7-Cent Fix? Ethereum Researcher Shares Quantum Security Plan

As reported by Wu Blockchain, Ethereum Foundation privacy project Kohaku lead Nico said Ethereum can begin preparing accounts for the post-quantum era today without requiring a hard fork.

According to Nico, the proposed account-level solution costs approximately $0.07 per account to deploy. The design has completed an initial review with Fable, with additional audits planned.

“Ethereum can already start preparing accounts for a post quantum world, without waiting for a hard fork. Today, it would be just $0.07. Further audits incoming. Though I squeezed in a review with Fable before Uncle Sam crashed my party. Verity formal proof included for my lean enjoyers,” Kohaku tweeted.

Quantum computers will eventually break ECDSA, the signature scheme that secures Ethereum and Bitcoin accounts today. Recent resource estimates by Babbush et al. bring this timeline closer than previously expected, making post-quantum signature verification at the execution layer an urgent problem.

Then comes SPHINCS-

Ethereum researchers are proposing SPHINCS-, which introduces efficient Stateless Post-Quantum Signature Verification on the EVM.

SPHINCS+ variants, a family of EVM-optimized variants, are derived from SPHINCS+ and from recent work on compact hash-based signatures. The goal remains simple: to minimize pure on-chain verification cost without relying on a precompile or a protocol change.

Ethereum researchers suggest that a Solidity implementation of a SPHINCS variant, aligned with NIST’s draft for limited-signature parameter sets, can already verify a standardized-style post-quantum signature on Ethereum at practical cost (150K gas). A formal proof of the verifier is provided using Lean 4 with Verity.

More aggressive non-standard variants that replace the standard hash components with an EVM-native keccak-based construction and reduce the signature budget to the range relevant for blockchain wallets will consequently be explored. Across these variants, the trade-off between verifier gas, signer work, signature size, and per-key signature budget is studied.