Cryptology ePrint Archive: Report 2019/986

Outpost: A Responsive Lightweight Watchtower

Majid Khabbazian and Tejaswi Nadahalli and Roger Wattenhofer

Abstract: In the context of second layer payments in Bitcoin, and specifically the Lightning Network, we propose a design for a lightweight watchtower that does not need to store signed justice transactions. We alter the structure of the opening and commitment transactions in Lightning channels to encode justice transactions as part of the commitment transactions. With that, a watchtower just needs to watch for specific cheating commitment transaction IDs on the blockchain and can extract signed justice transactions directly from these commitment transactions that appear on the blockchain. Our construction saves an order of magnitude in storage over existing watchtower designs. In addition, we let the watchtower prove to each channel that it has access to all the data required to do its job, and can therefore be paid-per-update.

Category / Keywords: applications /

Original Publication (in the same form): AFT '19: Proceedings of the first ACM conference on Advances in Financial Technologies

Date: received 29 Aug 2019

Contact author: tejaswin at ethz ch

Available format(s): PDF | BibTeX Citation

Version: 20190902:092445 (All versions of this report)

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