delvingbitcoin
Ephemeral Anchors and MEVil
Posted on: January 19, 2024 16:56 UTC
In an exploration of the intricacies of blockchain transactions, a specific scenario has been highlighted that reveals an anomaly in the "anti-MEVil" mechanism designed to mitigate malicious transaction ordering.
The peculiarity arises when an entity, which could be incentivized by a third-party payment, deliberately increases the ephemeral anchor value. This action gains significance in the context of a transaction that is subject to the bip125 rule3 pin.
An illustrative example provided delineates a situation where 'Bob' utilizes 'Alice's trimmed funds to instigate a conflict with another transaction, TxD
. A flowchart included in the explanation depicts four transactions: TxA with a fee of 1 and size of 1, TxB with a fee of 5, size 1, and conflicting with TxC, TxC with a fee of 106 and size 1, and TxD with a fee of 100 and a size of 100, also conflicting with TxC.
The anomaly discussed is a direct result of anti-DoS rules currently in place. Under normal circumstances, without these rules, there would be no extra incentive for adversaries to engage in such behavior, as it would only serve to increase the fee rate required for their own child transactions. However, due to these rules, there exists a motivation to artificially inflate the ephemeral anchor value, specifically when it can cause a child transaction to conflict with another, potentially leading to unintended consequences within the transaction validation process.