Location Based Encryption and Its Role In Digital Cinema Distribution

L. Scott, D.E. Denning

Abstract:	Each year, film studios spend over $1 billion on the mechanics of duplicating and distributing films to exhibition venues located across the U.S. With the advent of digital cinema projectors, much of this expense can be eliminated through more cost efficient digital distribution methods. SATCOM links provide for a very efficient and cost effective digital cinema distribution model but piracy is a major concern; SATCOM links are easy to intercept and loss of a pristine, successful, first run film to pirates could have major financial repercussions. The experience with Direct Satellite Services (DSS) has not been encouraging. There are an estimated 3 million unauthorized users using cloned versions of the tamper resistant smart cards that seek to prevent this. Furthermore, cinema stakeholders are risk adverse towards piracy based on the music industry's experience with Napsterization. Music sales are down for the fourth year in a row (9% in 2002) and company valuations are down 40%, in part because of piracy. As a consequence, there has been significant interest in providing location-based security for digital cinema distribution and forensic analysis in the event of piracy. In this application, the same, large (25 to 190 Gbyte), encrypted media file might be used at multiple theatre locations nationwide but with distinct GeoLocked keys specific to the intended recipient location and its exhibition license. This provides a secure and efficient point-to-multipoint distribution model for delivery via satellite or DVD. At the exhibition hall, robust watermarking/steganographic techniques can introduce location, time and exhibition license information into the exhibition for subsequent use in piracy investigations. This paper starts by describing a geo-encryption approach that builds on established cryptographic algorithms and protocols in a way that provides an additional layer of security beyond that provided by conventional cryptography. It allows data to be encrypted for a specific location(s) or for specific area(s), e.g. a studio's campus area. Constraints in time and velocity as well as location can also be enforced. We then discuss a process of applying successive geo-encryptions at the originating node to enforce specific geographic routings for transmission to the final destination node. We then describe the process of creating and distributing digital cinema content with an eye towards security requirements. One of the more difficult issues is the large number of mutually mistrustful parties involved in the process. We specifically show how time & location constraints introduced via geo-encryption can provide architectural features needed to allow untrusted parties to act cooperatively to bring the exhibition to the screen while maintaining a high degree of protection against piracy. Suborning a single party does not lead to "loss of the film". We also show how these mechanisms can help protect the fiduciary interests of the various parties by giving each an enforceable say in whether or not the exhibition can proceed.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	288 - 297
Cite this article:	Scott, L., Denning, D.E., "Location Based Encryption and Its Role In Digital Cinema Distribution," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 288-297.
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