Inputs and outputs of ODRL evaluators
Beatriz Esteves
Postdoctoral Researcher at KNoWS
Policy Evaluation and Enforcement on the Web with ODRL
Tutorial colocated with ESWC 2026, May 10th 2026
Short Bio
Health data sharing
My GP
Read
Blood Test Results
During consultation;
For clinical diagnosis
Financial data sharing
My bank
Read
Bank account statements
For loan
assessment
Rule
Permission
Prohibition
Obligation
Party
Action
Asset
Constraint
function
action
target
constraint
Open Digital Rights Language (ODRL)
Open Digital Rights Language (ODRL)
How to interoperably enforce ODRL policies?
Standardised
ODRL Policy
How to interoperably enforce ODRL policies?
Standardised
ODRL Policy
Not standardised
Input
Can I do some action?
Output
How to interoperably enforce ODRL policies?
Standardised
ODRL Policy
Input
ODRL evaluator
Output
Formalising
Not standardised
ODRL evaluator
This document specifies the expected behaviour of an ODRL Evaluator, a piece of software that performs computations based on a set of policies, a request and a certain state of the world.
ODRL evaluator
ODRL landscape: https://w3c.github.io/odrl/landscape/
If they are to behave deterministically & interoperate,
ODRL evaluators lack a common vocabulary to represent contextual inputs
Input models of other policy languages
How to interoperably enforce ODRL policies?
Standardised
ODRL Policy
Evaluation Request
ODRL evaluator
Output
Formalising
Not standardised
State of the world
Esteves, Beatriz, Wout Slabbinck, Yassir Sellami, Andrea Cimmino, Víctor Rodríguez-Doncel, and Ruben Verborgh. ‘Capturing Requests and Context for ODRL-Based Access and Usage Control’. Joint Proceedings of the 16th Workshop on Ontology Design and Patterns and the 1st Workshop on Bridging Hybrid Intelligence and the Semantic Web (WOP-HAIBRIDGE 2025) Co-Located with the 24th International Semantic Web Conference (ISWC 2025), 2025. https://ceur-ws.org/Vol-4093/paper5.pdf.
Contextual Inputs for ODRL Evaluators
Evaluation Request
Evaluation Request
Evaluation Request – Example
For instance, if Billie, i.e., http://example.com/party/billie, requests to play the asset http://example.com/music/1999.mp3, the EvaluationRequest in the example above must be presented to an ODRL evaluator to determine whether this request is permitted or not.
State of the world
State of the world
State of the world – Example
For instance, to demonstrate that Billie, i.e., http://example.com/party/billie, paid Sony, i.e., http://example.com/party/sony, to play http://example.com/music/1999.mp3, the SotW in the example above must be presented to an ODRL evaluator to have contextual information about the performed payments. Furthermore, each payment is linked with the corresponding duty that originated the payment, i.e., using the conditionID property.
How to interoperably enforce ODRL policies?
Standardised
ODRL Policy
Evaluation Request
ODRL evaluator
Formalising
State of the world
Compliance Report
Slabbinck, Wout, Julián Rojas Meléndez, Beatriz Esteves, Pieter Colpaert, and Ruben Verborgh. ‘Interoperable Interpretation and Evaluation of ODRL Policies’. In The Semantic Web, edited by Edward Curry, Maribel Acosta, Maria Poveda-Villalón, et al. Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-94578-6_11.
Compliance report as output of an ODRL Evaluator
Compliance Report Model
Deontic State Calculation
Report – Example
Test Suite
Company X allows employees to access documents during weekdays only, from the EU
Company X allows employees to access documents during weekdays only, from the EU
Policy
Request
Company X allows employees to access documents during weekdays only, from the EU
State of the World
Company X allows employees to access documents during weekdays only, from the EU
Compliance Report
Company X allows employees to access documents during weekdays only, from the EU
Challenges
Challenges – Dynamic Right Operands
Challenges
Challenges – Behaviour
Open
ALLOWED
Closed
DENIED
Evaluation