Bitcoin Core Developer Exits Lightning Network Due to “Difficulties”

Antoine Riard believes the Bitcoin community faces a “tough dilemma” as a new class of replacement bicycle attacks threatens the Lightning Network.

Security researcher and developer Antoine Riard will step down from Lightning Network development, citing security issues and fundamental challenges in the Bitcoin ecosystem.

According to a post on the Linux Foundation public mailing list, Riard believe Bitcoin community faces a ‘tough dilemma’ as a new class of replacement bike attacks puts Lightning in ‘danger’

Lightning Network is a second-layer solution built on the Bitcoin blockchain. It aims to improve the scalability and efficiency of Bitcoin transactions by supporting off-chain, peer-to-peer transactions.

Through the Lightning Network, users can open payment channels, conduct multiple off-chain transactions, and settle the final results on the Bitcoin blockchain. The replacement cycle attack targets these payment channels. This is a new type of attack in which an attacker can exploit inconsistencies between individual mempools to steal funds from channel participants. According to Riard:

“I think this new class of replacement bicycle attacks puts Lightning in a very dangerous position that can only be sustainably fixed at the base level, such as adding a memory-intensive history of all visible transactions or some consensus upgrade. The deployed mitigations are worthwhile in the face of simple attacks, though I don’t think they will stop pinging attackers as described in the first full disclosure email.”

Riard also noted that responding to new types of attacks may require changes to the underlying Bitcoin network:

“These types of changes require the utmost transparency and buy-in from the entire community as we are changing the security architecture of full node processing requirements or the integrity of the decentralized Bitcoin ecosystem.”

Lightning developers are grappling with a variety of challenges, including criticism surrounding the network’s complexity and demands for improved user experience. Since its inception in 2018, the second-layer network has gained popularity, with a total locked value of $159.5 million at the time of writing, according to However, compared to Bitcoin’s market cap of $587 billion, this number is still very modest.

Riard plans to focus on Bitcoin Core development now, but warned of upcoming challenges facing the primary cryptocurrency ecosystem:

“On the other hand, fully explaining why these changes are necessary for lightning and designing them well would likely require us to conduct a practical and critical attack on the ~5355 public BTC ecosystem in its entirety. This is a difficult dilemma. There may be lessons to be learned in terms of Bitcoin protocol deployment.”