Digital Rights Management (DRM) is a system to protect high-value digital assets and control the distribution and usage of those digital assets.  DRM – sometimes is called as "copy protection software" or "digital restrictions management". DMR is a broader term that can be used for both, technological protection measures (TPMs) (such as encryption of the protected material) and electronic rights management information (RMI) (such as digital identifiers).
The history of DRM technologies started in the beginning of the nineties when movie industry decided to protect the copyrighted works by creating a special digital fence that would prohibit copying of their works. The content on DVDs was scrambled, and the studios licensed DVD player manufacturers to build descrambling software into their DVD players.
It is often the case that technologies controlling access are based on encryption, which digitally scrambles content to prevent its use unless descrambled (decrypted) with a proper key. A simple encryption scheme called CSS, or the Content Scramble System is used on DVDs to encrypt the data so that only licensed DVD players can decode it. So when you play a commercial DVD, your actions are partly controlled by CSS. The DVD Copy Control Association licenses the keys to this encryption system to the manufacturers of DVD players. Without a key, most DVDs could not be played. The manufacturer then embeds this key in its hardware design in such a way that it is easy for your player to de-code and play the movie but hard, at least for a person of average technical competence, to copy the decoded ‘stream’.
The DRM tools prevent the making of copies, eg. the duplication of CDs or DVDs. Technology can also protect against, for instance, a distribution of copyrighted file in a network, prevent streaming of works over the Internet. The DRM can also limit the amount of copies made, for example, a single personal copy can be technologically enabled, but making further copies from that copy (serial copies) can be prevented. The use of a digital file can be technologically enabled for a limited period, after which the use of the file becomes impossible. Moreover, transmission of a certain file to specific terminals and devices can be enabled while preventing distribution to others.
Such a protection leads to the outcome that DRM technologies enable copyright owners to control the use of content even after sales or license. They can prevent users or consumers from transforming the content into other formats or playing on incompatible devices. In other words, a user is binding to a given licensor when the user wants to access and use a specific work.
However, the encryption scheme technology is possible to overcome with circumvention technologies. According to the English dictionary, circumvent means to go around, bypass, to avoid by deception. In the copyright law the circumvention technologies got a particular definition. Such technology allows to break the technological protection and to play DVD’s or CD’s on non licensed devices (for example using different operative system) and without a relevant source code necessary to read CSS protected works.
Todays’ copyright law forbids to bypass or break the CSS. Any use of circumvention technologies is prohibited. Such prohibition firstly was done at the international level, and later, the provisions were implemented in the national legal systems of most countries.
The emergence of digital technologies along with the establishment of Internet reshaped the landscape of copyright protection. The wish of authors to protect their works from unlawful reproduction is understandable. Furthermore, the technological protection measures allow authors control the access to copyrighted works and enforce copyright by a private implementation. Such measures are much cheaper and more flexible option than expensive and time-consuming judicial procedure. Moreover, nobody can prevent an author from protecting their works in any legal way.
So, from the perspective of copyright owners, the DRM provides another layer of security on their exclusive rights. Specifically, the DRM with accompanied technologies enables copyright owners to expand their copyright-like protection and strengthen the exclusive control on their digital works.  The copyrights of the author are now protected not only through the valid legislation, but as well though the technological tool, that prevents the reproduction of the work. Furthermore, that technological tool is also protected by law, so copyright owner now has a triple protection of his work.
1.Work protected by copyrights ©
2. Work protected by TMPs
3. TMPs protected by DRM laws
However, the enhanced level of protection and control often leads to severe tension between copyright owners and online users because users’ freedom and experiences on works are greatly affected and limited. The user cannot choose an unlicensed although legal software (for example Linux operative system) to read the legally own data protected by DRM (a music CD or movie DVD, iTunes files). Such a protection creates doubts if DRM tools do not conflict with the exhaustion of rights doctrine in the copyright law. Copyright owner’s right to control copies of their work should not extend beyond the point at which they receive reasonable remuneration for it. After obtaining a copy of particular work, a purchaser should have control over that copy, however DRM techniques might restrict such rights.
The preamble of the WIPO Copyright Treaty states that the law recognizes the need to maintain a balance between the rights of authors and the larger public interest, particularly education, research and access to information, as reflected in the Berne Convention. By banning all acts of circumvention, and all technologies and tools that can be used for circumvention, the DRM tools grant to copyright owners the power to unilaterally eliminate the public’s fair use rights. Already, the movie industry’s use of encryption on DVDs has curtailed consumers’ ability to make legitimate, personal-use copies of movies they have purchased.
With the technological protection measures, the balance between the rights of the author and the public becomes questionable. Although copyright is designed to solve the problem of market failure, the monopoly granted by copyright law should be limited in the case of the side effects. The guaranteed rights of the copyright holders now can be extended towards the legal limitations and exceptions.
(Full article can be downloaded from the Social Science Research Network (www.ssrn.com)
 Liu, Qiong, Reihaneh Safavi-Naini, and Nicholas Paul Sheppard. “Digital rights management for content distribution." Proceedings of the Australasian information security workshop conference on ACSW frontiers 2003-Volume 21. Australian Computer Society, Inc., 2003.
 Litman, Jessica “Real Copyright reform”, 2010, page 52.
 Edwards, Eddie “The Content Scramble System. A technical description” (http://www.tinyted.net/eddie/css.html)
 Boyle, James “The Public Domain. Enclosing the Commons of the Mind”, Yale University Press, 2008, page 85.
 Suni, Yang “Rightholder as the Center: the DRM system in Copyright after So Many Years”, page 6.
 In Oct. 1999 DeCSS technology was published by 15-year-old Norwegian Jon Johansen on LiVID project, an open source software development team working to build a DVD player for the Linux operating system.
 Suni, Yang “Rightholder as the Center: the DRM system in Copyright after So Many Years”, page 2.
 Id., page 3.
 Suni, Yang “Rightholder as the Center: the DRM system in Copyright after So Many Years”, page 7.