A bitmap indexing scheme for temporal access control to XML documents

As more and more sensitive information gets stored in the form of XML, proper access control to the XML documents becomes increasingly important. Moreover, XML documents may be available to users at certain time periods, and unavailable at others. To tackle such dynamic aspects, this paper proposes a bitmap-indexing scheme in which timed access control decisions can be effectively processed. The form (Auth_t, Auth_o) is used to present authorization policies which are encoded as bitmaps in the same manner as XML document indexes are constructed.