Systems and methods which facilitate secure multicast communications between any valid node of a cluster using authentication between a node joining the cluster and any single node which is validly part of the cluster are disclosed. In accordance with embodiments, a cluster key is utilized to provide security with respect to intra-cluster communications. The cluster key of embodiments is shared by a node which is already part of the cluster with a node joining the cluster only after these two nodes mutually authenticate one another. The mutual authentication handshake of embodiments implements a protocol in which a session key is calculated by both nodes, thereby providing a secure means by which a cluster key may be shared. Having the cluster key, each node of the cluster is enabled to securely communicate with any other node of the cluster, whether individually (e.g., unicast) or collectively (e.g., multicast), according to embodiments.