It was an honor and a privilege to chair the 24th IFIP International Information Se- rity Conference (SEC 2009), a 24-year-old event that has become a tradition for - formation security professionals around the world. SEC 2009 was organized by the Technical Committee 11 (TC-11) of IFIP, and took place in Pafos, Cyprus, during May 18–20, 2009. It is an indication of good fortune for a Chair to serve a conference that takes place in a country with the natural beauty of Cyprus, an island where the hospitality and frie- liness of the people have been going together, hand-in-hand, with its long history. This volume contains the papers selected for presentation at SEC 2009. In response to the call for papers, 176 papers were submitted to the conference. All of them were evaluated on the basis of their novelty and technical quality, and reviewed by at least two members of the conference Program Committee. Of the papers submitted, 39 were selected for presentation at the conference; the acceptance rate was as low as 22%, thus making the conference a highly competitive forum. It is the commitment of several people that makes international conferences pos- ble. That also holds true for SEC 2009. The list of people who volunteered their time and energy to help is really long.