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Comment by randomopining | Hacker News Reader

How do you attach a digital address to a physical item? Let’s say I buy a Nike shoe and then give 10 fake Nike shoes the same digital address. They are amazing fakes. Same issue as today right?

Unless there is a clever crossover to convert from digital verification to physical and back... seems worthless to me.

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Well, for any collectible item an important factor is "provenance", i.e. is there a legitimate reason to believe the item originated from a credible source.

At least nfts now require people to also forge the provenance, which provides an additional hurdle to forgers (my best attempt to steelman the "pro nft" argument)

For instance, if a great great grandson of Henry VII sells a medallion that he claims belonged to his ancestor, that would have more weight than a similar medallion from a random individual, because it's far less likely for a relative to also be a blatant forger. In theory at least, nfts provide a similar (limited) assurance.

The difference is provenance with NFTs is about the NFT itself, but not the item. Like mentioned elsewhere here, block # and timestamp will differ. But digital items don't have provenance.

To put it another way: the analogue is not original medallion vs new fake one. They're both 100% identical medallions in every conceivable way, but the receipt for one is older than the other. I don't know about you but I don't give a damn if your receipt is older than mine if the items are not unique in any way.

The only thing I can think of is embedding a physical unclonable function into the thing. As long as Nike holds on to custody of the physical tokens and only embeds them in real Nike products, then you could verify with the Nike database that it's a real token and a real product.

But you don't need a blockchain for that.

https://en.m.wikipedia.org/wiki/Physical_unclonable_function

Sure you do. Nike could go out of business and their records lost forever. Nike could suffer a hack. Nike could have a rogue employee manipulate the database values. Nike could be thrown off the internet by AWS. A public blockchain like Ethereum is plausibly neutral, decentralized into tens of thousands of nodes worldwide who carry copies of the ledger, and there is a strong economic incentive baked into the blockchain to keep blocks consistent and persistent.

And if you want to trade your Nike NFT with someone's Reebok NFT, it would help to use an open standard with an economic mechanism for trade between counterparties built-in.

Nike can just produce a set of PUF keys, cryptographically sign that list, and publish it. Then they embed one of these into a bunch of otherwise identical Nike products. The message could also describe the product's physical attributes so someone couldn't swap a PUF between differently-rare Nike products.

Knowing the PUF key doesn't let you fabricate a physical widget with the same key (that's the unclonable part). So they can all be public, and anyone can keep a copy of the batch of PUF keys that includes their object's PUF key. When they want to prove it's an authentic item, they can prove the PUF produces a key on that list and prove the list was signed by Nike by normal public key cryptography.

In this scheme, Nike published their public key in an SEC filing, so in the worst case you can go ask the SEC for it. Nike could also stick a copy of their public key in every product and advertisement they make if you want to be paranoid about verifying this in 50 years.

This seems more bombproof in some ways than relying on Ethereum to keep existing and well-governed.

You can’t give 10 Fake Nikes the address of Nikes original wallet, that’s not how this works. You can’t just assign an NFT any address you want, this is all verified via smart contracts. The point of the block chain is that it’s immutable.

Here’s Nikes patent for this:

https://pdfpiw.uspto.gov/.piw?docid=10505726

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