Alapan Arnab, Andrew Hutchison. Persistent access control: a formal model for DRM. In Moti Yung, Aggelos Kiayias, Ahmad-Reza Sadeghi, editors, Proceedings of the Seventh ACM Workshop on Digital Rights Management, Alexandria, VA, USA, October 29, 2007. pages 41-53, ACM, 2007. [doi]
Abstract is missing.