Ethereum Shouldn't Delay Preparing for Quantum Computing Threat, Says Vitalik Buterin

Ethereum co-founder Vitalik Buterin is pushing the network to adopt cryptography that can withstand future quantum computing attacks now—before they're a problem. The prominent Ethereum figurehead warned that waiting until the threat is real could turn blockchain security into a race it cannot afford to lose.

To prepare for the day a practical quantum computer comes online, in a post published Sunday on X, Buterin argued that Ethereum’s base layer must pass what he called the “walkaway test”—the idea that the network’s value should not depend on ongoing protocol upgrades or stewardship.

“Ethereum the blockchain must have the traits that we strive for in Ethereum's applications,” Buterin wrote. “Hence, Ethereum itself must pass the walkaway test.”

Even if development slows or stops, he said, Ethereum should remain stable, secure, and trustworthy for decades to come.

A central part of his argument is the looming threat posed by quantum computing. Buterin said Ethereum should not hold off on adopting cryptography that can withstand future quantum computers, even if current machines are not yet capable of breaking blockchain security.

“We should resist the trap of saying, ‘Let’s delay quantum resistance until the last possible moment in the name of eking out more efficiencies for a while longer,’” Buterin said. He added that individual users have the right to delay making changes in preparation for a quantum threat, but protocols do not.

“Being able to say 'Ethereum's protocol, as it stands today, is cryptographically safe for a hundred years' is something we should strive to get to as soon as possible, and insist on as a point of pride,” he said.

The post follows earlier comments from Buterin about the potential impact of quantum computing on blockchain security, but places greater focus on the risks of waiting. Buterin’s view on the quantum risk has changed over the years since 2019, when he downplayed Google’s quantum advancements. He now argues that systems like Ethereum cannot afford to treat quantum resistance as a last-minute upgrade once the technology becomes a reality.

Blockchains face particular exposure because networks like Bitcoin and Ethereum rely on elliptic-curve cryptography. While secure against today’s computers, it could be broken by sufficiently powerful quantum machines using Shor’s algorithm to extract private keys from public ones.

While researchers say today’s quantum machines remain too small and unstable to threaten real-world blockchains, progress in hardware, error correction, and system stability has refocused discussions around future timelines.

Despite Buterin’s call for action, others warn that enacting changes too quickly could have unintended consequences.

“Post-quantum crypto, oftentimes it’s about 10 times slower, 10 times larger proof sizes, and 10 times more inefficient,” Cardano founder and Ethereum co-founder Charles Hoskinson told Decrypt in a recent interview. “So if you adopt it, what you’re basically doing is taking the throughput of your blockchain and reducing it by cutting off a zero.”

Beyond the walkaway test, Buterin outlined technical priorities he said Ethereum must address to remain viable over the long term—including an architecture capable of scaling to thousands of transactions per second through mechanisms such as zero-knowledge EVM validation and data availability sampling, with future growth handled largely through parameter changes.

He also pointed to the need for a durable state design, a general-purpose account model that moves beyond “enshrined [Elliptic Curve Digital Signature Algorithm] signatures,” a gas schedule hardened against denial-of-service attacks, proof-of-stake economics that can remain decentralized into the future, and block-building mechanisms designed to resist centralization and remain censorship-resistant.

Buterin said the goal is to complete this work over the next several years, arguing future innovations should largely occur through client optimization and limited parameter changes rather than repeated upgrades.

“Every year, we should tick off at least one of these boxes, and ideally multiple,” he wrote. “Do the right thing once, based on knowledge of what is truly the right thing (and not compromise halfway fixes), and maximize Ethereum's technological and social robustness for the long term.”