Toward reliable actor services in wireless sensor and actor networks

Wireless sensor and actor networks (WSANs) are service-oriented environments, where sensors request actors to service their detected events and actors move to deliver the desired services. Because of their openness and unattended nature, these networks are vulnerable to various security attacks. In this paper we address service fraud attacks for the first time, whose objective is to stop the normal use of actor services by fake service requests and/or delivery. To mitigate this type of security attacks, we propose a novel cooperative authentication scheme. With the scheme, a sensor's service request is cooperatively authenticated by the sensors that witness the same event, and an actor's service delivery effort is cooperatively authenticated by the sensors that witness the actor's behavior. Considering the presence of compromised sensor/actor nodes, the trustworthiness of each authenticated service delivery process is subject to location consistency check and witness diversity check. It may then be taken into account to adjust the corresponding actor's trust rating so as to influence future actor service selection. We analyze the communication overhead and the security strength of the scheme. We show that our scheme ensures fraud-resistant actor services in our considered WSAN environment.