I. Introduction
A Wireless Sensor Network (WSN) may consist of a large number of sensor nodes, which have limited communication range, energy, bandwidth, and computational resources. These sensor nodes are randomly spread over an area of interest to serve applications such as battlefields surveillance, boarder monitoring, etc. [1]. Each sensor node probes its surroundings and transmits its measurements to an in-situ Base-Station (BS). To conserve energy and overcome the communication range constraint, data is routed to the BS over multi-hop paths. In other words, the BS acts as the sink of all data traffic in the WSN. The BS may also perform some essential network management functions, e.g., route setup and medium access scheduling, and coordinate the nodes activities to serve the application goals. Given the critical role that a BS plays, it becomes an attractive target for Denial of Service (DoS) attack by an adversary who opts to disrupt the WSN operation [2].