IP multicast is an efficient mufti-agent transport protocol. With the development of network

multicast will be morn and more important. Applications of multicast will be used in many areas..9s a fresh new thriving academic field

the main research is focused on multicast routing

the flow control

the congestion control and reliable multicast. But there are few results referred to mufticast security especially to group key management. In this paper

it will submit a scheme of group key management for large dynan vc multicast system.This scheme adopts hierarchical architectme

includes a control-center (main key management center: KMC) which is composed of a cluster of computers

and some sub key management center(SKMC) which manages its sub-domain.The scheme can efficiently handle the joining and leaving of group members and avoid one-point failure.It also enhances the robustness of the manage system.