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Credential Formats

EUDIPLO supports the credential formats specified in the European Digital Identity Wallet (EUDI Wallet) ecosystem. This page documents the supported formats and their specific features.

Supported Formats​

EUDIPLO supports two primary credential formats:

FormatDescriptionSpecification
SD-JWT VCSelective Disclosure JWT Verifiable CredentialIETF OAuth SD-JWT
mDOC / mDLISO mobile driving license and mobile documentsISO 18013-5

Both formats support selective disclosure, allowing users to reveal only the specific claims requested by a verifier rather than the entire credential.

SD-JWT VC (Selective Disclosure JWT Verifiable Credential)​

Overview​

SD-JWT VC combines JSON Web Tokens (JWT) with selective disclosure capabilities, enabling fine-grained control over which claims are revealed during presentation.

Key Features​

  • Selective Disclosure: Users can reveal only specific claims from the credential
  • JSON-based: Familiar JSON structure for claims and metadata
  • JWT Security: Standard JWT signing and verification mechanisms
  • Compact: Efficient encoding for mobile and web use cases

Trust Signaling​

SD-JWT credentials support two trust signaling modes:

ModeDescriptionUse Case
x5cEmbeds X.509 certificate chain in JWT headerTraditional PKI-based trust (default)
federationUses OpenID Federation for trust resolution via issuer (iss)Federation-based trust evaluation

Configure the trust format per credential in the issuance configuration:

{
  "credentialConfigId": "pid",
  "sdJwtTrustFormat": "federation"
}

See OpenID Federation for federation configuration details.

Verification​

EUDIPLO verifies SD-JWT VCs by:

  1. Validating the JWT signature against trusted issuer keys
  2. Checking certificate chains (when using x5c mode)
  3. Evaluating federation trust (when using federation mode and openid_federation is specified in DCQL trusted_authorities)
  4. Verifying selective disclosure proofs for requested claims
  5. Checking revocation status via OAuth Status Lists

mDOC / mDL (Mobile Documents / Mobile Driving License)​

Overview​

mDOC is the ISO 18013-5 standard for mobile documents, originally designed for mobile driving licenses (mDL) but extensible to other document types.

Key Features​

  • Selective Disclosure: Attribute-level selective disclosure using CBOR
  • Offline Verification: Supports offline presentation with device binding
  • ISO Standard: Internationally recognized standard for mobile documents
  • CBOR Encoding: Compact binary encoding optimized for mobile devices

Trust Mechanisms​

mDOC credentials use X.509 certificate chains embedded in the credential for trust validation. EUDIPLO verifies:

  1. Certificate chain validity and trust anchor
  2. Document signer certificate (DS certificate)
  3. Mobile Security Object (MSO) signature
  4. Issuer-signed attributes and selective disclosure

Verification​

EUDIPLO verifies mDOC credentials by:

  1. Validating the certificate chain against configured trust anchors
  2. Verifying the MSO signature
  3. Checking selective disclosure proofs for requested attributes
  4. Validating device authentication (for device-bound credentials)
  5. Checking revocation status via OAuth Status Lists (CWT format)

See mDOC verification details for detailed verification flows.

Status Management​

Both credential formats support revocation and suspension through the OAuth Token Status List mechanism:

  • Status List Format: JWT (for SD-JWT VC) or CWT (for mDOC)
  • Status Types: Revocation and suspension
  • Efficient Encoding: Bit-packed status lists for scalability
  • Privacy-Preserving: No correlation between status checks

See Status Management for configuration details.

Format Selection​

Choose the credential format based on your use case:

Use SD-JWT VC when:​

  • You need JSON-based claim structures
  • Your system already uses JWT/JWS infrastructure
  • You want federation-based trust evaluation
  • Web-based verification is primary

Use mDOC when:​

  • You're implementing mobile driving licenses or similar documents
  • Offline verification is required
  • Compact binary encoding is preferred
  • ISO standardization is important

References​