In this short paper, we propose a new key management architecture for Multicast communications. This architecture combines the complementary variable approach with hashed keys and hierarchical binary trees. This will reduce the number of transmissions at the joins/leaves of participants. Also, we explain a naming method, which allows to facilitate the understanding of the hierarchical binary tree of keys. This new naming method will also facilitates the treatments in the refresh of keys. Customised packets for the key exchange between the sender and the participants are introduced in this paper. KEYWORDS Secure Multicast, Key Distribution, Hierarchical Binary Trees, Hashed Keys, Identifiers.