Date Added: Aug 2013
Wireless Sensor Networks (WSN) are more prone to insider and outsider attacks as the sensor nodes are deployed in open environment for collecting data. The traditional cryptography based security mechanisms such as authentication and authorization are able to sort out issues of outside attacker, but they are not effective against insider attacks. Trust based approaches are used to defend against insider attacks in wireless sensor network. A trust model provides a way to quantify the trustworthiness of a sensor node. Watchdog is a popular mechanism to collect the information regarding the behavior of nodes.