This reference on network security integrates material on mobile computing and peer-to-peer communications. The author presents the initial steps that can be used to create systems that overcome security attacks through adaptation as opposed to the earlier fortress mentality, and provides instruction on creating disruptive applications that are much more secure than in the past. The book provides a fundamental understanding of design principles, and provides a model explaining mobile code and the methods that can be used to design secure robust peer-to-peer networks. Also included are recent research results on the information assurance aspects of mobile code.