ERC20-721Token的发行-冻结-多方签名功能

Posted on 2019-07-04 Edited on 2020-11-02

发行

ERC 代币的发行已经标准化，最好采用 openzeppelin 的模板，并搭配 solidity5.x 版本和 truffle 工具使用，效果更佳。

// ERC 721
pragma solidity ^0.5.0;

import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol';
import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Mintable.sol';

contract MyNFT is ERC721Full, ERC721Mintable {
    constructor() ERC721Full("MyNFT", "MNFT") public {
    }
}

// ERC 20
pragma solidity ^0.5.0;

import 'openzeppelin-solidity/contracts/token/ERC20/ERC20.sol';
import 'openzeppelin-solidity/contracts/token/ERC20/ERC20Detailed.sol';
import 'openzeppelin-solidity/contracts/ownership/Ownable.sol';

contract MyERC20 is ERC20, ERC20Detailed, Ownable {
    constructor(uint256 initialSupply) ERC20Detailed("MyToken", "MT", 18) public {
        _mint(msg.sender, initialSupply);
    }
}

Freeze 功能（openzeppelin-contracts v3.2.0之后）

也叫做 pause 或者 close，具体就是停止 Token 相关的 transfer（转账）功能

// ERC 20
pragma solidity ^0.5.0;

import 'openzeppelin-solidity/contracts/token/ERC20/ERC20.sol';
import 'openzeppelin-solidity/contracts/token/ERC20/ERC20Detailed.sol';
import 'openzeppelin-solidity/contracts/ownership/Ownable.sol';

contract MyERC20 is ERC20, ERC20Detailed, Ownable {
    bool public closed = false;

    event Close();
    event Open();

    constructor(uint256 initialSupply) ERC20Detailed("MyToken", "MT", 18) public {
        _mint(msg.sender, initialSupply);
    }

    // ------------------------------------------------------------------------
    // Don't accept ETH
    // ------------------------------------------------------------------------
    function() external payable {
        revert("Don't accept ETH");
    }

    function transfer(address _to, uint _value) whenOpen public returns (bool) {
        return super.transfer(_to, _value);
    }

    function transferFrom(address _from, address _to, uint _value) whenOpen public returns (bool) {
        return super.transferFrom(_from, _to, _value);
    }

    function close() onlyOwner whenOpen public {
        closed = true;
        emit Close();
    }

    function open() onlyOwner whenClosed public {
        closed = false;
        emit Open();
    }

    modifier whenOpen() {
        require(!closed);
        _;
    }

    modifier whenClosed() {
        require(closed);
        _;
    }
}

openzeppelin-contracts v3.2.0版本中的实现代码如下 ERC721Pausable

1
2
3

contract ERC721PresetMinterPauserAutoId is Context, AccessControl, ERC721Burnable, ERC721Pausable {
    ......
}

MultiSigWallet 多方签名

gnosis 的 multisignature 功能最为完善。已经有多个生产项目采用此工具。目前此工具合约的 solidity 版本为0.4.15，项目语言版本交旧，但没有发生过安全问题。

首先 ERC20 合约的初始化总金额地址需要给到 MultiSigWallet 的合约地址，由 MultiSigWallet 合约完成多方签名确认后，ERC20 代币从 MultiSigWallet 合约的地址发送到接收人的账户地址。

// ERC 20
pragma solidity ^0.5.0;

import 'openzeppelin-solidity/contracts/token/ERC20/ERC20.sol';
import 'openzeppelin-solidity/contracts/token/ERC20/ERC20Detailed.sol';
import 'openzeppelin-solidity/contracts/ownership/Ownable.sol';

contract MyERC20 is ERC20, ERC20Detailed, Ownable {
    bool public closed = false;

    event Close();
    event Open();

    constructor(uint256 initialSupply) ERC20Detailed("MyToken", "MT", 18) public {
        _mint(msg.sender, initialSupply);
    }

    // ------------------------------------------------------------------------
    // Do accept ETH, deposit token in contract address
    // ------------------------------------------------------------------------
    function() external payable {}

    function transfer(address _to, uint _value) whenOpen public returns (bool) {
        return super.transfer(_to, _value);
    }

    function transferFrom(address _from, address _to, uint _value) whenOpen public returns (bool) {
        return super.transferFrom(_from, _to, _value);
    }

    function close() onlyOwner whenOpen public {
        closed = true;
        emit Close();
    }

    function open() onlyOwner whenClosed public {
        closed = false;
        emit Open();
    }

    modifier whenOpen() {
        require(!closed);
        _;
    }

    modifier whenClosed() {
        require(closed);
        _;
    }
}

Live website 地址在这里，以下操作均为https://wallet.gnosis.pm/上的截图。

1.增加钱包。如下图，完成钱包增加配置

2.点击 Wallets Name，即点击’Lcoin’，进入钱包的详细页面，如下图，进入后需要手动添加 Tokens Name，其后点击 Withdraw，最后经过 2 位 Required confirmations 后，Executed 状态变为 Yes

注意，此处，由 MultiSigWallet 合约完成多方签名确认后，ERC20 代币从 MultiSigWallet 合约的地址发送到接收人的账户地址（a825），MultiSigWallet 合约执行 transfer 给到接收人的账户地址（a825），所以 MultiSigWallet 合约的地址上需要有足够的 Eth 作为 gas

即使用 MultiSigWallet 转账时，花费的 gas 是 2 位 Required confirmations 和一次 transfer 的总和