7. Supported Credential Formats and -Exchange Protocols, Wallets and DID¶
7.1 DID Methods¶
| did:web | did:ebsi | did:elsi | did:key | did:keri | did:op | |
|---|---|---|---|---|---|---|
| Tagus | X | |||||
| Loire | X | |||||
| Danube | X [1] | via extension [2] | via extension [2] | X [1] | via extension [2] | via extension [2] |
Note
- The did method is directly supported by the
Gaia-X Basic Functionscomponent of the DanubeGaia-X Core Engine. - The did method may be directly supported by a suitable extension of the
Gaia-X Core Engine.
In the table, the following did methods are mentioned:
- did:ebsi (European Blockchain Services Infrastructure; now the Europeum EDIC)
- did:elsi (linked to eIDAS)
- did:key (equivalent to allowing completely anonymous participants)
- did:keri (GLEIF)
- did:op (Ocean Protocol) or other DLT-based methods
7.2 Credential Formats¶
| JWS 2020 | VC-JWT | |
|---|---|---|
| Tagus | X | |
| Loire | X | |
| Danube | X |
where: - JWS 2020: W3C JSON Web Signature 2020 - VC-JWT: Verifiable Credential as JSON Web Token as specified in Securing Verifiable Credentials using JOSE and COSE
Rationale: JWS uses a signature embedded in the JSON file of the verifiable credential payload whereas VC-JWT takes the whole VC payload and wraps it into a JWT envelope. This separates the signature process from the actual VC contents. VC-JWT is also compatible with the eIDAS 2.0 EUDI Wallet and EUBW (Business Wallet).
7.3 Credential Exchange Protocols¶
Currently, the Gaia-X 3.0 “Danube” platform and other Gaia-X technically compatible compliance engines need to support the following credential exchange formats.
| Version | VC-API | OID4VC | Remarks |
|---|---|---|---|
| Tagus | X | will not be upgraded to OID4VC | |
| Loire | X | X | The Loire Compliance Engine itself does not support OID4VC. OID4VC access to Loire compliance is accomplished through the Gaia-X 3.0 “Danube” platform |
| Danube | X | X | Gaia-X 3.0 “Danube” platform supports both protocols for Loire compliance and any extension |
where:
- VC-API: simple HTTP/REST API typically exposed at
https://compliance-engine.company.com/v2/docs(example) - OID4VC: Open ID Foundation set of standards for verifiable credentials. Gaia-X currently uses OID4VCI (Issuance) and OID4VP (presentation)
Note on Gaia-X 3.0 “Danube” platform
The Danube platform supports OID4VC through its Gaia-X Compliance Dispatcher component.
Note on potential additional credential exchange protocols
We are well aware of various other credential exchange protocols such as
- CHAPI: Credential Handler API
- DCP: Decentralized Claims Protocol
- DIDComm: Decentralized Communication
- WACI: Wallet and Credential Interactions
In the current architecture of the Gaia-X 3.0 “Danube” platform, all in-bound API requests to the Danube platform are handled by the Gaia-X Compliance Dispatcher component (GXCD). That means that any additional credential protocol needes to be implemented directly in the GXCD.