Security in wireless sensor networks

Rapid advances in wired/wireless networking technology are gradually expanding the realm of ubiquitous high-speed network access. Such a process also encounters more and more threats and attacks from those who exploit vulnerabilities in networks. This has been motivating research on security in wireless networks.; Key establishment is the first step to develop all the other security mechanisms, because most security protocols depend on keys to operate correctly and provide desirable security performance. In my research, a scalable and deterministic key agreement model based on a multivariate polynomial and a multidimensional grid-based network topology was developed to enable key establishment in large scale networks with very low memory cost. I will show that my model can achieve the memory cost of several orders lower than the number of nodes in the network, while traditional models have the memory cost at the same order as the network size. My model has found applications in wireless sensor networks to establish hop-to-hop keys and end-to-end keys. In addition, I also proposed an access control protocol based on elliptic curve cryptography (ECC) for wireless sensor networks, which accomplishes node authentication and key establishment for new nodes. Different from conventional authentication methods, my protocol can defend against most well-recognized attacks in wireless sensor networks, and achieve better computation and communication performance due to the more efficient algorithms based on ECC.; Authentication is critical to ensure the origin of a multicast stream in hostile environments. Conventional block-based schemes suffer from drawbacks such as vulnerability to packet loss, authentication latency and Denial of Service (DoS) attacks. In my research, I developed a novel multicast authentication scheme based on batch signatures. In particular, each packet in a stream is attached with a signature. The receiver authenticates multiple packets by checking their signatures through only one verification operation. I proposed three implementations including two novel batch signature schemes. My approach can achieve computational efficiency while avoiding the drawbacks of conventional block-based schemes. I also proposed a broadcast authentication protocol for wireless sensor networks based on symmetric key techniques. Compared with the conventional symmetric key solutions, my scheme does not require time synchronization, eliminates the requirement of key chain, supports broadcast for infinite rounds, and is efficient due to the use of symmetric key techniques.; IEEE 802.16 (worldwide interoperability for microwave access, or WiMAX) is seen as a promising technology for next generation broadband wireless access, while security issues also draw the intentions in the literature. In my research, I analyzed the IEEE 802.16 standard and found out that though IEEE 802.16 provides some security measures in conventional one-hop networks, it is very vulnerable to malicious attacks in multihop environments such as wireless mesh networks. In order to strength the defense of IEEE 802.16 in mesh networks, I proposed a mesh-certificate-based access control and authentication scheme for WiMAX-based mesh networks.