Vitalik Buterin says Lean Ethereum will make privacy, quantum safety, STARKs and new state designs core protocol goals.

Vitalik Buterin has shared new details on Lean Ethereum after researcher meetings in Berlin. The discussions followed earlier talks with Ethereum client teams in Svalbard.

The updated plan sets a long-term path for Ethereum protocol development. It describes changes that could arrive over three to four years.

Buterin said Lean Ethereum is not one single upgrade. Instead, it is a group of changes across several core network areas.

The roadmap puts privacy, quantum safety, formal checks and scaling at the center. It also aims to limit disruption for existing Ethereum apps.

Lean Ethereum Sets Multi-Year Protocol Plan

Buterin described Lean Ethereum as Ethereum’s next major protocol phase. He compared its scale to earlier changes such as The Merge. 

The plan would replace several key parts of the network over time. A major change involves recursive STARKs becoming a core protocol feature. 

These proofs would support verification without relying on direct re-execution. This approach is being studied as Ethereum prepares for wider scaling needs. The roadmap also includes changes to consensus and gas design. 

Researchers are reviewing faster finality and multidimensional gas for network resources. Client architecture changes are also part of the long-term plan.

Privacy and Quantum Safety Move to Center

Buterin said privacy is now a main design goal for Ethereum. Researchers are considering private transactions when planning Frames, mempool updates and state changes. The focus includes systems that avoid trusted middle parties.

🚨VITALIK: ETHEREUM’S THIRD MAJOR ITERATION, “LEAN ETHEREUM” IS COMING!

After Berlin researcher meetings, Vitalik outlined “Lean Ethereum”, the next big multi-year upgrade, following Frontier and The Merge.

Key shifts: recursive STARKs as a core feature, full quantum safety,… pic.twitter.com/dy238OfO4C

— Crypto Banter (@crypto_banter) July 4, 2026

Quantum safety has also moved higher on Ethereum’s research agenda. Buterin said parts exposed to quantum risk should move to safer designs. 

Work on quantum-safe blob systems has already become more urgent. Formal verification is another key part of the Lean Ethereum plan. 

This process checks protocol designs with stricter mathematical methods. Buterin said it can make researchers more comfortable with clearer protocol definitions.

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State Design and Scaling Remain Key Areas

One major area of research involves Ethereum state, which stores network data. 

Buterin said the current dynamic state may remain mostly in place. However, new state types may support larger growth with more limits.

Two weeks ago, Ethereum researchers met in Berlin to continue charting the protocol’s long-term trajectory, following along discussions with client teams in Svalbard in April.

The updated strawmap is at https://t.co/HZEerH1xxI, and I attached a picture of it to this post.

My… pic.twitter.com/KPGayHSySf

— vitalik.eth (@VitalikButerin) July 4, 2026

Possible designs include UTXO storage, keyed nonces, ring buffers and temporary state. 

These models could work for tokens, NFTs and many DeFi uses. Complex contracts may still need the current state model.

Ethereum may also need another virtual machine beside the EVM. Buterin named leanISA and RISC-V as possible options for future proof systems. 

The roadmap also expects gas limit increases, more blobs and shorter slot times.