Scalable and Efficient Key Agreement Protocols for Secure Multicast Communication in MANETs

-In this paper protocols for group key distribution are compared and evaluated from the point of view of Mobile Ad Hoc Networks (MANETs). A MANET is a collection of wireless mobile nodes, communicating among themselves over possibly multihop paths, without the help of any infrastructure such as base stations or access points. So the need to render those networks as autonomous and secure as possible, since no central authorization can be assumed at all times, becomes emergent. Key management is the service that ensures the security of communication among nodes, and the capability of their cooperation as a secure group. It consists of three important services: key generation, user authentication and key distribution. In this work we assume that the participating users have already been authenticated with some mechanism, and we are focused only on studying and comparing protocols for group key establishment in MANETs. We are addressing the issues of FaultTolerance and Efficiency for key distribution protocols for group communications in MANETs. Most key distribution protocols that exist today are primarily designed for wireline networks. These protocols either fail to work as intended or cannot work at all when they are applied to the demanding environment of MANETs. The main reasons for this are: frequent node failures, network partitions and merges, inefficient computational and communication capabilities of certain wireless nodes, network delay, bad quality of signal etc. We determine the framework under which protocols can efficiently work in MANETs, design new protocols or modify existing ones, so that they can be robust, scalable and applicable in this environment. We classify these protocols in two families, contributory and non-contributory. We evaluate them from the point of view of MANETs and compare their performance.