User Profiling and Privacy in Digital Business -- User Profiling and Re-identification: Case of University-Wide Network Analysis -- Search Engines: Gateway to a New "Panopticon"? -- Privacy Enhancing Technologies and Identity Management -- Supporting Local Aliases as Usable Presentation of Secure Pseudonyms -- A Privacy-Preserving Platform for User-Centric Quantitative Benchmarking -- An Anonymous Credit Card System -- Security and Privacy in Real Life Applications -- A Cluster-Based Framework for the Security of Medical Sensor Environments -- Formal Specification and Automatic Analysis of Business Processes under Authorization Constraints: An Action-Based Approach -- A Formalization of HIPAA for a Medical Messaging System -- Reputation and Security Measurements -- Adaptive Dispatching of Incidences Based on Reputation for SCADA Systems -- Steering Security through Measurement -- Advanced Features in Bayesian Reputation Systems -- Access Control -- An MDA-Based Environment for Generating Access Control Policies -- An Extended Role-Based Access Control Model for Delegating Obligations -- The OPL Access Control Policy Language -- Authentication and Authorisation -- Operational Semantics for DKAL: Application and Analysis -- HB???MAC: Improving the Random???HB # Authentication Protocol.

This book constitutes the refereed proceedings of the 6th International Conference on Trust and Privacy in Digital Business, TrustBus 2009, held in Linz, Austria, in September 2009 in conjunction with DEXA 2009. The 16 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on user profiling and privacy in digital business; privacy enhancing technologies and identity management; security and privacy in real life applications; reputation and security measurements; access control; and authentication and authorisation.