Hello and welcome. These are the proceedings of the 9th International Workshop on Security Protocols, the ?rst to be held in the new millennium. This year our theme was "mobile computing versus immobile security." As usual, the insights and challenges which emerged during the workshop are re?ected in the position papers, which appear here in rewritten form. Transcripts are also included of the discussions which took place in C- bridge as the initial versions were presented. These transcripts are intended to provide a perspective on lines of argument which are worth pursuing further. Our...