Abstract Totally Distributed Key Management for Dynamic Groups in MANETs

Most existing solutions to group security in Mobile Ad Hoc Networks (MANETs) rely on a multicast Core Based Tree (CBT) for key distribution. Such solutions, although suitable for systems with low mobility and static characteristics, are highly unsuitable for dynamic and sparse groups with changing neighborhoods. Also, tree based solutions are prone to a man-in-the-middle attack. This might lead to network partitioning with the attacker controlling one or more sections of the network. Another issue with tree based schemes is that a group controller is required to control the key generation process. In this paper, we propose an entirely decentralized key generation mechanism. Using our approach, keys can be established between group members with absolutely no prior communication, as long as the group members are known. The solution relies on threshold cryptography and introduces a novel concept of Node-Group-Key (NGK) mapping. Although our primary focus has been on group communication, our scheme can be easily extended to peer-to-peer communication, establishment of a distributed certification authority etc. We have provided an extensive analytical model for the computations involved, the communication costs and have also provided a ‘lie ’ detection and prevention mechanism. Simulation results show appreciable performance improvement and enhanced robustness. I. INRODUCTION The last few years have witnessed increased research in the field of group security in ad hoc networks. A group ca