Quantum crisis approaching blockchain: Your crypto assets are being cracked by the "future"

Byline: Web4 Research Center

“The future is already here—it’s just not distributed evenly.” — William Gibson

Nine minutes is enough for a cup of coffee to go cold, and enough time for a quantum computer to crack your encrypted asset’s private key.

Imagine a scenario like this.

You’ve just initiated a transfer, confirmed the address, and hit send. Over the next ten minutes, the transaction sits quietly in the mempool, waiting for miners to package it. You feel safe—after all, elliptic curve cryptography (ECC) has protected the world’s most valuable digital assets for more than a decade, and it has never slipped.

But you don’t know that, somewhere on Earth, a quantum computer has already locked onto your transaction. It captures your public key on-chain, and then—nine minutes, faster than the average block time of mainstream crypto assets—your private key is derived, and your funds are moved to an address you don’t recognize.

This isn’t a sci-fi plot, and it’s not a Hollywood screenplay.

This is March 31, 2026, and the research conclusion that Google’s Quantum AI team has spelled out in black and white in its official technical blog post.

Based on the research data Google published, under a theoretical attack model involving partial precomputation by the attacker, a sufficiently advanced quantum computer can crack a crypto asset private key in about 9 minutes, while the average block time of mainstream crypto assets is 10 minutes. This means that in the time window where a transaction is waiting to be packaged, the attacker has about a 41% chance of successfully intercepting and tampering with the transaction.

Google’s research also points out that attackers may only need fewer than 500,000 quantum bits to launch an effective attack on existing cryptographic algorithms; and given between 1,200 and 1,450 high-quality quantum bits, certain types of real-world attacks have, at least theoretically, room to be carried out. This figure is clearly below the threshold of “millions of quantum bits,” a benchmark the industry has long cited for years.

This is the “quantum trust crisis”—a systemic risk hidden behind the compute evolution curve and currently counting down. It’s not targeting a single chain or protocol; it points to the entire world of digital assets that depend on elliptic curve cryptography. Once trust is shattered by quantum computers from the mathematical foundation, the core value proposition of crypto assets—“deterministic assurance without trust”—will no longer exist.

More importantly, in this blog post, Google provides an unprecedented hard timeline: by 2029, the post-quantum cryptography (PQC) migration must be completed. This is not a suggestion, and not a prediction—it’s a deadline in engineering terms. Google also announced that it has been working with institutions such as Coinbase, the Stanford Blockchain Research Center, the Ethereum Foundation, and others to jointly push forward this may be the deepest underlying security transformation since the birth of the crypto world.

There’s a line in the blog post that’s especially jarring—“Action urgency is steadily increasing.”

That line isn’t meant to scare you. Your crypto asset security window is closing at a visibly rapid pace.

The quantum crisis isn’t the end of the crypto world; it’s its coming-of-age ceremony—it forces the industry to move from “technical toys” to institutional-grade foundational infrastructure.

I. The “Achilles’ heel” of ECDLP-256: Why quantum computers can tear through it so easily?

To understand the essence of this crisis, you first need to clarify a basic question: why can quantum computers break the cryptographic systems currently in use?

Today, including Ethereum and most mainstream public chains, it relies on elliptic curve digital signature algorithms (ECDSA) and their underlying protocol ECDLP-256. The mathematical foundation of this system is the elliptic curve discrete logarithm problem—solving it with a traditional computer requires astronomical amounts of time.

You can think of it as an extremely difficult math problem. Traditional computers can only try answers one by one—trying until the universe ends will still not yield a solution. But when a quantum computer runs Shor’s algorithm, the way it “solves” the problem is completely different. It’s not “enumerating” answers; it uses the parallel computing capability of quantum superposition, fundamentally changing the problem’s computational complexity.

In fact, the main threat of quantum attacks is public-key cryptography systems, not hash algorithms. Grover’s algorithm provides only a quadratic speedup on hash functions, not an exponential one, so the hash portion is comparatively safe. The real risk lies at the moment the public key is exposed.

The moment the public key is exposed is the starting point for quantum attacks.

Google’s research report reveals two key findings that every crypto asset holder should take seriously.

First, the cracking threshold is far lower than people imagine. In the past, the industry generally believed that at least millions of quantum bits would be needed to threaten existing cryptographic systems. But Google’s estimate cuts that number dramatically—for certain attack scenarios, roughly 1,200 to 1,450 high-quality quantum bits could pose a real threat. This is a difference in orders of magnitude.

