Quantum computing has long been a distant, theoretical threat to blockchain cryptography. But over the past few months, that calculation has changed rapidly.
While the Bitcoin community has been discussing threats to its protocol for the past year, the Ethereum community looks set to take its first steps in 2026.
“Quantum computing is moving from theory to engineering,” said Thomas Coratger, who leads the Ethereum Foundation’s (EF) Post-Quantum (PQ) team. “It changes the timeline and that means we have to prepare.”
Earlier in January, the EC formally elevated post-quantum security to a strategic priority, creating a dedicated PQ team to drive real-world research, tooling and upgrades to protect the network’s cryptographic foundation.
At the same time, major industry players are building their own defenses: Coinbase announced an independent quantum advisory board staffed with leading cryptographers to guide long-term blockchain security planning, signaling that even custodial infrastructure must prepare for quantum-era risks.
And across the ecosystem, Optimism, one of Ethereum’s largest layer-2 networks, laid out a formal 10-year roadmap to transition its Superchain stack, from wallets to sequencers, toward post-quantum cryptography, which commits to phasing out vulnerable signatures and ensuring continuity across layer-2 networks.
Together, these moves mark a noticeable shift: post-quantum security is no longer a fringe topic of the distant future, but a living concern shaping development roadmaps, governance discussions, and ecosystem coordination across Ethereum and beyond.
For the EC, the move towards post-quantum security is not about sounding the alarm, but about not being caught flat-footed.
Coratger has spent the past year quietly working on post-quantum research within the EF before the effort was formally announced this month. The creation of a dedicated team publicized what had already become a growing concern internally: if quantum computers arrive sooner than expected, Ethereum must be ready well before that moment.
For now, the team is focused on Ethereum’s “consensus layer” — the part of the network that allows thousands of validators to agree on which transactions are valid and which blocks are added to the chain. Today, that system relies on cryptography that works well now but may eventually be broken by powerful quantum computers.
One of the biggest challenges is replacing Ethereum’s current signature system, which effectively collects thousands of validator approvals.
“That system works incredibly well today,” Coratger said. “But the post-quantum alternatives don’t have the same properties. Figuring out how to make them work at Ethereum’s scale is a big challenge.”
To solve that, the foundation is building what it calls leanVM, a highly specialized piece of software designed to combine many post-quantum proofs into a single proof that can be added to the blockchain without overwhelming it. Although the technology is complex under the hood, the goal is simple: keep Ethereum running, even if the cryptography underneath needs to change.
And this work is already happening in practice.
“We already have test networks running with post-quantum signatures,” Coratger said.
Importantly, Coratger emphasized that Ethereum is not in immediate danger. The gap between how quickly technology can change and how slowly decentralized networks can move is why the fund is acting now. The goal is to ensure that the transition is completed in good time, before quantum computers become a real threat.
“The worst-case scenario is that quantum computers arrive and we’re not ready,” Coratger said.
One thing that has stood out to Coratger over the past year is how quickly the underlying science is evolving.
“New breakthroughs happen all the time,” he said. “Sometimes it’s hard to keep up.”
To keep up, the Ethereum Foundation is working closely with external researchers and developers on post-quantum efforts.
For Coratger, the takeaway is that post-quantum security has crossed an important threshold.
It is no longer a distant thought experiment or a purely academic debate. For Ethereum, it’s becoming a long-term engineering project, one that will shape how the network evolves over time.
Read more: Ethereum Foundation Makes Post-Quantum Security Top Priority When Forming New Teams
