Design And Implementation Of Government Procurement System Based On Ethereum Smart Contract

Government procurement refers to the use of fiscal funds to purchase goods,projects,or services by governments at all levels of the country within the prescribed scope in accordance with the law and by means of public bidding.With the popularization of Internet applications,our country has now used electronic government procurement platforms to replace traditional paper procurement methods.Although the electronic government procurement platform solves the waste of human and material resources in traditional government procurement methods and improves procurement efficiency,it relies on human decision-making and data that may cause errors when implementing the bidding process and fulfilling the content of the contract.As a result,errors may occur in the bidding process and the execution of the contract due to the deviation of human understanding.A smart contract is a computerized contract that is pre-defined by both parties to the transaction and implemented using block-chain technology.After being triggered under specified conditions,the smart contract executes operations in strict accordance with the pre-defined process,avoiding errors caused by human factors.At the same time,the distributed nature of the block-chain can solve the security problems faced by centralized servers.In this paper,the behaviors of confirming the qualifications of bidders and opening bids at the specified time in the government procurement process are designed and implemented into smart contracts,which are judged and executed by the conditions specified in advance by the smart contracts.The operation of returning the bid bond and payment by the government unit to the supplier is implemented as a smart contract in accordance with the state and time of the procurement process as the trigger condition,and the smart contract for bid qualification certification is realized.The specific implementation process is as follows: through the secp256k1 hash operation and the ECDSA elliptic curve signature algorithm,the supplier identity authentication process based on the alliance chain is realized,and the real identityIVinformation of the supplier is bound with the account address in the block-chain.Based on web3.js,compile the front-end page of the government procurement system to interact with the government procurement smart contract.Realize the process of bid opening,bid evaluation,and bidding in government procurement,and write smart contracts based on supplier bid qualification verification and bid opening at a specified time.After confirming the winning bidder,the asset transfer smart contract uses the parameters provided by the trust node in the alliance chain and the specified time node as the trigger conditions,and the Ethereum accounts with different identities can transfer or withdraw funds to the contract account.The smart contract part of the system is written in solidity language,and the front-end page is developed in web3.js,html,css language,and is designed and implemented based on the truffle framework.The authenticity of the trigger conditions of the smart contract determines whether the execution result of the smart contract is correct.This article uses the chainlink smart contract oracle machine to obtain the real data related to the government procurement smart contract such as the ETH exchange rate from outside the block-chain.The implementation of Ethereum smart contracts is based on block-chain technology.Although block-chain technology can ensure that data is not maliciously tampered with,compared with traditional centralized databases,it has the disadvantages of expensive transaction costs and low access speed.Suitable for data storage as a database.IPFS(Interplanetary File System)is a distributed file system capable of permanent and decentralized storage of data and point-to-point file transfer.This article is designed to combine the underlying block-chain of government procurement smart contracts with the IPFS distributed file system and Mongo DB database,and store bidding documents,bidding document templates and other files in IPFS,which is convenient for users to download and view operations,while in the block-chain store the Hash value corresponding to the file in IPFS and use it for verification.When the government unit uploads the bidding information,the bidding information is synchronously stored in the Mongo DB distributed database,and the supplier's viewing operation of the bidding information is carried out in Mongo DB,which reduces unnecessary expenses caused by accessing data in the block-chain and improves query efficiency.Finally,deploy smart contracts in the local private chain ganache-cli,and conduct functional tests and vulnerability tests.After the test meets the expected requirements,the smart contract is finally deployed on the Rinkeby Ethereum test network,which can be tested and used by other smart contract developers.