The security in the multicast communication in the large groups is the major obstacles for effectively controlling access to the transmitting data. The IP Multicast itself does not provide any specific mechanisms to control the intruders in the group communication. Group key management is mainly addressing upon the trust model developed by Group Key Management Protocol (GKMP). On the Internet a multicast group is identified by a Class D IP address and any receivers can join or leave a multicast group by sending IGMP (Internet Group Management Protocol) messages to their local router. Any sender can send message to a multicast group by addressing the message to the group address. The trusted model gives a scope between the entities in a multicast security system. For secure group communication in the multicast network a group key shared by all group members is required. This group key should be updated when there are membership changes in the group such as when a new member joins or a current member leaves. There are several group key management protocols that are proposed our book will however elaborate mainly on Group key management which has a sound scalability.