2Davila J,Lopez J,Mana A.Development of secure intemet applications for governmental environments[C].Greenwich,London:11th International Workshop on Database and Expert Systems Applications,2000.362-365.
3Joshi J,Ghafoor A,Aref W G.Digital government security infra structure design challenges[J].Computer,2001,34(2):66-72.
4Dickson K W Chiu,Cheung S C,Sven Till.Three-layer architecture for E-contract enforcement in an E-service environment[C].Big Island,Hawaii:36th Annual Hawaii International Conference on System Sciences,2003.
5Douglas Stinson.Cryptography:Theory and practice[M].CRC Press,1995.
