bitcoin-dev
A "Free" Relay Attack Taking Advantage of The Lack of Full-RBF In Core
Posted on: July 22, 2024 22:08 UTC
The development of imbued Transaction Replaceability Under Consensus (TRUC) was significantly influenced by a live discussion with Lightning Network (LN) maintainers, as indicated in a transcript available at this link.
Further exploration of this concept took place across three discussions on the Delving Bitcoin Forum, specifically focusing on lightning transactions with v3 and ephemeral anchors, sibling eviction for v3 transactions, and the analysis of imbuing LN commitment transaction spends with v3 semantics. These discussions were comprehensively summarized in the Bitcoin Optech Newsletter, demonstrating the community's commitment to refining Bitcoin and LN protocols.
The implementation of a new policy that automatically applies to current LN anchors has been proposed to enable the removal of the CPFP carve-out rule. This change is pivotal for the development of a cluster mempool, facilitating more incentive-compatible replacements. Gregory Sanders suggested an interim strategy to address concerns regarding the timeline for LN to incorporate these modifications. This strategy involves temporarily treating transactions resembling current anchor-style LN commitment transactions specially, allowing for the deployment of cluster mempool without delay from LN development. Research into the application of v3 transaction relay policy to anchor-style LN commitment and fee-bumping transactions further supports this interim approach.
The term "imbue" has been actively discussed in the Bitcoin Core community, with significant contributions from various authors, including LN implementation maintainers. A draft implementation of imbued v3 is available for review, illustrating the ongoing efforts to integrate these concepts into Bitcoin Core. The inclusion of sibling eviction, aimed at enhancing replace-by-fee capabilities for certain transactions, marks another step forward in these developments.
All these initiatives and discussions are well-documented and accessible through various platforms, including Bitcoin Optech newsletters and topic pages dedicated to version 3 transaction relay/TRUC, CPFP carve-out, and anchor outputs. This openness reflects the collaborative nature of protocol development within the Bitcoin ecosystem. For those seeking to stay updated on these advancements, subscribing to the Bitcoin Optech newsletter offers a valuable resource for comprehensive updates and insights.