He served on the National Academy of Sciences expert panel whose members wrote the book "Trust in Cyberspace." He serves on the security directorate of IETF, has contributed to a number of IETF standards efforts including IPsec and S/MIME, and served as a member of the Internet Architecture Board (IAB). He was previously a Distinguished Engineer at IBM, where he was Chief Security Architect for Lotus Notes and Domino. He holds over 30 patents in the fields of computer security and computer networking.