Access control for XML documents and data

Protecting data over the web is today a crucial need for many companies and organizations. This requires not only the use of cryptographic and digital signature techniques for protecting data during transmission, but also the development of suitable access control models and mechanisms able to support the specification and enforcement of a variety of access control policies. In this paper, we first discuss which are the main access control requirements for web data, and compare some of the most important research proposals with respect to these requirements. We then present Author-X [6] as an example of comprehensive system for controlling access to web data.