A New Group Rekeying Method in Secure Multicast

摘要

LKH(Logical Key Hierarchy) is a basic method in secure multicast group rekeying. It does not distinguish the behavior of group members even they have different probabilities (join or leave). When members have diverse changing probability or different changing mode, the gap between LKH and the optimal rekeying algorithm will become bigger. If the probabilities of members have been known, LKH can be improved someway, but it can not be known exactly the changing probabilities of members. Based on the basic knowledge of group members' behavior (ex. active or inactive), the active members and inactive members are partitioned in the new method, and they are set on the different location in logical key tree firstly. Then the concept "Dirty Path" is introduced in order to reduce the repeat rekeying overhead in the same path. All these can decrease the number of encryptions in the Group Manager and the network communication overhead. The simulation results indicate that the new method has a better improvement over traditional LKH method even if the multicast group members' behavior could be distinguished "approximately".