If multicast communication appears as the most efficient way to send data to a group of participants, it presents also more vulnerabilities to attacks and requires services such as authentication, integrity and confidentiality to transport data securely. In this paper, we present the protocol Baal as a scalable solution to group key management problems and show how Baal resolves the user's revocation problem. This protocol is based on decentralized group key management with only one key shared among group members. We use then Network Simulator, ns-2, in order to evaluate the performance of our protocol in the case of group initialisation, and compare it with SKDC approaches.