ERC-5008

ERC-721 Nonce Extension

Add a `nonce` function to ERC-721.

Last CallStandards Track: ERC

Created: 2022-04-10Last Call Deadline : 2023-08-15

Anders (@0xanders), Lance (@LanceSnow), Shrug <shrug@emojidao.org>

1 min read

The ERC-5008 proposal suggests adding a nonce function to ERC-721 tokens to prevent attacks on NFT marketplaces. When users transfer an NFT to another wallet and then back to the original wallet, it can reactivate an order and list the token at a much lower price than intended. The addition of a nonce property to ERC-721 tokens would change the nonce when a token is transferred, allowing orders to be checked to avoid attacks. The proposal also suggests creating a standard for art NFTs, allowing artists to maintain a connection with the Ethereum blockchain and their fans who purchase their tokens. This would involve designating an original NFT and printed editions with signatures in a trustless manner, providing a standard method for designating the original and limited-edition prints with signatures from the artist. ERC-721 compliant contracts may implement this ERC for editions.

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Abstract

This standard is an extension of ERC-721. It proposes adding a nonce function to ERC-721 tokens.

Motivation

Some orders of NFT marketplaces have been attacked and the NFTs sold at a lower price than the current market floor price. This can happen when users transfer an NFT to another wallet and, later, back to the original wallet. This reactivates the order, which may list the token at a much lower price than the owner would have intended.

This EIP proposes adding a nonce property to ERC-721 tokens, and the nonce will be changed when a token is transferred. If a nonce is added to an order, the order can be checked to avoid attacks.

Specification

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.


/// @dev the ERC-165 identifier for this interface is 0xce03fdab.
interface IERC5008 /* is IERC165 */ {
    /// @notice Emitted when the `nonce` of an NFT is changed
    event NonceChanged(uint256 tokenId, uint256 nonce);

    /// @notice Get the nonce of an NFT
    /// Throws if `tokenId` is not a valid NFT
    /// @param tokenId The id of the NFT
    /// @return The nonce of the NFT
    function nonce(uint256 tokenId) external view returns(uint256);
}

The nonce(uint256 tokenId) function MUST be implemented as view.

The supportsInterface method MUST return true when called with 0xce03fdab.

Rationale

At first transferCount was considered as function name, but there may some case to change the nonce besides transfer, such as important properties changed, then we changed transferCount to nonce.

Backwards Compatibility

This standard is compatible with ERC-721.

Test Cases

Test cases are included in test.js.

Run:

cd ../assets/eip-5008
npm install
npm run test

Reference Implementation

See ERC5008.sol.

Security Considerations

No security issues found.

Copyright

Adopted by projects