042_去中心化交易所(DEX)安全：从AMM机制到闪电贷攻击的防御策略

// 恒定乘积模型核心实现
contract ConstantProductAMM {
    uint256 public constant MIN_LIQUIDITY = 10**3;
    mapping(address => uint256) public balanceOf;
    uint256 public reserve0;
    uint256 public reserve1;
    uint256 public totalSupply;
    
    // 更新储备并防止整数溢出
    function _update(uint256 balance0, uint256 balance1) private {
        reserve0 = balance0;
        reserve1 = balance1;
    }
    
    // 添加流动性
    function mint(address to) external returns (uint256 liquidity) {
        uint256 balance0 = IERC20(token0).balanceOf(address(this));
        uint256 balance1 = IERC20(token1).balanceOf(address(this));
        uint256 amount0 = balance0 - reserve0;
        uint256 amount1 = balance1 - reserve1;
        
        uint256 _totalSupply = totalSupply;
        if (_totalSupply == 0) {
            liquidity = sqrt(amount0 * amount1) - MIN_LIQUIDITY;
            _mint(address(0), MIN_LIQUIDITY); // 铸造成立费
        } else {
            liquidity = min(
                (amount0 * _totalSupply) / reserve0,
                (amount1 * _totalSupply) / reserve1
            );
        }
        require(liquidity > 0, "Insufficient liquidity minted");
        _mint(to, liquidity);
        
        _update(balance0, balance1);
    }
    
    // 移除流动性
    function burn(address to) external returns (uint256 amount0, uint256 amount1) {
        uint256 balance0 = IERC20(token0).balanceOf(address(this));
        uint256 balance1 = IERC20(token1).balanceOf(address(this));
        uint256 liquidity = balanceOf[address(this)];
        
        uint256 _totalSupply = totalSupply;
        amount0 = (liquidity * balance0) / _totalSupply;
        amount1 = (liquidity * balance1) / _totalSupply;
        require(amount0 > 0 && amount1 > 0, "Insufficient liquidity burned");
        _burn(address(this), liquidity);
        _safeTransfer(token0, to, amount0);
        _safeTransfer(token1, to, amount1);
        
        balance0 = IERC20(token0).balanceOf(address(this));
        balance1 = IERC20(token1).balanceOf(address(this));
        
        _update(balance0, balance1);
    }
    
    // 交换代币
    function swap(uint256 amount0Out, uint256 amount1Out, address to) external {
        require(amount0Out > 0 || amount1Out > 0, "Insufficient output amount");
        uint256 balance0 = IERC20(token0).balanceOf(address(this));
        uint256 balance1 = IERC20(token1).balanceOf(address(this));
        require(amount0Out < balance0 && amount1Out < balance1, "Insufficient liquidity");
        
        if (amount0Out > 0) _safeTransfer(token0, to, amount0Out);
        if (amount1Out > 0) _safeTransfer(token1, to, amount1Out);
        
        uint256 newBalance0 = IERC20(token0).balanceOf(address(this));
        uint256 newBalance1 = IERC20(token1).balanceOf(address(this));
        
        // 价格影响检查
        uint256 amount0In = newBalance0 > balance0 - amount0Out ? newBalance0 - (balance0 - amount0Out) : 0;
        uint256 amount1In = newBalance1 > balance1 - amount1Out ? newBalance1 - (balance1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, "Insufficient input amount");
        
        // 滑点保护
        uint256 balance0Adjusted = newBalance0 * 1000 - amount0In * 3;
        uint256 balance1Adjusted = newBalance1 * 1000 - amount1In * 3;
        require(balance0Adjusted * balance1Adjusted >= uint256(reserve0) * uint256(reserve1) * (1000**2), "Price impact too high");
        
        _update(newBalance0, newBalance1);
    }
    
    // 辅助函数
    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
    
    function min(uint256 x, uint256 y) internal pure returns (uint256) {
        return x <= y ? x : y;
    }
}

