Count of Monte Crypto: Accounting-based Defenses for Cross-Chain Bridges

Fuente: arXiv
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Main Authors: Liu, Enze, Luo, Elisa, Yan, Jian Chen, Izhikevich, Katherine, Grant, Stewart, Stefan, Deian, Voelker, Geoffrey M, Savage, Stefan
Format: Preprint
Published: 2024
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author Liu, Enze
Luo, Elisa
Yan, Jian Chen
Izhikevich, Katherine
Grant, Stewart
Stefan, Deian
Voelker, Geoffrey M
Savage, Stefan
author_facet Liu, Enze
Luo, Elisa
Yan, Jian Chen
Izhikevich, Katherine
Grant, Stewart
Stefan, Deian
Voelker, Geoffrey M
Savage, Stefan
contents Between 2021 and 2023, crypto assets valued at over \$US2.6 billion were stolen via attacks on "bridges" -- decentralized services designed to allow inter-blockchain exchange. While the individual exploits in each attack vary, a single design flaw underlies them all: the lack of end-to-end value accounting in cross-chain transactions. In this paper, we empirically analyze 10 million transactions used by key bridges during this period. We show that a simple invariant that balances cross-chain inflows and outflows is compatible with legitimate use, yet precisely identifies every known attack (and several likely attacks) in this data. Further, we show that this approach is not only sufficient for post-hoc audits, but can be implemented in-line in existing bridge designs to provide generic protection against a broad array of bridge vulnerabilities.
format Preprint
id arxiv_https___arxiv_org_abs_2410_01107
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Count of Monte Crypto: Accounting-based Defenses for Cross-Chain Bridges
Liu, Enze
Luo, Elisa
Yan, Jian Chen
Izhikevich, Katherine
Grant, Stewart
Stefan, Deian
Voelker, Geoffrey M
Savage, Stefan
Cryptography and Security
Between 2021 and 2023, crypto assets valued at over \$US2.6 billion were stolen via attacks on "bridges" -- decentralized services designed to allow inter-blockchain exchange. While the individual exploits in each attack vary, a single design flaw underlies them all: the lack of end-to-end value accounting in cross-chain transactions. In this paper, we empirically analyze 10 million transactions used by key bridges during this period. We show that a simple invariant that balances cross-chain inflows and outflows is compatible with legitimate use, yet precisely identifies every known attack (and several likely attacks) in this data. Further, we show that this approach is not only sufficient for post-hoc audits, but can be implemented in-line in existing bridge designs to provide generic protection against a broad array of bridge vulnerabilities.
title Count of Monte Crypto: Accounting-based Defenses for Cross-Chain Bridges
topic Cryptography and Security
url https://arxiv.org/abs/2410.01107