Vitalik Says 'The Scourge' Will Tackle Ethereum's Centralization Threats

Vitalik Buterin, Ethereum’s Chief scientist, outlined his vision for “The Scourge,” a key component of Ethereum’s long-term roadmap.

On Oct. 20, Buterin published a blog post emphasizing that centralization arising from economic pressures could pose a risk to Ethereum’s Proof of Stake consensus mechanism.

Buterin warned that economic incentives could compel smaller validators to join large staking pools over time, increasing the risks of “51% attacks, transaction censorship, and other crises.” Vitalik added that such a trend could also enable value extraction, where a small group captures value that would otherwise go to Ethereum’s users.

The post names large entities involved in maximal extractable value (MEV) extraction, the increasing dominance of liquid staking token (LST) providers over the supply ETH, and the rapidly growing share of ETH mobilized for staking as key issues of concern.

However, Buterin said The Scourge seeks to address the centralization risks posed by MEV and large staking pools, in addition to preventing “excessive value extraction from users.”

The Scourge is one of several components of Ethereum’s long-term roadmap, each of which is under concurrent development.

These include The Surge — which strives to bolster throughput of more than 100,000 transactions per second, The Verge — which improves the efficiency of block verification, The Purge — which eliminates technical debt, and The Splurge — which Buterin describes as “fix[ing] everything else.”

Staking economics

On the subject of staking economics, Buterin noted threats that could arise from staking participation continuing to sharply increase from its current level of roughly 30%.

Vitalik said that such a scenario would compel many ETH holders to treat staking as an economic necessity, likely resulting in users choosing the easiest and most profitable staking method available out of apathy — regardless of implications for the health of the network.

This could allow a single staking provider to capture the majority of ETH rewards, effectively diluting other users. Further, the credibility of Ethereum’s slashing mechanism would be undermined if almost all ETH is staked.

To remedy said threats, Vitalik suggests implementing a mechanism that lowers staking rewards as the supply of staked ETH increases. This would reduce the incentives for staking participation as more ETH is staked.

However, Buterin said such a mechanism could pose challenges to solo stakers, with staking returns less than 0.85% unlikely to cover the costs of solo operators. He suggested possible remedies could take the form of specialized hardware allowing solo stakers to perform additional tasks and airdrops and other rewards for solo stakers from Ethereum ecosystem projects.

Block construction

Buterin noted that the majority of blocks are produced through Flashbots’ MEVBoost software, which separates block proposers and builders in a bid to ensure decentralization and a fair MEV marketplace. “When a validator gets an opportunity to propose a block, they auction off the job of choosing block contents to specialized actors called builders,” he said.

However, Buterin notes that MEVboost's preference for maximum MEV extraction has given rise to two large blocking builder entities selecting the contents of roughly 88% of Ethereum’s blocks, posing a centralization risk to the network.

Vitalik suggested further distributing the task of Ethereum block production across a larger number of entities to reduce centralization. This could be achieved by making validators responsible for selecting transactions for inclusion within a block, with builders only able to order those transactions in addition to adding some of their own transactions.

An alternative system could introduce an auction mechanism allowing block proposers to bid to include one of multiple transaction orders offered by builders. In place of an auction, an algorithm could select from multiple lists of possible transaction orderings.

Vitalik also noted that developing encrypted memepools would be key to enabling possible solutions.

“Encrypted mempools are a technology where users broadcast their transactions in encrypted form, along with some kind of proof of their validity, and the transactions are included into blocks in encrypted form, without the block builder knowing the contents,” Buterin said. “The contents of the transactions are revealed later.”