Title I of the Digital Millennium Copyright Act, the “WIPO Copyright and Performances and Phonograms Treaties Implementation Act of 1998” added Chapter 12, Copyright Protection and Management Systems, to the Copyright Act.
At the time of the DMCA, there was great hope that digital rights management systems would provide a way of preventing copyright infringement while allowing authorized uses of a work. However, because rights management systems might be circumvented, Section 1201 makes it a violation to traffic in circumvention devices or provide a circumvention service. It was hoped that this would make circumvention appear illegitimate, and make it more difficult for the average user to find.
The Act was needed to implement the WIPO Copyright Treaty that the United States had recently signed because United States law did not directly address either Article 11's requirement for legal protection against circumvention, or Article 12's requirements for protecting rights management information. Section 1202 makes it violation to provide false copyright management information or to remove or alter existing copyright management information.
Section 1201 not only addresses circumvention devices that are used to infringe a copyright, but also that are used to access a copyrighted work such as by receiving an audio or video stream. Because the latter may not represent an infringement of copyright, depending on the particular technology being used, Section 1201(1)(1)(A) provides a new violation if you "circumvent a technological measure that effectively controls access to a work protected" by copyright.
There are a number of specific exceptions to the trafficking provisions, as well as triennial rulemaking by the Library of Congress to exempt classes of copyrighted works.