Digital Rights Management

Digital Rights Management (generally abbreviated to DRM) is an umbrella term that refers to any of several technologies used by publishers or copyright owners to control access to and usage of digital data or hardware, and to restrictions associated with a specific instance of a digital work or device. The term is often confused with copy protection and technical protection measures; these two terms refer to technologies that control or restrict the use and access of digital content on electronic devices with such technologies installed, acting as components of a DRM design.
Digital Rights Management is a controversial topic. Advocates argue DRM is necessary for copyright holders to prevent unauthorized duplication of their work to ensure continued revenue streams.[1] Some critics of the technology, including the Free Software Foundation, suggest that the use of the word "Rights" is misleading and suggest that people instead use the term Digital Restrictions Management.[2] The position put forth is that copyright holders are attempting to restrict use of copyrighted material in ways not granted by statutory or common law applying to copyright. Others, such as the Electronic Frontier Foundation consider some DRM schemes to be anti-competitive, citing the iTunes Store as an example.
Enterprise Digital Rights Management (E-DRM or ERM) refers to the use of DRM technology to control access to corporate documents (Microsoft Word, PDF, TIFF, AutoCAD files, etc), rather than consumer playable media. The technology usually requires a Policy Server to authenticate users' rights to access certain documents but more recently software that does not require this has been created. EDRM vendors include Microsoft, Adobe Systems, EMC Corporation and several smaller companies. There are open source implementations as well. EDRM is generally intended to apply to trade secrets, which are different from copyrighted material (though there is sometimes an overlap as some material is both copyrighted and a trade secret — e.g., the source code for some proprietary software), and for whom the primary issue is industrial or corporate espionage or inadvertent release. In most jurisdictions, there is no notion of fair use for trade secrets as there is for copyrighted material. Trade secrecy confidentiality measures are somewhat less controversial than DRM applied to copyrighted works sold to the public in many copies (e.g., audio or video recordings, texts).

for further reading: http://en.wikipedia.org/wiki/Digital_Rights_Management