A reliable trust management scheme in wireless sensor networks

Physical security of wireless sensor nodes cannot be provided because making sensor nodes tamperproof is prohibitively expensive. Due to this lack of physical security, intruders can easily compromise one or more sensor nodes to subvert network operations bypassing encryption and password security systems. Trust and reputation systems have been recently suggested as an effective security mechanism to overcome the shortcomings of cryptography-based schemes in securing wireless sensor networks (WSNs). Although researchers have been studying the problem of trust modeling and management in WSNs for over a decade, their focus was on trust based only on reputation which is by itself not sensitive enough to perceive suddenly spoiled nodes that may launch intelligent attacks against a trust-establishment mechanism. In this paper, we present a Trust Model based on Risk evaluation (TMR) to effectively deal with conflicting behaviors of malicious nodes. Unfortunately, risk factor evaluation can make the trust model more reliable because it becomes more sensitive to on-off attack.