Efficient privacy-preserving multicast in cloud data centers

Multicast is widely adopted by applications in cloud data centers. Due to the shortage of IP multicast groups, many efforts have been made to share multicast groups among multiple multicast sessions. However, existing group sharing schemes would lead to a serious privacy problem that some data will be exposed to receivers not belonging to the corresponding multicast session. In this paper, we propose a novel system called EPM for privacy-preserving multicast in cloud data centers. By enhancing a popular virtual machine manager Xen, it guarantees that the multicast packets received by each physical machine can be correctly forwarded only to virtual machines as destinations. Furthermore, we study a group assignment problem based on EPM to reduce redundant multicast traffic in cloud data centers, which will be solved by an efficient heuristic algorithm. We evaluate the effectiveness of EPM by implementing it on real systems, and conduct extensive experiments to show that the proposed algorithm can significantly reduce multicast traffic.