As quantum computing researchers celebrate one breakthrough after another, Web3’s $4 trillion asset base faces a ticking time bomb. Last December, Google announced that its Willow quantum chip performed a calculation in less than five minutes that would have taken a next-generation supercomputer ten. septillion years (approximately 100 billion times older than the age of our universe). Drug discovery, materials science, financial modeling, and optimization problems of all kinds will enter a golden age thanks to quantum technology. But most modern encryption, which relies on mathematical puzzles that are functionally impossible for a classical computer to solve, could be cracked instantly using quantum technology.
In Web3, adversaries are already collecting encrypted blockchain data to decrypt later, when quantum technology comes of age. An investment in cryptocurrency is, in essence, an investment in the integrity of cryptography, which quantum computing directly threatens.
Fortunately, researchers have shown that specialized zero-knowledge (ZK) cryptography can help quantum secure the industry’s most valuable blockchains, ensuring Web3 can harness the benefits of quantum technology (from new antibiotics to hyper-optimized supply chains) while insulating it from dangers.
The quantum advantage
On October 22, Google published verifiable results in Nature showing that its quantum chip is “useful for learning the structure of systems in nature, from molecules to magnets to black holes. [running] 13,000 times faster than the best classical algorithm on one of the world’s fastest supercomputers.” What is striking about these results is that they were not based on an artificial benchmark, like the example above, but on applied problems with direct scientific benefits.
Despite the obvious bounty of quantum technology to human cognition, it represents an undeniable threat to cryptography in general and the nearly $4 trillion digital asset base in particular. The Human Rights Foundation published a report showing that more than six million BTC are in the first types of “quantum vulnerable” accounts, including Satoshi’s 1.1 million idle BTC. These will likely be the first victims of “Q Day” (the day quantum becomes powerful enough to break public-key encryption).
Both Ethereum and Bitcoin rely on the Elliptic Curve Digital Signature Algorithm (ECDSA), which is famous for its vulnerability to “Short’s algorithm,” a quantum algorithm designed in the 1990s to quickly calculate the prime factors of large integers, a problem that would otherwise be completely intractable for classical computers. It’s even theoretically possible that quantum technology has already broken Bitcoin; We just haven’t realized it yet.
And yet many researchers have dismissed the threat. Jameson Lopp, of cypherpunk fame, posted on X that “fear and uncertainty about quantum computing may well be a bigger threat than quantum computing itself.” In other words, the only thing we have to fear is fear itself. But no matter who you ask, the quantum threat is non-zero. Vitalik Buterin estimates that the chance of quantum breaking Ethereum is 20% by 2030. And that means we have to be prepared.
The timeline matters, a lot. Harvest now, decrypt later, advance the timeline much sooner. Potential attackers (including nation states and hacking groups) are stockpiling encrypted blockchain data (from wallet backups to exchange escrow data) to be decrypted when quantum technology comes of age. Every transaction transmitted to the network, every public key exposed, becomes ammunition for future attacks. The window to implement quantum-resistant cryptography shrinks with each passing quarter.
Enter zero knowledge
The beauty of zero-knowledge (ZK) cryptography lies in its elegance and simplicity. A prover can convince a verifier that something is true without revealing any information beyond the validity itself. As ZK technology matured, test times were reduced from hours to seconds, while test sizes were reduced from megabytes to kilobytes. The computational cost of AI in particular remains high, limiting its usefulness to high-risk environments such as Web3, traditional banking, and defense.
Zero knowledge and quantum
At first glance, it may not be obvious how zero-knowledge technology can protect blockchains from quantum attacks. Zero-knowledge proofs are privacy tools, a way to prove that something is true without revealing any underlying information. But the same privacy-preserving techniques can also be built on quantum-resistant mathematics, making ZK a broad shield for blockchains. Hash-based proofs (using zk-STARK) and lattice-based proofs, based on problems that even powerful quantum machines struggle with, do not rely on vulnerable quantum elliptic curves.
But the quantum-resistant ZK tests are larger and heavier than current versions. That makes them harder to store and more expensive to verify on blockchains with tight space limits. But the benefit is huge: they offer a path to protecting billions of on-chain assets. without We need an immediate and risky revision of the base protocol.
In other words, ZK offers blockchains a flexible upgrade path. Instead of removing their entire signature system overnight, networks could gradually add quantum-safe ZK proofs to transactions, allowing old and new cryptography to coexist during the transition period.
The quantum benefit for Web3
Today’s computers can only fake randomness. They use formulas to generate “random” numbers, but those numbers are ultimately produced through a predictable process. That means that parts of a blockchain system, such as choosing which validator can propose the next block or determining the winner of a decentralized lottery, can be subtly influenced to the financial benefit of bad actors. But earlier this year, quantum researchers achieved a notable milestone: certified randomness.
Quantum systems take advantage of natural and unpredictable phenomena such as the spin of a photon or the decay of a particle. This is genuine, unfalsifiable randomness, something that classical computers cannot provide.
For blockchains, this is a big problem. The Web3 ecosystem needs a quantum-powered public randomness beacon to seed the core mechanisms that make blockchains work. With quantum technology, we can build one that is fair, tamper-proof, and impossible to tamper with. A solution that would address long-standing flaws in decentralized lotteries and validator selection.
Here’s the thing. Will Web3 get serious about quantum-resistant cryptography before quantum computers come of age? History suggests that base layer upgrades to large blockchain protocols can take years, in part due to the lack of central coordination inherent in decentralized systems. However, the industry cannot afford to wait for quantum technology to break the ECDSA before taking action.
We can argue about the exact timeline, but the quantum future is an increasingly closer certainty. ZK can protect Web3 during this transition, turning quantum threats into quantum opportunities.
The time to act is now, while we still can.