// MEV防护机制实现
contract MEVProtectedDEX {
    // 私有交易池
    struct PrivateTxPool {
        bytes[] pendingTransactions;
        uint256[] commitmentValues;
        mapping(bytes32 => bool) executed;
    }
    
    PrivateTxPool public privatePool;
    
    // 链下交易提交
    function submitPrivateTransaction(bytes memory encryptedTx, uint256 commitment) external {
        privatePool.pendingTransactions.push(encryptedTx);
        privatePool.commitmentValues.push(commitment);
    }
    
    // 批量执行私有交易
    function executePrivateBatch(bytes32[] calldata txHashes) external onlyExecutor {
        for (uint i = 0; i < txHashes.length; i++) {
            if (!privatePool.executed[txHashes[i]]) {
                // 解密并执行交易
                // ...
                privatePool.executed[txHashes[i]] = true;
            }
        }
    }
    
    // 时间加权交易排序
    function getTransactionPriority(address user, uint256 gasPrice) public view returns (uint256) {
        // 基础优先级 = Gas价格
        uint256 basePriority = gasPrice;
        
        // 用户历史奖励
        uint256 historyBonus = getUserHistoryBonus(user);
        
        // 时间戳随机性
        uint256 randomFactor = uint256(keccak256(abi.encodePacked(block.timestamp, user, block.difficulty))) % 10;
        
        // 综合优先级计算
        return basePriority + historyBonus + randomFactor;
    }
    
    // 盲拍机制
    struct BlindAuction {
        uint256 startTime;
        uint256 endTime;
        uint256 minBid;
        mapping(address => bytes32) bids;
        mapping(address => uint256) revealedBids;
        address[] bidders;
        bool revealed;
    }
    
    BlindAuction public currentAuction;
    
    // 开始新的盲拍
    function startBlindAuction(uint256 duration, uint256 minBid) external onlyOwner {
        currentAuction.startTime = block.timestamp;
        currentAuction.endTime = block.timestamp + duration;
        currentAuction.minBid = minBid;
        currentAuction.revealed = false;
    }
    
    // 提交盲拍
    function submitBid(bytes32 commitment) external {
        require(block.timestamp >= currentAuction.startTime, "Auction not started");
        require(block.timestamp <= currentAuction.endTime, "Auction ended");
        
        currentAuction.bids[msg.sender] = commitment;
        currentAuction.bidders.push(msg.sender);
    }
    
    // 揭示盲拍
    function revealBid(uint256 bidAmount, bytes32 nonce) external {
        require(block.timestamp > currentAuction.endTime, "Auction not ended");
        require(block.timestamp <= currentAuction.endTime + 1 hours, "Reveal period ended");
        
        bytes32 commitment = keccak256(abi.encodePacked(bidAmount, nonce, msg.sender));
        require(currentAuction.bids[msg.sender] == commitment, "Invalid commitment");
        require(bidAmount >= currentAuction.minBid, "Bid too low");
        
        currentAuction.revealedBids[msg.sender] = bidAmount;
    }
    
    // 确定交易顺序
    function determineTransactionOrder() external onlyOwner {
        require(block.timestamp > currentAuction.endTime + 1 hours, "Reveal period not ended");
        require(!currentAuction.revealed, "Already revealed");
        
        // 根据揭示的出价确定交易顺序
        // ...
        
        currentAuction.revealed = true;
    }
    
    // 防前端运行保护
    modifier antiFrontRunning() {
        // 检查调用者是否是已知的MEV机器人
        require(!isMEVRobot(msg.sender), "MEV robots not allowed");
        
        // 添加交易延迟
        if (block.timestamp - lastTransactionTime[msg.sender] < 2 seconds) {
            revert("交易频率过高，请稍后再试");
        }
        
        lastTransactionTime[msg.sender] = block.timestamp;
        _;
    }
    
    // 交易隐私保护
    function privateSwap(uint256 amountIn, address tokenIn, address tokenOut, uint256 minAmountOut) external antiFrontRunning {
        // 私有交换逻辑，使用加密或零知识证明保护交易细节
        // ...
    }
}

