Ethereum L1 abandons Poseidon and shifts towards SHA2 or BLAKE2 to advance the post-quantum cryptography route

Justin Drake posted on the X platform that Ethereum L1 will no longer use the SNARK-friendly hash function Poseidon, which has dominated since 2019, and will instead turn to traditional hash functions such as SHA2 or BLAKE2s.

This adjustment is based on advancements in the field of SNARK design, shifting the focus from "SNARK-friendly hashing" to "hash-friendly SNARK." By aligning Boolean operations in traditional hashing with binary field native, the proof performance of traditional hashing in SNARK has reached 1 million per second, with an overhead of about 100 times.

Research from Binius and Flock has driven relevant progress. The Ethereum Foundation's post-quantum team is advancing this route, with a roadmap that includes deploying production-level leanVM in 2027, and deploying in the consensus layer, execution layer, and data processing layer in 2028.

Justin Drake also stated that the enhanced capabilities of AI in cryptanalysis have recently led to setbacks for the lattice-based scheme HAWK and the homomorphic scheme SQIsign, with hash-based schemes being used for post-quantum signatures on the blockchain. The trend of open-source automated research is also accelerating, with SNARK.fast achieving 1.8 million BLAKE3 proofs per second.