  Even though the idea of partitioning provenance graphs for access control was
previously proposed, employing segments of the provenance DAG for fine-grained
access control to provenance data has not been thoroughly explored. Hence, we
take segments of a provenance graph, based on the extended OPM, and defined use
a variant of regular expressions, and utilize them in our fine-grained access
control language. It can not only return partial graphs to answer access
requests but also introduce segments as restrictions in order to screen
targeted data.
