This site requires a JavaScript-capable browser.

ViDe //
Video Development Initiative
Home Working Groups Calendar Resources Search About ViDe

Digital Rights Management: An Introduction

Before the advent of personal computers (and the Internet, in particular), intellectual property was a reasonably secure entity. Even though the ideas and concepts resided in the same ethereal state that they do today, the media with which they were shared (be it audio cassette, compact disc, printed book, or video tape) was physical, and thus could be protected from exploitation through traditional means. Now, though, information can be represented in 0s and 1s, stored in the form of electrical and magnetic impulses, copied and created and destroyed with little or no effort. Bit perfect copies of music, movies, and photographs can be sent from one user to another across broadband lines or with CD-R, enabling illegal sharing of such intellectual properties. Companies like Napster and Limewire were built on software that specifically allows and encourages such file swapping on a peer-to-peer basis, and the copyright owners are claiming now that such trading has done noticeable financial damage to their companies.

Enter Digital Rights Management, a concept that offers rights holders more control over their computer-encoded property. From e-books to MP3 files, from streaming to downloaded multimedia properties, digital rights management tools are making their presence felt. The creators of the files have the options of stronger security, as well as portability and reliability.

The basic heart of digital rights management is in the form of a license that unlocks a given file. For instance, let's say that you download a music file off of the Internet, and want to play it on your computer. Within that file is encoded a key, an algorithm of 128 or 160 bits that must be matched in order for your computer to access the rest of the information in the file (the music). The appropriate media player is told to check against an internal database for a number to unlock that algorithm; if it doesn't find it locally, it might search the Internet for an appropriate match. Upon finding the matching license, your player is now allowed to play the file normally. On the other hand, if no license is found, you might be redirected to a web page that tells you why you have been denied access to the file, or redirecting you to a site where you can purchase a license.

If it were just an issue of security, the problems inherent to digital rights management would be far simpler; the technology exists to create keys of 256 or 512 bits (as seen in common encryption algorithms). However, the issue is more complex than just allowing the rights holder to determine who can and can't access the media. There are also issues of portability, persistence, and reliability to be resolved, as well as standardizing the idea across platforms and applications.

The portability issue is becoming more and more well known with the controversial compact disc anti-pirating techniques that are emerging. The idea is that a lock on the compact disc will allow the music to be played on any stereo and some computers, but will prevent the music from being recorded to another CD or to a computer file. Newer companies like Pressplay, the company offering MP3 files for a subscription rate, allow you to stream or download their music to your computer, but those files are encoded so that you can not burn a CD-R of the songs, or make copies. While these ideas are good for the musicians, preventing people from stealing their music, there are problems for the end user. For instance, if the subscriber has paid his dues and downloaded three months worth of music, something as common as a hard drive failure could erase his entire library, and unlike other data, he would have no archival back-up. It also prevents him from listening to the music anywhere but at that single computer station. Recent trials of CD protection schemes (mechanisms that prevent commercially bought compact discs from being copied digitally) have demonstrated incompatibility with hardware, especially upper-end audio equipment and computer CD drives.

While security and portability are important dilemnas for the digital rights researchers, there are other questions that must be resolved as well. When a license is granted, how long should it remain valid (some say only temporarily, like a rented VHS tape, while others say for the life of the file, like a compact disc or purchased DVD)? There is also the issue of creating reliable technology, algorithms and applications that will work as they are supposed to (to prevent, for example, a user making a purchase only to receive an invalid license). And then, of course, there is the larger battle of agreeing on an industry wide standard.

With more and more media becoming available in digital format, and faster connections to the Internet becoming more prevalent, the issue of digital rights management will continue to stand at the forefront of technology debates. Because digital copying creates an exact duplication, with no generational format loss, there is a genuine need for strong security to prevent damage to music- and video-based industries, not to mention the software industry. There are also other questions that must be answered and reconciled with security, making digital rights management a complex but exciting area to watch.