solidity盲拍合约代码实例

以下是一个基于Solidity的盲拍合约的代码实例：

pragma solidity ^0.8.0;

contract BlindAuction {
    struct Bid {
        bytes32 blindedBid;
        uint deposit;
    }

    address payable public beneficiary;
    uint public biddingEnd;
    uint public revealEnd;
    bool public ended;

    mapping(address => Bid[]) public bids;

    address public highestBidder;
    uint public highestBid;

    mapping(address => uint) pendingReturns;

    event AuctionEnded(address winner, uint highestBid);

    modifier onlyBefore(uint _time) { require(block.timestamp < _time); _; }
    modifier onlyAfter(uint _time) { require(block.timestamp >= _time); _; }

    constructor(
        uint _biddingTime,
        uint _revealTime,
        address payable _beneficiary
    ) {
        beneficiary = _beneficiary;
        biddingEnd = block.timestamp + _biddingTime;
        revealEnd = biddingEnd + _revealTime;
    }

    function bid(bytes32 _blindedBid)
        public
        payable
        onlyBefore(biddingEnd)
    {
        bids[msg.sender].push(Bid({
            blindedBid: _blindedBid,
            deposit: msg.value
        }));
    }

    function reveal(
        uint[] memory _values,
        bool[] memory _fake,
        bytes32[] memory _secret
    )
        public
        onlyAfter(biddingEnd)
        onlyBefore(revealEnd)
    {
        uint length = bids[msg.sender].length;
        require(_values.length == length);
        require(_fake.length == length);
        require(_secret.length == length);

        uint refund;
        for (uint i = 0; i < length; i++) {
            Bid storage bidToCheck = bids[msg.sender][i];
            (uint value, bool fake, bytes32 secret) = (_values[i], _fake[i], _secret[i]);
            if (bidToCheck.blindedBid != keccak256(abi.encodePacked(value, fake, secret))) {
                continue;
            }
            refund += bidToCheck.deposit;
            if (!fake && bidToCheck.deposit >= value) {
                if (placeBid(msg.sender, value)) {
                    refund -= value;
                }
            }
            bidToCheck.blindedBid = bytes32(0);
        }
        msg.sender.transfer(refund);
    }

    function placeBid(address bidder, uint value) internal returns (bool success) {
        if (value <= highestBid) {
            return false;
        }
        if (highestBidder != address(0)) {
            pendingReturns[highestBidder] += highestBid;
        }
        highestBid = value;
        highestBidder = bidder;
        return true;
    }

    function withdraw() public {
        uint amount = pendingReturns[msg.sender];
        if (amount > 0) {
            pendingReturns[msg.sender] = 0;
            msg.sender.transfer(amount);
        }
    }

    function auctionEnd() public onlyAfter(revealEnd) {
        require(!ended);
        emit AuctionEnded(highestBidder, highestBid);
        ended = true;
        beneficiary.transfer(highestBid);
    }
}

在这个合约中，参与者可以在拍卖期限前进行出价，每次出价需要提供一定的保证金。在拍卖期限结束后，参与者需要在规定时间内提交自己的出价及其对应的密钥，以公开自己的出价。最终，合约将公布最高出价，并将拍卖物品转让给最高出价者。同时，所有未成功出价的参与者可以取回自己的保证金。