Ethereum preparing "biggest rebuild" since Merge, Buterin reveals
In brief
- Lean Ethereum is the third major protocol iteration following the 2022 Merge shift to proof-of-stake
- Quantum safety and privacy become first-class priorities in the multi-year rebuild
- Recursive STARKs cryptography replaces traditional verification, enabling network state growth beyond 100TB by 2030
- Internal strawmap roadmap details resource allocation priorities for the overhaul
Quantum and Privacy Move to Center Stage
Quantum safety has moved sharply up the list of priorities for Ethereum. The network now treats replacing every quantum-vulnerable part with a quantum-safe alternative as urgent, Buterin said. Privacy, too, has been elevated — raised to what Buterin called a "first-class goal" rather than an afterthought.
The shift reflects a maturation in protocol thinking. Rather than treating these as nice-to-haves, Ethereum researchers now see them as foundational. Two weeks ago, researchers met in Berlin to discuss the protocol's long-term trajectory, building on earlier discussions with client teams in Svalbard in April.
Cryptography and State Management
Instead of every node re-running every transaction, Ethereum plans to rely on recursive STARKs — a cryptographic proof method that allows a node to verify a compact proof that the work was done correctly rather than repeating it. This shift unlocks scale without sacrificing decentralization.
State management sits at the heart of the rebuild. State is a blockchain's current memory, the complete snapshot of everything that exists on a network at a specific point in time. The Lean Ethereum plan proposes keeping the current flexible "dynamic" state but only allowing it to grow moderately, while adding new, more restrictive types of state that are cheaper to scale. Doing so will allow the network to hold vastly more data — from the current 2 terabytes to over 100 terabytes by 2030.
The redesign includes a complete overhaul of the cheap data storage that rollups, the layer-2 networks built on top of Ethereum, depend on.
Beyond the EVM
Buterin said the network will need a virtual machine beyond the EVM, the software that runs its smart contracts, with RISC-V among the leading candidates. His preference is for the EVM to become a higher-level convenience while the protocol itself runs on a simpler base layer. He cautioned, though, that this shift is still far off.
Throughout the multi-year overhaul, Ethereum aims to keep disruption to existing applications low. The entire redesign is built around superior cryptography compared with most methods currently in use.
The update lands as ether has rallied more than 12% over the past seven days.
Frequently asked questions
What is Lean Ethereum?
Lean Ethereum is a multi-year plan to rebuild nearly every major part of the Ethereum protocol over three to four years. It was first laid out in July 2025 as a technical framework for the network's next decade and represents the third major iteration of Ethereum after the 2022 Merge.
Why is quantum safety suddenly a priority?
Quantum safety has moved sharply up the list of priorities for Ethereum. The network now treats replacing every quantum-vulnerable part with a quantum-safe alternative as urgent, reflecting growing concerns about long-term protocol security.
How will Ethereum scale without slowing nodes?
Instead of every node re-running every transaction, Ethereum plans to rely on recursive STARKs — a cryptographic proof method that allows nodes to verify a compact proof that work was done correctly. This allows the network to hold vastly more data, from 2 terabytes currently to over 100 terabytes by 2030.
