🧩 Offchain Labs Proposes WASM Over RISC-V for Ethereum’s Future — A Direct Challenge to Vitalik’s Vision

The Arbitrum core team says Ethereum doesn’t need one ISA to rule them all — and that WebAssembly is the real path forward.

Offchain Labs — the development team behind Arbitrum, one of Ethereum’s biggest L2 ecosystems — has published a bold research proposal outlining why the Ethereum Virtual Machine (EVM) should evolve toward WASM, not RISC-V. Their full analysis is detailed in a technical post shared on Ethereum Research.

Vitalik Buterin previously suggested adopting RISC-V as a unified architecture for execution and zero-knowledge proving — even arguing it could reduce ZK-proof costs by up to 100×. Offchain Labs agrees with the goal but questions the premise: “Why should one instruction set handle both execution and ZK proving?”

🚀 WASM vs. RISC-V: The Core of the Disagreement

Researchers Mario Alvarez, Matteo Campanelli, Tsahi Zidenberg, and Daniel Lumi argue that RISC-V is excellent for ZK-prover design but is not ideal for Ethereum L1 smart-contract execution. Their case for WASM focuses on four structural advantages:

• 🧩 Modular upgrades — WASM can evolve without breaking old contracts
• 🌐 Runs everywhere — efficient on standard hardware; RISC-V requires emulation
• 🔒 Strict validation — built-in type safety reduces entire classes of vulnerabilities
• 🛠️ Battle-tested tooling — WASM powers billions of real-world runtimes

Their conclusion: WASM is already a universal smart-contract layer waiting to happen.

🔀 The Key Distinction: dISA vs. pISA

Offchain Labs highlights what they say is the real misunderstanding. Ethereum needs two different instruction sets:

• dISA — delivery ISA (format deployed to L1)
• pISA — proving ISA (format used inside ZK-VMs)

And there is no technical reason for both to be the same.

🧪 The Arbitrum Model: WASM → RISC-V → ZK Proof

Arbitrum already uses this architecture in production:

1. 🟦 WASM is used as the execution layer
2. 🟥 WASM is compiled to RISC-V
3. 🧮 RISC-V is used as the proving backend in the ZK-VM

The team notes that real blockchain blocks are already being verified this way, proving that WASM + RISC-V is a working hybrid model — not a hypothetical one.

⚠️ RISC-V Is Moving Too Fast for Ethereum to Enshrine

The research warns that RISC-V is evolving at breakneck speed:

• 📏 ZK-VMs recently shifted from 32-bit → 64-bit RISC-V
• ⚙️ New proving architectures are emerging rapidly
• 🟣 WASM-based ZK-VMs like Ligetron are showing advantages RISC-V can’t match

Enshrining RISC-V at Ethereum L1 might “lock the protocol into an outdated standard before the dust settles.”

💸 “ZK Proofs Are Already Cheap”

The research stresses another key point: proof costs have collapsed.

ZK proofs now cost around:

$0.025 per block

Even with multiple proofs per block, these costs are negligible compared to:

• ⛽ gas fees
• ⚡ MEV revenue

Therefore, optimizing all of L1 around minimizing proving cost is no longer necessary.

🏛️ The Verdict: WASM Should Be Ethereum’s Future

Offchain Labs concludes that WASM is the superior choice for Ethereum’s long-term L1 architecture:

• Modular, safe, and production-tested
• Runs fast on every major hardware platform
• Easily compiles into whatever proving ISA the future demands
• Avoids locking Ethereum into one hardware-centric design

Their message is clear: Let WASM handle smart-contract execution. Let RISC-V evolve freely for ZK proving. Don’t merge the two.

⚠️ TL;DR

Offchain Labs argues that Ethereum should adopt WASM as its main execution ISA instead of RISC-V. They say RISC-V is great for ZK proving — but not for storing and executing smart contracts. Arbitrum already uses a hybrid model (WASM execution + RISC-V proving), and researchers warn that RISC-V is evolving too fast to be enshrined at the L1 level. WASM is safer, modular, widely supported, and compatible with future proving systems.