This book contains the proceedings of the 5th International Conference on Trust, Privacy and Security in Digital Business (Trust Bus 2008), held in Turin, Italy on 4-5 September 2008. Previous events in the Trust Bus series were held in Zaragoza, Spain (2004), Copenhagen, Denmark (2005), Krakow, Poland (2006), and Regensburg, Germany (2007). Trust Bus 2008 brought together academic researchers and industrial developers to discuss the state of the art in technology for establishing trust, privacy and security in digital business. We thank the attendees for coming to Turin to parti- pate and debate upon the latest advances in this area. The conference program included one keynote presentation and six technical paper sessions. The keynote speech was delivered by Andreas Pfitzmann from the Technical University of Dresden, Germany, on the topic of "Biometrics – How to Put to Use and How Not at All". The reviewed paper sessions covered a broad range of topics, – cluding trust and reputation systems, security policies and identity management, p- vacy, intrusion detection and authentication, authorization and access control. Each of the submitted papers was assigned to five referees for review. The program committee ultimately accepted 18 papers for inclusion in the proceedings.