Communication Security in Wireless Sensor Networks

A wireless sensor network (WSN) usually consists of a large number of small, lowcost devices that have limited energy supply, computation, memory, and communication capacities. Recently, WSNs have drawn a lot of attention due to their broad applications in both military and civilian domains. Communication security is essential to the success of WSN applications, especially for those mission-critical applications working in unattended and even hostile environments. However, providing satisfactory security protection in WSNs has ever been a challenging task due to various network & resource constraints and malicious attacks. This motivates the research on communication security for WSNs. This dissertation studies communication security in WSNs with respect to three important aspects. The first study addresses broadcast/multicast security in WSNs. We propose a multi-user broadcast authentication technique, which overcomes the security vulnerability of existing solutions. The proposed scheme guarantees immediate broadcast authentication by employing public key cryptography, and achieves its efficiency through integrating various techniques from different domains. We also address multicast encryption to solve data confidentiality concern for secure multicast. Utilizing the fact that sensors are both routers and end-receivers, we propose a lightweight multicast key management scheme that supports a broad range of multicast semantics. The second study addresses data report security in WSNs. A location-aware end-to-end security framework for WSNs is proposed, in which secret keys are bound to geographic locations so that the impact of sensor compromise are limited only to their vicinity. The proposed scheme effectively defeats both bogus data injection attacks and various denial of service (DoS) attacks. In addition, we address event boundary detection as a specific case of secure data aggregation in WSNs. We propose a secure and fault-tolerant event boundary detection scheme, which is a localized statistic approach that detects the boundaries of large spatial events. The third study addresses key management security in WSNs. We propose a keyed-hashchain-based key pool generation technique for random key pre-distribution, which leads to a higher scheme efficiency and better security resilience against sensor compromise.