Abstract: With the rapid development of Internet technology, many traditional auctions are gradually replaced by electronic auctions, and the security privacy protection problem in them becomes more and more concerned. Concerning the problems in the current electronic bidding and auction systems, such as the risk of the privacy of bidder being leaked, the expensive cost of third-party auction center is expensive, and the collusion between third-party auction center and the bidder, a sealed-bid auction scheme based on blockchain smart contract technology was proposed. In the scheme, an auction environment without third-party was constructed by making full use of the features of the blockchain, such as decentralization, tamper-proofing and trustworthiness; and the security deposit strategy of the blockchain was used to restrict the behaviors of bidders, which improved the security of the electronic sealed-bid auction. At the same time, Pedersen commitment was used to protect auction price from being leaked, and Bulletproofs zero-knowledge proof protocol was used to verify the correctness of the winning bid price. Security analysis and experimental results show that the proposed auction scheme meets the security requirements, and has the time consumption of every stage within the acceptable range, so as to meet the daily auction requirements.

Key words: blockchain, sealed-bid auction, zero-knowledge proof, Pedersen commitment, smart contract

摘要： 随着互联网技术的飞速发展，传统拍卖正逐渐转变为电子拍卖，其中隐私保护越来越受到关注。针对当前电子投标拍卖系统中出现的问题，如竞买人隐私存在被泄露的风险、第三方拍卖中心的费用昂贵、第三方拍卖中心可能与竞买人勾结等，提出一种基于区块链智能合约技术的密封式投标拍卖方案。该方案充分利用区块链的去中心化、防篡改和可信赖性等特征构建了一个无第三方的拍卖环境，并通过区块链上的安全保证金策略约束竞买人的行为，从而提高密封式电子拍卖的安全性。同时该方案利用Pedersen承诺保护竞买人的竞拍价格不被泄露，并通过Bulletproofs零知识证明协议验证中标价格的正确性。安全性分析和实验结果表明，提出的拍卖方案满足安全性要求，各个阶段的时间消耗均在可接受范围内，满足日常拍卖要求。

关键词: 区块链, 密封式投标拍卖, 零知识证明, Pedersen承诺, 智能合约