Presto authorization: a bitmap indexing scheme for high-speed access control to XML documents

XML (extensible markup language) is fast becoming the de facto standard for information exchange over the Internet. As more and more sensitive information gets stored in the form of XML, proper access control to the XML documents becomes increasingly important. However, traditional access control methodologies that have been adapted for XML documents do not address the performance issue of access control. This paper proposes a bitmap-indexing scheme in which access control decisions can be sped up. Authorization policies of the form (subject, object, and action) are encoded as bitmaps in the same manner as XML document indexes are constructed. These two are then efficiently pipelined and manipulated for "fast" access control and "secure" retrieval of XML documents.