The danger of quantum computers

1. Introduction: The quantum era has already begun

For years, talk of quantum computers sounded like science fiction, the kind of thing that only happens in movie laboratories with blue lights and formulas floating in the air. But reality has decided to catch up with us faster than expected. Today, large technology companies and entire governments are competing to master a technology that, if it ever fully matures, could upend everything we understand about digital security, privacy, and even computational reality .

Are we exaggerating? I hope so. Because quantum computing isn't just another technological evolution; it's a breakthrough, a complete disruption. Quantum computers don't think faster than classical computers… they think differently .

They use the strangest laws of physics to solve problems that, until now, were simply impossible or required centuries of processing.

And like any powerful tool, it also carries dangers. Not because they're inherently bad, but because they can be used to breach systems we once thought were inviolable . And that, right there, is where the disturbing part of this story begins.

This article isn't meant to demonize a technology that can and will bring extraordinary benefits, but it does want to make one thing very clear: if we don't prepare for what's coming, we could find ourselves naked in the middle of a quantum storm, and then, just putting a patch on won't be enough.

2. What is a quantum computer and why is it so special?

To understand why quantum computers represent a revolution, we must forget everything we know about traditional computing, since these devices do not work with bits that are equal to 0 or 1, they work with qubits , and qubits play by completely different rules.

A qubit, instead of being in just one state (0 or 1), can be in a superposition of both at the same time . That is, it can be both 0 and 1 simultaneously… until we measure it. The same thing happens in the famous Schrödinger's cat paradox . It's not magic, it's pure quantum physics.

Add to that quantum entanglement , a property that allows two qubits to be connected in such a way that the state of one depends on the other, even at a distance. The result: a web of probabilities and correlations as powerful as it is bewildering.

While a classical computer needs to go through each possibility sequentially, a quantum computer can explore multiple solutions in parallel thanks to these properties. That doesn't mean it can do everything faster, but it can do certain things radically more efficiently . And that's the key.

For example, solving equations with thousands of variables, simulating complex molecules, optimizing impossible logistics routes or, as we will see later, breaking cryptographic algorithms that were previously untouchable .

Quantum computers don't just promise improvement. They promise a breaking of boundaries . And that, while exciting, can also be dangerous if we don't know where we're stepping.

3. The End of Cybersecurity? The Great Invisible Risk

Quantum advantage isn't just a marketing slogan. It's a reality that's beginning to take shape, and with it comes a disturbing possibility: breaking the rules of the game . One thing quantum computers could do in an incomparably superior way is solve certain mathematical problems that underlie current digital security.

One of the most significant impacts of quantum computing is in the field of cybersecurity. This is not futuristic speculation: it's a scenario anticipated and actively studied by institutions such as the NSA, NIST, and European digital security agencies.

Most current cryptographic systems, such as RSA, DSA, or ECC, base their robustness on mathematical problems that are intractable for a classical computer. For example, the factoring of very large prime numbers or the discrete logarithm on elliptic curves. Solving them by brute force would take hundreds or thousands of years, making their exploitation impossible.

However, with a sufficiently advanced quantum computer, that assumption collapses . The quantum implementation of Shor's algorithm, one of the best known in this field, would allow large integers to be factored exponentially more efficiently than any classical method. In practice, this means that many of today's cryptographic standards could become obsolete once sufficiently robust quantum computing power is achieved, since the security they provided with algorithms that would take thousands of years to crack could be reduced to minutes.

It's important to note that we're not there yet. Current quantum computers don't have the number of qubits or the stability necessary to execute these types of attacks on a large scale. But their development is progressing, and with it, the urgent need to prepare .

This is where the concept of "cryptographic agility" comes into play, and above all, post-quantum cryptography : algorithms designed to resist both classical and quantum attacks. NIST, for example, has already selected a set of algorithms as candidates to become the new global standards.

Furthermore, we must consider a strategic threat known as "harvest now, decrypt later" : intercepting encrypted communications today that cannot be broken with current technology, but that could be decrypted in a few years, once the necessary quantum resources exist. Most worrying is that data encrypted today can be stored and decrypted tomorrow, when the technology is ready. And this is where cybersecurity as we know it begins to falter, especially given the number of large-scale data breaches and thefts that threaten large corporations, and which, unfortunately, are becoming more frequent.

Quantum computing does not pose an immediate threat to cybersecurity, but it does pose an inevitable challenge, and as with any structural change, anticipation will make the difference between a controlled transition and an avoidable crisis .

4. A technical marvel: True randomness

One of the most surprising and least discussed advances brought about by quantum computing is the ability to generate truly random numbers . It may sound trivial, but in the digital world, true randomness doesn't exist.

Classical computers, by definition, are deterministic. They execute instructions step by step following perfectly defined rules. Therefore, what we call "random numbers" generated by these machines are actually pseudorandom numbers . That is, sequences that appear random, but are actually produced by mathematical formulas. And if you know the formula and the initial seed, you can predict the outcome.

