Research On The Sealed-bid Auction Scheme For Blockchain Based On Secure Comparison Protocols

Sealed-bid auctions are a powerful trading tool that is able to achieve the maximum value of the goods in the transaction.As an emerging technology system,blockchain is distributed fault-tolerant,non-tamperable,traceable,decentralized,and quasi-anonymous.,which can help auction activities to be carried out safer and more equitably.However,the sealed-bid auction scheme for blockchain that can protect the privacy of the bids has the problem of excessive overhead,and the existing scheme may not be safe for malicious bidders or has no effective punishment for malicious bidders.In response to the above problems,the paper improves the DGK comparison protocol based on tools such as zero-knowledge proofs,and proposes a sealed-bid auction scheme suitable for blckchain by executing the improved DGK two-party comparison protocol in parallel through bidders,and combining smart contracts,digital money deposits.This scheme has less overhead and can directly punish malicious bidders,while protecting the privacy of bids.The main research contents of this paper are as follows:(1)Improved DGK comparison protocol based on zero-knowledge proofsThis paper improves the DGK comparison protocol based on the zero-knowledge proof protocol,by designing specific zero-knowledge proof protocols and proving they are security.In each stage of the comparison protocol,the participant sends the zero-knowledge proofs while sending the result of the operation.Then constructs a maliciously-secure two-party comparison protocol while existing a semi-honest judge party which verifies those zero-knowledge proofs.Compared with the scheme based on the Fischlin comparison protocol,the protocol in this paper has better computing overhead and communication overhead while under the same security level.(2)Security sealed-bid auction scheme based on blockchainOn the basis of the improved DGK comparison protocol,a sealed-bid auction scheme suitable for blockchain was constructed by executing the two-party comparison protocol in parallel between all bidders,and the process controlled by the smart contract.In the ideal scenario,the bidders who can win the bid in a fixed 4 blocks,and will not change with the increase of the number of bidders.At the same time,it can guarantee the bidder's bids privacy,and it is safe for malicious bidders that malicious bidders will be punished by losing his deposit.Compared with similar blockchain-based auction schemes Stain,the scheme presented in this paper has more effective punishments for malicious bidders and less overhead.