Ethereum Foundation drops Poseidon for post-quantum hashing in leanVM plans
Ethereum Foundation is pivoting away from the Poseidon hash function for its planned post-quantum architecture. Researcher Justin Drake said the foundation will instead use established alternatives such as SHA or BLAKE. The rationale is that recent advances in SNARKs (compact proofs) and proving efficiency allow conventional hash functions to run efficiently enough to replace Poseidon in Ethereum systems planned like leanVM.
Poseidon had been considered for future post-quantum designs, including leanVM, which could help Ethereum efficiently verify large volumes of blockchain activity. Drake said production-ready leanVM is targeted for 2027, followed by broader deployments across Ethereum’s consensus, data, and execution layers in 2028, though the dates are preliminary.
Eigen Labs founder Sreeram Kannan added that using battle-tested hash-based approaches may offer fewer known attack avenues and faster deployment because they’ve undergone years of scrutiny. He said joint work with the foundation and zero-knowledge proof firm Succinct increased proving speeds by 2.5x.
Overall, the update is a technical roadmap change for Ethereum’s post-quantum efforts rather than an immediate network upgrade or token-economic change. For traders, it mainly signals evolving cryptography choices and potential timelines for future zk/verification infrastructure.
Neutral
This is a roadmap-level cryptography change, not a near-term consensus or token-policy upgrade. While the abandonment of Poseidon in Ethereum’s post-quantum plans is meaningful technically, it does not imply immediate changes to ETH token supply, staking rules, or transaction validation today.
In past crypto patterns, when teams revise underlying cryptographic assumptions (e.g., switching proof systems or hash primitives), markets often react more to timing and delivery than to the theoretical choice itself. The article’s key dates (leanVM target 2027; wider layer deployments 2028) are still far enough that traders are unlikely to price it aggressively in the short term. That said, the mention of 2.5x proving-speed improvements and the shift to SHA/BLAKE could be perceived positively for the long-term feasibility of Ethereum’s zk scaling and verification stack, which can be supportive for medium/long-horizon sentiment.
Net effect: neutral for price and stability in the immediate window, with a slight long-term narrative tailwind for Ethereum’s post-quantum and zk infrastructure credibility.