Wireless Sensor Networks (WSNs) can be used to monitor environments and therefore have broad range of interesting applications. The applications which may use WSN can be of sensitive nature and therefore might require enhanced secured environment. As sensors are used to monitor sensitive areas therefore Security and energy efficiency is essential consideration when designing Wireless Sensor Networks (WSNs). The sensor nodes get their power from batteries. Since the sensor nodes are deployed in harsh environment they cannot be recharged. Due to unattended deployment and inability of recharging, the power consumption of the nodes should be optimal. To implement minimum power consumption Sensor networks periodically place nodes to sleep.