Ethereum has begun to publicly signal its push towards post-quantum security. ETH Foundation researcher Will Corcoran used a presentation at the Institutional Ethereum Forum in New York to explain both the threat model and the protocol work already underway. This initiative is important far beyond ETH, he argued. Because the core bottleneck is not specific to one chain. All proof-of-stake networks built on today’s cryptographic assumptions will eventually face the same scaling problem.
Alongside the talk, the Ethereum Foundation launched pq.ethereum.org, a new portal that packages a project roadmap, technical resources, FAQs for institutions, and a registration form for the Post-Quantum Retreat to be held in Cambridge in October 2026. Corcoran assembled the site as a way to synthesize years of research and respond to growing inbound interest from institutions about how Ethereum plans to prepare for a future where quantum computers fail. Elliptic curve cryptography.
Ethereum eyes post-quantum industry standards
Although that future is expected to still be years away, Corcoran said Ethereum is already working in tough conditions. He pointed to the current predictions for “Q-Day.” This means cryptographically relevant quantum computers will arrive around 2032, while the current roadmap puts the key post-quantum components of the “L” or “M” fork of the protocol around 2029.
A central argument of this presentation was that post-quantum security cannot be reduced to a simple signature exchange. Ethereum currently relies on elliptic curve cryptography throughout the stack: validator certificates at the consensus layer, blob proof data at the data layer, and transaction and wallet signatures at the execution layer. If that encryption is broken, a large part of the network’s security model is broken.
However, replacing this creates a secondary problem. Ethereum’s current BLS signatures are compact and very efficiently aggregated. Even 10,000 signatures compress to 96 bytes. The proposed post-quantum permutation, hash-based scheme that Corcoran calls Lean Sig, is about 3,000 bytes per signature, and simply aggregating them yields about 30 megabytes of data per slot.
This trade-off is not just a technical inconvenience. Corcoran repeatedly tied it to Ethereum’s decentralization constraints, arguing that larger signatures would raise bandwidth requirements, reduce the number of viable home validators, and weaken the chain’s security properties. The entire design challenge, he says, is downstream from that point.
“So making Ethereum post-quantum secure is not as simple as replacing the signature scheme, because that change cascades to everything else,” he said. “Bigger signatures require more bandwidth, which means fewer home validators, more decentralization, and weaker security guarantees, so one change has a cascading effect on everything.”
Ethereum’s proposed answer is a combination of proof systems called LeanSig and Lean Multisig, which Corcoran described as a STARK-based aggregation engine. Rather than transmitting all signatures directly, this system aims to prove that signatures have been correctly verified and compresses the output to approximately 125 kilobytes. He called the roughly 250x compression that would enable post-quantum consensus on Ethereum “moon math.”
Corcoran also used the talk to emphasize that this is no longer a purely theoretical research thread. He said Ethereum already has 10 client teams running development nets, has shipped four development nets to date, and is building around 3-slot finality and 4-second slots as a design base. He added that this extensive effort spans more than eight years of research, approximately $25 million in funding, and approximately 1,500 contributors across more than 250 organizations and teams.
The immediate message for Ethereum is that post-quantum readiness is becoming a visible part of the long-range protocol challenge. As for the remaining cryptocurrencies, Corcoran’s argument was broader.
“In fact, all proof-of-stake blockchains face the same challenge, and that challenge is the ability to aggregate hash-based signatures at scale. This is non-negotiable,” he said. “If we successfully ship LeanSig, LeanMultisig, and Lean Consensus, we believe this has the potential to become the de facto industry standard.”
At the time of writing, ETH was trading at $2,154.
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