X out of N Credential Requests using Presentation Exchange

Abstract

Self-sovereign identity (SSI) is a new management model for digital identities. Here, the exchange of so-called verifiable credentials - digitally signed pieces of (personal) data - is one of the main aspects of "using" such an identity. Therefore, one party called a verifier requests credentials from another one holding them. We note that the main problem is to find a way to formulate a credential request in such a way that the holding party can choose which credentials to be sent from a predefined pool. Using the Presentation Exchange specification in its current version 2.0.0 is the only way to achieve this directly. Finally, we describe a sample implementation that supports such a mechanism using this specification as part of DIDComm messages.