// 集中流动性模型安全增强版
contract ConcentratedLiquidityPool {
    // 流动性头寸结构
    struct Position {
        uint96 nonce;
        address operator;
        address token0;
        address token1;
        int24 tickLower;
        int24 tickUpper;
        uint128 liquidity;
        int256 feeGrowthInside0LastX128;
        int256 feeGrowthInside1LastX128;
        uint128 tokensOwed0;
        uint128 tokensOwed1;
    }
    
    // 价格范围保护
    mapping(int24 => uint256) public tickLiquidity;
    
    // 流动性集中度监控
    function monitorLiquidityConcentration() public view returns (bool) {
        uint256 totalLiquidity = getTotalLiquidity();
        uint256 highConcentrationLiquidity = 0;
        
        // 计算高集中度区域的流动性
        int24 currentTick = getCurrentTick();
        for (int24 i = currentTick - 100; i <= currentTick + 100; i++) {
            highConcentrationLiquidity += tickLiquidity[i];
        }
        
        // 如果10%的价格范围包含超过80%的流动性，认为集中度过高
        if (highConcentrationLiquidity * 100 / totalLiquidity > 80) {
            return true; // 集中度风险
        }
        
        return false;
    }
    
    // 流动性风险缓解
    function mitigateLiquidityRisk() external onlyOwner {
        if (monitorLiquidityConcentration()) {
            // 增加交易费用以鼓励更广泛的流动性分布
            increaseFeesTemporarily();
            
            // 触发流动性警报
            emit LiquidityConcentrationWarning();
        }
    }
    
    // 安全的流动性提供
    function safeMint(address recipient, int24 tickLower, int24 tickUpper, uint128 amount) external returns (uint256 tokenId) {
        // 验证价格范围合理性
        require(tickLower < tickUpper, "Invalid tick range");
        require(tickLower >= MIN_TICK && tickUpper <= MAX_TICK, "Tick range out of bounds");
        
        // 检查是否过于集中
        uint256 existingLiquidity = getLiquidityInRange(tickLower, tickUpper);
        uint256 totalLiquidity = getTotalLiquidity();
        if (totalLiquidity > 0) {
            require(existingLiquidity * 100 / totalLiquidity < 50, "Range too concentrated");
        }
        
        // 流动性提供逻辑
        // ...
        
        // 更新流动性映射
        updateLiquidityMap(tickLower, tickUpper, amount);
        
        return tokenId;
    }
    
    // 防止流动性突然撤出
    function safeBurn(uint256 tokenId, uint128 amount) external {
        Position storage position = positions[tokenId];
        require(msg.sender == position.operator, "Not authorized");
        
        // 检查是否会导致过度流动性减少
        uint256 remainingLiquidity = position.liquidity - amount;
        uint256 totalLiquidity = getTotalLiquidity();
        require(totalLiquidity - amount > totalLiquidity * 20 / 100, "Excessive liquidity reduction");
        
        // 流动性撤出逻辑
        // ...
        
        // 更新流动性映射
        updateLiquidityMap(position.tickLower, position.tickUpper, 0 - amount);
    }
    
    // 自动再平衡机制
    function autoRebalance() external {
        // 当检测到极端价格波动时，自动调整流动性激励
        if (getPriceVolatility() > 0.05) { // 5%以上的价格波动
            // 增加价格区间外的流动性奖励
            increaseOutOfRangeIncentives();
        }
    }
}

// 去中心化预言机系统
contract DecentralizedOracle {
    // 数据源结构
    struct DataSource {
        address source;
        uint256 weight;
        bool active;
        uint256 lastUpdate;
    }
    
    // 价格数据结构
    struct PriceData {
        uint256 price;
        uint256 timestamp;
        uint256 deviation;
        uint256 updateCount;
    }
    
    // 数据映射
    mapping(address => DataSource[]) public tokenSources;
    mapping(address => PriceData) public tokenPrices;
    
