Proof that you own asset without sending ADA from owning address

Developers Native Tokens
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Hi guys,

wanted to ask how owner of an NFT can prove that he/she owns the NFT on a given without sending ADA from this address to user that want to verify that this user is the real owner of the NFT?

Regards,
Adam.

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Ask them to send a specific amount to the the same address they claim to own. :slight_smile:

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The question is a bit wide.

Could you explain better the scenario of why do you need to verify that the user actually owns the NFT?

Depending on your use case there are different mechanisms that could apply.

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Hi,

Thanks for your reply.
We would like to generate vouchers for NFT holders for next collection sale. Because I would like avoid situation where we ask users to send ADA from address owning NFT and some users - even the ones not holding our NFT - will try to send funds and we would have to do refunds.

Regards,
Adam

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In this case, I would go for a simpler approach you can apply the voucher once the user buys a token of the new collection.

In that way, you only need to make your users aware that the discount will only be available if they buy the new tokens using the same address that holds the previously bought ones.

They will send the full price and you will apply the discount by sending back the ADA along with the new token.

I understand that you might want to let them know earlier if they apply or not. In that case, the only solution I can come up with right now is that you create a login system, maybe using SSO and you match a user account with an address.

That way you can verify if that address currently owns a token.

Another thing to notice is that you should keep track of the tokens used to apply for a discount. You don’t want people tricking the discount system by transferring their tokens. Think about that as used coupons.

I hope this helps,
Nacho

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There’s a ”sign message” option for btc. That way, ypu don’t have to send anything. If cardano doesn’t have this, it should.

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I very recently looked at this and I believe there are a couple of ways - but disclaimer this is speculation no real technical insights offered here… The Nami browser extension wallet has a sign message function which could be used in a number of ways - as a login to allow someone to mint etc or to prove ownership of a stake key. As more wallets make dApp connectors this will become more widely available.

After the wallet connects to your site you can query the UTXO of that wallet then use that UTXO to verify all of the held assets in the wallet (via blockfrost or Db-sync some other mechanism) or Nami may support this directly… if they hold your NFT then you know that user is whitelisted.

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