During Ethereum’s 92nd Consensus Layer Call, developers discussed some solutions to a potential wrinkle in the smooth execution of the network’s impending Merge, when Ethereum moves from its current proof-of-work (PoW) protocol to the Beacon Chain proof-of-stake (PoS) blockchain.
Alex Stokes, a researcher at the Ethereum Foundation, raised concerns over a possible MEV-boost failure. The vulnerability could affect the way that relay operators, which are intermediaries between block builders and validators, communicate with each other. As a result, the orderly addition of blocks to the blockchain could be disrupted.
The MEV-boost is an important component of “maximal extractible value” (MEV) for Ethereum. MEV refers to the income that miners (under PoW) and block builders and validators (under PoS) receive as a result of inserting or reordering of transactions within a block.
The MEV-boost, which is designed to avoid MEV centralization, is a middleware component that allows validators to request blocks from a network of builders. After the Merge, those interacting with the network will send their transactions over the blockchain to block builders. The MEV-boost feature will then collect these blocks and offer them to validators. Validators will select and propose the most profitable blocks to the Ethereum network.
If there is a malfunction in the MEV-boost, it will disrupt the entire PoS blockchain. A glitch with a relay operator would fail to release a block at the right moment. Then a series of blocks from validators running the MEV-boost could be missed. That would happen if the validator fails to propose a block because of a relay that didn’t have a way of signaling malicious behavior to validators.
The next set of validators would then be compromised, and if they were to propose a block that has dealt with the malicious relay, the same issues would continue on, preventing the production of blocks indefinitely.
During the call, one proposal addressed the possibility of introducing a circuit breaker. This could be as simple as writing code that tells the validor to automatically turn off if there are missed blocks. This would be a risky move because validators could deliberately withhold blocks from being proposed. There is incentive to do that, and by duping other validators, the person could monopolize MEV earnings.
Other developers also suggested that a third-party dashboard could watch over the relays. The Flashbots team, the developers behind MEV-boost, are already working to create some kind of public monitoring system for MEV-activity. Ben Edgington, the lead product owner for Teku at ConsenSys, who is involved in the Merge development, told CoinDesk that there are several options for achieving the right solution for the MEV-boost issue. “It’s just a question of choosing a good approach,” he said.
Christine Kim, a research associate at Galaxy Digital who took notes on the meeting, said that “MEV-boost already does place inherent trust in relay operators. The trust in relay operators for earning MEV has always been known but what wasn’t known before Thursday’s call was the ability of a relay operator to potentially cause network downtime in this process.”
After the call, Stokes told CoinDesk that developers are exploring options that would have users wait for the Merge to be completed before attempting to use the builder, or to introduce some kind of circuit breaker. Stokes said that the chances of an MEV-boost failure are very low, but he is pushing to get some kind of solution implemented in the event that it does happen.
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