OpenID VC spec shows interoperability between issuers, digital wallets

The OpenID Foundation has successfully completed an interoperability test of its OpenID for Verifiable Credential Issuance (OpenID4VCI) specification, which allowed seven credential issuers and digital wallets from five providers to work with each other.

OpenID Foundation Executive Director Gail Hodges writes in an announcement that there were five goals for the pairwise testing. OIDF wanted to prove the specification’s effectiveness before holding a final vote on it, and give the Digital Credentials Protocols Working Group interoperability findings and feedback from implementers. It wanted to have interoperability test results to share with other standards bodies, like ISO/IEC, W3C and ETSI, and show government partners the progress standards supporting their projects, like EU Digital Identity Wallets, the NIST NCCOE mDL project and the Japan Digital Agency’s pilot. The group also wanted to demonstrate the interoperability of the spec for issuers, digital wallets and vendors “for them to prove out their own implementations that use these specifications.”

The test included OpenID4VCI version 16, OpenID for Verifiable Credentials High Assurance Interoperability Profile Implementer’s Draft 2.0, mobile driving license (mDL) standard ISO/IEC IS 18013-5:2021 and the “mdoc” specification, ISO/IEC TS 18013-7:2024 and the IETF’s SD-JWT draft 17.

Participants in the test included the OpenWallet Foundation, MyMahi, OpenID, Fikua, Meeco, Lissi, Bundesdruckerei and Mattr.

Bundesdruckerei maintains the PointID terminals that are intended to streamline digital identity issuance in Germany. Mattr was just selected by New Zealand’s government to supply a digital wallet to go with its government service app.

Out of a possible 59 combinations of issuers and wallets, 47 pairwise tests were conducted, with 87 percent success. Another 11 percent failed with what OIDF describes as “resolvable issues,” while the reason for the failure of the other 2 percent was not immediately clear.

“OpenID4VCI’s focus on simplicity and interoperability across diverse ecosystems makes it a cornerstone for scalable and interoperable digital credential issuance,” says Mattr Technical and Standards Director for Europe Oliver Terbu.

The tests included configurations of OpenID4VCI with mdoc and no client authentication, with SD-JWT with client authentication based on wallet attestation with an x5c header, based on client assertion with private_key_jwt, and with no client authentication.

Further tests will be held, some with more mdoc credential types.

“Together, we are building a truly global digital identity ecosystem, one that empowers users, protects privacy and delivers real-world value,” Hodges says.

The 60-day public review of the OpenID4VP specifications end on August 28, and final publication is expected in mid-September. Self-certification for OpenID4VP and OpenID4VCI could be open by the end of September.

Article Topics

digital ID  |  digital identity  |  digital wallets  |  interoperability  |  OpenID Foundation  |  OpenID4VCI  |  verifiable credentials