This is no small problem. Cryptographic security, authentication protocols, scientific simulations, even online games—all depend on some form of randomness. If that randomness isn't truly unpredictable, the entire system can become vulnerable.

This is where quantum random number generators (QRNGs) make a difference. Based on fundamental physical phenomena, such as the decay of a particle or the passage of a photon through a slit, they produce numbers that are literally impossible to predict , even if the initial conditions of the system are known. Because the result doesn't depend on a formula, but on genuinely random quantum behavior.

This type of technology is already underway. Companies like ID Quantique in Switzerland, and research centers in Japan, the US, and China, are already marketing certified quantum generators for critical applications. And their use is beginning to spread to fields such as banking, defense, and critical infrastructure.

5. Advantages, curiosities and unthinkable scenarios

Talking about quantum computers isn't just about threats. It's also about possibilities that border on the incredible . Because beyond the risk to cybersecurity, this technology opens doors that have been sealed for decades by the limits of silicon and binary logic.

One of the clearest examples is the simulation of complex quantum systems , such as molecules, materials, or chemical reactions. Here, classical computers simply can't compete: the complexity multiplies exponentially and becomes insurmountable. However, a quantum computer is, by nature, perfect for modeling other quantum systems. This could accelerate the development of new drugs, optimize fertilizers, design superconducting materials, or find solutions to problems we don't even know how to fully formulate.

Another area with enormous potential is optimization . From logistics and air traffic to supply chains and energy management, quantum algorithms could find optimal configurations in scenarios where we currently only work with approximations.

Also worth mentioning is the quantum advantage Google achieved in 2019 with its Sycamore processor. Although it's still a controversial milestone with practical limitations, it was a first step toward demonstrating that a quantum computer can solve a specific task faster than any known classical supercomputer . It was a proof of concept. But, like every first, it opened the door to this new world.

Other interesting facts:

• IBM and D-Wave already offer access to quantum computers in the cloud.

• There are proposals to combine AI and quantum computing, creating what some call “quantum intelligence.”

• Countries like China are developing quantum communication networks, where a message cannot be intercepted without the recipient knowing.

All of this leads us to a clear point: we are not facing an improvement, but rather a paradigm shift . One that we do not yet fully understand, but that promises to redefine the limits of what is possible.

6. How should we prepare for a quantum future?

Accepting that quantum computing will transform the world is not enough. We need to prepare , and we must do so with seriousness, coordination, and a long-term vision, as this is not just a technological issue but a strategic, economic, and ethical challenge.

The first step is obvious, but not trivial: invest in research and specialized training . Companies, universities, and governments must focus on training professionals who master both the fundamentals of quantum physics and its practical applications in programming, cryptography, simulation, and optimization. The talent gap in this field is as large as it is urgent.

In parallel, a transition to infrastructures secure against quantum threats is imperative. This means adopting post-quantum cryptography algorithms even before quantum computers are capable of breaking current ones. We don't have to wait for the "digital blackout" to begin securing our systems: the migration must begin now , in a planned and phased manner.

But preparation isn't just technical; we must also reflect on the ethical and legal frameworks that must accompany this technology. How should its use be regulated? What limits should be set? Who guarantees that quantum power isn't used for purposes contrary to the collective interest? These questions can't be left to technologists alone. They require a multidisciplinary and global conversation so that new technologies contribute to the world and don't become enemies.

And of course, companies that store sensitive and confidential data today must accept that confidentiality can no longer be guaranteed with outdated standards. The threat of "harvest now, decrypt later" is already underway, and taking it seriously is not an option.

Ultimately, preparing for the quantum future is not just a matter of technological adaptation: it is a matter of digital sovereignty, institutional resilience, and collective responsibility .

7. Conclusion: The most powerful tool ever created… if it doesn't explode on us first

Quantum computing isn't just another advancement in the list of technological innovations. It is arguably the most powerful tool humanity has ever designed . Its potential to solve impossible problems, accelerate discoveries, and reinvent entire industries is as immense as it is undeniable. But so is its capacity to destabilize the foundations on which we currently build our digital trust.

This isn't about demonizing a technology that, if properly applied, could bring extraordinary benefits. It's about understanding that unprepared power is not only useless, but dangerous . That if we arrive late to the post-quantum transition, the cost won't just be technical: it will be social, economic, and strategic.

We need vision, foresight, and coordinated action. Quantum computing must be driven with the same ambition with which a nuclear power plant is built: with excitement, yes, but also with impeccable safety protocols . Because if we don't design the future well, we risk being overwhelmed by this marvel before we can control it.

The good news is that we still have time. The bad news is that the quantum clock has already started ticking.

Tick ​​tock, tick tock :)