Ethereum co-founder Vitalik Buterin has doubled down on two "deep" architectural shifts required to resolve the network's critical proving inefficiencies, arguing that incremental updates are insufficient to address the bottlenecks holding back client-side verification.

Buterin's latest analysis identifies the state tree and virtual machine (VM) as the primary constraints, noting together they represent more than 80% of the proving bottleneck. He characterized both components as "basically mandatory" for the future of zero-knowledge (ZK) proving use cases, warning that avoiding these structural changes in favor of pragmatism will fail to solve the core scalability issues.

Binary Trees Replace Hexary Structures

The most immediate technical pivot centers on EIP-7864, a proposal currently in draft stages since January 2025. The initiative seeks to replace Ethereum's current hexary Keccak Merkle Patricia Tree with a binary tree architecture. This structural shift is designed to produce Merkle branches four times shorter than today's structure, a reduction that significantly cuts data bandwidth requirements for light client tools such as Helios.

Buterin credited developer Guillaume Ballet and the broader community for the proposal's evolution. The binary design alone offers substantial gains, but the efficiency potential escalates when paired with a hash function swap. Replacing Keccak with Blake3 or a Poseidon variant could deliver a 3x to 100x improvement in proving efficiency. However, Buterin cautioned that while Blake3 appears promising, Poseidon variants still require further security review before deployment.

This binary approach marks a strategic pivot from earlier roadmaps. Verkle Trees were previously the leading candidate for inclusion in a 2026 hard fork, but concerns regarding quantum computing vulnerabilities in elliptic curve cryptography reignited interest in binary trees around mid-2024. The shift reflects a growing consensus that the current cryptographic assumptions may not withstand future quantum threats.

The RISC-V vs. WASM Debate

Parallel to the state tree overhaul, Buterin reiterated his April 2025 proposal to eventually replace the Ethereum Virtual Machine (EVM) with RISC-V. As an open-source instruction set architecture that most ZK provers already utilize internally, RISC-V offers a natural alignment for verification. Buterin outlined a three-stage deployment roadmap: first, utilizing RISC-V exclusively for precompiles; second, enabling user-deployed contracts on the new architecture; and finally, retiring the EVM entirely by converting it into a smart contract written in the new VM.

"Ethereum's whole point is its generality, and if the EVM is not good enough to actually meet the needs of that generality, then we should tackle the problem head-on, and make a better VM," Buterin wrote.

The proposal faces significant technical opposition. In November 2025, researchers from Offchain Labs, the core developer behind Arbitrum, published a rebuttal arguing that WebAssembly (WASM) is a superior long-term choice for Ethereum's smart contract format. Their analysis posits that while RISC-V excels at ZK proving, the "delivery ISA" and the "proving ISA" do not need to be identical. This suggests that a unified architecture might be less optimal than a hybrid approach where the execution layer differs from the proving layer.

2026 Upgrade Roadmap

These deep structural changes are scheduled to underpin Ethereum's 2026 upgrade cycle. The network is expected to undergo the Glamsterdam upgrade in the first half of 2026, followed by the Hegota upgrade later in the year. While developers have not yet finalized the headline EIPs for either fork, state tree changes and execution layer improvements remain central to ongoing planning.

Buterin has positioned himself as a vocal advocate for these non-incremental changes, noting that Ethereum has already executed one "jet engine change in-flight" with the Merge and can handle roughly four more. The proposed sequence includes the state tree overhaul, lean consensus, ZK-EVM verification, and the VM replacement. With market sentiment currently in extreme fear and ETH trading at $1,926.4, the push for these foundational upgrades signals a long-term bet on the network's ability to scale through cryptographic innovation rather than just transaction throughput.

Source: The Block | Analysis by Rumour Team