    // 治理参数
    uint256 public minSources = 5;
    uint256 public maxDeviation = 2; // 2%
    uint256 public updateInterval = 5 minutes;
    
    // 提交价格数据
    function submitPrice(address token, uint256 price) external {
        // 验证数据源
        require(isActiveDataSource(msg.sender, token), "Not an active data source");
        
        // 验证提交频率
        DataSource storage source = getDataSource(msg.sender, token);
        require(block.timestamp - source.lastUpdate >= updateInterval / 2, "Update too frequent");
        
        // 记录提交
        recordPriceSubmission(token, msg.sender, price);
        
        // 检查是否需要更新价格
        if (shouldUpdatePrice(token)) {
            updateAggregatedPrice(token);
        }
    }
    
    // 聚合价格计算
    function updateAggregatedPrice(address token) internal {
        // 获取所有有效数据源的价格
        (uint256[] memory prices, uint256[] memory weights) = collectPricesWithWeights(token);
        
        // 计算加权中位数价格
        uint256 medianPrice = calculateWeightedMedian(prices, weights);
        
        // 计算偏差
        uint256 deviation = calculateDeviation(prices, medianPrice);
        
        // 验证偏差在允许范围内
        require(deviation <= maxDeviation, "Too much price deviation");
        
        // 验证与外部参考价格的一致性
        uint256 referencePrice = getExternalReferencePrice(token);
        require(absDiff(medianPrice, referencePrice) * 100 / referencePrice <= 5, "Price too far from reference");
        
        // 更新价格数据
        tokenPrices[token] = PriceData({
            price: medianPrice,
            timestamp: block.timestamp,
            deviation: deviation,
            updateCount: tokenPrices[token].updateCount + 1
        });
        
        emit PriceUpdated(token, medianPrice, block.timestamp);
    }
    
    // 防操纵检查
    function verifyPriceIntegrity(address token, uint256 price) public view returns (bool) {
        // 检查价格变化率
        if (tokenPrices[token].timestamp > 0) {
            uint256 timeElapsed = block.timestamp - tokenPrices[token].timestamp;
            uint256 priceChange = absDiff(price, tokenPrices[token].price) * 100 / tokenPrices[token].price;
            
            // 根据时间调整允许的价格变化
            uint256 maxAllowedChange = (timeElapsed * 5) / updateInterval;
            if (priceChange > maxAllowedChange && priceChange > 10) {
                return false; // 价格变化过快
            }
        }
        
        return true;
    }
    
    // 紧急价格保护
    function emergencyPriceFreeze(address token) external onlyGovernance {
        tokenPrices[token].timestamp = block.timestamp + 24 hours; // 冻结价格24小时
        emit PriceFrozen(token, block.timestamp);
    }
    
    // 获取安全价格
    function getSafePrice(address token) external view returns (uint256) {
        PriceData memory priceData = tokenPrices[token];
        
        // 验证数据新鲜度
        require(block.timestamp - priceData.timestamp <= updateInterval * 3, "Stale price data");
        
        // 验证数据质量
        require(priceData.deviation <= maxDeviation, "High price deviation");
        
        return priceData.price;
    }
    
    // 辅助函数
    function absDiff(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a - b : b - a;
    }
}

// 跨链DEX安全实现
contract CrossChainDEX {
    // 跨链消息验证器
    IMessageVerifier public messageVerifier;
    
    // 跨链资产映射
    mapping(uint256 => mapping(address => address)) public chainAssetMapping;
    
    // 交易状态跟踪
    enum TransactionState { Initiated, Confirmed, Executed, Failed, Reverted }
    struct CrossChainTx {
        uint256 sourceChainId;
        uint256 targetChainId;
        address user;
        address sourceAsset;
        address targetAsset;
        uint256 amount;
        uint256 fee;
        uint256 deadline;
        uint256 nonce;
        TransactionState state;
        uint256 confirmations;
    }
    
    mapping(bytes32 => CrossChainTx) public crossChainTransactions;
    uint256 public requiredConfirmations = 3;
    
