mdoc
An mdoc is a mobile document in the ISO/IEC 18013-5 format: a credential held on a phone as compact, issuer-signed data elements that a reader can verify on the spot, including when neither side has a network connection.
The format grew out of the mobile driving licence and was then generalised, so an mdoc can carry any set of attributes, not only licence data. Its data elements are encoded in CBOR and covered by a Mobile Security Object: the issuer signs a list of salted hashes rather than the values themselves, which is what lets the holder release individual attributes and no more. The credential is bound to a key held on the device, so a reader can tell the holder is presenting it rather than replaying a copy, and the exchange runs over Bluetooth or NFC in person as well as online. The EUDI ARF names mdoc alongside SD-JWT VC as a format wallets must support.