Doug Tygar has a joint appointment in computer science and the School of Information. He works in computer security, privacy and electronic commerce. You can visit his computer science website at tygar.net. Doug Tygar is the author of three books: Computer Security in the 21st Century, Secure Broadcast Communication, and Trust in Cyberspace. He designed the secure postage standard for the U.S. Postal Service. He is one of the founders of the field of "usable security" and has explored why computer security systems are often impossible for ordinary users to understand. He has also demonstrated vulnerabilities in systems that attempt to use machine learning to defend security.