‘We need to prepare’ for quantum computing

Quantum computing has long been a distant, theoretical threat to blockchain cryptography. But over the past few months, that calculus has shifted rapidly.

While the Bitcoin community has been debating threats to its protocol for the past year, the Ethereum community seems to be taking its first steps in 2026.

“Quantum computing is moving from theory into engineering,” said Thomas Coratger, who leads the Ethereum Foundation’s (EF) Post-Quantum (PQ) team. “That changes the timeline, and it means we need to prepare.”

Earlier in January, the EF formally elevated post-quantum security to a strategic priority, creating tjat dedicated PQ team to drive research, tooling and real-world upgrades to protect the network’s cryptographic foundations.

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, which is 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, committing to phase out vulnerable signatures and ensure continuity across layer-2 networks.

Together, these moves mark a noticeable shift: post-quantum security is no longer a fringe topic for the far future, but a live concern shaping development roadmaps, governance discussions and ecosystem coordination across Ethereum and beyond.

For the EF, the move toward post-quantum security isn’t about sounding an alarm, but it’s about not getting 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 made public what had already become a growing concern internally: if quantum computers arrive sooner than expected, Ethereum needs to be ready well before that moment.

For now, the team is focused on Ethereum’s “consensus layer” — the part of the network that enables 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 could eventually be broken by powerful quantum computers.

One of the biggest challenges is replacing Ethereum’s current signature system, which efficiently bundles 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 major challenge.”

To address that, the foundation is building what it calls leanVM, a highly specialized piece of software designed to combine many post-quantum approvals into a single proof that can be added to the blockchain without overwhelming it. While the technology is complex under the hood, the goal is simple: keep Ethereum running smoothly even if the cryptography underneath it 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 stressed that Ethereum is not in immediate danger. That gap between how fast technology can change and how slowly decentralized networks can move is why the foundation is acting now. The aim is to ensure the transition is completed well 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 advancing.

“New breakthroughs are happening all the time,” he said. “Sometimes it’s hard to keep up.”

To keep up, the Ethereum Foundation is working closely with outside researchers and developers on post-quantum efforts.

For Coratger, the takeaway is that post-quantum security has crossed an important threshold.

It’s 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 a top priority as new team forms