Conferences papers are the papers presented at a conference, meetings, symposia, etc. by individual speakers.
Proceedings are the collection of conference papers that are published by the organizing institution of the conference or via a publisher. They are distributed as printed books, on CDs, or made available on the Web. Proceedings may include whole papers or just the abstracts.
The USENIX Security Symposium brings together researchers, practitioners, system administrators, system programmers, and others interested in the latest advances in the security and privacy of computer systems and networks