Towards scalable key management for secure multicast communication

Secure multicast communication allows a sender to deliver encrypted messages to a group of authorized receivers. A practical approach is that the sender uses a common key shared by the authorized receivers to encrypt the transmitted messages. The common key must be renewed to ensure forward/backward secrecy when group members leave/join the group, called the rekeying process. Thus, the rekeying problem is a critical issue for secure multicast communication. Many key management schemes have been proposed to improve the performance of the rekeying process. In 2010, Lin et al. proposed two key management schemes without the rekeying process. However, the transmission size required in their schemes increases linearly with the number of group members. In this article, we use the time-bound concept to propose two new key management schemes without the rekeying process. The point is that the required transmission size is constant. Performance analysis is given to demonstrate that our schemes have better performance as compared with the recently proposed key management schemes in terms of transmission size and computational cost. Under several security assumptions, we prove that the proposed schemes satisfy the requirements of secure multicast communication.