Research And Implementation Of Online Auction Smart Contract Mechanism Based On Blockchain

As an important mechanism for resource allocation and commodity pricing in today’s era,online auctions are widely used in commercial activities in various fields.With the development of Internet technology,more and more online auction schemes have been proposed successively.In recent years,the rise of blockchain and smart contract technology has brought a new model to online auctions.The online auction mechanism based on blockchain has become a hot research topic in the application of blockchain-related technologies.However,most of the current blockchain auction schemes are based on the assumption of a semi-honest model,and there is more trust in the auction user entity.There are still some deficiencies in the public verification of auction results,transparency of the execution process,and privacy protection of participants’ bids.Due to the lack of an effective credit system and punishment mechanism,the malicious behavior of buyers and sellers during the auction process cannot be effectively punished,and the anonymity of public blockchain accounts makes it difficult for the auction process on the chain to be effectively supervised by a third-party endorsement agency,resulting in legitimate rights and obligations of buyers and sellers on the chain cannot be effectively guaranteed and supervised off the chain.In order to solve the problems existing in the new online auction mode based on blockchain technology and improve the existing blockchain auction mechanism,this paper designs an improved secure multi-party sorting protocol for secure calculation of auction results,and combines credit model,the blockchain-based online auction smart contract mechanism is researched and developed.The main contributions of this paper are as follows:1.An improved secure multi-party sorting protocol based on elliptic curve cryptography and El Gamal cryptography is proposed,which solves the core algorithm problem of building a blockchain online auction smart contract mechanism.The protocol uses the blockchain as a nontamperable trusted data storage center to reduce data communication between participants,and adopts the method of aggregating encryption keys in advance,so that the participants in the sorting process do not need to collaborate to calculate the sorting results,and build smart contract homomorphic encryption calculation framework,ensures that the key processes of the algorithm are executed under the condition of complete encryption of the data,and the whole process is open,transparent and verifiable under the premise of protecting the privacy input of the participants.Experimental analysis shows that the protocol has fewer interactions and lower communication and computing costs than the original protocol.2.Design and implement the blockchain-based online auction smart contract mechanism and system based on the improved secure multi-party sorting protocol proposed in Contribution 1.First,using the credit mechanism combined with the smart contract auction liquidat ion process,and expanding on the basis of the improved secure multi-party sorting protocol,an online auction smart contract mechanism with security under the concealed attack model is designed.Secondly,combined with the permission system consortium blockchain to build a real-name auction system,introduce credit endorsement institutions to manage the credit value of participants and participate in the auction process,so as to realize the supervision of the whole auction process.Extend the onchain credit punishment mechanism from a single auction penalty to a real-name account credit accountability system,so that the legitimate rights and interests of the on-chain auction can be effectively guaranteed off the chain,establish a more complete credit management and supervision system,and solved the deficiencies of the existing blockchain auction schemes in these aspects.Finally,the auction smart contract mechanism is implemented,tested and analyzed.The experimental results show that the auction mechanism can meet the needs of online auctions and has high reliability and practicability.