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Verifiable Credentials use case questions

From: Eric <e.garcia.ribera@gmail.com>
Date: Sun, 26 Sep 2021 19:45:27 +0100
Message-ID: <CA+Bz4c0h=EEgM1AWR-FR46aoTtTtAvLvGDGwxqW4NeiHDPQAwQ@mail.gmail.com>
To: public-credentials@w3.org
Cc: Brian Martinez <brianmartinez78@gmail.com>, lm.liuteria@gmail.com
Hello all,

I would like to quickly explain the use case we are working on at the
moment and ask a question we'll need to solve in order to start pushing the
use case forward. Appreciate your time in advance.

Our main goal was to use NFTs as a proof of ownership for physical objects.
The real world object would be linked to NFTs, and the owners of those
could sell or buy other NFTs in demand. Once we started developing the idea
and a PoC, we quickly identified an issue with NFTs that could stop our
progress. The issue was that the owner of a physical object (linked to an
NFT) had no straightforward way of proving him/herself as the real owner.
Imagine the scenario where person A just wants to prove person B is the
owner of an NFT. Since the NFT owner is identified by an address, the owner
would need to prove ownership by opening the wallet and show that the NFT
owner's address it's him/hers. Doing this in the real world when you are in
front of the verifier (person that wants to check you own a specific NFT)
can be done by showing your wallet owns that address. However, doing this
online, doesn't seem to be straightforward. Maybe I'm mistaken and there is
an easy way of proving ownership. If this exists, I would really appreciate
an explanation on that since I'm not aware of any.

At this point, we discovered DIDs and Verifiable Credentials. When we read
the standards we came to the conclusion that VCs could be used as NFTs,
since these provide similar features (a DID could identify the creator of
an object, and another DID, signed by the creator, could identify the
created object. Later on, the creator could issue a VC to the first buyer,
giving the buyer the ownership of the DID of the object). More importantly,
we discovered that with VC, an owner of it can show very easily that he/she
is actually the owner of it, making life easier for our use case. However,
we had a question regarding this:

- In the standard, we can see the possibility of transferring VCs. Based on
the diagram of the standard (Figure 10 in
https://www.w3.org/TR/vc-data-model/), it looks like the holder of a VC can
transfer it to another holder without involving the issuer. Would this be
possible somehow? This is crucial for our use case, since we want to
decentralise as much as possible our solution. We wouldn't like any 3rd
party or intermediary stopping the holder of a VC from selling it to
another holder. Remember at this point that we see VCs as NFTs (maybe our
assumption is wrong), that's why we would like to decentralise this.

If transferring a VC from holder A to holder B is not possible without
involving the issuer, do you think this could be done with a Smart
Contract? I know this may not be the best forum to ask this, but we somehow
visualise the idea of using a smart contract as the issuer of DIDs so that
everybody could trust the issuer at any point.

Thank you very much in advance. I would really appreciate your input on
this :)

Best regards,
Received on Monday, 27 September 2021 08:34:18 UTC

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