DRM refers to a cohort of access control technologies used to restrict access, editing, or modification of copyrighted digital properties beyond the agreed terms of service. The primary goal of DRM is to protect intellectual property from being copied and distributed without properly compensating the owners of the property.
Most commonly, DRM is applied to mass-produced media including video games, software, audio CDs, HD DVDs, Blue-ray discs and ebooks. DRM can come in the form of encryption, scrambling, digital watermarks, CD keys, etc.
The Digital Millennium Copyright Act, amended to the US copyright law, criminalized the use of techniques intended to circumvent DRM technology. Not surprisingly, DRM remains a controversial technology, with some even calling it anti-competitive. Others criticize DRM for restricting normal use of something purchased by the user.
As mentioned previously, Information Rights Management is the application of DRM to documents created by individuals such as Microsoft Office documents, PDFs, emails, etc. Unlike DRM, which is generally intended to protect copyrighted material, IRM is more often intended to protect the security of highly sensitive information that may be contained in a document.
A hospital may, for example, apply IRM to patient records in order to maintain compliance with HIPAA-HITECH and prevent access to this information in the event that the patient records fall into unauthorized hands. Another example would be when an organization applies IRM to executive communication to protect sensitive information from leaking to the media or to competitors.