6Hallqvist N,Keromytis A D.Implementing Internet Key Exchange (IKE).In Proceedings of the Annual USENIX Technical Conference,Freenix Track,2000-06 :201-214.
7Sandhu R,Coyne E J,Feinstein H L,et al.Role-based Access Control Models.IEEE Computer,1996,29(2) : 38-47.