The11thInternationalConferenceonInformationandCommunicationsSecurity (ICICS 2009) was held in Beijing, China during December 14-17, 2009. The ICICS conferenceseriesis anestablished forum that bringstogether people from universities,researchinstitutes, industry and governmentinstitutions, who work in a range of ?elds within information and communications security. The ICICS conferencesgiveattendeestheopportunitytoexchangenewideasandinvestigate developments in the state of the art. In previous years, ICICS has taken place in the UK (2008), China (2007, 2005, 2003, 2001 and 1997), USA (2006), Spain (2004), Singapore (2002), and Australia (1999). On each occasion, as on this one, the proceedings have been published in the Springer LNCS series. In total, 162 manuscripts from 20 countries and districts were submitted to ICICS 2009, and a total of 37 (31 regular papers plus 6 short papers) from 13 countries and districts were accepted (an acceptance rate of 23%). The accepted papers cover a wide range of disciplines within information security and applied cryptography. Each submission to ICICS 2009 was anonymously reviewed by three or four reviewers. We are very grateful to members of the Program C- mittee, which was composed of 44 members from 14 countries; we would like to thank them, as well as all the external referees, for their time and their valuable contributions to the tough and time-consuming reviewing process.