Trust models for sensor networks

The range of applications of wireless sensor networks is so wide that it tends to invade our every-day life. In the future, a sensor network will surveil our health, our home, the roads we follow, the office or the industry we work in, or even the aircrafts we use, in an attempt to enhance our safety. However, the wireless sensor networks themselves are prone to security attacks. The list of security attack is already very long and will impede the deployment of these solutions, if not efficiently addressed. In this paper, we focus on the security threats against routing, which is a basic networking service, required for any sensor network communication. Preventing the integrity and data freshness of the exchanged packets is a requirement but is not enough to secure the routing procedure. It is required to set-up a trust management scheme which allows the nodes to select trusted paths rather than secure routes in the network by observing the sincerity in participation by other nodes. A trust management system can be useful for detecting a node which is not behaving as expected (either faulty or maliciously). Current trends in trusted routing for ad-hoc networks are reviewed, followed by comments on their applicability in sensor network and guidelines for trust model design for new sensor applications.