Paper 2023/868

Breaking the Chains of Rationality: Understanding the Limitations to and Obtaining Order Policy Enforcement

Sarisht Wadhwa, Duke University
Luca Zanolini, Ethereum Foundation
Francesco D'Amato, Ethereum Foundation
Aditya Asgaonkar, Ethereum Foundation
Fan Zhang, Yale University
Kartik Nayak, Duke University

Order manipulation attacks such as frontrunning and sandwiching have become an increasing concern in blockchain applications such as DeFi. To protect from such attacks, several recent works have designed order policy enforcement (OPE) protocols to order transactions fairly in a data-independent fashion. However, while the manipulation attacks are motivated by monetary profits, the defenses assume honesty among a significantly large set of participants. In existing protocols, if all participants are rational, they may be incentivized to collude and circumvent the order policy without incurring any penalty. This work makes two key contributions. First, we explore whether the need for the honesty assumption is fundamental. Indeed, we show that it is impossible to design OPE protocols under some requirements when all parties are rational. Second, we explore the tradeoffs needed to circumvent the impossibility result. In the process, we propose a novel concept of rationally binding transactions that allows us to construct AnimaguSwap(A key design in AnimaguSwap is that user orders may transform to a different direction---like the fictional creatures Animagi in Harry Potter---in order to achieve the desired game theoretic properties) , the first content-oblivious Automated Market Makers (AMM) that is secure under rationality.

Available format(s)
Cryptographic protocols
Publication info
BlockchainsDe-FiMEVRationalityMechanism Design
Contact author(s)
sarisht wadhwa @ duke edu
2023-06-13: revised
2023-06-07: received
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Creative Commons Attribution


      author = {Sarisht Wadhwa and Luca Zanolini and Francesco D'Amato and Aditya Asgaonkar and Fan Zhang and Kartik Nayak},
      title = {Breaking the Chains of Rationality: Understanding the Limitations to and Obtaining Order Policy Enforcement},
      howpublished = {Cryptology ePrint Archive, Paper 2023/868},
      year = {2023},
      note = {\url{}},
      url = {}
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