OpenID4VC

OpenID4VC covers OpenID4VCI (credential issuance) and OpenID4VP (credential presentation), the OAuth 2.0-based protocols behind the EUDI Wallet.

OpenID4VC is the family of OpenID Foundation protocols for verifiable credentials: OpenID4VCI (OpenID for Verifiable Credential Issuance) covers issuance (how a wallet obtains a credential from an issuer) and OpenID4VP (OpenID for Verifiable Presentations) covers presentation (how a wallet proves attributes to a relying party). Both build on OAuth 2.0 patterns that the industry already runs at scale, and both specifications have matured through several drafts to 1.0 final versions, with the OpenID4VC High Assurance Interoperability Profile (HAIP) defining the stricter profile used by the EUDI Wallet.

They are the prescribed transport protocols of the EUDI Wallet, carrying SD-JWT and mdoc credentials online via OpenID4VP, or, for proximity/offline mdoc presentation, via ISO/IEC 18013-5 device retrieval. Presentation can happen same-device, where the wallet and relying party share one device, or cross-device, where the relying party displays a QR code that the wallet scans, typically with a phone while browsing on a laptop. Same-device no longer means app-to-app redirects only: the W3C Digital Credentials API gives the browser itself a way to hand a request to a wallet, support for it is arriving in the major browsers, and the wallet ecosystem is moving that way. Treat the redirect flows as the older of the two mechanisms rather than as the only one. For issuers such as a QTSP issuing attestations, OpenID4VCI is the interface to implement.