    // 跨链交易发起
    function initiateCrossChainSwap(uint256 targetChainId, address sourceAsset, address targetAsset, uint256 amount, uint256 deadline) external {
        require(targetChainId != block.chainid, "Cannot swap on the same chain");
        require(chainAssetMapping[targetChainId][targetAsset] != address(0), "Target asset not supported");
        require(amount > 0, "Amount must be positive");
        require(deadline > block.timestamp, "Deadline too soon");
        
        // 计算费用
        uint256 fee = calculateCrossChainFee(targetChainId, amount);
        
        // 锁定源资产
        IERC20(sourceAsset).transferFrom(msg.sender, address(this), amount + fee);
        
        // 创建交易记录
        bytes32 txId = keccak256(abi.encodePacked(block.chainid, targetChainId, msg.sender, sourceAsset, targetAsset, amount, fee, deadline, nonce));
        crossChainTransactions[txId] = CrossChainTx({
            sourceChainId: block.chainid,
            targetChainId: targetChainId,
            user: msg.sender,
            sourceAsset: sourceAsset,
            targetAsset: targetAsset,
            amount: amount,
            fee: fee,
            deadline: deadline,
            nonce: nonce,
            state: TransactionState.Initiated,
            confirmations: 0
        });
        
        nonce++;
        
        // 发送跨链消息
        messageVerifier.sendCrossChainMessage(targetChainId, txId, abi.encode(msg.sender, targetAsset, amount));
        
        emit CrossChainSwapInitiated(txId, block.chainid, targetChainId, msg.sender, sourceAsset, targetAsset, amount);
    }
    
    // 验证跨链消息
    function verifyCrossChainMessage(uint256 sourceChainId, bytes32 txId, bytes memory message) external {
        // 验证消息
        require(messageVerifier.verifyCrossChainMessage(sourceChainId, txId, message), "Invalid message");
        
        // 解析消息
        (address user, address targetAsset, uint256 amount) = abi.decode(message, (address, address, uint256));
        
        // 更新交易状态
        CrossChainTx storage txn = crossChainTransactions[txId];
        require(txn.state == TransactionState.Initiated, "Invalid transaction state");
        
        // 增加确认计数
        txn.confirmations++;
        
        // 如果达到所需确认数，执行交易
        if (txn.confirmations >= requiredConfirmations) {
            executeCrossChainSwap(txId, user, targetAsset, amount);
        }
    }
    
    // 执行跨链交易
    function executeCrossChainSwap(bytes32 txId, address user, address targetAsset, uint256 amount) internal {
        CrossChainTx storage txn = crossChainTransactions[txId];
        require(block.timestamp <= txn.deadline, "Transaction expired");
        
        // 检查流动性
        require(availableLiquidity[targetAsset] >= amount, "Insufficient liquidity");
        
        // 更新状态
        txn.state = TransactionState.Executed;
        
        // 释放目标资产
        IERC20(targetAsset).transfer(user, amount);
        
        // 更新流动性
        availableLiquidity[targetAsset] -= amount;
        
        emit CrossChainSwapExecuted(txId, user, targetAsset, amount);
    }
    
    // 紧急取消
    function emergencyCancel(bytes32 txId) external {
        CrossChainTx storage txn = crossChainTransactions[txId];
        require(txn.user == msg.sender || isGovernance(msg.sender), "Not authorized");
        require(txn.state == TransactionState.Initiated, "Cannot cancel executed transaction");
        require(block.timestamp > txn.deadline || isEmergency(), "Cannot cancel active transaction");
        
        // 更新状态
        txn.state = TransactionState.Failed;
        
        // 退还用户资产
        IERC20(txn.sourceAsset).transfer(txn.user, txn.amount);
        
