Study On Key Management Of Multicast

Multicast is a new technology with high efficiency for network transport. Multicast affords one to many and many to many transport mechanisms, which can reduce network bandwidth and alleviate the server load. Multicast has been widely used in numerous areas, such as real-time data transport, multimedia conference, network game. However, there also exist some issues which would block further use of multicast. That is multicast security.Although unicast security is well resolved, however, since the multicast architecture is more complex than that of unicast, multicast security still exists many problems need to research. The requirements of multicast security include secrecy, group member identity, source identity, anonymity and integrity. Above all of these security issues, key management is the vital problem.In multicast communication, how to distribute and manage keys for secure communication is the research scope of multicast key management. The emphases of this paper are to find methods for multicast key management, which is to generate, distribute and update keys and to solve the problem of scalability, robustness and reliability. In this paper, we give an introduction to typical protocols of multicast key management such as GKMP protocol, Iolus protocol, Clique protocol, key management protocol based on Key Graphs and analyze them on architecture, amount of keys, key updating and reliability.Based on exist key management schemes, two efficient wireless multicast key management schemes have been proposed. In the first scheme, we design a clever key storage method which can significantly reduce the communication cost for rekeying by increasing the key storage number. The experiment results indicate that this scheme can efficiently reduce the rekeying communication cost. The second key management scheme called hybrid key management scheme (HKM), HKM adopts topology matching(TM) subtrees and topology independent (TI) subtrees, and uses these two kinds of subtrees to separately manage high speed mobile user nodes and low speed mobile user nodes. This scheme can efficiently reduce rekeying communication cost caused by broadcast for rekeying on topology independent key management trees and communication cost of rekeying for handoffs on topology matching key management trees.