ERC-5008: ERC-721 Nonce Extension


  Ethereum Improvement Proposals
        
        
          
            
              
            
          
        

        AllCoreNetworkingInterfaceERCMetaInformational

      



      
        
  
    

  
    
    
    
    
      📢 Last Call
    
    
      Standards Track: ERC
    
  
  
    
      ERC-5008: ERC-721 Nonce Extension
    
    
      
        
      
    
    
      
        
      
    
  

  Add a `nonce` function to ERC-721.

  	Authors	Anders (@0xanders), Lance (@LanceSnow), Shrug <shrug@emojidao.org>
	Created	2022-04-10
	Last Call Deadline	2023-08-15
	Requires	

  EIP-165, 

  EIP-721




  


  
    
      
      
        This EIP is in the process of being peer-reviewed. If you are interested in this EIP, please participate using this discussion link.
      

    

  

  
    Table of Contents

    	Abstract
	Motivation
	Specification
	Rationale
	Backwards Compatibility
	Test Cases
	Reference Implementation
	Security Considerations
	Copyright



  


  
      
      
         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
      
      
    


Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Anders (@0xanders), Lance (@LanceSnow), Shrug <shrug@emojidao.org>, "ERC-5008: ERC-721 Nonce Extension [DRAFT]," Ethereum Improvement Proposals, no. 5008, April 2022. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-5008.






      
    
  

  

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