The volume contains the papers presented at the fifth working conference on Communications and Multimedia Security (CMS 2001), held on May 21-22, 2001 at (and organized by) the GMD -German National Research Center for Information Technology GMD - Integrated Publication and Information Systems Institute IPSI, in Darmstadt, Germany. The conference is arranged jointly by the Technical Committees 11 and 6 of the International Federation of Information Processing (IFIP) The name "Communications and Multimedia Security" was first used in 1995, Reinhard Posch organized the first in this series of...