Inclusion Lists: Enhancing Ethereum's Censorship Resistance

Definition

Inclusion Lists represent a proposed protocol upgrade for Ethereum, specifically EIP-7547, designed to enhance the network's censorship resistance. At its core, an Inclusion List allows the block proposer for a given slot to specify a set of transactions that must be included in the block produced for that slot. This mechanism ensures that certain transactions, even those potentially deemed undesirable by external block builders, are processed promptly and cannot be arbitrarily excluded. It introduces a crucial layer of control for proposers over the final content of the blocks they propose, addressing a significant concern within the current block production landscape, particularly in the context of the MEV-Boost ecosystem.

An Inclusion List is a list of transactions specified by an Ethereum block proposer that must be included in the block for their assigned slot, thereby improving censorship resistance by guaranteeing transaction processing.

Key Takeaway

The primary objective of Inclusion Lists is to bolster Ethereum's censorship resistance by rebalancing the power dynamic between block proposers and block builders. By enabling proposers to mandate the inclusion of specific transactions, the protocol ensures that the network remains open and neutral, preventing any single entity or group from systematically excluding legitimate transactions. This move is designed to safeguard the fundamental principle of open access to the blockchain, ensuring that all valid transactions eventually find their way into a block, regardless of external pressures or builder preferences.

Mechanics

The operational mechanics of Inclusion Lists revolve around a two-step process involving the block proposer and the subsequent block builder. When a validator is selected as the proposer for a specific slot (say, slot N), they can create an Inclusion List. This list contains a set of transactions that the proposer deems essential for inclusion. This list is then broadcast to the network. The critical aspect is that for any subsequent block (slot N+1, N+2, etc.) to be considered valid, it must include all transactions from the Inclusion List of slot N that have not yet been processed. This creates a strong incentive for builders to include these transactions promptly.

Currently, in the post-Merge Ethereum environment, many proposers utilize MEV-Boost, a middleware that allows them to outsource block building to specialized block builders. These builders compete to create the most profitable blocks by optimizing Maximal Extractable Value (MEV), and the proposer selects the highest-bidding block. A major drawback of this system is that builders have ultimate discretion over transaction inclusion. If a builder chooses to censor certain transactions, the proposer using MEV-Boost has limited recourse without sacrificing potential MEV rewards by building the block locally. Inclusion Lists provide a middle ground: proposers can still use MEV-Boost to maximize their rewards, but they retain the ability to enforce the inclusion of specific transactions, thereby mitigating the risk of censorship without incurring a significant financial penalty. The EIP-7547 proposal outlines that the proposer for slot N specifies the list, and any block for slot N+1 (or later, if N's block is skipped) must include these transactions. This ensures that even if the block for slot N is not built or is censored, the transactions from its Inclusion List will still be picked up by subsequent blocks.

Trading Relevance

For traders and market participants, the introduction of Inclusion Lists carries significant implications for market fairness, predictability, and the overall integrity of transaction execution. In a system where transactions can be arbitrarily censored by block builders, traders face the risk of their orders being intentionally delayed or excluded, potentially leading to missed opportunities or adverse price movements. Inclusion Lists directly address this by guaranteeing that specified transactions will be processed. This enhanced certainty can lead to a more level playing field, reducing the potential for opaque or manipulative practices stemming from transaction censorship.

Furthermore, the mechanism could influence MEV strategies. While Inclusion Lists do not eliminate MEV, they shift some control back to the proposers, potentially reducing the absolute power of builders to dictate transaction order and inclusion for their own profit. This might lead to a more transparent and less exploitative MEV landscape, benefiting regular users and smaller traders who are often at a disadvantage against sophisticated MEV searchers. For high-frequency traders and arbitrageurs, the guarantee of transaction inclusion could streamline their operations, allowing for more reliable execution of complex strategies, although they would still compete for priority within the included transactions. The overall effect is a reduction in systemic risk associated with transaction finality and a boost in confidence for on-chain activities.