        // 保留费用
        IERC20(txn.sourceAsset).transfer(feeCollector, txn.fee);
        
        emit CrossChainSwapCancelled(txId);
    }
    
    // 桥安全监控
    function monitorBridgeSecurity() external onlyGovernance {
        // 检查桥接状态
        bool bridgeStatus = messageVerifier.getBridgeStatus();
        
        if (!bridgeStatus) {
            // 暂停跨链功能
            pauseCrossChainFunctionality();
            emit BridgeSecurityAlert();
        }
    }
    
    // 流动性风险监控
    function monitorLiquidityRisk() external {
        for (uint i = 0; i < supportedChains.length; i++) {
            uint256 chainId = supportedChains[i];
            uint256 totalLiquidity = getTotalLiquidity(chainId);
            uint256 crossChainPending = getPendingCrossChainAmounts(chainId);
            
            // 如果待处理交易超过总流动性的50%，发出警报
            if (crossChainPending * 100 / totalLiquidity > 50) {
                emit LiquidityRiskAlert(chainId, crossChainPending, totalLiquidity);
            }
        }
    }
}

// Certora Prover 规范示例（用于DEX验证）
spec DecentralizedExchange {
    // 导入规范库
    import "ProverSpecs/munging.sol" as munging;
    import "ProverSpecs/util.sol" as util;
    
    // 状态不变式：总流动性守恒
    invariant totalLiquidityConserved() {
        uint256 totalLiquidity = 0;
        forall address user in users {
            totalLiquidity += balanceOf(user);
        }
        assert totalLiquidity == totalSupply;
    }
    
    // 状态不变式：资金守恒
    invariant fundConservation() {
        uint256 token0Balance = IERC20(token0).balanceOf(address(this));
        uint256 token1Balance = IERC20(token1).balanceOf(address(this));
        
        // 储备金应该等于合约余额减去未提取的费用
        assert token0Balance >= reserve0 && token1Balance >= reserve1;
    }
    
    // 交易安全属性
    property swapSafety(address user, uint256 amountIn, address tokenIn) {
        require(user != address(0));
        require(amountIn > 0);
        require(tokenIn == token0 || tokenIn == token1);
        
        // 保存交易前状态
        uint256 userBalance0Before = IERC20(token0).balanceOf(user);
        uint256 userBalance1Before = IERC20(token1).balanceOf(user);
        uint256 reserve0Before = reserve0;
        uint256 reserve1Before = reserve1;
        
        // 模拟交易
        swap(amountIn, tokenIn, user);
        
        // 验证用户余额增加
        uint256 userBalance0After = IERC20(token0).balanceOf(user);
        uint256 userBalance1After = IERC20(token1).balanceOf(user);
        
        if (tokenIn == token0) {
            assert userBalance1After > userBalance1Before;
        } else {
            assert userBalance0After > userBalance0Before;
        }
        
        // 验证x*y >= k
        assert reserve0 * reserve1 >= reserve0Before * reserve1Before;
    }
    
    // 闪电贷安全属性
    property flashLoanSafety(address user, uint256 amount0, uint256 amount1, bytes memory data) {
        require(user != address(0));
        require(amount0 > 0 || amount1 > 0);
        
        // 保存调用前状态
        uint256 reserve0Before = reserve0;
        uint256 reserve1Before = reserve1;
        
        // 假设回调正确执行
        assumeFlashLoanCallbackSucceeds(user, amount0, amount1, data);
        
        // 模拟闪电贷
        flashLoan(user, amount0, amount1, data);
        
        // 验证储备金恢复
        assert reserve0 >= reserve0Before;
        assert reserve1 >= reserve1Before;
    }
    
    // 价格操纵抗性
    property priceManipulationResistance(uint256 largeAmount, address tokenIn) {
        // 验证大额交易不会导致过度的价格影响
        address attacker = munging.create_address(1);
        
        // 假设攻击者有足够的资金
        assume(attackerTokenBalance(attacker, tokenIn) >= largeAmount);
        
        // 获取初始价格
        uint256 initialPrice = getSpotPrice(tokenIn);
        
