network is a very critical task, as sensor nodes are deployed in unattached environment and are prone to possible hostile network attacks. Any authentication protocol in WSN must be designed keeping the fact that sensor nodes have limited computing power, memory, energy and communication capabilities. In this paper,animproved user authentication protocol based on Elliptic Curve Cryptography (ECC) has been introduced for hierarchical wireless sensor networks (HWSN). This paper shows that the ECC based protocol is suitable for wireless sensor networks where higher security is demanded. Besides thisthe proposed scheme provides mutual authentication and a secret session key for communication between the user and the cluster head. It also providesan option for addition or replacement of cluster head in the network whenever there is a need.