Trust and Privacy in Digital Business : First International Conference TrustBus 2004 Zaragoza Spain August 30 September 1 2004. Proceedings This book constitutes the refereed proceedings of the First International Conference on Trust and Privacy in Digital Business TrustBus 2004 held in Zaragoza Spain in August September 2004. The 29 revised full papers presented together with an invited paper were carefully reviewed and selected from close to 100 submissions. The papers are organized in topical sections on trust access control e business issues privacy e voting protocols copyright protection multicast and PKI and signature schemes