Ethereum Tests Post-Quantum Wallet Security with SPHINCS- Design
Ethereum researchers have proposed SPHINCS-, a post-quantum signature design that can verify quantum-resistant signatures within the Ethereum Virtual Machine without requiring any protocol changes.
The proposal, published on June 12th on Ethereum Research, aims to address the long-term problem of wallet security in the face of powerful quantum computers. The researchers have chosen KECCAK256 as a replacement for SHAKE256, which is already native to Ethereum and can be used in Solidity verification logic.
The C13 variant of SPHINCS- has a verification cost of 127,000 gas and a signature size of 3,704 bytes. This is compared to the SLH-DSA-SHA2-128-24 scheme, which costs 142,000 gas and uses a 3,856-byte signature.
The researchers argue that normal Ethereum addresses do not need an unlimited signing budget, and therefore have narrowed the signature budget for SPHINCS- to between 2^14 and 2^20 signatures per key. This is in contrast to the broader standard target of 2^64 signatures per key.