6th CCS 1999 Message from the General Chair I would like to take this opportunity, on behalf of Kent Ridge Digital Labs, to extend a warm welcome to all of you to the Sixth ACM Conference on Computer and Communications Security. The first five conferences were held in Fairfax, Virginia (1993 and 1994), New Delhi, India (1996), Zurich, Switzerland (1997) and San Francisco, California (1998). For the sixth in the series, we are very pleased to welcome you to Singapore, the Lion City. In the past five years, this conference brought together the community of industry and academia who are involved in the research, development, use, and management of computer and communications security technology. The conference has established itself as a forum at which research as well as practical aspects of computer and communications security are enthusiastically addressed. We hope to continue this tradition by offering you another successful forum with an interesting program. This conference was put together with the support of several people. To begin with we are extremely grateful to Ravi Sandhu who proposed to have the conference in Singapore. Our conference is sponsored by ACM SIGSAC and hosted by Kent Ridge Digital Labs. Two conference exhibitors, DigiSafe Pte Ltd and Internet Appliance Pte Ltd kindly sponsored tea breaks to the conference. We thank these organizations for their financial support and encouragement. Special thanks also to the conference organizing committee, in particular Desai Narasimhalu (Local Arrangement Chair), Jianying Zhou (Publicity Chair), Victorine Chen-Toh (Registration Chair), Robert Deng (Exhibits Chair), Ngair Teow Hin (Tutorial Chair), and Matt Franklin (Publication Chair). The success of the conference depends on the quality of the program selection. We are indebted to our Program Chair Gene Tsudik, the Program Committee members, and the external referees for the wonderful job they have done. Finally we would like to thank the authors who submitted papers and the participants from all over the world who have chosen to honor us with their attendance. Hope you enjoy the conference and have a pleasant time in Singapore! Juzar Motiwalla CEO Kent Ridge Digital Labs Singapore