Security researcher and developer Antoine Liard is withdrawing from development of the Lightning Network, citing security issues and fundamental challenges to the Bitcoin ecosystem.
According to a thread on the Linux Foundation’s public mailing list, Riard believe The Bitcoin community faces a “tough dilemma” as a new type of permutation cycle attack puts Lightning in a “compromised position”.
How does the Lightning Displacement Cycling Attack work?
There’s a lot of discussion on mailing lists about this newly discovered vulnerability, but the actual mechanism is a little difficult to understand.
So here’s an illustrated guide…
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— Mononaut (@mononautical) October 21, 2023
The Lightning Network is a second layer solution built on top of the Bitcoin blockchain. It is designed to improve the scalability and efficiency of Bitcoin transactions by enabling off-chain peer-to-peer transactions.
Through the Lightning Network, users can open payment channels, perform multiple transactions off-chain, and settle the final results on the Bitcoin blockchain. Alternative cycling attacks target these payment channels. This is a new type of attack that allows attackers to exploit mismatches between individual memory pools to steal funds from channel participants. According to Liard,
“I think this new class of replacement cycle attacks puts Lightning in a very dangerous position. Sustainable remediation is only possible at the base layer, and for example, by removing the memory-intensive history of every transaction. You can only add to it or upgrade some kind of consensus. Mitigations introduced As stated in the first full disclosure email, they have some value against simple attacks, but for advanced attacks I don’t think it’s preventing that.”
Riard also said that changes to the underlying Bitcoin network may be needed to deal with new types of attacks.
“These types of changes require the utmost transparency and buy-in from the entire community, as they change the security architecture of full-node processing requirements and the integrity of the decentralized Bitcoin ecosystem.”
Lightning developers grapple with challenges such as criticism of network complexity and demands for user experience. Since its creation in 2018, Layer 2 Network has gained popularity, with the total amount locked up reaching $159.5 million as of this writing. according to With data from DefiLlama. However, this number is still very modest when compared to Bitcoin’s market capitalization of $587 billion.
Leard will now focus on developing Bitcoin Core, but warned that there will be challenges ahead for the major cryptocurrency ecosystem.
“On the other hand, to fully explain why such changes are justified for lightning and to properly design them, there are practical and critical implications for the public BTC ecosystem of ~5,355 may need to deploy a complete attack, presenting a difficult dilemma that may hold lessons for the deployment of the Bitcoin protocol. […]”
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