Date Added: Jan 2011
With a widespread growth in the potential applications of Wireless Sensor Networks (WSN), the need for reliable security mechanisms for them has increased manifold. Security protocols in WSNs, unlike the traditional mechanisms, need special efforts and issues to be addressed. This is attributed to the inherent computational and communicational constraints in these tiny embedded system devices. Another reason which distinguishes them from traditional network security mechanisms, is their usage in extremely hostile and unattended environments. The sensitivity of the data sensed by these devices also pose ever-increasing challenges. The authors present a layer based classification of WSN security threats and defenses proposed in the literature, with special focus on physical, link and network layer issues.