How Does Multi-Format Issuance Future-Proof Digital Credentials?
Learn how issuing in multiple formats ensures verifiable digital credentials work across wallets, devices, and borders.
As states modernize digital identity programs, one architectural decision stands above the rest: what credential format to issue. But here's the reality, there's no single format that works everywhere. Airport security, online age verification, healthcare check-ins, and cross-border transactions each rely on different ecosystems. Issuing in only one format means leaving residents stranded when they step outside that ecosystem.
Multi-format issuance solves this problem. It means issuing the same credential in multiple standardized formats simultaneously, so residents can use their digital identity wherever they go, on whatever device or wallet they choose.
The Case for Multiple Formats
As states consider rolling out verifiable digital credentials, we recommend that, rather than picking one “winner,” states should consider issuing in multiple formats to maximize utility across contexts.
This means issuing mobile driver’s licenses via ISO/IEC 18013 series (or mdocs from ISO/IEC 23220 series) for TSA checkpoint acceptance and native use in the OEM (Apple, Google, Samsung) wallets, but also issuing as IETF SD-JWTs and W3C VCs to maximize interoperability and portability. This mirrors the emerging best practice in U.S. pilots and ensures one credential works both in person and online, today and cross-border tomorrow under EU-style wallet models.
What Each Format Offers
ISO/IEC 18013 mDLs are the standard for high-assurance credentials such as driver licenses and state IDs. TSA already supports them through Transportation Security Administration Identity Framework (TSIF) pilots, and AAMVA's Digital Trust Service enables cross-state acceptance. Wallets can store ISO-compliant mDLs and other mdocs with privacy-protective offline validation. Crucially, readers validate credentials without contacting the issuer—no surveillance risks, no "phone home" architecture.
IETF SD-JWTs build on the JSON Web Token format already used across government and enterprise systems. The key benefit: selective disclosure. A resident can prove they're over 21 without revealing their birthdate or address. SD-JWT+KB additionally enables holder key binding, ensuring the credential can't be transferred or replayed. Issuance is transport-agnostic and works over existing protocols, such as OID4VCI. Wallets store the SD-JWT and its disclosures, then at presentation time reveal only the requested claims. Verifiers request only what they need, and the holder's wallet returns the SD-JWT with blinded claims and minimal disclosures—nothing more.
W3C Verifiable Credentials (VCDM 2.0) offer the most flexibility, with issuance over web protocols using OID4VCI. They work across high- and low-assurance use cases, and SD-JWT can be used as a VC format under VCDM 2.0. Wallets can store multiple credential types. Selective disclosure is supported by formats such as SD-JWT VCs, while advanced cryptographic techniques enable unlinkability—meaning even repeated presentations can't be correlated back to the same person. This format has strong momentum in online and cross-sector adoption, with a global ecosystem of implementers.
A Foundation for Long-Term Success
Multi-format issuance isn't about hedging bets, it's about designing for the world as it actually works. Residents need credentials that function at TSA checkpoints, on campus ID systems, in healthcare portals, and across state lines. Issuing in SD-JWT, ISO mDL, and W3C VC formats ensures that digital credentials meet people where they are, on the devices and wallets they already use.
All of this happens under the hood. To a resident, the experience is simple: their ID, permit, or pass just works when and where they need it. They don't need to know which format is being used at the airport versus the pharmacy versus a state benefits portal. The complexity lives behind the scenes in the architecture, not in the user's hands.
This is a key architectural decision that determines whether a digital identity program becomes infrastructure or just another pilot. By supporting multiple formats, states protect against obsolescence, enable healthy vendor competition, and give residents genuine choice over how they prove who they are.
If your state is designing a digital identity program and wants to understand how multi-format issuance can maximize adoption and interoperability, we'd love to chat.
About SpruceID: SpruceID is building a future where users control their identity and data across all digital interactions. We build privacy-preserving digital identity infrastructure that empowers people and organizations to control their data. Governments, financial institutions, and enterprises use SpruceID’s technology to issue, verify, and manage digital credentials based on open standards.
