It was a pleasure to take part in the 2005 European Workshop on Security and Privacy in Ad Hoc and Sensor Networks (ESAS 2005), held on July 13¿14 in Visegrad (Hungary) in conjunction with the First International Conference on Wireless Internet (WICON) . As Program Co-chairs, we are very happy with the outcome of this year¿s ESAS workshop. It clearly demonstrates the continued importance, popularity andtimeliness oftheworkshop¿stopic: securityandprivacy inadhocandsensor networks.Atotalof51fullpapersweresubmitted.Eachsubmissionwasreviewed by at least three expert referees. After a short period of intense discussions and deliberations, the Program Committee selected 17 papers for presentation and subsequent publication in the workshop proceedings. This corresponds to an acceptance rate of 33% ¿ a respectable rate by any measure. First and foremost, we thank the authors of ALL submitted papers. Your con?dence in this venue is much appreciated. We hope that you will continue patronizing ESAS as authors and attendees. We are also very grateful to our colleagues in the research community who served on the ESAS Program C- mittee. Your sel?ess dedication is what makes the workshop a success. Finally, we are very grateful to the ESAS Steering Group: Levente Buttyan, Claude Castelluccia, Dirk Westho? and Susanne Wetzel. They had the vision and the drive to create this workshopin the ?rst place; they also provided many insightsandlotsofhelpwiththisyear¿sevent.Weespeciallyacknowledgeand- preciate the work of Levente Buttyan whose dedication (as Steering Committee member, PC member and Local Arrangements Chair) played a very important role in the success of the workshop.