This volume contains a selection of refereed papers from participants of the workshop Construction and Analysis of Safe, Secure and Interoperable Smart Devices (CASSIS), held from the 10th to the 13th March 2004 in Marseille, France: http: //www-sop.inria.fr/everest/events/cassis04/ The workshop was organized by INRIA (Institut National de Recherche en InformatiqueetenAutomatique), Franceandthe UniversitydelaM editerran ee, Marseille, France. The workshop was attended by nearly 100 participants, who were invited for their contributions to relevant areas of computer science....