A system for secure multicast including a plurality of participants that can send and receive multicast messages. A traffic distribution component is coupled to the participating entities, where the traffic distribution component supports multiple receiver communication. A participant key management component operates within each participant entity where the participant key management component uses a first key that is shared with all of the other participants, and a second key that is shared with a subgroup of participants. A group key management component is implemented using a flat data structure having a size that is logarithmically proportional to the number of participants.