Ethereum Foundation plans to replace Poseidon hash with SHA or BLAKE as part of quantum-safe cryptography roadmap, with leanVM deployment targeted for 2027–2028.
Tech & Launches ·
An Ethereum Foundation researcher outlined plans to transition the protocol's L1 cryptography away from Poseidon hashing toward standard functions like SHA or BLAKE. The shift reflects recent progress in binary-field SNARK technology, which has made it feasible to prove traditional hash functions efficiently within zero-knowledge proof systems—eliminating the earlier necessity for SNARK-optimized hashing algorithms. The change supports a broader focus on quantum security and privacy within Ethereum's roadmap.
The rollout is structured in stages: a production-grade implementation called leanVM is targeted for 2027, with subsequent deployment across Ethereum's consensus, data, and execution layers planned for 2028. This timeline indicates a phased approach to integrating the new cryptographic infrastructure across the protocol's core systems.
Open questions include the specific performance characteristics of SHA and BLAKE within Ethereum's proving environment, the scope of backward compatibility required during the transition, and how the upgrade will coordinate with other layer-1 improvements scheduled for the same period.