Research On Group Key Management Based On Logical Key Hierarchy

Multicast is an effective way to reduce the load of server and network. Because the Internet had had a sharp increase in capabilities of transmission and processing, large numbers of multicast applications emerged (such as text communication, visual telephone, network meeting, video-on-demand and collaborative computing). But the Internet faces the problem of multicast security. In order to meet the confidentiality and integrity of multicast communication, group members need to share a group key, which is used to encrypt group communication content. Once a changing occurs, the group key needs to be updated to prevent unauthorized users from obtaining the communication content. How to update the group key in a highly efficient and scalable way is the main problem that group key management needs to solve. This paper researches the issues of group key management. The main work is as follows:In this paper, we design and implement a group key rekeying scheme based on secret sharing (Secret Sharing Group Key Distribution). The scheme uses secret sharing to construct the rekeying message. Compared with the LKH scheme, our scheme has the same communication overhead complexity, but reduces the computational overhead complexity of the group members significantly. This paper describes in detail the procedures of initialization, member joining and member leaving, and analyzes the forward security, backward security, communication overhead, computational overhead and storage overhead of the scheme.This paper proposes an improved batch rekeying scheme, which intend to solve the problem of the imbalance of key tree. Our scheme keeps the key tree balance when rekeying. At the same time it doesn’t increase additional balance operations and reduce the communication overhead and computational overhead caused by the imbalance of key tree.In this paper, we do simulation experiments of the Secret Sharing Group Key Distribution scheme with the Visual C++(VC) and Miracl. The experiments prove the feasibility of the scheme. Then this paper compares the Secret Sharing Group Key Distribution scheme and the LKH scheme in communication overhead, computational overhead and storage overhead.