A Hierarchical and Role Based Secure Routing Protocol for Mobile Wireless Sensor Networks

Nodes in wireless sensor networks are highly resource constrained and topology of such networks remains highly dynamic due to sudden death of sensor nodes and break of links. When mobility to such nodes is introduced, it gives rise to a highly complex network system since the topology becomes even more dynamic. Providing security in the routing layer of wireless sensor network is a highly critical issue mainly due to the stringent resource constraints and dynamic topology. In this paper, we propose a Secure Hierarchical and Role based Routing Protocol for Mobile Wireless Sensor Network (SHaRP) which is a combination of symmetric and asymmetric cryptographic approach. In the SHaRP framework, the sensor field is divided into some logical clusters and each cluster contains nodes with different roles such as ordinary sensor node (OSN), cluster head (CH) and gateway node (GN). Different keys are used by the nodes with distinct roles for message encryption and message decryption. The overall security has been entrusted on different roles in a distributed manner instead of relying on one authority and that is why this approach is safe from single point of failure problem. This also enhances the security in the network system. In this paper, we focus more on various security aspects in the routing process rather than the issues like cluster formation and role distribution. We shift most of the computing overhead to the base station as it is assumed to be a resourceful and reliable node. This obviously improves the energy efficiency of the protocol. We also report a security analysis along with implementation issues of the proposed protocol.