  User transactions on Ethereum's peer-to-peer network are at risk of being
attacked. The smart contracts building decentralized finance (DeFi) have
introduced a new transaction ordering dependency to the Ethereum blockchain. As
a result, attackers can profit from front- and back-running transactions.
Multiple approaches to mitigate transaction reordering manipulations have
surfaced recently. However, the success of individual approaches in mitigating
such attacks and their impact on the entire blockchain remains largely
unstudied.
  In this systematization of knowledge (SoK), we categorize and analyze
state-of-the-art transaction reordering manipulation mitigation schemes.
Instead of restricting our analysis to a scheme's success at preventing
transaction reordering attacks, we evaluate its full impact on the blockchain.
Therefore, we are able to provide a complete picture of the strengths and
weaknesses of current mitigation schemes. We find that currently no scheme
fully meets all the demands of the blockchain ecosystem. In fact, all
approaches demonstrate unsatisfactory performance in at least one area relevant
to the blockchain ecosystem.
