Vitalik Buterin is concerned about "Big FOCIL" and encrypted memory pools to prevent centralization in the block construction process.

Odaily Planet Daily reports that Ethereum co-founder Vitalik Buterin recently published a series of technical articles discussing the future roadmap of Ethereum. In his latest article, he focused on analyzing potential centralization risks in the block building pipeline and proposed solutions such as expanding the FOCIL mechanism and introducing encrypted mempools to enhance the network’s resistance to censorship.

According to the plan, Ethereum will launch the Glamsterdam upgrade in the first half of 2026, which will introduce the “Proposer-Builder Separation” (ePBS) mechanism. This mechanism allows block proposers to outsource block construction to an open, permissionless marketplace, reducing centralization risks at the staking layer.

However, Buterin pointed out that while ePBS can prevent block construction rights from concentrating in a few staking pools, the process of block building itself may still centralize among a few high-tier participants due to specialization and maximized MEV (Maximal Extractable Value), leading to new centralization trends.

To address this issue, Ethereum developers plan to simultaneously introduce the FOCIL (Forward Obligatory Commitment to Inclusion Lists) mechanism in the Glamsterdam upgrade. The initial version will randomly select 16 witnesses and require certain transactions to be included in the block; otherwise, the block will be rejected. Buterin stated that even if block building is controlled by a malicious entity, FOCIL can still ensure that transactions cannot be fully censored.

Additionally, Buterin discussed the possibility of expanding the scale of FOCIL (“big FOCIL”) and introducing encrypted mempools to further weaken information asymmetry and power concentration during block construction.

Recently, Buterin has been actively speaking on topics such as quantum resistance roadmaps, execution layer improvements, and block building mechanisms, indicating that the Ethereum core development team is systematically designing and assessing risks for the next phase of protocol upgrades.