2026-11-05 –, Lotus Stage 1
Post-quantum Ethereum needs a signature scheme that does not yet exist. SPHINCS comes closest: it is standardized, and its security rests on hash functions alone. But it was built for everyone, not for us. leanSPHINCS is the search for the best stateless scheme once you fix Ethereum's requirements: 128-bit security, a 2^24 key lifetime, and keygen and signing fast enough for a hardware wallet. The Ethereum Foundation is running sig.golf, an open autoresearch competition, to find it.
Every Ethereum account today is protected by a signature that a large quantum computer would break. That machine does not exist yet, but migrating away takes years, so the work has to start early.
The most conservative post-quantum option is hash-based signatures, which rely only on hash functions and none of the newer mathematics that could prove weaker than we think. SPHINCS is already standardized. It is just not built for Ethereum.
Standards have to work for everyone, so they are tuned for a world where nobody knows how the scheme will be used. Ethereum is more specific. We know roughly how often a key will sign, how strong the security must be, and the hardest constraint of all: it has to run on a hardware wallet, fast enough that people will use it.
Narrow the requirements that far and a huge space of possible designs opens up, too large to explore by hand. So the Ethereum Foundation is running sig.golf, an open competition where AI-driven search does the exploring
Nicolas Consigny is a researcher at the Ethereum Foundation working on wallets, privacy protocols and post-quantum cryptography. His current work spans SPHINCS-, a family of EVM-optimized hash-based signature variants, for PQ smart accounts. He leads Kohaku, a privacy-focused wallet initiative and research in the competition for leanSPHINCS the post quantum signature of the future lean Ethereum