The Krupp steel manufacturing facility in Germany played a deadly game during the late 19th and early 20th Centuries. They would manufacture cannons that would penetrate the best armor, then develop better armor that would resist the new cannons. Krupp did this many times, actually contributing to the outbreak of the Franco-Prussian War. This is all documented in William Manchester’s magisterial book, The Arms of Krupp. I see a parallel between that and the history of Digital Rights Management software, which seeks to control the uses to which digital recordings can be put. Every time a new rootkit is introduced, intrepid members of the hacker community devise stronger armor (software) to resist it. This has been going on as long as digital media has been an economic force, and Ars Technica has published a good introductory history entitled “Hacking Digital Rights Management” by Nate Anderson.