Ethereum Abandons Poseidon in Post-Quantum Shift

The Ethereum Foundation has made a significant shift in its post-quantum plan by abandoning the Poseidon hash function. According to researcher Justin Drake, the foundation is turning to established alternatives such as SHA or BLAKE due to advances in SNARKs. This move will enable conventional hashes to efficiently perform tasks that would previously require Poseidon.

The change affects planned systems like leanVM, which helps Ethereum verify large volumes of blockchain activity. Although these systems have not yet been deployed on mainnet, a production-ready leanVM is targeted for 2027, followed by deployments across Ethereum's consensus, data, and execution layers in 2028.

Eigen Labs founder Sreeram Kannan believes that established hash-based systems like SHA or BLAKE have fewer known avenues of attack than other post-quantum approaches. This, combined with the fact that they have already undergone years of scrutiny, makes them a more viable option for deployment. Joint work between Eigen Labs and zero-knowledge proof company Succinct has increased proving speeds by 2.5 times.