Halderman, J. Alex, and Edward W. Felten. “Lessons from the Sony CD DRM episode.” Center for Information Technology Policy, Princeton University, February 14, 2006.

Summary: The authors analyze the design, implementation, and deployment of two systems for digital restrictions management by which a corporation attempted to enforce copying limits on purchasers of their products, thereby weakening the security of the purchasers' computers. The systems turn out to be cumbersome, complex, fragile, obnoxious, and ineffective. The authors point out the lessons for would-be enforcers of intellectual property restrictions (and, incidentally, for potential purchasers of DRM-protected products).