This book constitutes the thoroughly refereed post-proceedings of the 8th International Workshop on Security Protocols held in Cambridge, UK in April 2000. The 21 papers presented with transcriptions of the discussion following the presentation have gone through two rounds of revision and selection; also included are a keynote address and a discussion summary and an afterword by the volume editors. Among the topics addressed are authentication, trust in cyberspace, identification protocols, administration and government issues, specification, access privileges, PKI certificates, trust-based billing systems, public-key cryptosystems, denial of service, anonymous auction protocols, and certification.