2J/ Intro to Verifiable Cliams by W3C VCWG Members

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Verifiable Claims by the W3C

Wednesday 2J

Convener: John Tibbetts

Notes-taker(s): Dan Finlay

Discussion notes, key understandings, outstanding questions, observations, and, if appropriate to this discussion: action items, next steps: Trebuchet 11

Verifiable claims are a data format for encoding claims & their verifiability!

Does not have opinions on storage or transmission strategies, only defines schema & format.

Use cases:

  • Loyalty Cards
  • Digital Receipts
  • Digital Offers
  • Education
  • (unofficially) Refugees

The document has 4 components:

  • Subject Identifier
  • Claims about Subject
  • Claims Set Metadata
  • Digital Signature by Issuer

Claims About Subject Example:


“@context”: “https://w3id.org/credentials/v1”, // defines spec in detail.

id: http://example.gov/credentials/13431,

type: [“Credential”, “ProofOfAge”],

issuer: “dmv.gov”,

issued: “2010-01-01”,

claim: {

id: “did:method:aeorihareiahr”,

ageOver: “21” // Can include any number of claims per document.


signature: { … }


Signature Example


type: “RsaSignature2016”,

created: …

creator: link_to_key,

domain: “www.example.com”,

nonce: “9824592db”,

signatureValue”: “BavE110/I1oahera…”  // Dependent on signature type


You can play with this serialization format on JSON-LD Playground


Pelle Brandegard from uPort objects to using JSON-LD as the base format, since it has a lot of required metadata fields, increasing the claim size by about 3-5x. Suggests taking more inspiration directly from JSON Web Tokens instead.

Nathan George from SOVRN agrees that they have been treating many of these metadata fields as optional, and that the standard might want to consider making some of the JSON-LD metadata fields officially optional.

Additional notes from Colin Jaccino

A document in which you can a cert a set of attributes about an entity or set of entities.

Components of a verifiable claim:

- Set of verifiable claims

- Subject Identifier
- Claims about a subject
- claim set metadata
- digital signature by issuer

Three use cases:

  Loyalty Cards

  Digital Authors


Subject Identifier 


“id”: “http://example.cov.credentials/3732”,

"type: [“Credential,”, “ProofOfAgeCredential”]

“issuer”: “https://dmv.example.gov”,

“issued”: “…date…”,

“claim”: “did:method:8719238471234”,

“ageOver”: 21


“signature”: “{ _ }”