How to solve MEV problems in PBS?

In a Proposer-Builder Separation (PBS) system, separating block proposers from builders mitigates Maximum Extractable Value (MEV) by reducing the proposer's incentive to manipulate transaction ordering for economic gain.

Feb 26, 2025 at 11:54 pm

Key Points

• Understanding MEV in PBS
• Mitigation Strategies for MEV
• Hybrid Consensus Mechanisms
• Proposer Builder Separation (PBS)

Steps to Solve MEV Problems in PBS

Understanding MEV in PBS

Maximum Extractable Value (MEV) refers to the economic profits obtained by reorganizing transaction ordering within a block. In Proof-of-Stake (PoS) blockchains, block proposers have the power to determine the order of transactions, creating opportunities for MEV extraction.

In a PBS system, block proposers are separate entities from builders, who construct and submit blocks to the proposer. This separation can mitigate MEV by reducing the proposer's incentive to censor or reorder transactions.

Mitigation Strategies for MEV

• Flashbots Auction: A decentralized auction mechanism that allows builders to submit bids to include their transactions in blocks. Proposers choose the highest-bidding transactions, reducing MEV extraction opportunities.
• MEV-Boost Relay: A protocol that allows validators to stake their ETH to receive MEV rewards. By participating in the relay network, validators can contribute to securing the blockchain and earn a share of MEV.
• Transaction Ordering by a Committee: A mechanism where a committee of validators determines the transaction ordering within a block. This method decentralizes the ordering process, reducing MEV opportunities for individual proposers.

Hybrid Consensus Mechanisms

• Proof-of-Stake with MEV Auction: A hybrid mechanism that combines PoS consensus with an MEV auction. Proposers receive MEV rewards for including high-value transactions in their blocks.
• Proof-of-Work with PBS: A hybrid mechanism that uses PoW to secure the blockchain but employs PBS for block construction. This combination leverages the security of PoW while mitigating MEV through transaction ordering separation.

Proposer Builder Separation (PBS)

PBS involves separating block proposers from builders. This approach reduces MEV because proposers are not directly incentivized to extract MEV through transaction reordering.

• Flashbots PBS: A decentralized network where proposers and builders interact through an auction process. Builders submit transactions to the network, and proposers select the most profitable blocks to propose.
• Celestia PBS: A modular blockchain protocol that separates transaction ordering from block validation. Celestia validators verify block headers, while builders construct and submit transactions to proposers.

FAQs

Q: Can MEV be completely eliminated in PBS systems?
A: MEV cannot be fully eliminated, but it can be significantly mitigated through various strategies and mechanisms.

Q: What are the main advantages of using PBS to reduce MEV?
A: PBS separates block proposing and transaction ordering, reducing the proposer's power to extract MEV and creating a fairer and more competitive transaction market.

Q: What are some challenges in implementing PBS systems?
A: Challenges include ensuring proposer fairness, mitigating collusion, and maintaining network security while separating block construction and validation.

Q: What are the potential benefits of hybrid consensus mechanisms for MEV mitigation?
A: Hybrid mechanisms can combine the benefits of different consensus protocols, such as the security and decentralization of PoS with the MEV mitigation capabilities of PBS.

Q: How does Flashbots PBS differ from Celestia PBS?
A: Flashbots PBS is a standalone network where proposers and builders interact through an auction, while Celestia PBS is a modular protocol where validators and builders operate on separate layers.