6Bertino E, Sandhu R.Database security concepts approaches and challenges[J].IEEE Transactions on Dependable and Secure Computing,2005,2( 1 ) :2-19.
7Gabriel G,Panos K,Khoshgozaran A,et al.Private queries in location based services:Anonymizers are not necessary[C]//Proceedings of the 2008 ACM SIGMOD International Conference on Management of Data.Vancouver: ACM Press, 2008 : 121-132.
8Ateniese G,Kevin F,Matthew G,et al.lmproved proxy re-encryption schemes with applications to secure distributed storage[J]. ACM Transactions on Information and System Security, 2006,9 (4) : 1-30.
9Ahitub N, Lapid C, Neumann S.Processing encrypted data[J]. Communications of the ACM, 1987,30(99) :777-780.
10Hacigumus H, Lyer B, Mehrotra S.Providing database as a service[C]//Proceedings of the ICDE.San Jose: IEEE Press, 2002: 29-38.
