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.