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6. SDCJ Ecosystem — Selective-Disclosure, Cross-Jurisdiction Identity

The SDCJ ecosystem extends Gaia-X Danube onboarding to participants identified by national business registration numbers outside the EU-centric identifier set (EORI, EUID, vatID, LEI, taxID). The reference implementation verifies the Republic of Korea Business Registration Number (사업자등록번호) live against the Korean National Tax Service, and issues compliance credentials that support selective disclosure: any verified registration attribute can be withheld or revealed per presentation using IETF SD-JWT-VC, alongside the standard VC-JWT path.

The SDCJ ecosystem description includes:

6.1 Governance

  • Governance Authority / Maintainer: Circular Solution Co., Ltd. (KR BRN 175-88-03648)
  • Contact: bowen.chong@circularsolution.co.kr
  • Domain: Cross-jurisdiction identity and trust
  • Trust scope: SDCJ_COMPLIANCE (Gaia-X Compliance Dispatcher)
  • Version: 1.1 — last updated 2026-07-16
  • Ontology alignment: Gaia-X Metaregistry Ontology
  • Origin: 2nd prize, Gaia-X Hackathon #9 (Tech-X Athens, May 2026)

6.2 Rulebook — compliance criteria

ID Criterion Validation method
SDCJ-C1 Presentation and embedded credentials carry valid signatures; the signer certificate chain anchors in the Gaia-X Registry trust anchors Automated (Gaia-X Basic Functions signature validation + Registry /api/trustAnchor/chain)
SDCJ-C2 All participant DIDs resolve and verify Automated (Gaia-X Basic Functions DID verification)
SDCJ-C3 Credentials conform to the SDCJ SHACL shapes Automated (see sdcj.shacl.ttl)
SDCJ-C4 The business registration number is registered and active with the national authority First-party automated verification against the authority API; evidence recorded per number as sdcj:jurisdictionAttestations (sdcj:taxAuthority, sdcj:verifiedAt, sdcj:businessStatus)

6.3 Jurisdictions

Country Authority Verification Status
KR National Tax Service (NTS) Live status API lookup (b_stt_cd = active) Production
JP National Tax Agency (NTA) Corporate number check Experimental

Additional jurisdictions are added as adapters against a shared interface.

6.4 Credentials

Type Direction Example Schema
sdcj:ParticipantCredential input example shapes · ontology
sdcj:ComplianceCredential output example ontology

6.5 Credential formats

  • application/vc+jwt — default; W3C VC 2.0 secured with JOSE.
  • application/dc+sd-jwt — opt-in via Accept header; IETF SD-JWT-VC with selectively disclosable attestation claims: sdcj:registrationNumber, sdcj:businessStatus, sdcj:taxType, sdcj:closedDate. Country code, tax authority and verification timestamp remain always visible.

6.6 Endpoints

Purpose URL
Compliance issuance POST https://circularsolution.services/gxdch/sdcj/validateAndSignVcFromVp?vcid=<id>
SD-JWT presentation POST https://circularsolution.services/gxdch/sdcj/sd-jwt/present
SD-JWT verification POST https://circularsolution.services/gxdch/sdcj/sd-jwt/verify
Ontology https://circularsolution.services/gxdch/sdcj/rdf/ontology
SHACL shapes https://circularsolution.services/gxdch/sdcj/rdf/shapes
API documentation https://circularsolution.services/gxdch/sdcj/docs
  • Issuer DID: did:web:circularsolution.services:gxdch:sdcj

6.7 Trust

Issuer keys are anchored via an EV-SSL certificate chain validated against the Gaia-X Registry trust anchors. Foreign trust service providers accepted by the ecosystem are declared in the Ecosystem Trust Profile: participants compliant under the Gaia-X Loire trust scope are accepted into SDCJ without re-verification.

6.8 Roadmap

  • Registration-number notary role: issuing gx:-vocabulary registration-number credentials, eligible for the Gaia-X Registry trusted-issuers list, so SDCJ-verified participants count inside Gaia-X Loire compliance.
  • Compliance Dispatcher format passthrough, enabling SD-JWT-VC selection end-to-end through the dispatcher and OID4VCI wallet flow.
  • Accreditation of the Korean NTS as a Gaia-X Trusted Data Source (Compliance Document / PRC).
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