SPHINCS- is envisioned as a bridge to a future leanSPHINCS system that would further cut verification costs through aggregation, enabling cheaper post-quantum security.

The SPHINCS- approach is envisioned as a bridge toward a future leanSPHINCS system that would further cut verification costs through aggregation, potentially enabling protection for as little as $0.07 per account.

SPHINCS- is framed as an interim bridge toward a longer-term, more cost-efficient system named leanSPHINCS, which would use signature aggregation to further cut verification costs.

The approach avoids urgent hard forks and governance complications, offering a practical path to post-quantum readiness that can scale with ecosystem improvements.

A Ethereum Foundation researcher proposes a low-cost, pre-fork method to post-quantum protect Ethereum accounts using a variant of SPHINCS+ called SPHINCS-, aiming to reduce on-chain verification costs without protocol changes.

The proposal adapts SPHINCS+, a post-quantum signature standard from NIST, into a version called SPHINCS- to reduce on-chain verification costs without changing the protocol or requiring a precompile.

Ethereum could add post-quantum protections to accounts at a cost as low as $0.07 without a hard fork, based on a proposal from Nicolas Consigny, lead of Ethereum's Kohaku project.

The broader goal is to mitigate long-term risk to Ethereum’s current ECDSA-based cryptography from future quantum capabilities, enabling earlier readiness for post-quantum security.

This proposal addresses the long-term risk that quantum computing could compromise Ethereum’s current elliptic-curve signatures, by exploring an efficient post-quantum signature verification method compatible with existing Ethereum architecture.

The approach targets long-term quantum threats to Ethereum's elliptic-curve cryptography and aims for deployment ahead of a dedicated hard fork.

Key questions moving forward include validating on-chain performance in real conditions, ensuring low verification costs persist at scale, and planning the eventual transition to leanSPHINCS and broader post-quantum deployment.

The idea does not require a hard fork or precompile and could be deployed before a dedicated post-quantum hard fork, making the transition potentially smoother for users.