RE: ERC-721 Non-Fungible Token Standard on Ethereum vs. VCs on Hyperledger Indy

Thank you Carlos and Will,

The user scenario is one of those classic “art on the blockchain” kinds of scenarios …so transferability is important.

I believe the ability to revoke a VC for the old owner of a piece of artwork and to re-issue a new VC for the new owner of the artwork should be sufficient for this scenario.  Thoughts?

The existence of existing ECR-721 market places is an important Ethereum advantage: e.g. https://opensea.io/

Thank you both,
Michael


From: Carlos Bruguera <cbruguera@gmail.com>
Sent: February 12, 2021 4:10 AM
To: Will Abramson <wip.abramson@gmail.com>
Cc: Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net>; Credentials Community Group <public-credentials@w3.org>
Subject: Re: ERC-721 Non-Fungible Token Standard on Ethereum vs. VCs on Hyperledger Indy

Just a quick comment, ERC-721 defines an interface the token contracts should implement to comply with it, but it doesn't enforce any particular behavior, therefore it's possible to write a non-transferable ERC-721, still complying with the interface as long as the `transfer` function is provided, it would either revert or not do anything.

On Fri, Feb 12, 2021 at 5:51 PM Will Abramson <wip.abramson@gmail.com<mailto:wip.abramson@gmail.com>> wrote:
An immediate difference is that ERC-721 or I believe any token on Ethereum is transferable. I can send it to you, you could sell it to someone else using a platform like OpenSea, etc.

This is not obviously possible using the Indy stack today without some hack involving the issuer of the credential revoking and re-issuing it. I believe there is some work in Ursa around the crypto for transferrable credentials but not sure what status and priority this has.

Also, the ERC-721 keeps track of tokens and token holder addresses available to anyone who queries the contract.

They are a couple that come to mind,

Will

On Thu, Feb 11, 2021 at 11:05 PM Michael Herman (Trusted Digital Web) <mwherman@parallelspace.net<mailto:mwherman@parallelspace.net>> wrote:
I hope this isn’t stretching the favorable use of the CCG mailing list…

When are Hyperledger Indy/Sovrin VCs better than Ethereum smart contracts for NFEs/NFTs (non-fungible entities/tokens)?

It seems obvious but I don't have a detailed/worked out answer.  One project I'm associated with wants to use the ERC-721 Non-Fungible Token Standard on Ethereum but I believe VCs are a better route to take. Part of the desire to stay on Ethereum is there is quite a vibrant NFT community on Ethereum and lots of different EC-721 tokens.

https://eips.ethereum.org/EIPS/eip-721


What are the considerations/decision points/knock-offs?

Best regards,
Michael Herman
Sovrin Foundation Self-Sovereignist

Self-Sovereign Blockchain Architect
Trusted Digital Web
Hyperonomy Digital Identity Lab
Parallelspace Corporation

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