A fine-grained access control system for XML documents

TLDR

Web-based applications increase information availability, yet secure, selective access is required for transactions, and existing file-system–level approaches ignore data-level protection; XML’s extensibility offers a standard for fine-grained access control. The authors propose an access control model that exploits XML’s structure to define and enforce restrictions directly on document content. They introduce a restriction specification language using standard notations and describe a system architecture that enforces these restrictions with existing technology. The resulting system is flexible, powerful, and integrates easily with current solutions.

Abstract

Web-based applications greatly increase information availability and ease of access, which is optimal for public information. The distribution and sharing of information via the Web that must be accessed in a selective way, such as electronic commerce transactions, require the definition and enforcement of security controls, ensuring that information will be accessible only to authorized entities. Different approaches have been proposed that address the problem of protecting information in a Web system. However, these approaches typically operate at the file-system level, independently of the data that have to be protected from unauthorized accesses. Part of this problem is due to the limitations of HTML, historically used to design Web documents. The extensible markup language (XML), a markup language promoted by the World Wide Web Consortium (W3C), is de facto the standard language for the exchange of information on the Internet and represents an important opportunity to provide fine-grained access control. We present an access control model to protect information distributed on the Web that, by exploiting XML's own capabilities, allows the definition and enforcement of access restrictions directly on the structure and content of the documents. We present a language for the specification of access restrictions, which uses standard notations and concepts, together with a description of a system architecture for access control enforcement based on existing technology. The result is a flexible and powerful security system offering a simple integration with current solutions.