Efficient group key management for multi-privileged groups

Multi-privileged group communications containing multiple data streams have been studied in the traditional wired network environment and the Internet. With the rapid development of mobile and wireless networks and in particular mobile ad-hoc networks (MANETs), the traditional Internet has been integrated with mobile and wireless networks to form the mobile Internet. The multi-privileged group communications can be applied to the mobile Internet. Group users can subscribe to different data streams according to their interest and have multiple access privileges with the support of multi-privileged group communications. Security is relatively easy to be guaranteed in traditional groups where all group members have the same privilege. On the other hand, security has been a challenging issue and is very difficult to handle in multi-privileged groups. In this paper, we first introduce some existing rekeying schemes for secure multi-privileged group communications and analyze their advantages and disadvantages. Then, we propose an efficient group key management scheme called ID-based Hierarchical Key Graph Scheme (IDHKGS) for secure multi-privileged group communications. The proposed scheme employs a key graph, on which each node is assigned a unique ID according to access relations between nodes. When a user joins/leaves the group or changes its access privileges, other users in the group can deduce the new keys using one-way function by themselves according to the ID of joining/leaving/changing node on the graph, and thus the proposed scheme can greatly reduce the rekeying overhead.