Sound analysis and migration of data from Ethereum smart contracts

Abstract

With the addition of multiple blockchain platforms in the ecosystem, the Dapp owners need to migrate their smart contracts from one platform to another to remain competitive, cost-effective, and secure. A smart contract is a piece of code that contains logic and data. To migrate a smart contract, whether it’s on the same blockchain platform or a different one, we need both its source code that represents the logic and data that indicate the state of the contract. The source code can be easily set up, but to complete the migration, we have to extract the current state of the contract. In this paper, we have developed an advanced state extraction technique that uses static analysis to analyze the smart contract’s call graph and events, and extracts the entire storage state from the storage trie, along with the proper associations across function calls, enabling users to visualize, manage, and transform the state as desired for migration. The soundness of the extracted state was confirmed using the method of abstract interpretation. Further, the migration adapter is designed to transform the extracted state into slot-value pairs and migrate it to the target blockchain. Using our new approach, we were able to completely analyze 14% more smart contracts with the extraction of 53% more data by analyzing function calls and event logs from 67,993 contracts and also migrated some contracts to the multiple popular EVM-compatible blockchains.