PODC 2003 Tutorial

Sunday 13 July 2003

Content Protection Technologies

Jeffrey B. Lotspiech
Tushar Chandra
Donald E. Leake Jr.

The entertainment industry is in the midst of a digital revolution, the growth of which seems only limited by concerns about the unauthorized redistribution of perfect copies that digital technology enables. Several content protection technologies have been deployed already in consumer electronic devices, and more are in the works. In the near future, the average person's encounter with cryptography will not be restricted to access to ATM machines, but will include his TV, his stereo, and his home entertainment network.  We trace the history of digital content protection technologies, starting with Copy Generation Management System found on Digital Audio Tape, to the Content Scrambling System used on DVD video, and moving on to more cryptographically sound technologies like Digital Transmission Content Protection used on the IEEE digital 1394 bus, and Content Protection for Recordable Media used on DVD Audio, DVD video recorders, and the Secure Digital Memory Card. It turns out that the relatively new area of cryptography called broadcast encryption has found an enthusiastic acceptance in content protection applications. In fact, the content protection application has inspired recent theoretical advances in this area.

One newly-defined problem in content protection is called "authorized domains". The idea is that the consumer's extended home becomes a domain in which content can be copied and moved without restriction. The consumer only encounters technical obstacles when he/she tries to widely redistribute the copyrighted content. This requires that the entertainment devices in the home, which may be only intermittently connected, act as a distributed system to agree upon common cryptographic keys. Although public-key systems can provide this function, it turns out that broadcast encryption can also work in this application, and has some intriguing advantages.

However, not all content protection is based on cryptography. We discuss signal-processing based technologies like MacroVision and digital watermarking. Our view is that cryptography and signal-based technologies are not competitors, but instead complement each other. Cryptographic solutions should dominate while the content remains in the digital domain. Once the content is rendered in analogue form for viewing or listening, signal processing takes over, to provide the last line of defense.

As technologists we would like to think that content protection is fundamentally about solving the technical problems, but we have come to realize that is actually the lawyers, not engineers, that have the tougher job. A complete content protection solution is mainly about licensing, not about the technology. The technology acts as the licensing "hook". It is the license that the manufacturer signs to, for example, obtain keys to play a DVD audio, that obligates him to build devices that obey the copying rules. In an ideal world, all the licenses for all the different copy protection schemes interlock to form a chain of license obligations, from the original source down to the final rendering in the user's home.

Biographical Sketches

Jeff Lotspiech received a BS and MS in Computer Science from the Massachusetts Institute of Technology in 1972. He has been working for IBM since then, most recently at the Almaden Research Center. Since 1994, his research focus has been on content protection technologies. He is a co-inventor of CPRM (Content Protection for Recordable Media), which is used in DVD Audio, DVD recorders, and Secure Digital memory cards, and has over thirty filed patents in cryptography, digital rights management systems, and tamper-resistant software.

Tushar Chandra received his B. Tech. in Computer Science from the Indian Institute of Technology, Kanpur, in 1988 and his Ph.D. from Cornell University in 1993.  He has been working for IBM Research every since, initially at the Thomas J . Watson Research Center and more recently as a senior manager at Almaden Research Center.  He has worked on a variety of topics in distributed computing including failure detection, shared memory, clusters, high performance messaging, autonomic computing, and digital rights management.

Don Leake brings over 35 years of IBM experience in the IT industry to his current position of program director for copy protection business development, IBM Research Division.  Leake is responsible for promoting the use of IBM's extensive menu of content protection technologies in IBM's products and industry initiatives as the use of rich digital media becomes pervasive in IT applications.  IBM's content protection technologies include encryption, watermarking, fingerprinting and software tamper resistance.  Leake also works closely with the Media and Entertainment Industry, in its transition to digital, through his participation in standards organizations, consortia, alliances and multi-company working relationships. As such, Leake is currently the IBM representative to the 4C group, the Copy Protection Technical Working Group, the Pro-MPEG Forum, and formerly was the IBM rep to the Secure Digital Music Initiative.  Previously, Leake managed the marketing, sales and customer support functions for the group in IBM that develops MPEG and set top box chips.  In this role, Leake was responsible for establishing IBM leadership in the digital media chip business.  Prior to that, Mr. Leake held a number of marketing and product planning management positions in IBM's high-end and mid-range systems development organizations, including managing product planning for IBM's largest commercial processors.  He holds Bachelor of Science degree in Mathematics and Masters of Science degree in Statistics from Penn State University.

This page maintained by Gil Neiger.

Last modified: July 11, 2003