Optimizing the Secure Evaluation of Twig Queries

Publisher Summary

This chapter focuses on the problem of secure evaluation of eXtensible Markup Language (XML) twig queries, for the simple, but useful, multilevel security model. The rapid emergence of XML as a standard for data exchange over the Web has led to considerable interest in the problem of securing XML documents. In this context, query evaluation engines need to ensure that user queries only use and return XML data that the user is allowed to access. These added access control checks can considerably increase query evaluation time. Companies are using the Web as the main means of information dissemination, sparking interest in models, and efficient mechanisms for controlled access to information content over the Web. In this respect, securing XML documents is an important step, because XML is rapidly emerging as the standard for data representation and exchange over the Web.