Rights Expression Language

A Rights Expression Language (REL) provides a means to present a formal description of the rights associated with an item of content or a service. Rights here refer to rights in content held by a user such as authors, publishers, distributors, or consumers. The advantage of expressing them formally is that it will be clear to everyone what actions are allowed by these rights and potentially computers can automatically resolve these rights.

In most cases the REL forms part of a larger system of Digital Rights Management (DRM) used to manage or even enforce the rights associated with an intellectual work such as a item of music.

Open Rights Expression Languages

One of the problems of DRM systems is that there are many different propriatery systems and many of them and they can't talk to each other. Thus they fragment the market and inconvenience many users who would prefer to access any item of content on any system. In the absence of a universal DRM system this leads to the call for interoperable DRM. This in turn requires standard and open rights expressions or at least interoperable RELs.

Among a large field of proprietary RELs there are two main contenders striving to produce an open REL standard:

• The eXtensible rights Markup Language (XrML) uses the extensible markup language (XML) to "provide a universal method for securely specifying and managing rights and conditions associated with all kinds of resources including digital content as well as services." It is "based on years of research at Xerox Palo Alto Research Center (PARC), which invented the digital rights language concept, and backed by patented technology, XrML is currently governed by ContentGuard, Inc."

• The Open Digital Rights Language (ODRL) "initiative is an international effort aimed at developing and promoting an open standard for rights expressions. ODRL is intended to provide flexible and interoperable mechanisms to support transparent and innovative use of digital content in publishing, distributing and consuming of digital media across all sectors and communities." One possible advantage of ODRL is that it is license-free.

Further Reading:

• For further discussion of the need for interoperability at all levels of information exchange and in particular at the level of DRM and RELs see the Berkman Center's white papers 'Breaking Down Digital Barriers'. (http://cyber.law.harvard.edu/interop/)