μSec: A security protocol for unicast communication in wireless sensor networks

Secure communication in wireless sensor networks (WSNs) not only needs to provide the basic security but also to defend various attacks. The challenge in providing security in this network is that the securing mechanism must be lightweight to make it implementable in resource-constrained nodes. In this paper we have devised a link layer protocol for securing unicast communication in wireless sensor network (WSN). The protocol (μSec) is developed in TinyOS platform which is an event-driven operating system used in WSN for networked applications. Our protocol supports the basic security features such as confidentiality, authentication and integrity along with defense against replay attacks. We have modified an existing cryptographic algorithm with a target to minimize computational overhead to make it implementable in WSN. A simple, counter based defense mechanism is proposed to thwart replay attack. Both qualitative and quantitative analyses are performed to measure the efficacy of the protocol. The protocol is compared with some of important security protocols developed around TinyOS. We claim that that μSec, in addition to basic security, thwarts replay attack with same overhead as in other protocols which have considered basic securities only. We further claim that the μSec requires 10% (avg.) less overhead compared to its competitor which also defends replay attack.