        // 模拟大额交易
        swap(largeAmount, tokenIn, attacker);
        
        // 获取操纵后价格
        uint256 manipulatedPrice = getSpotPrice(tokenIn);
        
        // 验证价格偏差在合理范围内
        uint256 deviation = absDiff(manipulatedPrice, initialPrice) * 100 / initialPrice;
        assert deviation <= 10; // 最多允许10%的偏差
    }
}

// DEX安全最佳实践示例
contract SecureDEX {
    // 权限控制
    using AccessControl for AccessControl.Role;
    bytes32 public constant ADMIN_ROLE = keccak256("ADMIN_ROLE");
    bytes32 public constant OPERATOR_ROLE = keccak256("OPERATOR_ROLE");
    
    // 紧急控制
    bool public paused;
    uint256 public constant MAX_PAUSE_DURATION = 7 days;
    uint256 public pauseStartTime;
    
    // 安全参数
    struct SecurityParams {
        uint256 maxSwapAmount;
        uint256 maxPriceDeviation;
        uint256 minLiquidity;
        uint256 twapWindow;
    }
    
    SecurityParams public securityParams;
    
    // 事件记录
    event SwapExecuted(address user, address tokenIn, address tokenOut, uint256 amountIn, uint256 amountOut);
    event EmergencyPaused(uint256 timestamp);
    event EmergencyUnpaused(uint256 timestamp);
    event SecurityParamsUpdated(SecurityParams newParams);
    
    // 构造函数
    constructor() {
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _setupRole(ADMIN_ROLE, msg.sender);
        
        // 初始安全参数
        securityParams = SecurityParams({
            maxSwapAmount: 1000 ether,
            maxPriceDeviation: 5, // 5%
            minLiquidity: 10 ether,
            twapWindow: 1 hours
        });
    }
    
    // 访问控制修饰器
    modifier onlyAdmin() {
        require(hasRole(ADMIN_ROLE, msg.sender), "Not admin");
        _;
    }
    
    modifier onlyOperator() {
        require(hasRole(OPERATOR_ROLE, msg.sender), "Not operator");
        _;
    }
    
    // 暂停机制
    modifier whenNotPaused() {
        require(!paused, "Contract is paused");
        _;
    }
    
    function emergencyPause() external onlyAdmin {
        require(!paused, "Already paused");
        paused = true;
        pauseStartTime = block.timestamp;
        emit EmergencyPaused(block.timestamp);
    }
    
    function emergencyUnpause() external onlyAdmin {
        require(paused, "Not paused");
        paused = false;
        emit EmergencyUnpaused(block.timestamp);
    }
    
    // 自动解除暂停
    function autoUnpause() external {
        require(paused && block.timestamp - pauseStartTime > MAX_PAUSE_DURATION, "Pause duration not exceeded");
        paused = false;
        emit EmergencyUnpaused(block.timestamp);
    }
    
    // 安全的交换函数
    function swap(address tokenIn, address tokenOut, uint256 amountIn, uint256 minAmountOut) 
        external 
        whenNotPaused 
        nonReentrant 
        returns (uint256 amountOut)
    {
        // 1. 参数验证
        require(tokenIn != address(0) && tokenOut != address(0), "Invalid token address");
        require(tokenIn != tokenOut, "Same token");
        require(amountIn > 0, "Amount must be positive");
        require(minAmountOut > 0, "Min amount must be positive");
        
        // 2. 交易限制
        require(amountIn <= securityParams.maxSwapAmount, "Amount exceeds limit");
        
        // 3. 流动性检查
        require(getPoolLiquidity(tokenIn, tokenOut) >= securityParams.minLiquidity, "Insufficient liquidity");
        
        // 4. 价格影响检查
        uint256 spotPrice = getSpotPrice(tokenIn, tokenOut);
        uint256 twapPrice = getTWAPPrice(tokenIn, tokenOut, securityParams.twapWindow);
        uint256 priceDeviation = absDiff(spotPrice, twapPrice) * 100 / twapPrice;
        require(priceDeviation <= securityParams.maxPriceDeviation, "Price deviation too high");
        
