Some issues in these categories were addressed by multi-sensor application or sensor fusion. However, advancement in technology and advent of wireless sensors in a networked environment, brought along a new risk factor related to the security in wireless sensor network. Therefore security in Wireless Sensor Network WSNs is challenging and critical to the functionality of the networked sensors. The problem of security is due to the wireless nature of the sensor networks and constrained nature of resources on the wireless sensor nodes, which means that security architectures used for traditional wireless networks are not viable.