Capability-based access control for multi-tenant systems using OAuth 2.0 and Verifiable Credentials
This addresses the need for standardized and interoperable capability-based access control in multi-tenant systems, but it is incremental as it builds on existing OAuth 2.0 and VC technologies.
The paper tackles the problem of limited interoperability and adoption of Verifiable Credentials (VCs) for access control by integrating them into the OAuth 2.0 authorization flow, resulting in a solution that requires minimal changes to existing code bases and simplifies verification using JSON Web Signatures.
We propose a capability-based access control technique for sharing Web resources, based on Verifiable Credentials (VCs) and OAuth 2.0. VCs are a secure means for expressing claims about a subject. Although VCs are ideal for encoding capabilities, the lack of standards for exchanging and using VCs impedes their adoption and limits their interoperability. We mitigate this problem by integrating VCs into the OAuth 2.0 authorization flow. To this end, we propose a new form of OAuth 2.0 access token based on VCs. Our approach leverages JSON Web Tokens (JWT) to encode VCs and takes advantage of JWT-based mechanisms for proving VC possession. Our solution not only requires minimum changes to existing OAuth 2.0 code bases, but it also removes some of the complexity of verifying VC claims by relying on JSON Web Signatures: a simple, standardized, and well supported signature format. Additionally, we fill the gap of VC generation processes by defining a new protocol that leverages the OAuth 2.0 "client credentials" grant.