Second, the attack window is far smaller than people imagine. As mentioned earlier, within the ten minutes while a transaction is waiting for confirmation, a quantum computer may be able to complete the cracking of the public key. This means that even if you’re just initiating a normal transaction, you could be attacked during the process—not because your address is being targeted, but because your “this transaction” is being targeted.

The Taproot upgrade plays a complicated role in this issue. Google’s research team specifically points out that while Taproot improves transaction efficiency and privacy, for certain transaction types it “presets” earlier and exposes public key information more on-chain; as a result, address types that were previously more strongly protected become easier to lock onto in quantum attack scenarios.

This isn’t meant to scare you. According to Google’s research estimates, there are currently about 6.9 million public keys of mainstream crypto assets fully exposed on-chain, accounting for about one-third of total supply. This includes about 1.7 million coins obtained from early mining. Another report jointly released by ARK Invest and Unchained provides similar data, showing that about 35% of supply is at potential quantum threat risk.

Alex Thorn, research director at Galaxy Digital, also notes that the current risk is mainly limited to specific addresses whose public keys have been exposed on-chain, including reused addresses, addresses held by certain custodians, and assets in legacy address formats. Analysis from the security organization Project Eleven shows that about 7 million (roughly $470 billion at recent prices) are in this kind of “long-term exposure” state.

Behind these numbers are real dollars and real cents.

What’s truly dangerous isn’t quantum computing itself—it’s the industry pretending this problem doesn’t exist.

II. 2029: Not a “distant goal,” but a hard deadline

Time is the cruelest variable in this story.

2029 isn’t a “far-off future.” It’s a hard deadline—your crypto asset security window is closing.

Why 2029? Google’s roadmap wasn’t made up out of thin air. Over the past two years, the pace of quantum hardware progress has exceeded expectations for many people.

In December 2024, Google introduced the 105-qubit Willow quantum chip, capable of completing a standard benchmark calculation that would take a traditional supercomputer about 1,025 years to finish—within less than five minutes. More importantly, Willow achieves “below-threshold” quantum computation—when more qubits are added to the system, the error rate drops exponentially, which is a milestone breakthrough in the field of quantum error correction.

After that, major players like IBM and PsiQuantum also released their hardware roadmaps. Without any coordination, they all locked onto the goal of “thousand-level logical qubits” within the 2028 to 2030 range. Those dates aren’t a coincidence— the entire industry is converging toward a critical point.

But the 2029 Google gives is not referring to “quantum computers cracking crypto assets in that year.” Google’s meaning is: it plans to migrate all of its own infrastructure to a post-quantum cryptography system before 2029. In other words, 2029 isn’t the time when the threat arrives—it’s when the security window closes.

Why is this deadline so important for the crypto world?

Because a mainstream public chain’s hard fork—from proposal, to community discussion, to testnet deployment and mainnet activation—typically takes 18 to 24 months. From the publication of this article to 2029 is about 34 months remaining. That means there’s almost no room for trial and error.

If a mainstream public chain still hasn’t started PQC migration on its testnet by the end of 2027, the 2029 deadline will be almost impossible to meet on time. For those chains that enshrine “immutability” as a principle, this timeline is especially brutal.

Nic Carter has issued sharp criticism. The founder partner of Castle Island Ventures has publicly accused some developers of long ignoring quantum-related proposals and taking attitudes such as “denial, gaslighting, setting thresholds, and ostrich mindset.” He pointed out that widely used elliptic curve cryptography “is becoming obsolete—it’s just a matter of time.” Whether it’s 3 years or 10 years, it’s already obsolete. The only question is how quickly developers realize they need to bake cryptographic mutability into the network.

This debate is tearing the crypto world into two camps: one is actively planning and listing post-quantum security as the “top strategic priority”; the other is moving slowly amid a long and painful consensus tug-of-war.

Slow is the most expensive cost during this time window.

III. Who is acting? Who is watching from the sidelines?—industry divergence in progress

In response to quantum threats, different public chains have vastly different speeds, and this could very likely become an important variable in how the industry landscape changes in the coming years.

Ethereum is moving at the front.

In January 2026, the Ethereum Foundation made a landmark decision: it placed post-quantum security as a “top strategic priority” and announced the formation of a dedicated post-quantum (PQ) security team.

This team is led by Ethereum Foundation cryptography engineer Thomas Coratger. Members include cryptographers and engineers who are testing quantum-safe systems through development networks (devnets). The Ethereum Foundation has also allocated a total of about $2 million for this effort—$1 million to improve the Poseidon hash function, and another $1 million to support broader post-quantum research.

