如何实现ERC-20代币不可转让？仅允许合约发起转账的技术问询

问题1：如何使ERC-20代币具备不可转让属性？ #

要实现完全不可转让的ERC-20代币，核心是禁用transfer和transferFrom这两个核心转账方法。你可以通过重写这两个方法，让它们在被调用时直接回滚交易：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract NonTransferableERC20 is ERC20 {
    constructor(uint256 initialSupply) ERC20("NonTransferableToken", "NTT") {
        _mint(msg.sender, initialSupply);
    }

    // 重写transfer方法，直接回滚
    function transfer(address to, uint256 amount) public pure override returns (bool) {
        revert("NonTransferableERC20: transfers are disabled");
    }

    // 重写transferFrom方法，直接回滚
    function transferFrom(address from, address to, uint256 amount) public pure override returns (bool) {
        revert("NonTransferableERC20: transfers are disabled");
    }
}

如果需要保留特定场景的转账权限（比如仅合约部署者可以操作），可以结合Ownable合约添加权限控制：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract RestrictedNonTransferableERC20 is ERC20, Ownable {
    constructor(uint256 initialSupply) ERC20("RestrictedNTT", "RNTT") {
        _mint(msg.sender, initialSupply);
    }

    function transfer(address to, uint256 amount) public override returns (bool) {
        require(msg.sender == owner(), "RestrictedNonTransferableERC20: only owner can transfer");
        return super.transfer(to, amount);
    }

    function transferFrom(address from, address to, uint256 amount) public override returns (bool) {
        require(msg.sender == owner(), "RestrictedNonTransferableERC20: only owner can transfer");
        return super.transferFrom(from, to, amount);
    }
}

问题2：如何实现代币仅可由其智能合约发起转账，钱包持有者无法自行转账？ #

这种需求下，需要禁止外部账户直接调用transfer和transferFrom，仅允许合约内部通过底层的_transfer函数发起转账。可以通过以下方式实现：

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract ContractOnlyTransferERC20 is ERC20 {
    constructor(uint256 initialSupply) ERC20("ContractOnlyToken", "COT") {
        _mint(msg.sender, initialSupply);
    }

    // 禁止外部调用transfer
    function transfer(address to, uint256 amount) public pure override returns (bool) {
        revert("ContractOnlyTransferERC20: direct transfers not allowed");
    }

    // 禁止外部调用transferFrom
    function transferFrom(address from, address to, uint256 amount) public pure override returns (bool) {
        revert("ContractOnlyTransferERC20: direct transfers not allowed");
    }

    // 内部专属转账方法，仅合约内部可调用
    function _contractTransfer(address from, address to, uint256 amount) internal {
        _transfer(from, to, amount);
    }

    // 示例：合约触发转账的业务逻辑（可根据需求自定义）
    function distributeTokens(address[] calldata recipients, uint256[] calldata amounts) external {
        require(recipients.length == amounts.length, "ContractOnlyTransferERC20: arrays length mismatch");
        for (uint256 i = 0; i < recipients.length; i++) {
            _contractTransfer(msg.sender, recipients[i], amounts[i]);
        }
    }
}

关键逻辑：外部用户无法直接调用transfer/transferFrom，所有转账必须通过合约内部定义的业务方法触发，这些方法可根据需求添加权限控制或条件判断，最终调用_transfer完成转账操作。

内容的提问来源于stack exchange，提问作者devon taylor