6th CCS 1999 Message From the Program Chair This year's crop of submissions was truly outstanding in both quality and number. A total of 83 submissions were received testifying to the growing popularity and importance of ACM CCS. (This is despite many competing conferences and workshops.) Submissions came from around the world and spanned a very broad range of subjects: from classical cryptography and formal methods to intrusion detection and experimental systems. The program committee met on June 23, 1999 at USC/ISI in Marina del Rey, CA. After a very long and arduous day, 16 papers were selected representing the very best of the state-of-the-art. Like the pool of submissions they were drawn from, these 16 papers provide an excellent and broad coverage of the field. They represent timely and important advances in their subject areas and attest to the talents and dedication of the authors. In addition to the technical papers the conference program includes tutorials by Bruce Schneier and Ravi Sandhu, an opening talk by Robert Deng, a panel session moderated by Dan Boneh, a newly introduced Rump Session for short talks reporting on very recent research, and two outstanding invited talks by Edward Felten and Victor Shoup. There are many people I would like to thank, for their help and support. First off, I am very grateful to the authors of all submitted papers for their patronage of ACM CCS and for the hard work invested in the submissions. Collectively representing the research community, they are both the backbone and the target audience of this conference. Members of the program committee have done an exceptional job this year and I cannot thank them enough for the time and effort in reviewing papers, partaking in the PC meeting and otherwise helping out in many related tasks and activities. It has been a pleasure and and an honor to work with them. Likewise, I would like to express my gratitude to the delegated reviewers for their selfless community service and insightful reviews. A special word of thanks goes to Mike Reiter who, as previous year's Program Chair, shared his knowledge and experience. Same sentiments are due to Matt Franklin for a great job as the Proceedings Chair and Jianying Zhou for promoting and advertising CCS as the Publicity Chair. I am also thankful to Juzar Motiwalla and Ravi Sandhu (General Chair and Steering Committee Chair, respectively) for their help and support. Having followed ACM CCS from its inception in 1992 - as an attendee, author or organizer - I am very happy to note its continuing growth in popularity, quality and maturity. I believe that it is now firmly entrenched as the premier security conference. In closing, I am very proud of my affiliation with this conference and appreciative of the opportunity to serve as the Program Chair. Gene Tsudik Program Chair, ACM-CCS-6