This book constitutes the refereed proceedings of the International Conference on Emerging Trends in Information and Communication Security, ETRICS 2006, held in Freiburg, Germany, in June 2006. The book presents 36 revised full papers, organized in topical sections on multilateral security; security in service-oriented computing, secure mobile applications; enterprise privacy; privacy, identity, and anonymity; security engineering; security policies; security protocols; intrusion detection; and cryptographic security.