This volume constitutes the refereed proceedings of the 4thInternational Conference on Information Security and Assurance, ISA2010, held in Miyazaki, Japan, in June 2010.The 30 revised full papers presented in this volume were carefullyreviewed and selected from 280 submissions. The concepts of Security andAssurance are emerging rapidly as an exciting new paradigm to providereliable and safe life services. The papers focus on the various aspectsof advances in information security and assurance and present recentprogress in the area of information security and assurance includingmodeling, simulation and novel applications associated with theutilization and acceptance of computing devices and systems.