Ethereum Makes Major Cryptography Pivot to Prepare for Quantum Era

The Ethereum Foundation is abandoning the Poseidon hash function on its base layer, moving to options like SHA or BLAKE, according to researcher Justin Drake.

The shift reshapes the network’s long-term plan to resist future quantum computers. Drake announced the decision on August 13, calling it the conclusion of an eight-year research effort.

Ethereum Ditches Poseidon in Post-Quantum Security Shift

The Ethereum Foundation has been funding “SNARK-friendly hashes” since 2018. Poseidon arrived in 2019, becoming the dominant SNARK-friendly hash.

However, Drake said that “breakthrough SNARK designs” have challenged the assumption that specialized SNARK-friendly hash functions, such as Poseidon, are necessary.

“Off-the-shelf traditional hash functions like SHA2 and BLAKE2s can now match Poseidon in a SNARK. In hindsight the key was not SNARK-friendly hashes, but hash-friendly SNARKs,” he said.

The shift comes from proof systems built over binary fields, which work directly with the bit-level operations behind traditional hashes. Earlier systems relied on large prime numbers, making those operations expensive to represent.

Drake credited the Binius research by Benjamin Diamond and Jim Posen in 2023, which adapted proof techniques to capture standard hashes efficiently, alongside newer work called Flock. 

He said the designs can prove roughly 1 million traditional hash calls per second on a laptop, only about 100x slower than native CPU compute.

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The Case Against Riskier Structures

Drake framed the security case around minimal assumptions, arguing that plain hashes give Ethereum a foundation it can trust for decades. He also argued that riskier approaches have stumbled.

“As AI becomes exceptional at cryptanalysis, the contrarian bet to avoid riskier structures like lattices and isogenies is visibly paying off. The past weeks have been brutal. Lattice-based “HAWK” and isogeny-based “SQIsign,” both signature schemes in NIST’s Round 3, have suffered blows. Sources I trust say more blood is coming,” he added.

The approach also removes the need to wait years for Poseidon to survive cryptanalysis, speeding deployment. The strawmap points to a production-grade leanVM in 2027. Consensus, data, and execution layer deployments are penciled in for 2028. 

The move does not make Poseidon obsolete, nor force existing projects to migrate. It marks a proposed shift in Ethereum’s future Layer 1 design, one that will be tested as standard hashes hold that parity as systems scale.

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