Ethereum co-founder Vitalik Buterin has called for the removal of the modular exponentiation (modexp) precompile, a function he once designed to enhance cryptographic performance. Buterin now argues that the feature, instead of helping, has become a critical obstacle to Ethereum’s scalability, particularly as zero-knowledge (ZK) solutions grow in importance.
In a recent proposal, Buterin suggested replacing the precompiled code with equivalent EVM code through an upcoming Ethereum Improvement Proposal (EIP). The goal is to modernize Ethereum’s cryptographic foundation and remove outdated components that limit its efficiency.
Why Modexp Must Go
Buterin outlined several reasons for the change:
- Inefficiency and complexity: The modexp precompile relies on Ethereum’s 256-bit architecture, which is ill-suited for today’s 32- or 64-bit computational standards. This makes it slow and overly complex to maintain.
- Scaling bottleneck: ZK proofs, essential for layer-2 scaling solutions like zkEVMs and rollups, are severely constrained by modexp’s structure. Buterin called the situation “catastrophic” for ZK scalability.
- Consensus risks: The precompile adds unnecessary complexity to Ethereum’s execution model, creating what Buterin describes as “huge amounts of consensus failure risk.”
By transitioning to standard EVM code, Ethereum would eliminate these risks and align more closely with modern ZK-proof systems.
Short-Term Costs, Long-Term Gains
While the proposed removal is expected to simplify Ethereum’s codebase, it may introduce temporary drawbacks. Developers who rely heavily on modexp, especially for RSA-based cryptography, could see short-term increases in gas fees.
However, the long-term benefits are significant. Removing modexp would reduce technical debt, improve Ethereum’s resilience, and streamline zero-knowledge proof generation, an essential component of Ethereum’s next major scaling phase.
Broader Context: A Step Toward Ethereum’s RISC-V Future
This proposal fits within Buterin’s broader vision for a leaner, more modular Ethereum architecture. In April 2025, he floated the idea of eventually replacing the EVM with a RISC-V virtual machine, a move that would drastically simplify Ethereum’s execution environment.
By targeting modexp removal first, Buterin aims to lay the groundwork for cleaner, faster, and more reliable ZK scaling, a crucial step as Ethereum transitions into its next generation of scalability and performance upgrades.
