lightning-dev

Proposal: Bundled payments

Proposal: Bundled payments

Original Postby Thomas Voegtlin

Posted on: June 20, 2023 08:45 UTC

In an email exchange, Thomas Voegtlin proposes an extension to BOLT-11, the Lightning Network protocol.

The proposal aims to address the need for prepayment of a mining fee in services like submarine swaps and JIT channels. Currently, services using dedicated client software can ask for a prepayment, but competitors without dedicated wallets cannot do the same. This vulnerability makes them susceptible to DoS attacks where attackers force them to pay on-chain fees. To address these issues, Voegtlin suggests bundling the prepayment and the main payment in the same BOLT-11 invoice.The proposal outlines the semantics of bundled payments, including waiting for all HTLCs (Hash Time-Locked Contracts) of both payments to arrive before fulfilling the prepayment HTLCs. Once both sets of HTLCs have arrived, the receiver fulfills the prepayment HTLCs and broadcasts their on-chain transaction. Voegtlin believes that implementing this change in BOLT-11 would level the playing field among lightning service providers. Additionally, the proposal could benefit ACINQ by enabling their pay-to-open service to become fully non-custodian.In response to Voegtlin's proposal, Bastien TEINTURIER highlights the importance of senders understanding the new fields involved. TEINTURIER suggests extending BOLT-12 instead of updating BOLT-11 since it requires new sender code anyway. TEINTURIER also discusses strategies for providing JIT liquidity and mentions the use of 0-conf transactions until BOLT-12 is deployed.The email exchange concludes with Voegtlin expressing his belief that the proposed change is a small one that could have significant impacts on the competition between Lightning service providers. He emphasizes the importance of implementing this change earlier rather than later and notes that the understanding of its significance among stakeholders remains to be seen.The email provides necessary information about Electrum Technologies GmbH, including their location, legal registration, and managing director (Thomas Voegtlin). It also includes links to the Lightning-dev mailing list and the mailing list's information page hosted on the Linux Foundation website. The purpose of the email seems to be providing contact information and legal details about the company while responding to the original message sent to the Lightning-dev mailing list.