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Re: Identifiers in Verifiable Credentials

From: Steve Capell <steve.capell@gmail.com>
Date: Mon, 7 Jun 2021 19:14:58 +1000
Message-Id: <B1A698D1-E6D4-4D5C-80E8-21CFE802DF8A@gmail.com>
Cc: public-credentials@w3.org
To: David Chadwick <d.w.chadwick@verifiablecredentials.info>
What about the case where there is a subject but the VC is also presented by a bearer 

For example 

Issuer (border agency) issues a VC about a subject (ACME) that asserts that ACME is an Australian Trusted Trader.  

ACME provides that VC (together with several others like an IP rights ownership VC (about a product ) and a certificate of origin VC (about a consignment) with their export document bundle to their customer (importer) who gives some of them to a customs broker who passes them to the importing border authority (customs) who is the verifier of the trusted trader VC and the origin VC (but doesn’t care about the IP rights vc). The IP rights VC is a direct exporter (ACME) holder to verifier (importer) VC.

This is pretty much business as usual in international trade - which comprises maybe 10 billion consignments (and hence VC bundles) per year 

We have a combination of 
- pure bearer VCs (eg the origin certificate where the subject is a consignment of goods)
- traditional holder VCs (eg the trusted trader status) - except that the holder is not the presenter so it’s kind of a holder VC used like a bearer VC
- pure holder is presenter (the scenario most often discussed in this group but the least common in cross border trade)

Whet is the correct use of subject ID and VC assertion ID in each of these cases?

Steven Capell
Mob: 0410 437854

> On 7 Jun 2021, at 6:52 pm, David Chadwick <d.w.chadwick@verifiablecredentials.info> wrote:
> 
> 
> 
> 
> On 06/06/2021 22:57, Kerri Lemoie wrote:
>> Hello all,
>> 
>> I have a question about identifiers in verifiable credentials. The documentation states:
>> 
>> "When expressing statements about a specific thing, such as a person, product, or organization, it is often useful to use some kind of identifier so that others can express statements about the same thing. This specification defines the optional id property for such identifiers. The id property is intended to unambiguously refer to an object, such as a person, product, or organization. Using the id property allows for the expression of statements about specific things in the verifiable credential."
>> 
>> 
>> In the credentialSubject property it seems clear that the id can represent the subject that the claim is about but I’m not clear on the uses for the optional id in the vc assertion. It would be helpful to learn about some examples or suggested uses.
> The id is optional for the case where the VC is a bearer VC e.g. a ticket to an event. This means that the properties are not bound to a subject, but can be presented by anyone who possesses the VC.
> 
> Kind regards
> 
> David
> 
> 
> 
>> 
>> 
>> For some context: in VC-EDU, we’re discussing Open Badges as VCs. Open Badges have historically mostly been verified via issuer hosted URLs.  One of the reasons to move away from hosted URLs is to remove the dependence on the issuer for verification. However, there may continue to be use cases for when an Open Badge should still be verified through its hosted url. 
>> 
>> 
>> Thanks,
>> 
>> Kerri
>> 
>> 

Received on Monday, 7 June 2021 09:15:37 UTC

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