ERC-5192 Reference Implementation

• Specification: EIP-5192: Minimal Soulbound NFTs
• Community: Chat on Telegram

ERC-5192 enables all degrees of permanently transferrable to permanently non-transferrable ERC-721 tokens. Examples include: Soulbound tokens, Account-bound tokens, non-transferrable tokens, lockable tokens.

ERC-5192 is in status final meaning it won't change again. If you want to learn about how ERC-5192 was created, check out PEEPanEIP #89: EIP-5192: Minimal Soulbound NFTs with Tim Daubenschütz by the Ethereum Cat Herders.

Installation

forge install https://github.com/attestate/ERC5192

npm install erc5192

Usage

ERC5192 is an abstract contract that can be used to implement custom business logic. ERC5192 uses OpenZeppelin's ERC721 implementation, so we can use function safeMint to start minting tokens.

Below is an example of a non-transferrable token:

import {ERC5192} from "ERC5192/ERC5192.sol";

contract NTT is ERC5192 {
  bool private isLocked;
  constructor(string memory _name, string memory _symbol, bool _isLocked)
    ERC5192(_name, _symbol, _isLocked)
  {
    isLocked = _isLocked;
  }
  function safeMint(address to, uint256 tokenId) external {
    _safeMint(to, tokenId);
    if (isLocked) emit Locked(tokenId);
  }
}

contract UseNTT {
  function useNTT() public {
    string memory name = "Non-transferrable NFT";
    string memory symbol = "NTT";
    bool isLocked = true;

    NTT ntt = new NTT(name, symbol, isLocked);

    address minter = address(this);
    uint256 tokenId = 0;
    ntt.safeMint(minter, tokenId);

    ntt.transferFrom(minter, receiver, tokenId); // revert. token is locked.
  }
}

However, more dynamic use cases are possible where a token's transferrability is only locked temporarily or based on specific conditions.

License

See License file.