Identification (the UNI): crosswalk to external standards
The external standards in the crosswalk domains of identification (the UNI), from the register, with the relation of each to the Nexus Standards. Each row links to the issuing body, and each relation is evidenced by attestations identified by UNIs (Unique Nexus Identifier).
- Nexus Standards: NS-1, NS-3, NS-6, NS-7, NS-9.
- Open standards: DataCite Metadata Schema 4.5; Research Organization Registry (ROR); ORCID iD; SoftWare Hash IDentifier (SWHID) v1.2; Decentralized Identifiers (DIDs) v1.0; UN M49 standard country or area codes.
- Data and feeds: ROR REST API v2; DataCite REST API (DOIs); ORCID public API v3.0; Wikidata Query Service.
- Couples with: Registries and the resolver; Data and datasets; Documentation and publication; Naming, marks and intellectual property.
The process.
The crosswalk as a table: 10 external standards by domain
| Domain | External standard | Issuing body | Relation |
|---|---|---|---|
| Identifiers and cataloguing | DataCite Metadata Schema 4.5 | DataCite Metadata Working Group | adopt |
| Identifiers and cataloguing | Digital Object Identifier system – ISO 26324 | ISO/TC 46/SC 9; International DOI Foundation | crosswalk |
| Identifiers and cataloguing | International Standard Name Identifier (ISNI) – ISO 27729 | ISO/TC 46/SC 9; ISNI International Agency | cite |
| Identifiers and cataloguing | ISO 3166-1 Codes for the representation of names of… | ISO/TC 46; ISO 3166 Maintenance Agency | adopt |
| Identifiers and cataloguing | Open Badges 3.0 | 1EdTech Consortium | adopt |
| Identifiers and cataloguing | ORCID iD (subset of ISNI, ISO 27729) | ORCID Inc. | adopt |
| Identifiers and cataloguing | Research Organization Registry (ROR) | ROR (California Digital Library, Crossref, DataCite) | adopt |
| Identifiers and cataloguing | SoftWare Hash IDentifier (SWHID) Specification V1.2… | Software Heritage; ISO/IEC JTC 1 | adopt |
| Identifiers and cataloguing | UN M49 Standard country or area codes for statistical use | United Nations Statistics Division | adopt |
| Identifiers and cataloguing | W3C Decentralized Identifiers (DIDs) v1.0 | W3C DID Working Group | profile |
Nexus Standards in the graph: NS-1, NS-3, NS-9. A relation is a register entry, never a compliance claim.
3 Nexus Standards · 1 domains · 10 external standards · 10 issuing bodies · 0 implementing repositories. Relations (adopt, profile, crosswalk, cite) are as recorded in the register; names and standards remain with their stewards.
Crosswalk graph24 nodes and 23 links from the registry of external standards, programme areas and implementations (the external standards register, the consumers register. Relations (adopt, profile, crosswalk, cite) are shown as recorded in the register.
- Nexus Standards
- 5
- NS-1, NS-3, NS-6
- Open standards
- 6
- named, never copied
- Data and feeds
- 4
- listed for reference
- Couplings
- 4
- with other areas
Identifiers and cataloguing
10 register entries.
| Standard | Body | Version | Relation | Access | Verified |
|---|---|---|---|---|---|
| SoftWare Hash IDentifier (SWHID) Specification V1.2; ISO/IEC 18670:2025 | Software Heritage; ISO/IEC JTC 1 | 1.2 (ISO/IEC 18670:2025, April 2025) | adopt | open | verified |
| W3C Decentralized Identifiers (DIDs) v1.0 | W3C DID Working Group | W3C Recommendation 19 July 2022 | profile | open | verified |
| DataCite Metadata Schema 4.5 | DataCite Metadata Working Group | 4.5 (22 January 2024) | adopt | open | verified |
| Digital Object Identifier system – ISO 26324 | ISO/TC 46/SC 9; International DOI Foundation | ISO 26324:2022 withdrawn March 2025 and replaced by ISO 26324:2025 | compatibility profile (restricted) | paywalled | unverified |
| ORCID iD (subset of ISNI, ISO 27729) | ORCID Inc. | 16-digit identifier with ISO/IEC 7064 MOD 11-2 check digit | adopt | open | verified |
| International Standard Name Identifier (ISNI) – ISO 27729 | ISO/TC 46/SC 9; ISNI International Agency | ISO 27729 | cite | paywalled | unverified |
| Research Organization Registry (ROR) | ROR (California Digital Library, Crossref, DataCite) | schema v2 (v1 retired December 2025 per secondary source); CC0 data | adopt | open | verified |
| ISO 3166-1 Codes for the representation of names of countries and their subdivisions – Part 1: Country codes | ISO/TC 46; ISO 3166 Maintenance Agency | current (alpha-3 used in the UNI REGION segment) | adopt | free-to-read | unverified |
| UN M49 Standard country or area codes for statistical use | United Nations Statistics Division | online edition of Series M, No. 49 | adopt | open | verified |
| Open Badges 3.0 | 1EdTech Consortium | 3.0 | adopt | open | unverified |
Unverified entries rest on a secondary source for at least one field, as indicated in the register.
Relation types and their evidence
| Relation | Meaning | Evidence |
|---|---|---|
cite | The Nexus Standard refers to the external standard as context. | Identifier, version and URL in the register. |
profile | The Nexus Standard constrains or specialises an open external standard (for example STAC, DCAT, PROV-O, DataCite, CAP). | Conformance tests against the external standard’s own validator where one exists. |
crosswalk | Elements of the external standard map to Nexus elements (clauses, record fields). | A crosswalk table in the register entry; each row cites the external clause by number, never by text. |
adopt | The Nexus Standards use the external standard as it is for a function (for example ISO 3166-1, SPDX, ORCID, ROR). | Validation of values against the external scheme. |
extend | A Nexus Standard adds machine-readable, real-time or provenance elements that the external standard lacks. | The extension is a Nexus clause or field; the external standard is cited as the baseline. |
gap | No external standard covers the concern; a Nexus Standard specifies it. | The gap statement in the landscape study. |
Questions and answers.
Does a crosswalk establish that a identification (the UNI) artefact conforms to these standards?
Why are some relations shown as compatibility profile (restricted)?
Why are some entries marked unverified?
Around identification (the UNI).
Shape the standards for identification (the uni).
Governments, regulators, standards bodies, industry, academia and communities are invited to shape the catalogue ahead of its first official release, targeted for 2030: comment on a draft, propose a change, join a working group or host a field exercise.
Status and use. The Nexus Standards are proposed standards developed through an open process under NS-13 and published for voluntary use; they do not constitute certification, accreditation or regulatory approval, and adoption remains a decision of the Global Standards Council and, in each country, of its National Standards Council. A UNI (Unique Nexus Identifier) identifies an artefact; it does not certify it. Names of standards bodies and their standards belong to their stewards and are used only to identify the documents; no text of an external standard is reproduced here. Nexus Standards is not affiliated with, endorsed by or certified by any standards body named here.
Licences: CC BY 4.0 for standards text, registries, schemas and data; Apache-2.0 for reference code. External standards are cited by name, number and link under their own licences. Third-party data, libraries and fonts keep their own licences: see Third-party notices.