A Study on Efficient Access Control for XML Ducuments

In access control for XML (Extensible Markup Language) documents, the security level for particular XML nodes differs depending on the user´s id or role. In this paper, we introduce Policy Tables for each roles, and discuss optimization of these tables. In general, there is a trade-off between the power of policy description and the time required for an access decision. We discuss two approaches to the reduction of time for the access decision. The first is the creation of the Policy Tables beforehand. The second approach is a simplification of the Policy Tables by exploiting the consecutive property of the decision result for XML elements.