In spite of their popularity, developing secure smart contracts remains a challenging task. Existing solutions are either impractical as they do not support many complex real-world contracts or leave the burden to developers for fixing bugs. In this paper, we propose the first practical smart contract compiler, called HCC, which automatically inserts security hardening checks at the source-code level. HCC develops a code property graph (CPG) to model control-flows and data-flows of a given smart contract. Due to the CPG notation, HCC can be applied to various smart contract platforms and programming languages. We demonstrate the effectiveness of this approach on Ethereum's Solidity smart contracts and show that it efficiently mitigates reentrancy and integer bugs. We also show how to integrate HCC within other blockchain platforms such as Hyperledger Fabric. Our evaluation on 10k real-world contracts demonstrates that HCC is highly practical and effective.
Open Access version
Under review (preprint)