The Ethereum Foundation is abandoning the Poseidon hash function for Ethereum’s layer-1 roadmap after an eight-year, eight-figure research effort, according to researcher Justin Drake. In an Aug. 13 post on X, Drake described the pivot to established functions such as SHA-2 and BLAKE2s as the conclusion of an “epic 8-year, 8-figure rabbit hole” in post-quantum cryptography.
Why Poseidon mattered. Poseidon emerged in 2019 as a hash function designed for zero-knowledge proof systems, offering cheaper SNARK processing than traditional hashes. It became common across zk-rollups and zkVMs. The change concerns Ethereum’s future L1 architecture and does not require existing projects to replace the function immediately.
Hash-friendly SNARKs. Drake said binary-field SNARKs can prove about 1 million traditional hash calls per second on a laptop, with roughly 100 times overhead compared with native CPU execution. “In hindsight the key was not SNARK-friendly hashes, but hash-friendly SNARKs,” he wrote. Research projects Binius and Flock contributed to the performance gains, while SNARK.fast reached 1.8 million BLAKE3 compressions per second.
Post-quantum roadmap. Hash-based signatures are central to Ethereum’s defense against quantum computers. Drake cited AI-assisted cryptanalysis setbacks for lattice-based HAWK and isogeny-based SQIsign as strengthening the case for simpler hash-based signatures. The plan includes aggregating many signatures into compact SNARK proofs. A June test used a SPHINCS-based verifier costing about 127,000 gas and roughly $0.07 per account.
Institutional context and timeline. NIST finalized its first post-quantum cryptography standards in August 2024. A Coinbase advisory board paper in April warned that replacing vulnerable signatures could take years and that some alternatives could increase data requirements up to 38 times. The Ethereum Foundation is targeting a production-grade leanVM in 2027 and deployments across consensus, data, and execution layers in 2028.
