Hierarchical key management and distributed multimodal biometric authentication in mobile ad hoc networks

Hierarchical key management is suitable for military applications where the organization of the network is already hierarchical in nature. Existing key management schemes concentrate only on network structure and key allocation algorithms, and the dynamic nature of MANETs is largely ignored. In this thesis, we propose a distributed hierarchical key management scheme that can select the best nodes to work as private key generator (PKG) from all available nodes based on their security conditions and energy states. The proposed scheme can improve the network security and increase the network lifetime. The node selection is formulated as a stochastic restless bandit problem. A primal dual index heuristic is used to solve the problem, which decreases the computational complexity.;Another security challenge addressed in this thesis is multimodal biometric-based authentication. We propose a distributed multimodal biometric authentication scheme that can dynamically decide which biometric device should be used for authentication. The proposed scheme is distributed as each biometric device works independently to decide if an authentication is required. Simulation results show the effectiveness of the proposed schemes.