Abstract

In 2006 Tim Berners-Lee, the inventor of the Web, proposed a new shift on the way we use the web. He proposed that instead of publishing and interconnecting documents, we do the same for data and provided a few guidelines on how this had to be done. This Web of Data (as opposed to the classical Web of Documents) is built using mainly the RDF data format and has been growing steadily over the last few years and on September 2011 the open data published in the web already contained 31 billion RDF triples, interlinked by more than 500 million RDF links. All sorts of data can be found in the web of data, including geography, biology (www.geneontology.org, bio2rdf.org), music, publications, library, census and government data. One of the biggest data sources that is connected to almost in the open web of Data is the DBPedia which publishes the Wikipedia data in RDF. There are many challenges yet to be addressed to allow companies or institutions to publish their data on the Web. One of the issues that needs to be addressed is an access control framework to protect sensitive or private data in such a way that it is only released to authorized people and/or for authorized purposes (e.g., health data). There is thus a need for a powerful and flexible access control system able to enforce the different requirements that the data publishers may want to impose on the access to their information. The objective of this proposal is to specify access control policies over RDF data with ontologies, study their properties and provide enforcement mechanism over large RDF data repositories. The access control policy will be based on permissions over queries, should ensure that no access is given to forbidden data through inference from the allowed queries using the ontology of the RDF data. We will provide efficient enforcement mechanisms and study the impact of the evolution or modification of the ontologies over the policy.