Author-X: A Java-Based System for XML Data Protection

Author-χ is a Java-based system for access control to XML documents. Author-χ implements a discretionary access control model specifically tailored to the characteristics of XML documents. In particular, our system allows (i) a set-oriented and single-oriented document protection, by supporting authorizations both at document type and document level; (ii) a differentiated protection of document/document type contents by supporting multi-granularity protection objects and positive/negative authorizations; (iii) a controlled propagation of authorizations among protection objects, by enforcing multiple propagation options.