A distributed key management protocol for dynamic groups

With the popularity of group-oriented applications, secure and efficient communication among all group members has become a major issue. We propose a distributed key management protocol for group members to share a secret group key, which can be used to protect shared information. The protocol manages the group key of a dynamic group, where members can freely join or leave, and each time the key is updated using two broadcast messages. The protocol algorithms provide group key secrecy, forward group key secrecy, and backward group key secrecy. The complexities of the group key computation time, the storage space for every member, and the total communication bandwidth to update the group key are approximately of logarithmic order of the group size, which make the protocol attractive for environments with less computation power and smaller storage.