A Four-Tier Smart Contract Model with On-Chain Upgrade

Abstract

When there are loopholes in smart contracts or changes in demand, the existing three-tier model can only implement partial on-chain upgrades and the security of on-chain upgrades cannot be guaranteed. In this study, we optimized the three-tier smart contract model and proposed a four-tier smart contract model that includes the proxy, verification, business, and storage layers. The proxy layer is used to link contracts with other layers, the verification layer is used to check the integrity, boundary values, and abnormal processes of contracts, the business layer is used to execute business logic, and the storage layer is used to store data uniformly. On the basis of the proposed model, an on-chain upgrade and verification algorithm is proposed, which implements on-chain upgrade, on-chain verification, and version compatibility of contracts. We then design an information exchange system based on the proposed model and algorithm and test it based on the FISCO BCOS platform. Experiments show that, compared to the three-tier model, the proposed four-tier model and algorithm can implement the on-chain upgrade and reduce the contract complexity and data migration cost at the cost of some overall deployment.