The Future of Censorship Resistance in an MEV-Optimized L2

Most L2s use a single, permissioned sequencer to order transactions for MEV efficiency. This creates a single point of failure for OFAC-level censorship.\n- No forced inclusion: Users cannot bypass the sequencer to get transactions on-chain.\n- Opaque filtering: Sequencers can silently drop transactions without cryptographic proof.

Adapting Ethereum's PBS model to L2s separates block building (MEV capture) from block proposing (censorship decisions).\n- Permissionless builder market: Anyone can build blocks, creating censorship-resistant redundancy.\n- Credible neutrality: Proposer (sequencer) selects the highest-paying, valid block, not its contents.

To prevent frontrunning and enable private transactions, L2s are exploring encrypted mempools. This introduces a new censorship risk: validators can't see the transactions they're censoring.\n- Threshold decryption: Requires a committee to decrypt, preventing individual sequencer abuse.\n- Integration with PBS: Encrypted bundles are decrypted only after being included in a block, preserving MEV capture.

Replaces the single sequencer with a PoS-based decentralized network, using HotShot consensus. This directly attacks the central point of censorship.

• Key Benefit: Timely Inclusion Guarantees via cryptographic proofs, not promises.
• Key Benefit: Enables shared sequencing for a rollup-agnostic mempool, improving cross-L2 atomic composability.

Provides a shared, decentralized sequencing layer that rollups can plug into, abstracting away the hardest part of the stack.

• Key Benefit: Censorship resistance is baked into the base layer, not a rollup afterthought.
• Key Benefit: Native atomic composability across all connected rollups (e.g., Celestia-based stacks) without bridging delays.

Ethereum's core innovation for MEV. It separates block building (by searchers/builders) from block proposing (by validators).

• Why it Matters: Prevents validators from frontrunning their own chains. Builders compete on inclusion, creating a market for block space.
• The L2 Gap: Rollups today have a monopolistic sequencer acting as both builder and proposer, creating a single point of failure and censorship.

Aims to decentralize the entire MEV supply chain by creating a separate chain for preference expression and block building.

• Key Benefit: Decentralizes block building across chains, breaking builder oligopolies like Flashbots.
• Key Benefit: Intent-centric flow where users express desired outcomes, moving beyond simple transaction submission. This is the UniswapX model applied chain-wide.

A regulatory backstop. If a sequencer censors, users can force their tx into an L1 inbox contract after a delay.

• Why it's Flawed: It's a slow, costly last resort (e.g., 24h delay on Optimism). Defeats the purpose of an L2.
• The Reality: This is the minimum viable decentralization most L2s ship with. It's insurance, not a solution.

The endgame. Users submit what they want, not how to do it. Solvers compete to fulfill the intent optimally.

• Key Benefit: Removes transactional MEV at the source; the solver's execution is the settlement.
• Key Benefit: Native integration with cross-chain intents via protocols like Across and LayerZero, making bridges less relevant. This is where CowSwap and UniswapX are pointing.

A single, permissioned sequencer can blacklist addresses, creating regulatory capture risk and breaking the credible neutrality of the base layer.\n- Key Risk: A single entity can be legally compelled to censor.\n- Key Consequence: Breaks atomic composability with L1 and other L2s if transactions are filtered.

Adopt a Proof-of-Stake validator set for sequencing, but design the economic and slashing logic to resist MEV-driven centralization seen in L1s like Ethereum.\n- Key Benefit: Censorship requires collusion of a supermajority, not one entity.\n- Key Benefit: Enables native, trust-minimized cross-rollup communication (like LayerZero) without a trusted relay.

Even with decentralized sequencing, sophisticated actors can extract value via frontrunning and sandwich attacks, making the chain hostile to retail.\n- Key Risk: High MEV attracts validator centralization (e.g., Lido dominance on Ethereum).\n- Key Consequence: Degrades user experience and trust, as seen in early DeFi on Ethereum.

Implement a threshold encryption scheme (like Shutter Network) for transaction content and a fair ordering protocol (like Aequitas) for the plaintext sequence.\n- Key Benefit: Prevents frontrunning by hiding transaction intent until block proposal.\n- Key Benefit: Democratizes MEV rewards via a redistribution mechanism (e.g., to protocol treasury or public goods).

If users pay fees only in the L2's native token or a whitelisted stablecoin, the entity controlling that token's bridge can de facto censor by freezing funds.\n- Key Risk: Centralized stablecoin issuers (USDC) become de facto L2 regulators.\n- Key Consequence: Contradicts Ethereum's 'gas token neutrality' principle.

Mandate ETH as the base fee token, leveraging Ethereum's native censorship resistance. Support permissionless, canonical bridges (like the standard rollup bridge) for all other assets.\n- Key Benefit: Fee payment is anchored to the most censorship-resistant asset.\n- Key Benefit: Removes the L2 team or a single bridge operator as a token censorship vector.