A general approach to securely querying XML

Access control models for XML data can be classified in two major categories: node filtering and query rewriting systems. The first category includes approaches that use access policies to compute secure user views on XML data sets. User queries are then evaluated on those views. In the second category of approaches, authorization rules are used to transform user queries to be evaluated against the original XML dataset. The aim of this paper is to describe a model combining the advantages of these approaches and overcoming their limitations. The model specification is given using a Finite State Automata, ensuring generality and easiness of standardization w.r.t. specific implementation techniques

A general approach to securely querying XML

XML access control requires the enforcement of highly expressive access control policies to support schema-, document and object-specific protection requirements. Access control models for XML data can be classified in two major categories: node filtering and query rewriting systems. The first category includes approaches that use access policies to compute secure user views on XML data sets. User queries are then evaluated on those views. In the second category of approaches, authorization rules are used to transform user queries to be evaluated against the original XML data set. The pros and cons for these approaches have been widely discussed in the framework of XML access control standardization activities. The aim of this paper is to describe a model combining the advantages of these approaches and overcoming their limitations, suitable as the basis of a standard technique for XML access control enforcement. The model specification is given using a Finite State Automata, ensuring generality w.r.t. specific implementation techniques

Protection of relationships in XML documents with the XML-BB model

Abstract. Since XML tends to become the main format to exchange data over the Internet, it is necessary to define a security model to control the access to the content of these documents. Several such models have already been suggested, but we claim that none of them is sufficiently expressive to properly express some basic security requirements, especially those related to entity relationships protection. To cope with these limitations, we suggest to structure the access control policy using the new concept of block. This is used to hide relationships between nodes selected in different blocks. It provides means to specify confidentiality restriction associated with some relationships. An access control model, called XML-BB (XML Block Based Access Control), that includes this concept of block is presented and a formal semantics for this model is defined.