Instruction Verification of Ethereum Virtual Machine by Formal Method

In recent years, many smart contracts on the ethereum platform are increasingly closer to our life. The existence of smart contract enables us to complete complicated transactions without depending on the third party. It should be not only fast, but also secure guaranteed. When the smart contract is requested to execute, the action is performed by ethereum virtual machine (EVM). If EVM occurs errors in the process of implementation, the contract execution result will also have mistaken. Therefore, ensuring the correctness of the EVM is very important. In this work, we propose a framework to formally verify EVM instruction implementations by model checking to check whether the instruction operation behaviors working on EVM is the same as the expected definitions in the ethereum yellow paper. In addition, we also define a set of interfaces specifically for EVM instruction verification to achieve the reusability of our proposed verification environment. The experimental results indicate that the formal verification method used in this work is more trustworthy than the conventional testing method. It can exactly capture the errors in the design which may be undetected by testing/simulation methods. The defined instructions are divided into 11 categories, and our work has completed to verify 7 categories, including 92 instructions of total 134, in 50 hours.