Paper 2021/117

FPPW: A Fair and Privacy Preserving Watchtower For Bitcoin

Arash Mirzaei, Amin Sakzad, Jiangshan Yu, and Ron Steinfeld


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.

Available format(s)
Publication info
Published elsewhere. MAJOR revision.Financial Cryptography and Data Security 2021
Contact author(s)
amin sakzad @ monash edu
2021-02-05: received
Short URL
Creative Commons Attribution


      author = {Arash Mirzaei and Amin Sakzad and Jiangshan Yu and Ron Steinfeld},
      title = {FPPW: A Fair and Privacy Preserving Watchtower For Bitcoin},
      howpublished = {Cryptology ePrint Archive, Paper 2021/117},
      year = {2021},
      note = {\url{}},
      url = {}
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