A Research On Blockchain Smart Contract System-Oriented Mechanism Design

Blockchain is a cross-application technology integrating various underlying technologies,the most core technologies of which include cryptography,distributed computing and mechanism design.Cryptography and distributed computing mainly solve the data storage and communication problems of blockchain,while mechanism design plays a crucial role in solving a series of problems arising from the strong social attributes of blockchain P2P network nodes.These problems are usually distributed in the consensus layer,incentive layer and smart contract layer of the blockchain.In recent years,the Blockchain Smart Contract System(BSCS)has been rapidly developing,and smart contracts as computer programs running in the distributed network of blockchain have greatly broadened the application area of blockchain technology.At present,the industry lacks a unified formal definition of smart contracts,which leads to low contract reusability and data redundancy;the existing mainstream consensus mechanism is poorly applicable to BSCS,which is prone to waste of computational resources and centralization of bookkeeping rights;the anonymity and one-time interaction of smart contracts make it difficult to achieve default recovery and increase the possibility of malicious contracts on the chain.In order to solve the above problems,this paper is oriented to the mechanism design problem of blockchain smart contract system,and the main research contents are as follows.(1)Research on the formalization of smart contracts based on conditional response and finite state automata.Based on the theory of finite state automata,we analyze the execution process of smart contracts from a logical perspective and describe them formally in terms of directed acyclic graphs;we study the influence of the environment on the execution process of smart contracts,including contract state migration and conditional trigger mechanisms,and establish the environment-state-trigger(VST)model of smart contracts;taking a realistic housing lease contract as an example,we use the VST model to describe the creation of a smart contract based on the contract,its deployment,and the design of the contract.The VST model is used to describe the life cycle of creating a smart contract based on the contract,and its deployment,execution,and completion.(2)Study of consensus mechanism based on the degree of interaction in the smart contract domain.Considering that smart contracts are used in multiple domains in BSCS,an algorithm is designed to find out the interaction degree of contract creation nodes in one or more domains to prove the contribution of nodes to the blockchain network,based on which a proof of interaction degree(PoE)mechanism is designed to assign bookkeeping rights.The performance of the PoE mechanism is tested by simulation experiments against the mainstream consensus mechanism under the same settings,and the experimental results show that the PoE mechanism has more flexibility compared to PoW and PoS.(3)Research on the incentive mechanism of smart contract system based on reputation value.Based on(1)and(2),we define the smart contract completion degree based on the VST model,which is used as the basis for calculating the node reputation value in BSCS.In order to reduce the possibility of successful malicious contracts on the chain and increase the probability of quality contracts on the chain,a jury mechanism is designed based on the reputation value,and the actions of nodes holding different action preferences(adversarial nodes,rational nodes,and honest nodes)under three different percentage distributions(uniform distribution,normal distribution,and exponential distribution)are simulated through experiments,and the results show that the jury mechanism exhibits adversarial robustness in most cases and improves the probability of quality contracts on the chain.improves the probability of quality contracts on the chain.In this paper,we study the consensus,incentive,and contract layers of BSCS,model the smart contract formally from the perspective of software engineering and mechanism design,and design and improve the consensus and incentive mechanisms of BSCS.The results show that the proposed mechanism plays a positive role in optimizing the distribution of bookkeeping rights and incentivizing node behavior.