According to Ethereum researcher Justin Drake, after years of low-key development, the Ethereum Foundation leadership has officially elevated post-quantum security from an abstract research topic to a core strategic focus. A multi-client post-quantum consensus development network is already up and running, and multiple teams are participating through weekly compatibility meetings and collaborating to move things forward. A biweekly developers meeting led by Ethereum researcher Antonio Sanso for post-quantum transactions has also begun.

Ethereum plans to hold “Post-Quantum Day” before the March 2026 ETHCC conference, and to host a larger-scale post-quantum event in October 2026 to showcase progress and plan subsequent steps.

On the exchange side, Coinbase’s actions are also fast.

In January 2026, Coinbase disclosed that it has formed an independent quantum advisory committee. Members include Scott Aaronson, a top scholar in quantum computing; Dan Boneh, a cryptographer; and multiple experts from the Ethereum Foundation and blockchain security. The committee will assess the impact of quantum computing progress on the cryptography of major networks including Ethereum, and will publish public research and guidance documents for developers, institutions, and users. The first position paper is expected to be released in early 2027.

Coinbase also released a three-pillar post-quantum security roadmap covering product upgrades, strengthening internal key management, and long-term cryptography research—for example, integrating post-quantum signature schemes with secure multiparty computation. CEO Brian Armstrong emphasized that security is Coinbase’s top priority and urged early preparation before quantum hardware becomes mature.

On another mainstream public chain, however, the situation is much more complicated.

A proposal that was the first to formally list quantum resistance in a long-term technical roadmap removed the key-path spending option in Taproot by introducing the Pay-to-Merkle-Root script, thereby minimizing the risk of elliptic curve public key exposure. But in essence, it’s a careful and incremental update, not a wholesale overhaul of the cryptographic system. It doesn’t upgrade existing UTXOs, nor does it replace ECDSA/Schnorr signatures with post-quantum alternatives. One of the co-authors of the proposal noted that the number of comments it received has exceeded that of any other proposal in that improvement proposal’s history. The depth of community involvement is a sign of the network’s resilience, but it also means consensus formation is extremely slow.

In the face of a quantum crisis, speed itself is a kind of security.

IV. The three trials of the upgrade path: Why migration is so difficult?

Even with standards, teams, and roadmaps, moving from ECDSA to PQC remains littered with technical traps. This is not a simple software upgrade—it’s a thorough reconstruction of the underlying cryptographic infrastructure.

The first trial is compatibility. Today’s mainstream post-quantum signature algorithms (such as ML-DSA) produce signature lengths far larger than ECDSA—from 32 bytes expanding to over a thousand bytes. This difference directly affects block space, the Gas model, and network throughput. On Ethereum, this means the number of transactions that each block can hold drops significantly; on other networks, it means the controversy over block sizes will be reignited.

Cryptography has no permanent shield—only constantly upgrading spears and shields.

The second trial is protection of legacy assets. How do UTXOs or accounts already existing in old addresses migrate? A simple answer is: have users actively move assets to new PQC addresses. But the problem is that those long-idle addresses—including a large number of dormant addresses with lost private keys, early miner addresses, and certain founders’ addresses—will never be able to complete the migration. Once these “ghost assets” are cracked by quantum computers, they could be concentratedly dumped in the market, triggering a catastrophic price collapse.

The third trial is governance. Post-quantum migration almost inevitably involves a hard fork. And in the crypto world, hard forks have never been just a technical issue—they’re a political one. When a chain splits into two—one upgrading to PQC and the other keeping the original cryptographic system—how will compute power, community, and liquidity be allocated? History has already issued a warning.

Discussions about technical paths are ongoing as well. In addition to direct PQC migration, developers have proposed alternative solutions such as “hourglass” mechanisms—gradually restricting spending permissions for addresses that have already exposed public keys, reducing systemic risk without forcing migration. Each of these options has its pros and cons, but they all require time and verification, along with community consensus.

You can’t dismantle bridge supports while traffic is already crossing. Migration must be phased, verifiable, and equipped with rollback mechanisms.

V. Your security window is closing—action checklist

Facing this looming crisis, what should crypto asset holders do?

Don’t panic and sell off. Quantum attacks haven’t become a real threat yet. As Alex Thorn, research director at Galaxy Digital, said, investors shouldn’t mistake this long-term technical challenge as a reason to avoid it immediately. But “don’t panic” doesn’t mean “don’t act.”

