Vitalik suggests private NFTs using ‘stealth addresses’ to hide the owner’s identity
Ethereum founder Vitalik Buterin puts forward the idea of private NFTs whose owners remain anonymous through blockchain data.
Concept added to Ethereum Research Position Focused on adding “ERC721 extension for zk-SNARK”.
Idea: ERC721 stealth address.
A low-tech approach to adding tons of privacy to the NFT ecosystem.
So for example you can. Sending her NFT to vitalik.eth so that no one but me (the new owner) can find out who the new owner is.https://t.co/UdqK6NAYjn
—vitalik.eth (@VitalikButerin) August 8, 2022
ERC721 Extension for zk-SNARK
An extension to ERC721 (NFT standard) was proposed by Nerolation. Nerolation said he believed his methodology was “an exact implementation of what Vitalik described” when talking about private POAP.
In an article introducing the world to the concept of SBT, Vitalik talks about the potential need for private Soulbound Tokens (SBT). he said,
“Privacy is an important part of making this kind of ecosystem work well … In the future, if vaccination becomes POAP, one of the worst things we can do is automatically promote POAP. It is to create a system that allows them to influence their medical decisions by what looks cool in their particular social circle.
The proposal to use ZK-SNARK compatible ERC721 tokens attempts to solve this by using a stealth address containing a hash of the user’s address, the token ID, and the user’s secret.
The information is then added to the Merkle tree on-chain, and the token is stored in an “address derived from the user’s leaf of the Merkle tree.”
To prove ownership of the token (NFT), the address must give the stealth address “access to the private key”. This passes the matched information to the leaves of the Merkle tree when the message is signed. The circuit can compare “calculated roots with user-provided roots for verification”.
normal stealth address
In a reply to Nerolation, Vitalik explained that he believes there is a cleaner and simpler solution to this problem, using “much lighter weight technology.”he said “normal stealth address No need for complex Merkle trees.
Vitalik explained that every user has a private key that can be used as a base point for elliptic curve groups to create new private keys, as is commonly done with regular stealth addresses.
You can then generate a “one-time private key” and derive the paired public key from the base of the elliptic curve.
The sender and receiver can “compute a shared secret” by combining private and private keys.
A new address is generated using this shared secret by hashing the above information together.
As Vitalik concludes, senders can send ERC20 tokens to this address.
“Recipients scan everything sent S.values, generating addresses corresponding to each S.If you find an address with an ERC721 token, record the address and key so you can track the ERC721 and send it quickly in the future. “
Vitalik argued that Merkle trees or ZK-SNARKs were unnecessary because “there is no possibility of creating an ‘anonymous set’ of ERC721.” His method means that on-chain data indicates that his ERC721 was sent to some address, but does not reveal the valid owner of the token.
cost
This solution comes with costs that may be impractical on the Ethereum mainnet. Gas fees included in Vitalik’s method may require the sender to “send enough ETH to pay the fee 5-50 times for him to send more.”
Whether Vitalik’s solution is the more sophisticated implementation is up to the Ethereum open source community to decide. Still, it’s interesting that Vitalik seems to have embraced the need for an element of privacy within the Ethereum ecosystem. His SBT revelation has opened up a world of possibilities for tokenized assets. Additionally, the need to keep some assets confidential has resurfaced in his thoughts.
At a private press conference on August 6, Vitalik explained:Over the past decade, opinions on many issues have certainly changed. ’” he continued.
“Even today, I think the Ethereum project is getting to a point where it can fully function without me.
Vitalik has only contributed 7 times to the Ethereum Research Forum since January 2022. Meanwhile, in January 2022, he posted nine comments in that month alone. He’s clearly starting to move Ethereum out of the way of other developers in the ecosystem. However, it remains to be seen whether investors will be confident that he can continue Ethereum without him if Vitalik exits entirely.
