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Rights Expression Languages, licensing tools & compliance checking

by taspel | November 08, 2016

Rights Expression Languages (RELs) are a subset of Digital Rights Management technologies that are used to explicate machine-readable rights for purposes of Digital Asset Management. RELs are used to control access, explicate usage rights and govern behavioural aspects of a transaction process. Among the most prominent REL-vocabularies are MPEG-21, ODRL-2.0 (and derivatives like RightsML), ccREL, XACML and WAC to name but a few.[1] Each REL has been developed to serve specific purposes. I.e. MPEG-21 is optimized for purposes in the area of multimedia (espec. digital television) and has been standardized by the OASIS group. ccREL (Creative Commons Rights Expression Language) and ODRL (Open Digital Rights Language) are designed for broader application areas and have gained popularity especially in the area of data licensing, but they have not yet become an officially supported standard. Simple tools to create, compare and process machine-readable licenses do not exist. A rudimentary version of a policy composition tool based on ODRL has been provided by the Ontology Engineering Group[2] of the University of Madrid, but this tool should be considered as a proof of concept and has not been tested under real world circumstances. The same holds true for the IPTC working group on RightsML[3] (which is based on ODRL) who have started to provide experimental libraries for generating RightsML and ODRL licenses in Python and JavaScript. But again, these serializations are just proof of concepts and lack a sufficient level of usability and legal validation to be suitable for commercial purposes. Complementary to this, we have seen developments in the area of open source software that address the problem of licensing conflicts in the compilation of software from multiple open source components. I.e. the Free Software Foundation provides a rich textual guide on potential licensing conflicts between open source standard licenses. But this information is not provided in a machine-readable way. Recently US-based auditing firms like TLDR Legal (https://tldrlegal.com/) or TripleCheck (http://triplecheck.net/index.html) have started to provide commercial services that help to detect open source licensing conflicts. What these initiatives have in common is 1) that they are specialized on software licensing, 2) that compliance checking is provided as a commercial service conducted by auditing experts on top of proprietary tools, 3) none of these tools / services allows to create custom licenses, thus limiting the compliance check to standard licenses, and 4) no machine-readable representations of the licenses are being provided to the public for advanced analytics and further reuse. [1] A detailed discussion of  RELs is provided by Kirrane, Sabrina; Mileo, Alessandra; Decker, Stefan (2015). Access Control and the Resource Description Framework: A Survey. In: Semantic Web Journal. See also: http://www.semantic-web-journal.net/content/access-control-and-resource-description-framework-survey [2] See http://oeg-upm.github.io/odrlapi/ & http://conditional.linkeddata.es/ldr/manageren, accessed January 4, 2016 [3] See http://dev.iptc.org/RightsML-Implementation-Examples, accessed January 4, 2016


CCREL, IPTC, MPEG-21, ODRL, rights expression language, RightsML


Licensing Technologies, Project Details, Rights Expression Language