Buterin Pitches 'Big FOCIL' and Privacy Tools to Check Ethereum Block‑Builder Power

Overview

• Big FOCIL, outlined in Vitalik Buterin’s new blog post, would expand inclusion lists to cover many or all transactions in a block, narrowing builders’ roles to MEV-focused ordering and execution.
• FOCIL’s base design—slated for Glamsterdam—has 16 randomly selected attesters each nominate transactions that must appear, with any block omitting them deemed invalid.
• Enshrined proposer‑builder separation in Glamsterdam creates a market for builders and helps isolate staking from builder influence, though it does not by itself resolve builder concentration risks.
• Buterin proposes encrypted mempools to blunt toxic MEV such as frontrunning and sandwich attacks by hiding transaction details until inclusion, with validation and timely decryption still under study.
• He also calls for stronger network‑layer privacy via anonymized routing like Tor, mixnets and Flashnet, references the Kohaku initiative, and sketches a longer‑term shift toward more distributed block building.