Investigations on an optimized key management system for secure multicast communication

Abstract

Multicasting is a type of communication between computers in a network, that enables a computer to send one stream of data to many interested receivers without interrupting computers that are not interested. In this thesis, we study the efficiency versus security requirements and tradeoffs in group key management for multicast communication. Efficiency is in terms of minimizing the group rekeying cost, the key storage cost and transmission cost, while security is in terms of achieving backward secrecy, forward secrecy, and resistance to collusion. This work considers one of the most challenging features of multicast deployment: an effective secure key management. In essence, the thesis summarizes the important existing key management algorithms available for use in multicast networks, and studies the weaknesses of the current schemes. A combinatorial based optimization technique Exclusion Basis System (EBS) was developed, which produces optimal results based on the size of the group, the number of keys stored by each member, and the number of rekey messages. A refined decentralized contributory key management technique was proposed, which reduces the rekeying cost of the multicast network. With the help of a Partially Full Maximum Height Tree (PFMH), a Tree-based Contributory Group Key Agreement (PACK) protocol with an optimal communication cost as well as computation cost was achieved. More secure and faster multicast content distribution was achieved by using the Multiple Edge Sharing Tree (MEST) tree construction. It is used to balance the resource allocation especially in Mobile Ad hoc NETworks (MANET). The overall results of the analytical evaluation show that our scheme allows a fine-tuning of security versus efficiency requirements at runtime, which is not possible with the previous group key management schemes. The solutions are actually application-specific ones. Based on the need of applications, the proposed solutions are selected and they can be used to achieve better results. newline newline newline