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You can do the exact same thing with a blockchain NFT - there's absolutely no difference in terms of outcome. Each "sale" generates a unique digital signature N

You can do the exact same thing with a blockchain NFT - there's absolutely no difference in terms of outcome. Each "sale" generates a unique digital signature NFT because the public key of the person buying is incorporated as part of the cryptographic signature.

kkjjkgjjgg 5y ago
Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible. Of course it depends on the implementation, how do you identify an object? Leonardo could still create one NFT saying "this is ownership of my painting of the woman that always looks at the beholder" and another saying "this is ownership of my painting "Mona Lisa" and it would perhaps not be immediately clear that they are the same painting. Nevertheless, that is the "minting" problem and not the "spending" (or transfer) problem. Edit: HN does not allow me any more replies at this point, sorry.
- root_axis 5y ago
  > Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible Just use a different private key for each sale.
  - kkjjkgjjgg 5y ago
    The private key identifies the artist, so that is not a solution.
    - stale2002 5y ago
      No, the private key does not identify the artist. Instead, what identifies the artist, is the artist saying "hey, this thing over here is the real one!". None of which involves a Blockchain.
      - kkjjkgjjgg 5y ago
        Not sure if you understand how public key cryptography works? The artists says "this is my key" to their public key. Then they can use their key to sign things, and people can verify the signature because they can check that it belongs to the public key, which the artist has publicly announced.
        lottin 5y ago
        That doesn't work, because anyone can falsely claim to be the artist.
        kkjjkgjjgg 5y ago
        Obviously you need a way to identify the real artist. For example if they put their public key on their official web site, it would be a pretty good indicator. People also used to create chains of trust with public key infrastructure. Maybe you trust Bob, and Bob trusts Alice, and Alice has personally met the artist at Burning Man and verified their key there. Or you go to the government and let them provide a register of identities. In any case it is a separate problem. If you can't verify the artist, don't buy the NFT, or only buy it at a discount, accounting for the risk. Forgeries are a problem with physical works of art, too.
        stale2002 5y ago
        > Obviously you need a way to identify the real artist Thats the point though. Nothing about the blockchain has anything to do with this part, and this is really the only part that matters. So, once again, my point stands. The private key has nothing to do with identifying the real artist. Instead, it is something else entirely that identifies the real artist. > on their official web site So then the official website is what is doing the identifying here, of what the real art it. Not the blockchain. It is the artist themselves, saying "This art is the real one", not cryptography. It is not proof of work, or proof of signed private keys. Instead, it is proof of "official website". > In any case it is a separate problem. It is the only problem that matters. The actual way to identify the real artist, separate from the blockchain, is what is actually doing all of the heavy lifting here. The private key isn't doing anything on the important part.
- lottin 5y ago
  > Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible. There is an infinite number of blockchains.
  - deleted 5y ago
    [deleted]
  - kkjjkgjjgg 5y ago
    The people decide which blockchain to use.
  - kkjjkgjjgg 5y ago
    I want to add, while I suppose in reality people would settle for specific blockchains (like you can identify the Bitcoin blockchain), I can see a problem for NFTs. As long as there is not the ONE blockchain for NFT ownership, it would be difficult to prevent somebody "selling" the same thing on different NFTs. Even if the seller says "xyz is the official blockchain", it does not really solve the problem, as they could just say that several times for different blockchains. It does not actually add new information (signing something and putting it on blockchain xyz is equivalent to signing something, putting it on blockchain xyz, and saying "xyz is the official blockchain for my NFTs").

kkjjkgjjgg 5y ago

Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible. Of course it depends on the implementation, how do you identify an object? Leonardo could still create one NFT saying "this is ownership of my painting of the woman that always looks at the beholder" and another saying "this is ownership of my painting "Mona Lisa" and it would perhaps not be immediately clear that they are the same painting. Nevertheless, that is the "minting" problem and not the "spending" (or transfer) problem. Edit: HN does not allow me any more replies at this point, sorry.

root_axis 5y ago
> Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible Just use a different private key for each sale.
- kkjjkgjjgg 5y ago
  The private key identifies the artist, so that is not a solution.
  - stale2002 5y ago
    No, the private key does not identify the artist. Instead, what identifies the artist, is the artist saying "hey, this thing over here is the real one!". None of which involves a Blockchain.
    - kkjjkgjjgg 5y ago
      Not sure if you understand how public key cryptography works? The artists says "this is my key" to their public key. Then they can use their key to sign things, and people can verify the signature because they can check that it belongs to the public key, which the artist has publicly announced.
      - lottin 5y ago
        That doesn't work, because anyone can falsely claim to be the artist.
        kkjjkgjjgg 5y ago
        Obviously you need a way to identify the real artist. For example if they put their public key on their official web site, it would be a pretty good indicator. People also used to create chains of trust with public key infrastructure. Maybe you trust Bob, and Bob trusts Alice, and Alice has personally met the artist at Burning Man and verified their key there. Or you go to the government and let them provide a register of identities. In any case it is a separate problem. If you can't verify the artist, don't buy the NFT, or only buy it at a discount, accounting for the risk. Forgeries are a problem with physical works of art, too.
        stale2002 5y ago
        > Obviously you need a way to identify the real artist Thats the point though. Nothing about the blockchain has anything to do with this part, and this is really the only part that matters. So, once again, my point stands. The private key has nothing to do with identifying the real artist. Instead, it is something else entirely that identifies the real artist. > on their official web site So then the official website is what is doing the identifying here, of what the real art it. Not the blockchain. It is the artist themselves, saying "This art is the real one", not cryptography. It is not proof of work, or proof of signed private keys. Instead, it is proof of "official website". > In any case it is a separate problem. It is the only problem that matters. The actual way to identify the real artist, separate from the blockchain, is what is actually doing all of the heavy lifting here. The private key isn't doing anything on the important part.
lottin 5y ago
> Every sale is on the blockchain, so if somebody creates multiple sales of the same item, it would immediately be visible. There is an infinite number of blockchains.
- deleted 5y ago
  [deleted]
- kkjjkgjjgg 5y ago
  The people decide which blockchain to use.
- kkjjkgjjgg 5y ago
  I want to add, while I suppose in reality people would settle for specific blockchains (like you can identify the Bitcoin blockchain), I can see a problem for NFTs. As long as there is not the ONE blockchain for NFT ownership, it would be difficult to prevent somebody "selling" the same thing on different NFTs. Even if the seller says "xyz is the official blockchain", it does not really solve the problem, as they could just say that several times for different blockchains. It does not actually add new information (signing something and putting it on blockchain xyz is equivalent to signing something, putting it on blockchain xyz, and saying "xyz is the official blockchain for my NFTs").