Quantum computing has long posed a distant theoretical threat to blockchain cryptography. But in recent months, that calculus has changed rapidly.
While the Bitcoin community has been debating the threats to its protocol for a year, the Ethereum community seems 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). “It changes the timeline and that means we have to prepare.”
Earlier in January, the EF officially elevated post-quantum security to a strategic priority, creating a dedicated PQ team to drive research, tools, 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 the creation of an independent quantum advisory board 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, has established a formal 10-year roadmap to transition its Superchain stack from wallets to sequencers to post-quantum cryptography, committing to phasing out vulnerable signatures and ensuring continuity across Layer 2 networks.
Together, these developments mark a notable shift: post-quantum security is no longer a fringe topic for the distant future, but a real concern that shapes development roadmaps, governance discussions, and ecosystem coordination across Ethereum and beyond.
For the EF, the move towards post-quantum security is not about sounding the alarm, but it is about not being caught off guard.
Coratger spent the last year quietly working on post-quantum research within the EF, before the effort was officially announced this month. Creating 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 then.
For now, the team is focusing 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 to add to the chain. Today, this system relies on cryptography that works well today, but could eventually be dismantled by powerful quantum computers.
One of the biggest challenges is replacing Ethereum’s current signature system, which efficiently aggregates thousands of validator approvals.
“This 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 major challenge.”
To solve this problem, the foundation is building what it calls leanVM, highly specialized software designed to combine many post-quantum endorsements into a single proof that can be added to the blockchain without overloading it. Although the technology is complex under the hood, the goal is simple: to keep Ethereum running smoothly even if the underlying cryptography needs to change.
And this work is already coming to fruition.
“We already have test networks working with post-quantum signatures,” Coratger said.
Importantly, Coratger emphasized that Ethereum is not in immediate danger. This gap between how quickly technology can evolve and how slowly decentralized networks can evolve is why the foundation is acting now. The goal is to ensure that the transition is completed well before quantum computers become a real threat.
“The worst case scenario is that quantum computers come and we’re not ready,” Coratger said.
One thing that has stood out to Coratger over the past year is how quickly the science behind it is advancing.
“New advances are happening all the time,” he said. “Sometimes it’s hard to keep up.”
To keep pace, the Ethereum Foundation is working closely with external researchers and developers on post-quantum efforts.
For Coratger, what must be remembered is that post-quantum security has crossed an important threshold.
This is no longer a distant thought experiment or a purely academic debate. For Ethereum, this is a long-term engineering project, which will shape the evolution of the network over time.
Read more: Ethereum Foundation makes post-quantum security a top priority as new team forms
