A key establishment scheme for wireless mesh networks using identity-based cryptography and threshold secret sharing

Wireless Mesh Networks (WMNs) are an emerging research area that provide low-cost and high-speed network services for the end users. Key establishment, on the other hand, is the most important and critical security concern for WMNs as all the other types of wireless networks. However, the conventional solutions for key establishment do not fit in the unique constraints and requirements of WMNs. In this thesis, we propose two efficient and secure key establishment protocols elaborated at the sake of WMNs. Our security model is based on Identity-based Cryptography (IBC) and Threshold Secret Sharing (ThSS). By the utilization of IBC, we eliminate the necessity of certificates used in infrastructure based schemes along with meeting the security requirements. With the utilization of ThSS, we provide a more resilient network working in a self-organizing way to provide the key establishment service, without the assumption of a trusted authority. In the schemes we propose, master private key of the network is distributed among the mesh nodes. The user private key generation service is handled with collaboration of k mesh nodes, where k is the threshold value. A high threshold value increases the resiliency of the network against attacks; however, this negatively affects the system performance. We performed simulative performance evaluation in order to show the effect of both the number of mesh nodes in the network and the threshold value k on the performance. For the threshold values smaller than 8, at least 90% of the mesh nodes compute their private keys within at most 70 seconds. When we increase the number of mesh nodes in the network from 40 to 100, the rate of successful private key generations increase from 75% to 100% at the threshold value 8 where the latency of the key establishment is around 80 seconds. Considering the same increase in the number of mesh nodes, network performs up to 42% better at worst case, for the threshold values larger than 8, and the latency becomes at most 90 seconds on the average