This book presents the proceedings of the 6th International Conference on Trust, Privacy and Security in Digital Business (TrustBus 2009), held in Linz, Austria d- ing September 3-4, 2009. The conference continues from previous events held in Zaragoza (2004), Copenhagen (2005), Krakow (2006), Regensburg (2007) and Turin (2008). The advances in the information and communication technologies (ICT) have raised new opportunities for the implementation of novel applications and the pro- sion of high-quality services over global networks. The aim is to utilize this 'infor- tion society era' for...