The Ethereum Foundation has formally launched its public initiative to prepare the Ethereum network for the era of quantum computing, unveiling a detailed roadmap and a new online hub. The announcement was made by Ethereum Foundation researcher Will Corcoran during a presentation at the Institutional Ethereum Forum in New York.
The core challenge, as outlined by Corcoran, is not unique to Ethereum but affects every proof-of-stake blockchain. Current cryptographic systems, which rely on elliptic-curve cryptography, are vulnerable to being broken by future quantum computers. The estimated "Q-Day"—when a cryptographically relevant quantum computer arrives—is projected to be around 2032. Ethereum's roadmap aims to implement key post-quantum components in a protocol fork, referred to as the "L" or "M" fork, roughly around 2029.
The transition is far from a simple signature swap. Ethereum's current BLS signatures are compact, allowing 10,000 signatures to be aggregated into just 96 bytes. The proposed post-quantum replacement, a hash-based scheme called LeanSig, is about 3,000 bytes per signature. Naive aggregation would result in roughly 30 megabytes of data per slot, which would drastically increase bandwidth requirements, reduce the number of viable home validators, and threaten the network's decentralization and security.
To solve this, Ethereum is developing a pairing of LeanSig with a STARK-based aggregation engine called Lean Multisig. This system aims to prove that signatures were verified correctly and compress the output to around 125 kilobytes, achieving roughly a 250x compression. Corcoran described this as "the moon math" that makes post-quantum consensus viable.
The Foundation has launched pq.ethereum.org, a portal consolidating over eight years of research. The site includes the full technical roadmap, open-source repositories, specifications, academic papers, Ethereum Improvement Proposals (EIPs), and a detailed FAQ for institutions. It also features a registration form for a post-quantum retreat in Cambridge in October 2026.
Corcoran emphasized that the work is already well underway, with more than 10 client teams participating in weekly developer network (devnet) builds through PQ Interop initiatives. The broader effort has involved roughly 1,500 contributors across over 250 organizations and teams, supported by about $25 million in funding. The design basis is being built around three-slot finality and four-second slots.
Corcoran concluded with a bold vision for the project's impact, stating, "When we succeed in shipping LeanSig and LeanMultisig and Lean consensus, we think that this could really become the de facto industry standard." At the time of the announcement, ETH was trading at $2,154.
