Digital rights management or digital restrictions management, commonly abbreviated DRM, is an umbrella term for any of several arrangements by which the usage of copyrighted data by someone who has purchased a copy of it may be restricted by the copyright holder. The context is most commonly digital (ie, as in a computer or computerized device), hence the 'digital' in DRM. In contrast to existing legal restrictions which copyright status imposes on the owner of a copy of such data, DRM would allow additional restrictions to be imposed solely at the discretion of the copyright holder, through hardware and software code under the copyright holder's control. In the extreme, such control is proposed within other's computers and computerized devices. The Trusted Computing Platform Architecture scheme proposed by Intel and others is an example. So are several laws proposed or already enacted in various jurisidictions (State, Federal, non-US). Most would include in all computer systems obligatory mechanisms controlling use in ways deemed by copyright holders to be unacceptable. See Professor Edward Felten's freedom-to-tinker Web site for information and pointers.
An early example of a DRM system is the Content Scrambling System (CSS) employed by the DVD Consortium[?] on movie DVD disks. The data on the DVD is encrypted so that it can only be decoded and viewed using an encryption key, which the DVD Consortium kept secret. In order to gain access to the key, a DVD player manufacturer would have to sign a licence agreement with the DVD Consortium which restricted them from including certain features in their players such as a digital output which could be used to extract a high-quality digital copy of the movie. Since the only hardware capable of decoding the movie was controlled by the DVD Consortium in this way, they were able to impose whatever restrictions they chose on the playback of such movies. See also DIVX for a more draconian and less commercially successful variation.
The Digital Millennium Copyright Act was passed in the United States in an effort to make the circumvention of such systems illegal. Despite this law, which has received substantial opposition on constitutional grounds, it is now relatively easy to find DVD players which bypass the limitations the DVD Consortium sought to impose. The cryptographic keys themselves have been discovered and widely disseminated (see DeCSS). See Professor Edward Felton's freedom-to-tinker Web site (www.freedom-to-tinker.com) for some observations on the DCMA, its proposed successors, and their consequences, intended and unintended hilarious (www.freedom-to-tinker.com/archives/cat_fritxs_hit_list/).
New DRM initiatives have been proposed in recent years which could prove more difficult to circumvent, including copy-prevention codes embedded in broadcast HDTV signals and the Palladium operating system. A wide variety of DRM systems have also been employed to restrict access to eBooks[?]. See the TCPA / Pallidium FAQ maintained by Professor Ross J Anderson on his Web site at www.cl.cam.ac.uk/~rja14/tcpa-faq/ for a clear discussion of two prominent proposals.
Examples of existing "digital rights management" and "copy protection" systems:
Opponents of DRM have noted that the proposed use of some DRM schemes to restrict the ability to copy and distribute documents can be used by the criminal as a means of preventing enforcement of laws against fraud and other wrongdoing. Since DRM is unlikely to be so used by individuals, only corporate skullduggery is likely to be concealed this way.
See also copy protection.