On Delegation of Verifiable Presentations

In this work, we study the problem of producing a delegation of verifiable presentations derived from verifiable credentials to enable a credential holder (the delegator) to securely authorize another party (the delegatee) to present a credential on their behalf. We define the notion of a verifiable presentation delegation scheme, with the core algorithms for delegation issuance, delegated presentation, and presentation verification, and formalize the security properties that such a scheme must satisfy, namely correctness and unforgeability. Then, we design a verifiable presentation delegation scheme that can be applied to the verifiable credentials used in the European Digital Identity Wallet Architecture Reference Framework (EUDI ARF) and we prove that our scheme satisfies the security properties under the assumption of a secure digital signature scheme. Finally, we briefly discuss and provide some insight on how to instantiate our scheme in the context of the European Blockchain Services Infrastructure (EBSI) and EUDI frameworks.