A multi-channel defense against communication denial -of -service attacks in wireless networks

In this dissertation, we focus on the security and reliability of wireless sensor networks (WSNs). We specifically address attacks which target the availability of the wireless communication medium. Due to their unattended functioning and over-the-air communication, WSNs are particularly vulnerable to link-level denial-of-service (DoS) attacks against the communication channel. Our main contribution is to design reactive solutions that can achieve a higher throughput out of an attacked region via the use of parallel communication paths. Our approach uses a hybrid Medium Access Control layer consisting of both CSMA and time-slotted channel access mechanisms. We define and analyze a set of distributed transmission scheduling algorithms for use in the attacked region, ranging from management-free to precise coordinated scheduling. To implement our techniques, we develop a distributed data exfiltration protocol which has two variants, one to act as a response against single-hop attacks and another which provides resilience against attacks affecting multi-hop regions. Extensive experimental evaluation shows that under many attack scenarios our approach achieves a data delivery rate comparable to pre-attack conditions and far lower latency than other similar approaches. Furthermore, a simulation-based evaluation of the data exfiltration methods and protocols as a fault-tolerance mechanism in protecting a critical infrastructure has demonstrated that its incorporation in the application’s design will lead to increased reliability and robustness in WSNs