Multicast gives large-scale content distribution by providing an efficient transport mechanism for one-to-many and many-to-many communications. There are various security issues in multicast communication, related to the nature of multicast. Group Diffie-Hellman key exchange protocol is a well known protocol for establishing common key on the open channel; however, due to middle-man-attack, the confidentiality can be compromised. To remove the man-in-middle attack in Group Diffie-Hellman, we propose a secure identity-based key management scheme, which combines the principles of Group Diffie-Hellman and of trusted third party; scheme uses the identity of the nodes to establish the common key for a group.