As quantum computing researchers celebrate breakthrough after breakthrough, 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 state-of-the-art supercomputer ten minutes. septillion years (about 100 trillion times longer than the lifespan of our universe). Drug discovery, materials science, financial modeling, and optimization problems of all kinds will enter a golden age thanks to quantum. But most modern encryptions, which rely on mathematical puzzles that are impossible for a classical computer to solve, could be cracked instantly by quantum.
In Web3, adversaries are already collecting encrypted data from the blockchain to hack it later, when quantum comes of age. An investment in cryptography is, in essence, an investment in the integrity of cryptography, which quantum computing directly threatens.
Fortunately, researchers have demonstrated that specialized zero-knowledge (ZK) cryptography can help quantum-protect the industry’s most valuable blockchains, ensuring that Web3 can reap the benefits of quantum – from new antibiotics to hyper-optimized supply chains – while insulating it from dangers.
The quantum advantage
On October 22, Google published testable results in Nature demonstrating 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 surprising about these results is that they were not based on an artificial benchmark, as in the previous example, but on applied problems with direct scientific benefits.
Despite quantum’s obvious bounty for human knowledge, it poses an undeniable threat to crypto in general and to the nearly $4 trillion digital asset base in particular. The Human Rights Foundation released a report showing that more than six million BTC are in early and “quantum vulnerable” account types, including Satoshi’s 1.1 million dormant 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 known to be vulnerable to “Shor’s Algorithm”, a quantum algorithm designed in the 1990s to quickly calculate the prime factors of large integers, an otherwise completely intractable problem for classical computers. It is even theoretically possible that quantum has already broken Bitcoin; we just haven’t realized it yet.
And yet, many researchers have pooh-poohed the threat. Jameson Lopp, famous cypherpunk, posted on In other words, the only thing we have to fear is fear itself. But no matter who you ask, the quantum threat isn’t zero. Vitalik Buterin estimates a 20% chance of breaking Ethereum by 2030. And that means we need to be prepared.
Timing matters – a lot. Harvest now, decipher later, moves the timeline back much earlier. Potential attackers (including nation states and hacker groups) store encrypted blockchain data – from wallet backups to custodial data exchanges – to hack when the quantum matures. Every transaction broadcast on the network, every public key exposed becomes ammunition for future attacks. The window for implementing quantum-resistance cryptography is narrowing every quarter.
Enter zero knowledge
The beauty of zero-knowledge cryptography (ZK) 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 has evolved, proof times have increased from hours to seconds, while proof sizes have increased from megabytes to kilobytes. The computational cost of AI in particular remains high, limiting its usefulness to high-stakes environments like Web3, traditional banking, and defense.
Zero and quantum knowledge
At first glance, it may not be obvious how zero-knowledge technology can protect blockchains against 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, turning ZK into a broad shield for blockchains. Hash-based proofs (using zk-STARK) and network-based proofs, built on problems that even powerful quantum machines struggle with, do not rely on quantum vulnerable elliptic curves.
But the quantum-resistant ZK proofs are larger and heavier than current versions. This makes them harder to store and more expensive to verify on blockchains with tight space limits. But the benefit is huge: they offer a way to protect billions of assets on-chain. without requiring an immediate and risky overhaul of the basic protocol.
In other words, ZK offers blockchains a flexible upgrade path. Instead of removing their entire signature system overnight, networks could gradually add quantum-secure ZK proofs to transactions, allowing old and new cryptography to coexist during the transition period.
The quantum advantage of Web3
Today’s computers can only simulate chance. They use formulas to generate “random” numbers, but these numbers are ultimately produced by a predictable process. This means that certain parts of a blockchain system – such as choosing which validator will propose the next block or determining the winner of a decentralized lottery – can be subtly influenced for the financial benefit of bad actors. But earlier this year, quantum researchers achieved a remarkable milestone: certified randomness.
Quantum systems exploit natural and unpredictable phenomena such as the rotation of a photon or the decay of a particle. This is authentic, tamper-proof randomness, something that classical computers cannot provide.
For blockchains, this is a big problem. The Web3 ecosystem needs a quantum-powered public random beacon to bootstrap the basic mechanisms that make blockchains work. With quantum, we can build one that is fair, tamper-proof and impossible to manipulate. A solution that would address the long-standing flaws of decentralized lotteries and validator selection.
Therein lies the question. Will Web3 take quantum-resistant cryptography seriously before quantum computers come of age? History suggests that upgrading the base layer to large blockchain protocols can take years, in part because of the lack of central coordination inherent in decentralized systems. However, the industry cannot afford to wait for quantum to break ECDSA before taking action.
We can quibble over the exact timeline, but the quantum future is a near certainty. ZK can protect Web3 throughout this transition, turning quantum threats into quantum opportunities.
The time to act is now, while we still can.