        // 5. 计算输出金额
        amountOut = calculateSwapOutput(tokenIn, tokenOut, amountIn);
        require(amountOut >= minAmountOut, "Insufficient output amount");
        
        // 6. 状态更新先于外部调用
        updatePoolReserves(tokenIn, tokenOut, amountIn, amountOut);
        
        // 7. 安全的代币转移
        require(safeTransferFrom(tokenIn, msg.sender, address(this), amountIn), "Input transfer failed");
        require(safeTransfer(tokenOut, msg.sender, amountOut), "Output transfer failed");
        
        // 8. 事件记录
        emit SwapExecuted(msg.sender, tokenIn, tokenOut, amountIn, amountOut);
        
        // 9. 异常监控
        if (amountOut * 100 / calculateTheoreticalOutput(tokenIn, tokenOut, amountIn) < 95) {
            emit AbnormalSwapDetected(msg.sender, tokenIn, tokenOut, amountIn, amountOut);
        }
    }
    
    // 更新安全参数
    function updateSecurityParams(SecurityParams calldata newParams) external onlyAdmin {
        // 验证参数合理性
        require(newParams.maxPriceDeviation <= 20, "Deviation too high");
        require(newParams.minLiquidity > 0, "Invalid min liquidity");
        require(newParams.twapWindow >= 1 minutes && newParams.twapWindow <= 24 hours, "Invalid TWAP window");
        
        // 应用新参数
        securityParams = newParams;
        emit SecurityParamsUpdated(newParams);
    }
    
    // 安全的流动性提供
    function addLiquidity(address tokenA, address tokenB, uint256 amountA, uint256 amountB, uint256 minLiquidity) 
        external 
        whenNotPaused 
        nonReentrant 
        returns (uint256 liquidity)
    {
        // 1. 参数验证
        require(tokenA != address(0) && tokenB != address(0), "Invalid token address");
        require(tokenA != tokenB, "Same token");
        require(amountA > 0 && amountB > 0, "Amounts must be positive");
        
        // 2. 记录当前余额
        uint256 balanceA = IERC20(tokenA).balanceOf(address(this));
        uint256 balanceB = IERC20(tokenB).balanceOf(address(this));
        
        // 3. 安全转移
        require(safeTransferFrom(tokenA, msg.sender, address(this), amountA), "Token A transfer failed");
        require(safeTransferFrom(tokenB, msg.sender, address(this), amountB), "Token B transfer failed");
        
        // 4. 计算实际收到的金额
        uint256 amountAReceived = IERC20(tokenA).balanceOf(address(this)) - balanceA;
        uint256 amountBReceived = IERC20(tokenB).balanceOf(address(this)) - balanceB;
        
        // 5. 添加流动性逻辑
        liquidity = _addLiquidity(tokenA, tokenB, amountAReceived, amountBReceived);
        require(liquidity >= minLiquidity, "Insufficient liquidity minted");
        
        // 6. 发放LP代币
        _mint(msg.sender, liquidity);
        
        // 7. 事件记录
        emit LiquidityAdded(msg.sender, tokenA, tokenB, amountAReceived, amountBReceived, liquidity);
    }
    
    // 辅助函数
    function absDiff(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a - b : b - a;
    }
    
    // 更多实现函数...
}

□ 权限控制机制正确配置
□ 紧急暂停功能正常工作
□ 预言机安全实现并验证
□ 价格操纵防护措施已添加
□ 重入保护已实现
□ 整数溢出检查已添加
□ 形式化验证通过
□ 至少三家安全公司审计通过
□ 模糊测试覆盖所有关键功能
□ 测试网充分测试
□ 漏洞赏金计划已启动
□ 异常监控系统已部署
□ 多签钱包保护管理功能
□ 时间锁控制参数更新
□ 跨链功能（如适用）安全验证