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Re: usage of credentialSubject WITHOUT id?

From: Niels Klomp <nklomp@sphereon.com>
Date: Sun, 6 Mar 2022 11:38:28 +0000
To: Giuseppe Tropea <giuseppe.tropea@cnit.it>
CC: "public-credentials@w3.org" <public-credentials@w3.org>
Message-ID: <716437f6-9b95-4638-9658-89df40877712@email.android.com>
Hi Giuseppe,

Indeed the use case is for so called bearer credentials (
https://www.w3.org/TR/vc-data-model/#bearer-credentials). The example of a concert ticket mentioned in there is a good one, although the actual bachelor degree example nr 33 is questionable since a degree is not subject independent.  That seems to come more from the fact that the degree is used throughout the spec as an example.
So yes your example is a generic claim from an issuer with no ties to any subject and thus should be issued as a bearer credential.

The net result is that you can make a VP containing a bearer credential, but you can never have the holder being the subject, since there is no subject id. See also https://www.w3.org/TR/vc-data-model/#subject-is-the-holder.


Kind regards,

Niels Klomp


Op 6 mrt. 2022 10:33 schreef Giuseppe Tropea <giuseppe.tropea@cnit.it>:
dear CCG,
in chapter "4.4 Credential Subject”, of the Verifiable Credentials Data Model v1.1, I read that "Each object MAY contain an id”.
Can somebody clarify the use-case when the subject does NOT contain an id? As follows?:


{
  "id": "http://example.edu/credentials/3732",
  "type": ["VerifiableCredential", “WeatherCredential"],
  "issuer": "https://example.edu/issuers/565049",
  "issuanceDate": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    “weather": {
      “value": “it rains!"
    }
  },
  "proof": { ... }
}

Is the above (i.e. claims that use impersonal verbs) the only indented use-case for VCs without id in the credentialSubject property?

Or am I completely off track and there is more, or a different idea altogether?

Thank you,
giuseppe

—
Giuseppe Tropea
CNIT - Italy
giuseppe.tropea@cnit.it<mailto:giuseppe.tropea@cnit.it>
—


Received on Sunday, 6 March 2022 11:38:44 UTC

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