Quantum Computers Are More Dangerous Than You Think

Añadido: 2026-05-28

[00:00:00]Qday. That's the name some researchers have given the moment quantum computers finally break the encryption protecting the modern world. The day that encrypted bank transactions become readable, private messages become exposed, and state secrets become vulnerable, and that little padlock icon in your browser suddenly means nothing. For years, this sounded like a distant science fiction scenario, something that might happen decades from now, if it happened at all.

[00:00:30]But new research suggests that Qday may be arriving far sooner than expected.

[00:00:36]Recent breakthroughs have dramatically reduced the amount of quantum computing power needed to crack the encryption systems that secure everything from global finance to cryptocurrency.

[00:00:47]At the same time, quantum hardware is advancing at an extraordinary speed.

[00:00:52]That combination has triggered growing alarm amongst cyber security experts because if quantum computers arrive before the world can upgrade its security systems, the consequences could be catastrophic.

[00:01:06]And there's an even more unsettling possibility. Hostile actors may already be harvesting encrypted data today, storing it until quantum computers become powerful enough to unlock it later. Here at Neo Scientists, we've been following the rise of quantum computing for decades, reporting on the breakthroughs, the setbacks, and the growing warnings coming from the field itself. And in this video, we're going to explore why many experts believe the countdown to Q day may have already begun. We will uncover how quantum computers actually work, where they are fundamentally different from every computer that has come before them, and how these machines could threaten the security of the modern world and unlock breakthroughs in medicine, energy, material science, and even our understanding of reality itself. Because quantum computers aren't just simpler, faster computers. They're machines built on entirely different sets of physical laws. And once they fully arrive, the world may never look the same again.

[00:02:09]Chapter one, the day the internet breaks. You're probably used to seeing a little padlock on the top of your web browser window. It gives you confidence that your online actions are secure, that your credit cards and bank account details are encrypted and immune to attack. On Q day, that little padlock will mean nothing. But it's not just your money that will be exposed when a sufficiently powerful quantum computer is up and running. On Q day, the world's financial systems, including cryptocurrencies, will be open to anyone with access to a machine. National and corporate secret documents and communications will therefore be open to scrutiny. And that includes longheld secrets, some of which will have been intercepted and stored by hostile actors in the encrypted form for decades. in a strategy dubbed harvest now and decrypt later. Surprising as it may seem, today will be the result of a revolution in the way we apply the laws of physics to computing.

[00:03:11]>> Quantum computing uses the principles of quantum mechanics to do things that are just impossible for any standard computer that's only based on the laws of classical physics. For decades, we built our encryption tools on the back of mathematical problems that standard classical computers can't solve efficiently. But the quantum world of ions, electrons, and photons operate by slightly different sets of mathematical principles to classical physics.

[00:03:39]>> Quantum mechanics has all sorts of strange phenomena within it such as quantum superposition and quantum entanglement.

[00:03:46]>> That's why quantum computers are revolutionary. They are built from subatomic elements that follow these alternate principles and so can solve a different set of mathematical problems that protect our encryption thanks to an algorithm invented by MIT mathematician Peter Shaw. But how exactly do these quantum computers come together and what's so special about them? Chapter 2.

[00:04:11]A computer that doesn't follow the rules. Quantum computing's radical potential is a result of the distinction between classical and quantum computers.

[00:04:20]In traditional classical processors, electrons accumulate in a component called a transistor in order to turn electrical currents on and off. That's what's happening at a basic hardware level. That hardware level is then abstracted into information, a series of ones and zeros or binary digits that can represent, say, numbers or letters. But quantum physics teaches us that's not the end of the story. There's a a higher form of information out there which we call quantum information and its units instead of zeros and ones bits are quantum bits. But in a quantum processor information is encoded into quantum wavelike properties of light or particles like electrons and that changes everything. Quantum bits or cubits offer more encoding choices than just ones or zeros. Instead, they can represent any linear combination of ones and zeros. Think of it a bit like a compass. If ordinary bits can either point north or south, cubits can take on any diagonal direction on that compass, which makes it very useful for specific kinds of computation. An example is breaking down a very large number into its prime factors. Take the number 10,43.

[00:05:38]It's actually the product of two prime numbers. 101 and 103. Now, a calculation like this might seem trivial, but it's actually a bedrock of modern encryption.

[00:05:49]In fact, it's basically how a form of encryption known as RSA works. It's a type of problem we call an NP problem.

[00:05:57]Problems that have solutions that are very easy to verify. All you need to do is multiply 101 by 103 to get back 10,43.

[00:06:08]But it's really really hard for people outside a trusted network to guess those prime factors. While a traditional computer would just brute force a solution by manually checking whether a big number is divisible by a super long list of prime factors. A quantum computer can search for solutions much more efficiently. A really good visual metaphor is to suppose we start from some initial point A. We're trying to get to a solution at some location B.

[00:06:39]Well, a traditional computer can only walk in two directions, up and down, left and right, until it stumbles upon the location B. A quantum computer has more directions available to it, or the diagonal directions that can help it find solutions faster. The delicate art of quantum computing is actually about creating algorithms that can massage this compass or quantum state vector. So they point in the direction of useful answers to computational problems. In 1994, Peter Shore proposed such an algorithm that would help quantum computers find the factors of large numbers with ease. It was the first step on the path towards Qday. We've talked about quantum computers and cubits at an abstract level. But what does all of this actually look like? Well, I've come to Quantum Motion here in London to actually find out.

