This paper describes how code protection is done via “virtual machines” and techniques used in popular virtual machines, giving a considerable level of understanding of such virtual machines for readers from beginners to professionals.
more here..............http://www.scribd.com/doc/222907805/Introduction-to-Modern-Code-Virtualization
more here..............http://www.scribd.com/doc/222907805/Introduction-to-Modern-Code-Virtualization