mdoc

mdoc is the ISO 18013-5 credential format used in the EUDI Wallet, enabling selective disclosure and offline, in-person identity presentation.

mdoc is the credential format from ISO/IEC 18013-5, used both for the mobile driving licence (mDL) and for other digital identity attestations in the EUDI Wallet. Data is encoded in CBOR and secured with COSE signatures: each attribute is hashed into a single signed structure, the MSO (Mobile Security Object), which enables per-element selective disclosure without signing every attribute separately. Cryptographic binding between the mdoc and the wallet's private key (mdoc authentication) proves that whoever presents the data actually holds the credential.

ISO/IEC 18013-5 covers proximity presentation (NFC/BLE/QR, e.g. a traffic stop) as well as online retrieval via a server; fully remote, web-based presentation of mdocs, for example over OpenID4VP, is defined in the companion standard ISO/IEC 18013-7.

mdoc is the second prescribed format of the EUDI Wallet, next to SD-JWT: mdoc is the natural fit for in-person scenarios, SD-JWT for web flows. Selective disclosure alone does not make presentations unlinkable: because the same signed MSO is reused, verifiers who share data can still correlate a holder's separate presentations.