ODRL Policy Comparison Through Normalisation
arXiv:2603.12926v1 Announce Type: new Abstract: The ODRL language has become the standard for representing policies and regulations for digital rights. However its complexity is a barrier to its usage, which has caused many related theoretical and practical works to focus on different, and not interoperable, fragments of ODRL. Moreover, semantically equivalent policies can be expressed in numerous different ways, which makes comparing them and processing them harder. Building on top of a recently defined semantics, we tackle these problems by proposing an approach that involves a parametrised normalisation of ODRL policies into its minimal components which reformulates policies with permissions and prohibitions into policies with permissions exclusively, and simplifies complex logic constraints into simple ones. We provide algorithms to compute a normal form for ODRL policies and simplifying numerical and symbolic constraints. We prove that these algorithms preserve the semantics of p
arXiv:2603.12926v1 Announce Type: new Abstract: The ODRL language has become the standard for representing policies and regulations for digital rights. However its complexity is a barrier to its usage, which has caused many related theoretical and practical works to focus on different, and not interoperable, fragments of ODRL. Moreover, semantically equivalent policies can be expressed in numerous different ways, which makes comparing them and processing them harder. Building on top of a recently defined semantics, we tackle these problems by proposing an approach that involves a parametrised normalisation of ODRL policies into its minimal components which reformulates policies with permissions and prohibitions into policies with permissions exclusively, and simplifies complex logic constraints into simple ones. We provide algorithms to compute a normal form for ODRL policies and simplifying numerical and symbolic constraints. We prove that these algorithms preserve the semantics of policies, and analyse the size complexity of the result, which is exponential on the number of attributes and linear on the number of unique values for these attributes. We show how this makes complex policies representable in more basic fragments of ODRL, and how it reduces the problem of policy comparison to the simpler problem of checking if two rules are identical.
Executive Summary
The article proposes a normalization approach for ODRL policies to address complexity and interoperability issues. By reformulating policies with permissions and prohibitions into policies with permissions exclusively, and simplifying complex logic constraints, the approach enables comparison and processing of semantically equivalent policies. The authors provide algorithms to compute a normal form for ODRL policies and prove that these algorithms preserve the semantics of policies.
Key Points
- ▸ Normalization approach for ODRL policies
- ▸ Reformulation of policies with permissions and prohibitions
- ▸ Simplification of complex logic constraints
Merits
Improved Interoperability
The proposed approach enables comparison and processing of semantically equivalent policies, improving interoperability between different fragments of ODRL
Simplified Policy Representation
The normalization approach simplifies complex policies, making them representable in more basic fragments of ODRL
Demerits
Exponential Size Complexity
The size complexity of the result is exponential on the number of attributes, which may lead to scalability issues
Expert Commentary
The proposed normalization approach for ODRL policies is a significant step towards addressing the complexity and interoperability issues that have hindered the widespread adoption of ODRL. By providing a standardized and simplified policy representation, the approach enables more efficient policy comparison and processing, which is crucial for digital rights management. However, the exponential size complexity of the result may pose scalability challenges, highlighting the need for further research and optimization.
Recommendations
- ✓ Further research on optimizing the normalization algorithm to reduce size complexity
- ✓ Development of tools and frameworks to support the implementation of the proposed approach
