Research And Implementation Of Smart Contract System Based On Chaincode

With the increasing development of digital currencies such as Bitcoin,blockchain technology has gradually become an emerging technology.In recent years,blockchain can be used as a programmable distributed credit infrastructure to support smart contract applications.The most popular type of blockchain at present is the consortium blockchain,which can be combined with other technologies to realize the value of the blockchain by writing some smart contracts.The typical representative of the consortium blockchain is Hyperledger Fabric,and its smart contracts are called Chaincode.However,there are some problems with Chaincode.For example,all users have to write repetitive business logic by themselves,and nodes need to manually install and deploy new contracts.The update cost is high and the user experience is poor.In addition,Fabric uses Kafkabased ordering service as its consensus algorithm in version 1.0,which can achieve very high throughput,but this message queue-based consensus algorithm cannot tolerate Byzantine nodes.Therefore,in view of the existing problems,this paper studies and designs a new smart contract system,which can effectively solve the above problems.The system can realize the basic functions of smart contract execution,including the simulation execution of contracts,the generation of read and write sets,the generation of transactions,the consensus and the verification process,to ensure the normal operation of the contract system.On this basis,the function of automatic update and deployment of the contract is added.For the consensus process of transactions,a message queue consensus algorithm based on Byzantine fault tolerance is proposed,which solves the problem that the message queue consensus algorithm cannot tolerate Byzantine nodes and improves the robustness of the smart contract system.In addition to the realization of the basic functions of smart contracts,this paper provides an online programming tool that depends on the system.This tool is a platform for users to simulate contract execution.Users can write the required smart contracts on the platform,and then users can easily deploy the contracts to the blockchain and implement the calls to the contracts.Finally,it is proved by experiments that the system can complete the required functions,and complete the life cycle process of a smart contract from writing to calling through the online programming tool.And the Byzantine fault tolerance is realized on the consensus algorithm,which further ensures the security and reliability of the smart contract system.At present,the system has been delivered to the project team for deployment.