Quantum computing has long been a theoretical and distant threat to blockchain cryptography. But in recent months, that calculus has changed rapidly.
While the Bitcoin community has been debating threats to its protocol for the past year, the Ethereum community appears to be taking its first steps in 2026.
“Quantum computing is moving from theory to engineering,” said Thomas Coratger, who leads the Post-Quantum (PQ) team at the Ethereum Foundation (EF). “That changes the schedule and means we have to prepare.”
In early January, the EF formally elevated post-quantum security to a strategic priority, creating a dedicated PQ team to drive real-world research, tools, and updates 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 made up of leading cryptographers to guide long-term blockchain security planning, signaling that even custody infrastructure must prepare for the risks of the quantum era.
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 phasing out vulnerable signatures and ensuring continuity across Layer 2 networks.
Together, these moves mark a notable shift: post-quantum security is no longer a fringe topic for the distant future, but a living concern shaping development roadmaps, governance discussions, and ecosystem coordination on Ethereum and beyond.
For the European Fund, progress towards post-quantum security is not about sounding an alarm, but about not being surprised.
Coratger 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 internal concern: if quantum computers arrive sooner than expected, Ethereum must be ready long before then.
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 is based on cryptography that works well, but could eventually be dismantled by powerful quantum computers.
One of the biggest challenges is replacing Ethereum’s current signing system, which efficiently pools thousands of validator approvals.
“That system works incredibly well today,” Coratger said. “But post-quantum alternatives don’t have the same properties. Figuring out how to make them work at the scale of Ethereum is a big challenge.”
To address this, the foundation is building what it calls leanVM, highly specialized 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 underlying crypto needs to change.
And this work is already being done in practice.
“We already have test networks up and running with post-quantum signatures,” Coratger said.
Importantly, Coratger emphasized that Ethereum is not in immediate danger. That gap between how quickly technology can change and how slowly decentralized networks can move is why the foundation is acting now. The goal is to ensure that the transition is complete long before quantum computers become a real threat.
“The worst case scenario is that quantum computers arrive and we are not prepared,” Coratger said.
One thing that has caught Coratger’s attention over the past year is how quickly the underlying science is advancing.
“New developments are happening all the time,” he said. “Sometimes it’s hard to keep up.”
To keep up, the Ethereum Foundation is working closely with third-party researchers and developers on post-quantum efforts.
For Coratger, the bottom line 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 is becoming a long-term engineering project, one that will shape the evolution of the network over time.
Read more: Ethereum Foundation makes post-quantum security a top priority as new team forms
