In 2003, the American Bar Association published a book  on intellectual property, covering patents, copyrights, and trademarks. In the section on copyrights, the author writes that for copyright, you should “avoid it like the plague.” What the author is alluding to is the general confusion and vagueness of what can be protected beyond the literal copy of something, caused by the ill-defined idea/expression dichotomy that is the weak foundation of copyright law.
Commercially, most copyright enforcement involves literal copying, like the infamous Napster system. For such copying, the question is: How do you strongly protect distribution, especially for financial gain, in today’s increasingly digital economy? In the Internet era, where it costs nothing to make and distribute copies of copyrighted works such as music, books, and movies that cost a lot to create, inventors and producers of such products need protection. While copyright law provides strong enforcement laws, there is a need for strong protection technology.
Digital rights management (DRM) systems are one option for addressing this problem, and are usually based on some form of encrypted control. In this paper, which begins with a brief history of copyright policy, Camp reviews three DRM systems (Adobe eBook, CSS, Giovanni) and two DRM-breaking systems (AeP and DeCSS) for how they treat six aspects of distributing copyrighted works: author monetary incentive, reputation right, attribution and integrity, persistence and archiving, access, and personal annotation.
For each DRM system, she briefly reviews the history, and then explores how the above six aspects interact. The paper provides a useful format for analyzing the hundreds of patented DRM systems currently available. The DRM patents should have been mentioned in the article because patents affect licensing and adoption of DRM, and also provide alternative models with stronger protection (the Adobe, CSS, and Giovanni systems are susceptible to well-known attacks).
For those considering the adoption of DRM systems, the paper is helpful for analyzing the tradeoffs, since no system is perfect.