This volume contains the papers presented at the Third International Conference on Security in Pervasive Computing (SPC 2006), held April 19-21, 2006 in York, UK. The conference focused on methods, tools, principles, and practices for assessing and achievingsecurityinapervasiveenvironment.Newsecurityconceptswerediscussed, in domains and applications such as handheld devices, mobile phones, smartcards, RFID chips, and smart labels, as well as new, emerging technological spaces. The conf- ence also presented work on fundamental themes such as risk identi?cation and mi- gation, security policies for pervasiveenvironments, privacymeasures (especially cr- tographic protocols), and mobility and location-aware services. Submissions included work on biometrics, ambient intelligence, Web services, security requirements, and many other topics. We received 56 submissions, and accepted 16 full papers for presentation. Each submission was reviewed by the international Programme Committee. We are grateful to the Programme Committee members, and the additional reviewers, for their timely completion of the reviewing process, and for the quality and detail of their reviews and discussion. Our thanks go to all members of the ProgrammeCommittee for their efforts; the - ditional reviewers; the authors, for submitting their papers; the keynote speaker, Frank Stajano; the invited speaker, Howard Chivers; and the Department of Computer S- ence, University of York, for supporting the event. April 2006 John A. Clark (Program Chair) Richard F. Paige Fiona A.C. Polack Phillip J. Brooke Organization SPC 2006 was organized by the Department of Computer Science, University of York.