Hephaestus: Modeling, Analysis, and Performance Evaluation of Cross-Chain Transactions
Rafael Belchior, Peter Somogyvari, Jonas Pfannschmidt, André Vasconcelos, Miguel Correia
Abstract
Ecosystems of multiple blockchains are now a reality. Multichain applications and protocols are perceived as necessary to enable scalability, privacy, and composability. Despite being a promising emerging area, we have been witnessing devastating attacks on cross-chain bridges that have caused billions of dollars in losses, and no apparent solution seems to emerge from the ongoing chaos. In this article, we present our contribution to minimizing bridge attacks, by monitoring a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cross-chain model</i> . In particular, we aggregate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cross-chain events</i> into <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cross-chain transactions</i> , and verify if they follow a set of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cross-chain rules</i> , which then generate a model. We propose <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hephaestus</monospace> , the first cross-chain model generator that captures the operational complexity of cross-chain applications. <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hephaestus</monospace> can generate cross-chain models from local transactions in different ledgers, realizing arbitrary cross-chain use cases and allowing operators to monitor their applications. Monitoring helps identify outliers and malicious behavior, which can enable programmatically stopping attacks (“a circuit breaker”), including bridge hacks. We conduct a detailed evaluation of our system, where we implement a cross-chain bridge use case. Our experimental results show that <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hephaestus</monospace> can process 600 cross-chain transactions in less than 5.5 s in an environment with two blockchains using sublinear storage, paving the way for more resilient bridge designs.