Ethereum Researcher Says Post-Quantum Account Protection Can Start For $0.07

Ethereum Foundation researcher Nico Consigny says Ethereum accounts can start preparing for the post-quantum era today, with an account-level design that does not require a hard fork and costs about $0.07 under current conditions.

The proposal centers on SPHINCS-, an EVM-optimized post-quantum signature verification design built for Ethereum accounts. The goal is to make quantum-resistant account protection possible through smart-account patterns and Solidity verifier contracts, rather than waiting for a new precompile or a protocol-wide migration.

Consigny’s public update said Ethereum can already start preparing accounts for a post-quantum world without waiting for a hard fork. He also said further audits are incoming and that he completed an initial review with Fable before Anthropic’s recent access disruption.

That puts the work directly inside Ethereum’s broader wallet-security push. Kohaku, the privacy and security wallet project led by Consigny and Vitalik Buterin, already includes a post-quantum 4337 account implementation in its repository. Ethereum Foundation materials describe Kohaku as a project focused on wallet privacy, stronger security primitives and safer account design across the Ethereum ecosystem.

How SPHINCS- Lowers The Cost

SPHINCS- is derived from SPHINCS+, a stateless hash-based post-quantum signature scheme. The Ethereum-specific version takes advantage of the EVM’s cheap KECCAK256 opcode, allowing verification to run directly onchain without a new protocol feature.

The research post presents a standardized-style post-quantum verifier at roughly 150,000 gas and an optimized C13 variant at about 127,000 gas. The C13 version uses a 3,704-byte signature and is designed around EVM verifier efficiency, while other variants trade different balances between signing cost, signature size, hardware-wallet practicality and standards alignment.

Ethereum gas tracker data showed mainnet gas near 0.24 gwei around the update window, helping explain how the cost can land in the sub-ten-cent range. The exact dollar figure depends on ETH price, gas conditions and the final account pattern used, but the headline result is clear: post-quantum verification has moved into a practical cost band for early account-level deployment.

The design also includes formal verification work through Lean 4 and Verity. That gives the proposal a stronger research foundation, though it does not remove the need for additional audits, production testing and wallet integration before ordinary users rely on it.

Quantum Risk Is A Future Threat, Not A Current Wallet Emergency

Ethereum users do not need to move funds today. Ethereum’s current post-quantum guidance says no quantum computer can break Ethereum’s cryptography today, and wallet software will guide users when migration becomes necessary.

The longer-term risk is ECDSA, the signature scheme that protects ordinary Ethereum accounts. Once an account sends a transaction, its public key is exposed onchain. A sufficiently powerful future quantum computer could derive the private key from that exposed public key, putting funds at risk if the account has not migrated to a quantum-safe scheme.

SPHINCS- does not replace Ethereum’s full post-quantum roadmap. Broader protocol work, including EIP-8141, is still moving through draft and research stages. That future path could make account abstraction and post-quantum signatures more native to Ethereum, while today’s SPHINCS- work gives wallets, treasuries and security-focused accounts an earlier bridge.

The Fable review adds another layer to the story because Anthropic has since disabled Fable 5 and Mythos 5 after a U.S. export directive. That timing puts Ethereum’s post-quantum account research beside a wider debate over advanced AI access, security review and frontier-model restrictions.