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| | | see [[Rights Expression Language]] |
| =Description=
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| By G.R. Gangadharan and Michael Weiss, from the article, An Introduction to Rights Expression Languages:
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| "The foundation of DRM technology relies
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| on our ability to represent the rights over digital assets. RELs
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| represent the rights over assets in a machine-understandable way. RELs
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| describe different aspects of usage control, payment, and access, for a
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| digital access environment.
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| According to Parrott, a REL consists of four components:
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|
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| * Subjects, the actors who perform some operation or action
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| * Objects, the content against which a subject wants to perform an
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| operation
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| * Operations or what the subjects wants to do to the object
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| * A set of constraints or conditions under which an operation can be
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| performed
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| These components and their relations support a range of models, each
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| describing a way of applying digital rights. In general, a REL expresses
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| the rights of an information asset either in some form of logic or in an
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| XML-based language."
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| (http://www.osbr.ca/archive.php#A4)
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| =History=
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| By G.R. Gangadharan and Michael Weiss
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| "What follows is a brief history of RELs. A pioneering formal language
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| called DigitalRights describes a mathematical model of simple licenses
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| that consists of payment and rendering events and a formal
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| representation of licenses. LicenseScript is a logic-based REL.
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| Logic-based RELs express general prepositions of a permissive or
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| obligatory (restrictive) statement. However, these languages cannot
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| express a finer level of granularity of the assets, actors, or actions
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| involved. Logic-based RELs cannot interoperate with other types of RELs.
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| XML-based RELs support interoperable ways of expressing the rights of an
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| information asset. An XML-based REL allows asset producers to specify
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| flexible expressions. The [[Extended Rights Markup Language]] ([[XrML]]) and the
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| [[Open Digital Rights Language]] (ODRL) are two XML-based RELs which have
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| gained international recognition and are widely used in industry.
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| XrML is the basis for the REL of the MPEG-21 multimedia framework. It
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| focuses on the license through which a rights holder confers usage
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| rights to a consumer. A license can be digitally signed by the rights
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| holder, now also referred to as the issuer, to confirm that the holder
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| grants the rights contained in the license. An XrML license contains one
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| or multiple grants and the license issuer. A grant is the element within
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| the license that authorizes a subject to exercise a right on some object
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| under some constraints. Note that the actual terminology used by XrML is
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| slightly different from this.
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| ODRL is an open standard language for the
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| expression of terms and conditions over assets in open and trusted
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| environments. ODRL consists of an expression language and a data
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| dictionary. The expression language defines basic terms of rights
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| expressions and their organization using a set of abstract concepts. The
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| data dictionary defines the semantics of the concrete terms used to
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| express an instance of a rights specification.
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| ODRL is based upon an extensible model for rights expression, and
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| defines the following three core entities and their relationships:
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| * Assets, the objects being licensed
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| * Rights, the rules concerning permitted activities, the constraints
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| or limits to these permissions, the requirements or obligations needed
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| to exercise the permission, and the conditions or specifications of
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| exceptions that, if true, terminate the permissions and may require
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| re-negotiation of the rights
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| * Parties, the information regarding the service provider, consumer,
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| or broker
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| With these entities, ODRL can express offers (proposals from rights
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| holders for specific rights over their assets) and agreements (contracts
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| or deals between the parties with specific offers). ODRL supports the
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| declaration of a wide range of expressions. It can also be extended to
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| different types of domains. For example, we can use ODRL to specify that
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| a consumer of a geocoding web service can only use this service in a
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| non-commercial context, as well as the number of times the service can
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| be accessed each day. ODRL has been published by the World Wide Web
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| Consortium (W3C), and has received wide acceptance. ODRL is supported by
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| several industry consortia such as the Dublin Core Metadata Initiative
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| (DCMI) and the Open Mobile Alliance (OMA).
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| Two applications of ODRL are an ODRL profile of the semantics of
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| Creative Commons (CC) licenses and the ODRL profile for services
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| (ODRL-S). The core semantics of CC licenses have been expressed in ODRL.
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| This profile supports extensions to these semantics, and defines an XML
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| Schema. ODRL-S is an extended version of ODRL to express clauses for
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| service licensing, creating a machine-understandable service license."
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| (http://www.osbr.ca/archive.php#A4)
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| [[Category:IP]]
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| [[Category:Standards]]
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