Paper 2011/216

Provably Secure Group Key Management Approach Based upon Hyper-sphere

Shaohua Tang, Lingling Xu, Niu Liu, Jintai Ding, and Zhiming Yang

Abstract

Secure group communication systems become more and more important in many emerging network applications. For a secure group communication system, an efficient and robust group key management approach is essential. In this paper, a new group key management approach with a group controller GC using the theory of hyper-sphere is developed, where a hyper-sphere is constructed for a group and each member in the group corresponds to a point on the hyper-sphere, which is called the member's private point. The GC computes the central point of the hyper-sphere, intuitively, whose ``distance" from each member's private point is identical. The central point is published and each member can compute a common group key via a function invoking each member's private point and the central point of the hyper-sphere. This approach is provably secure under the pseudo-random function (PRF) assumption. The performance of our approach is analyzed to demonstrate its advantages in comparison with others, which include: 1) it requires both small memory and little computations for each group member; 2) it can handle massive membership change efficiently with only two re-keying messages, i.e., the central point of the hyper-sphere and a random number; 3) it is very efficient and very scalable for large-size groups. Our experiments confirm these advantages and the implementation of our prototype presents very satisfactory performance for large-size groups.