International Conference on Computational Intelligence and Security (CIS) is a major annual international conference to bring together researchers, engineers, developers and practitioners from academia and industry working in all areas of two crucial fields in information processing: computational intelligence (CI) and information security (IS), to share the experience, and exchange and cross-fertilize ideas. In particular, the series of CIS conference provides an ideal platform to explore the potential applications of CI models, algorithms and technologies to IS. Following the great success of CIS'2005 and CIS'2006, CIS'2007 serves as a forum for the dissemination of state-of-the-art research, development, and implementations of systems, technologies and applications in these two broad fields. CIS'2007 is co-organized by Harbin Institute of Technology and Guangdong University of Technology. Also, it is co-sponsored by Xidian University, IEEE (Hong Kong) Computational Intelligence Chapter, and Hong Kong Baptist University.