The DMCA prohibits gaining unauthorized access to a work by circumventing a technological protection measure put in place by the copyright owner where such protection measure otherwise effectively controls access to a copyrighted work.² This prohibition on unauthorized access takes effect two years after enactment on the DMCA. Over this two year period, the Librarian of Congress is to conduct a rulemaking proceeding to determine appropriate exceptions to the prohibition.³

To facilitate enforcement of the copyright owner’s right to control access to his copyrighted work, the DMCA also prohibits manufacturing or making available technologies, products and services used to defeat technological measures controlling access.⁴ Similarly, the DMCA prohibits the manufacture and distribution of the means of circumventing technological measures protecting the rights of a copyright owner, e.g., measures which prevent reproduction. But to ensure that legitimate multipurpose devices can continue to be made and sold, the prohibition applies only to those devices that:

The DMCA does not affect rights, remedies, limitations, or defenses to copyright infringement, including fair use, nor does it alter the existing doctrines of vicarious and contributory liability.⁵ However, a defense to copyright infringement is not a defense to the prohibition established in Chapter 12. The DMCA also does not require manufacturers of consumer electronics, telecommunications, and computing products to design their products to respond to any particular technological protection measure.⁶ (However, as discussed below, manufacturers of certain analog recording devices will be required to respond to two known analog copy protection technologies.)

Congress recognized that there may be legitimate reasons for engaging in circumvention. In addition to the rulemaking noted above, Congress specifically provided for a number of exceptions to the prohibition on circumvention and circumvention devices.