ABSTRACT
This chapter presents a comprehensive overview of various security issues in Wireless Sensor Networks (WSNs). It outlines the constraints of WSNs, security requirements in these networks, and various possible attacks and their corresponding countermeasures. The chapter presents holistic view of the security issues. These issues are classified into six categories: Cryptography, key management, secure routing, secure data aggregation, intrusion detection, and trust management. The chapter presents the security requirements in WSNs. It discusses various attacks that can be launched on WSNs. The chapter presents the numerous countermeasures for all possible attacks on WSNs. It explores some future directions of research in WSN security. A WSN consists of a large number of sensor nodes that are inherently resource-constrained devices. Unreliable communication is another serious threat to sensor security. The security mechanism in a WSN should ensure that no message in the network is understood by anyone except the intended recipient.
