Paper 2022/700

Grief-free Atomic Swaps

Tejaswi Nadahalli, ETH Zurich
Majid Khabbazian, University of Alberta
Roger Wattenhofer, ETH Zurich

Atomic Swaps enable exchanging crypto-assets without trusting a third party. To enable these swaps, both parties lock funds and let their counterparty withdraw them in exchange for a secret. This leads to the so-called griefing attack, or the emergence of an American Call option, where one party stops participating in the swap, thereby making their counterparty wait for a timelock to expire before they can withdraw their funds. The standard way to mitigate this attack is to make the attacker pay a premium for the emerging American Call option. In these premium-paying approaches, the premium itself ends up being locked for possibly an even longer duration than the swap amount itself. We propose a new Atomic Swap construction, where neither party exposes itself to a griefing attack by their counterparty. Notably, unlike previous constructions, ours can be implemented in Bitcoin as is. Our construction also takes fewer on-chain transactions and has a lower worst-case timelock.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. ICBC 2022
Bitcoin Atomic Swaps Griefing
Contact author(s)
tejaswin @ ethz ch
2022-06-02: approved
2022-06-02: received
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Creative Commons Attribution


      author = {Tejaswi Nadahalli and Majid Khabbazian and Roger Wattenhofer},
      title = {Grief-free Atomic Swaps},
      howpublished = {Cryptology ePrint Archive, Paper 2022/700},
      year = {2022},
      note = {\url{}},
      url = {}
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