Group key management scheme for simultaneous multiple groups with overlapped membership

Consider several groups engaged in a single project. Group members of one group happens to communicate with other group members. How might the communication among the members be carried out securely? How to ensure that a group member of one group communicate securely with its own group and with other group members as well?. We predict that secure group key management schemes for simultaneous multiple groups which allow inter-group communication become increasingly popular. We detail this problem under secure group communication model. Following the work of [1], we provide an efficient secure multiple groups key management scheme with overlapping membership based on the proposed Key-User Tree structure with following properties. a) Scheme handles multiple groups simultaneously. b) Group members within a group can communicate securely. c) Group members of one group can communicate with other group members securely. We analyze join and leave protocols of the scheme for storage, encryption and key changes upon membership change. Our scheme scales well as the overlapping memberships across the multiple groups increases rapidly. Our scheme achieves significant reduction in rekeying cost, storage and scales well in comparison with [1].