ISO/IEC 18013-5
ISO/IEC 18013-5 is the international standard for a mobile driving licence: it defines how a credential is stored on a phone and presented to a reader in person, including when neither device has a network connection.
The standard specifies two presentation channels, offline over Bluetooth or NFC straight to a nearby reader and online to a remote relying party, both encrypted end to end so the holder controls exactly which fields are shared and the reader can confirm the response came from the phone presenting it. Although it was written for driving licences, the underlying data model generalises to any credential: the mdoc format carries the same offline/proximity model for attributes beyond a licence. The EUDI ARF names ISO/IEC 18013-5 alongside SD-JWT VC as a format wallets must support, which is why HAIP profiles it as a credential format too.