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 tran*ions 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