Efficient Key Management for Secure Wireless Multicast

Along with the rapid development of mobile devices and widespread deployment of wireless networks, more and more content and service providers are increasingly interested in provide multicast applications over wireless networks. Before wireless group-oriented applications can be deployed in large scale, security must be guaranteed. Group key management is a critical issue in the wireless multicast security. In this paper, we propose a new key management scheme dedicated to wireless networks. In the proposal, we divide group members into several small operation units to perform the micro key management. Compared to the logical key hierarchy (LKH), our proposal can significantly reduce the workload of key server and provide efficient key management operations for secure wireless multicast.

I. Introduction

Multicasting is a more efficient communication technology to support group-oriented applications than unicast, as it transmits messages to a set of users simultaneously by using fewer network resources. Along with the rapid development of mobile devices and widespread deployment of wireless networks, more and more content and service providers are interested in supporting multicast in wireless networks. Therefore, it is reasonable to believe that many group-oriented applications such as software distribution, video conferencing and distance education will be appearing over wireless networks very soon. Before large-scale multicast applications are deployed in wireless networks, security must be guaranteed. However, multicast lacks of security mechanisms, especially access control, as it was designed on an open structure. Access control for the multicast applications can be achieved by applying cryptography. Group messages are encrypted by a shared key, called group key or traffic encryption key (TEK). This key is only known by the authorized users, that means only legitimate users can access to the group communications. Thus, the management of the group key becomes a critical issue in secure wireless multicast. Multicast has been supported in wired networks for at least 10 years, therefore many group key management schemes [1]–[11] have been proposed in literature. Nevertheless, these proposals were designed for the wired environment; they cannot be applied in wireless networks directly. The two main challenges are: (1) the network structure of wireless networks, (2) the mobility of users.