Cryptology ePrint Archive: Report 2021/117

FPPW: A Fair and Privacy Preserving Watchtower For Bitcoin

Arash Mirzaei and Amin Sakzad and Jiangshan Yu and Ron Steinfeld

Abstract: In this paper, we introduce FPPW, a new payment channel with watchtower scheme for Bitcoin. This new scheme provides fairness w.r.t. all channel participants including both channel parties and the watchtower. It means that the funds of any honest channel participant are safe even assuming that other two channel participants are corrupted and/or collude with each other. Furthermore, the watchtower in FPPW learns no information about the off-chain transactions and hence the channel balance privacy is preserved. As a byproduct, we also define the coverage of a watchtower scheme, that is the total capacity of channels that a watchtower can cover on a scale of 0 to 1, and show that FPPW's coverage is higher than those of PISA and Cerberus. The scheme can be implemented without any update in Bitcoin script.

Category / Keywords: applications / Bitcoin and Security and Privacy and Payment channel and Lightning network and Generalized channel and Watchtower

Original Publication (with major differences): Financial Cryptography and Data Security 2021

Date: received 1 Feb 2021

Contact author: amin sakzad at monash edu

Available format(s): PDF | BibTeX Citation

Version: 20210205:123039 (All versions of this report)

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