Key set up and distribution in sensor network is a complex task due to inherent limitations in sensor networks. For reducing the “communication and computation overhead” we proposed that the sensor network is partitioned into different zones. Each zone has a separate intrusion detection system (IDS) and key distribution center (KDC).IDS can detect the activity in its area and communicate with its KDC. KDC is controlled by the base station. Our main concern is that how to make a secure link in between KDC to sensor nodes and KDC to the Base station. Here we will try to reduce the computation and communication overhead of the already overloaded base station by separating the intrusion detection work of the base station with a separate entity in each zone.