Here's the summary for the wikipedia article you mentioned in your comment:

Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) like access control technologies, can restrict the use of proprietary hardware and copyrighted works. DRM technologies govern the use, modification and distribution of copyrighted works (e.g. software, multimedia content) and of systems that enforce these policies within devices. DRM technologies include licensing agreements and encryption.Laws in many countries criminalize the circumvention of DRM, communication about such circumvention, and the creation and distribution of tools used for such circumvention. Such laws are part of the United States' Digital Millennium Copyright Act (DMCA), and the European Union's Information Society Directive – with the French DADVSI an example of a member state of the European Union implementing that directive.Many users argue that DRM technologies are necessary to protect intellectual property, just as physical locks prevent personal property from theft. For examples, they can help the copyright holders for maintaining artistic controls, and supporting licenses' modalities such as rentals. Industrial users (i.e. industries) have expanded the use of DRM technologies to various hardware products, such as Keurig's coffeemakers, Philips' light bulbs, mobile device power chargers, and John Deere's tractors. For instance, tractor companies try to prevent farmers from making repairs via DRM.DRM is controversial. There is an absence of evidence about the DRM capability in preventing copyright infringement, some complaints by legitimate customers for caused inconveniences, and a suspicion of stifling innovation and competition. Furthermore, works can become permanently inaccessible if the DRM scheme changes or if a required service is discontinued. DRM technologies have been criticized for restricting individuals from copying or using the content legally, such as by fair use or by making backup copies. DRM is in common use by the entertainment industry (e.g., audio and video publishers). Many online stores such as OverDrive, use DRM technologies, as do cable and satellite service operators. Apple removed DRM technology from iTunes around 2009. Typical DRM also prevents lending materials out through a library, or accessing works in the public domain.

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