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JSON-LD

JSON-LD (JavaScript Object Notation for Linked Data) is a lightweight Linked Data format designed to integrate seamlessly with web technologies and APIs. It allows data to be serialized in a human-readable and machine-processable format, facilitating data linking and sharing across different systems.

Key Features of JSON-LD​

JSON-LD is a lightweight syntax to structure data using the principles of Linked Data. It provides a way to make data more accessible and understandable both by humans and machines.

  • Compatibility with JSON: JSON-LD is fully compatible with JSON, making it easy to integrate into existing systems.
  • Context: The @context attribute allows you to map terms in your data to URLs, providing a way to specify the meaning of each term.
  • Compaction and Expansion: JSON-LD can be compacted or expanded to simplify data exchange.
  • Internationalization: Support for multilingual data through @language and @direction.
  • Framing: JSON-LD framing allows you to query and transform JSON-LD data into a desired shape.

Compaction, Expansion, and Framing in JSON-LD​

Compaction​

Compaction is the process of transforming JSON-LD data into a more compact form, using the @context to replace URLs with short names.

Expansion​

Expansion transforms JSON-LD data into a form where all the terms are expanded to their full URLs.

Framing​

Framing allows you to specify a frame (template) to query and restructure JSON-LD data. This is useful for extracting specific data from a larger JSON-LD document.

Example​

The following JSON-LD example represents the credential of a Natural Person:

{
  "@context": ["https://www.w3.org/ns/credentials/v2", "https://oid.spherity.com/contexts/oid/v1.jsonld"],
  "type": ["VerifiableCredential", "LegalEntityCertificate"],
  "id": "urn:uuid:f086cced-1153-4540-993b-b4d52ca499c2",
  "validFrom": "2019-12-03T12:19:52Z",
  "validUntil": "2029-12-03T12:19:52Z",
  "issuer": "did:key:z6MkiY62766b1LJkExWMsM3QG4WtX7QpY823dxoYzr9qZvJ3",
  "credentialSubject": {
    "id": "did:key:fictive-1",
    "type": "NaturalPerson",
    "givenName": "John",
    "familyName": "DOE",
    "gender": "Male",
    "birthDate": "1970-01-01",
    "domicile": {
      "postalCode": "10119",
      "addressCountry": "Germany",
      "addressLocality": "Berlin"
    }
  }
}

Using JSON-LD in OID application​

In OID application, we use JSON-LD to ensure data interoperability and connectivity with external datasets. Notably, JSON-LD is the format used in W3C Verifiable Credentials, which is why we have adopted it for our credential management.

The whole JSON-LD handling will be abstracted by the libraries used in the W3C-VC implementation. If we would have some custom JSON-LD operations, we would use the the jsonld.js library, which provides robust tools for parsing, manipulating, and serializing JSON-LD data.

But on the application level, we will mostly work with the jsonld-signatures and jsonld-document-loader to create and verify digital signatures on JSON-LD data.

For more detailed information, visit the JSON-LD website.