DIIP
DIIP, the Decentralized Identity Interop Profile, is not a specification of its own but a profile: it picks one coherent set of existing specs — credential format, signature algorithm, identifiers, issuance and presentation protocol, revocation — and makes the optional parts mandatory, so "we use DIIP v5" replaces a paragraph of spec references.
Started in the Dutch Blockchain Coalition, DIIP is now maintained by the FIDES Community, which releases a new version roughly twice a year and includes Credenco on its editor team. It targets interoperability where device binding is not required and the wallet itself does not need to be trusted, such as diplomas, certificates, licences, permits and business wallets; strong customer authentication and PID sharing are explicitly out of scope, which is HAIP territory instead. Versions have tracked the underlying specs as they matured: v1 (2023) profiled JWT-VC over early OpenID4VCI and OpenID4VP drafts with Presentation Exchange, v2 (2024) moved to later drafts of the same set, v4 (2025) added SD-JWT VC as a required format alongside W3C VCDM 2.0 and replaced Status List 2021 with the IETF Token Status List, and DIIP v5 (January 2026, current) aligns on the final OpenID4VCI and OpenID4VP 1.0 specifications and adds optional trust establishment through OpenID Federation; v6 is in development.