You need to understand risk tiering. Under quantum threats, different types of addresses face different levels of risk. The most dangerous are old, long-idle addresses—especially those created before 2019—and addresses that reuse public keys (such as some exchanges’ withdrawal addresses). Ordinary wallet addresses face relatively lower risk—if your address has never spent assets (i.e., the public key hasn’t been made public), quantum computers can’t attack it at present. The lowest current risk is for addresses that have already migrated to PQC protocols, but such protocols barely exist on mainstream public chains.

In matters of security, passive waiting is active risk-taking.

Specific actions you can take include: diversify storage—spread large holdings across multiple addresses to reduce the impact of a single-point crack; watch for migration signals—prioritize exchanges and wallets that explicitly publish PQC roadmaps; Coinbase is already ahead here; for those with extreme risk aversion, you can consider converting part of your assets into projects with PQC roadmaps clearly outlined, but you should stay clear-eyed—there are currently no PQC blockchain products that have been validated in real-world practice.

Don’t believe any token marketing that claims it is “already quantum-resistant.” This is still a field being continuously validated in laboratories and testnets.

Thorn at Galaxy Digital offers a judgment worth remembering: quantum risk should be monitored, but it shouldn’t be used as an excuse to comprehensively avoid action. And to put it in ARK Invest’s terms, the threat of quantum computing isn’t a sudden “singularity” that arrives out of nowhere—it’s a gradual process that can be tracked and evolves in stages.

In a report jointly released by Ark Invest and Unchained in March 2026, the market’s understanding of this long-term risk is supported by a structured set of tools: it builds a five-stage framework and makes it clear that at the current time point, the so-called “Q-Day” does not constitute an urgent threat. The report also notes that millions of crypto assets may already be permanently lost, while many other assets can be migrated to safer addresses when technical threats emerge—provided the community has started taking action.

Your security window won’t stay open forever. It’s closing, day by day, getting narrower.

The quantum crisis makes us realize that the true challenge for blockchain isn’t performance, and it isn’t scaling—it’s whether it can truly become a trust infrastructure for human civilization. When cryptography can be broken by quantum computers, the only trustworthiness comes from those governance mechanisms that have been stress-tested.

VI. From “technical toys” to “institutional-grade infrastructure”: A coming-of-age ceremony you have to go through

There’s a saying among historians: humans always overestimate the short-term impact of technology and underestimate its long-term impact.

Crypto’s attitude toward quantum computing is exactly the opposite. It has underestimated the short-term urgency of the quantum threat, and it has underestimated the long-term complexity of migration itself.

But if we zoom out, we’ll find a more interesting conclusion: the quantum crisis isn’t an ending—it’s a coming-of-age ceremony.

Heidegger once asked about the essence of technology, arguing that modern technology is a kind of “standing-reserve,” bringing everything—including human beings—into an order that can be calculated and controlled. The very original purpose behind the creation of crypto assets was to resist this standing-reserve—to create a value network that isn’t controlled by any central power. Ironically, quantum computers, as an extreme force of technology, are now threatening the mathematical foundations of that network from the outside.

To deal with this threat, the crypto world must complete self-iteration. It will no longer be that “code is law” geek utopia; it must evolve into institutional-grade infrastructure capable of actively managing cryptographic risk, with governance resilience, and accepting external audits.

This requires three fundamental upgrades.

The first is an upgrade in cryptographic resilience. Future blockchains will have to embrace replaceable, upgradeable cryptographic frameworks, no longer hard-coding signature algorithms into the consensus layer. This means moving from “one-time design” to an “evolvable architecture.”

The second is an upgrade in governance maturity. Hard forks will no longer be only a debate about scaling or internal infighting within the community; they will involve “infrastructure upgrades” at the level of national security. This requires more transparent decision-making mechanisms, broader stakeholder participation, and stricter timeline management.

The third is an upgrade in user awareness. Advancing from “Not your keys, not your coins” to “Your keys can be cracked—prepare for migration.” Users will manage their addresses like they manage security today: regularly check whether their addresses are exposed to quantum risk, and proactively execute migration.

The quantum crisis is a mirror—it reflects the crypto world’s immaturity, and it also reflects the only path to maturity it must follow.

In “Summer” (L’Été), Camus wrote: “In the depth of winter, I finally learned that within me there lay an invincible summer.”

Quantum winter is approaching, but the crypto world’s summer—an institutional-grade infrastructure stress-tested, quenched, and reborn—is also being cultivated in this crisis.

That cup of coffee hasn’t fully gone cold yet.

Now, it’s day one of action.