Vitalik Buterin’s “Lean Ethereum” roadmap now includes an “Extremely Lean Chain” proposal aimed at radically simplifying Ethereum’s consensus layer over a three-to-four-year upgrade cycle. The design would use ZK-STARKs to reduce on-chain consensus data to about 6 bytes per validator, shift state management and proof generation to validators, support millions of validators and introduce daily anonymous key rotation to strengthen validator privacy. The update builds on Buterin’s broader plan to rebuild much of Ethereum with privacy and quantum resistance treated as core protocol goals, while supporters and critics alike continue to focus on whether such a sweeping overhaul can be executed on the proposed timeline.