EVMBT: A Binary Translation Scheme for Upgrading EVM Smart Contracts to WASM

Abstract

Ethereum is the first and largest blockchain that supports smart contracts. For better scalability and security, one major planned change of Ethereum 2.0 (Eth2) is to upgrade the smart contract interpreter from Ethereum Virtual Machine (EVM) to WebAssembly (WASM). In the meanwhile, many other popular blockchains have adopted WASM. Since Ethereum hosts millions of smart contracts, it is highly desirable to automatically migrate EVM smart contracts to WASM code to foster the prosperity of the blockchain ecosystem while inheriting the historical transactions from Ethereum. Unfortunately, it is non-trivial to achieve this purpose due to the challenges in converting the EVM bytecode of smart contracts to WASM bytecode and adapting the generated WASM bytecode to the underlying blockchain environment. In particular, none of the existing tools are adequate for this task because they fail to achieve accurate translation and compatibility with the blockchain environment. In this paper, we propose a novel solution and use Eth2 as the target blockchain to demonstrate its feasibility and performance because Eth2 is highly attractive to both industry and academia. Specifically, we develop EVMBT, a novel EVM2WASM bytecode translation framework that not only ensures the fidelity of translation but also supports plugins to improve smart contracts. Extensive experiments demonstrate that EVMBT can successfully translate real-world smart contracts with high fidelity and low gas overhead.