Risks

While Inclusion Lists aim to enhance censorship resistance, their implementation is not without potential risks and complexities. One concern is the potential for proposers to abuse the mechanism. If a proposer can force the inclusion of transactions, there might be scenarios where they prioritize their own transactions or those of favored parties, potentially leading to a different form of unfairness or even a subtle form of censorship by crowding out other legitimate transactions. Although the EIP is designed to prevent this by only allowing a limited number of transactions and requiring them to be valid, the exact parameters and their long-term effects need careful monitoring.

Another risk lies in the increased complexity of the block building and validation process. Validators and builders would need to integrate new logic to handle Inclusion Lists, ensuring that all required transactions are indeed present. This added complexity could introduce new vectors for bugs or exploits, potentially impacting network stability or performance. Furthermore, if Inclusion Lists become heavily utilized, they could consume a significant portion of block space, potentially increasing transaction fees for other users or leading to network congestion if the list sizes are not carefully managed. The balance between guaranteeing inclusion and maintaining efficient block space utilization is a delicate one that requires continuous optimization and community oversight.

History and Examples

The concept of Inclusion Lists, specifically EIP-7547, emerged as a direct response to growing concerns about censorship resistance on Ethereum, particularly in the wake of the network's transition to Proof-of-Stake (the Merge) and the widespread adoption of MEV-Boost. Post-Merge, the separation of block building and block proposing roles, while efficient for MEV extraction, inadvertently created a vulnerability where block builders could, in theory, choose to exclude transactions based on external pressures or their own preferences. This became a prominent discussion point, especially after certain entities began to comply with sanctions, leading to fears of transaction censorship at the protocol level.

For instance, if a transaction originated from a sanctioned address, a builder might choose to omit it to avoid legal repercussions. Without Inclusion Lists, a proposer using MEV-Boost would have to either accept this censorship or forgo the higher MEV rewards offered by the censoring builder and build their own block, which is often less profitable. EIP-7547 was proposed to address this dilemma, offering a protocol-level solution that empowers proposers to enforce inclusion without sacrificing economic incentives. While EIP-7547 is still a proposal and not yet implemented, its development signifies a proactive effort by the Ethereum community to fortify the network's core values of decentralization and censorship resistance against evolving challenges in the block production supply chain. It represents a crucial step in ensuring that Ethereum remains a neutral and permissionless platform for all users globally.

Common Misunderstandings

One common misunderstanding about Inclusion Lists is that they are intended to eliminate Maximal Extractable Value (MEV). This is incorrect. Inclusion Lists do not aim to remove MEV; rather, they seek to rebalance the control over transaction inclusion, mitigating the censorship risk associated with MEV-Boost's builder-centric model. MEV will continue to exist as long as there are opportunities for profitable transaction ordering and inclusion, but Inclusion Lists ensure that proposers have a baseline level of control over what must be included, regardless of MEV considerations. They are a tool for censorship resistance, not an anti-MEV mechanism.

Another misconception is that Inclusion Lists provide a complete and absolute solution to all forms of censorship on Ethereum. While they significantly enhance censorship resistance at the block production layer, they do not address censorship that might occur at other layers, such as at the client software level, RPC providers, or even at the user's internet service provider. Inclusion Lists focus specifically on the block builder's ability to exclude transactions from a block. Furthermore, the effectiveness of Inclusion Lists relies on a sufficient number of proposers utilizing them and the network's ability to enforce their rules. It's a powerful tool, but part of a broader, multi-faceted approach to maintaining Ethereum's resilience against various forms of censorship.

Summary

Inclusion Lists, as outlined in EIP-7547, represent a pivotal development in Ethereum's ongoing commitment to censorship resistance. By empowering block proposers to mandate the inclusion of specific transactions, this mechanism directly addresses the vulnerabilities introduced by the separation of block building and proposing in the MEV-Boost ecosystem. It ensures that critical transactions are processed promptly, fostering a more equitable and predictable environment for all network participants. While not a panacea for all forms of censorship or a tool to eliminate MEV, Inclusion Lists are a strategic protocol enhancement designed to reinforce Ethereum's foundational principles of openness and neutrality, safeguarding its role as a global, permissionless computing platform.