Distributed Group Key Management using Hierarchical Approach with Diffie hellam and Symmetric Algorithm

Abstract

Secure and reliable group communication is an active area of research. Its popularity is caused by the growing importance of group-oriented and collaborative applications.Various network applications require sending data to one or many members within the network, maintaining security in the large groups is among the biggest obstacles for controlling access.Unfortunately, IP multicast does not provide any security over the group communication. Group key management is a fundamental mechanism for secured multicast and unicast. The most widely used technique in a network is group communication. This helps in the reduction of the bandwidth usage. The major concern in group communication is message security. Group key provides security of messages and hence proper group key management is a necessity in a group communication. While centralized methods are often appropriate for key distribution in large multicast-style groups, many collaborative group settings require distributed key agreement techniques. Ensuring secure communication in an ad hoc network is extremely challenging because of the dynamic nature of the network and the lack of centralized management. For this reason, key management is particularly difficult to implement in dynamic networks .Group key management is a fundamental building block for secure group communication systems. We will present an efficient many-to-many group key management protocol in distributed group communication. In this protocol, group members are managed in the hierarchical manner logically. Two kinds of keys are used, asymmetric and symmetric keys. The leaf nodes in the key tree are the asymmetric keys and all the intermediate node keys are symmetric keys assigned to each intermediate node and uses a simple rekeying procedure which is suitable for large and dynamic networks. For asymmetric key, a more efficient key agreement will be introduced. To calculate intermediate node keys, members use codes assigned to each intermediate node key tree. Group members calculate intermediatetheir own node keys rather than distributed by a sponsor member. The features of this approach are that, no keys are exchanged between existing members at join, and only one key, the group key, broadcasted to remaining members at leave.This work investigates a novel group key agreement approach which blends so-called key trees with Diffie-Hellman key exchange.