th This volume contains the papers presented at the 9 Information Security Conference (ISC 2006) held on Samos Island, Greece, during August 30 – September 2, 2006. The Conference was organized by the University of the Aegean, Greece. ISC was first initiated as a workshop, ISW in Japan in 1997, ISW 1999 in Mal- sia, ISW 2000 in Australia and then changed to the current name ISC when it was held in Spain in 2001 (ISC 2001). The latest conferences were held in Brazil (ISC 2002), UK (ISC 2003), USA (ISC 2004), and Singapore (ISC 2005). ISC 2006 provided an international forum for sharing original research results and application experiences among specialists in fundamental and applied problems of - formation security. In response to the Call for Papers, 188 papers were submitted. Each paper was - viewed by three members of the PC, on the basis of their significance, novelty, and technical quality. Of the papers submitted, 38 were selected for presentation, with an acceptance rate of 20%.