This book is an overview of current research in theoretical and practical aspects of security in distributed systems, in particular in information systems and related security tools. Issues treated in the book are security in XML-based management systems, security of multimedia data, technology and use of smart cards, applications of cryptography, security of distributed applications and adherence to standards, model and security issues associated with the organization of components (architectures) of information systems, such as networked systems (Internet and WWW-based), client/server architectures, andlayered architectures. Contributions come both from the academic and the industrial field.