[00:07:35]>> Thank you.

[00:07:37]Yeah. So, thank you so much for having us. Tell us where are we at the moment?

[00:07:42]We are in one of Quantum Motion's lab spaces where we develop our quantum computers.

[00:07:49]And yeah, what we're looking at here is one of the dilution refrigerators that we use to house our experiments and our quantum chips um in the development stages. So pretend like I'm going shopping for a quantum computer. What are all the different parts that I would need to make a working one?

[00:08:07]>> If you think about the hardware that you need to build a quantum computer, you could start at the heart of it, which essentially is the quantum chip. And that quantum chip contains the cubits that carry the information that needs to be stored and processed in a quantum computer. And they are essentially quantum states that need to be manipulated, controlled, and read out in order to really operate the computer.

[00:08:34]And those that that happens using different electrical and magnetic signals. And those signals are fed through the control lines that you can see in this setup. What you see here are the different stages of the dilution refrigerator. So those are temperature stages and the lowest temperature stage is here at the bottom. Every single time I see pictures of quantum computers online, they always seem to look like these golden chandeliers. Is this a universal thing? Why do they kind of look like this or why is this kind of configuration standard?

[00:09:11]>> What you are looking at here isn't so much the the heart of the quantum computer but really the cooling system.

[00:09:16]So that golden chandelier is the dilution refrigerator that we are using to go to the low temperatures. So all the quantum computers that require low temperatures which is typically the chip based approaches they do need setups like this. And the reason they always look similar is that they have different cooling stages. So these different platforms correspond to different temperature stages and we need to operate at the very lowest of those temperature stages. That gives us a few tens of mill. It sounds like keeping things very very cold is a pretty critical part of making a quantum computer work. So tell me why is it that you need to put so much effort to building a refrigeration system like this? the quantum information that we use for the computation is um at very low energy scales and if we operate those those computers at room temperature then there's too much noise and the information gets lost we cannot use it for computational purposes chapter 3 why Qday suddenly got closer quantum computing is now a multi-billion dollar industry and the investment from public and private research efforts is finally paying off. Experts have known since the 1990s that quantum computers could break our encryption protocols.

[00:10:38]However, a huge complication snuck in the following decades that assuaged our fears. Errors. This means that quantum computers tend to accumulate lots of small errors as they perform calculations, rendering their outputs unreliable. This meant that we thought that an actual quantum computer capable of breaking modern encryption would require millions of cubits.

[00:11:02]>> Error correction is going to be fundamental to enable quantum computers to reach very large sizes and solve very large and complex problems. It it's still possible to do really interesting things before the era of full-scale quantum error correction, but it error correction will enable quantum computers to do much more. But we can't breathe a sigh of relief yet. The race is on to build a useful quantum computer that is fault tolerant. And it is here that quantum computers have made huge progress. So thanks to researchers ingenuity, we have significantly squeezed the time span in which quantum computing poses a threat. On the theory front, researchers have optimized quantum hacking algorithms to reduce the actual amount of computing power needed.

[00:11:49]Back in 2019, the best estimate for the number of cubits the quantum equivalent of a traditional computer bit needed to crack RSA 2048 was 20 million. In February of 2026, that number became just 100,000. Another more audacious research team claimed in March 2026 that they had an architecture that could crack state-of-the-art encryption with just 10,000 cubits. That same month, Google's quantum research arm took aim at the encryption underpinning cryptocurrency, which is slightly more resilient to quantum hacking than RSA.

[00:12:26]But Google said that even that fell, saying that they reckon a machine of 500,000 cubits could do the trick in as little as 9 minutes. Google's team has chosen not to release the full details of their decryption algorithm, citing security concerns, but they have said that such a quantum computer could be used to intercept a cryptocurrency transaction and redirect the funds, essentially stealing them in a brief period of time before the transaction is actually recorded. In other words, Bitcoin and other cryptocurrencies also look vulnerable to quantum attack earlier than we previously thought. At the same time, quantum computers have grown bigger and bigger. In 2019, state-of-the-art quantum computers barely passed 50 cubits. Today's largest quantum computers have more than 1,000 cubits, and the largest cubit array, as though it hasn't actually been used for computation yet, has 6,100 cubits. There's been very impressive developments in quantum hardware in recent years and also impressive developments in the architecture and algorithms that run on quantum hardware.

[00:13:36]So what that means is that the time scale to running Shaw's algorithm and breaking some of these cryptographic uh schemes um is not that far away now. You might say within the next 5 years or or so or perhaps even less. So, how has this nightmare scenario gone from being decades away to suddenly being an imminent threat? What happened? Chapter 4, the solutions that led to problems.

[00:14:05]In the past couple of years, several teams have made significant progress towards error corrected quantum computers. Researchers at Google quantum AI have even showed that they can increase the number of cubits in their willow quantum computer in such a way that a bigger machine actually makes fewer errors. This is exactly what is necessary to make large fault tolerant machines a reality. And then in a moment that crystallized what's at stake, a team at the University of Texas at Austin showed that these machines really are all we hoped and feared. They used a 12 cubit quantum computer to perform a computation that would require almost 30 times more classical computing power. A rigorous mathematical investigation of the protocol involved showed that classical algorithm could only achieve the same performance with 330 bits. The result is mathematically bulletproof, meaning that we know that the so-called quantum advantage is proven and permanent. Though this computation wasn't exactly useful in itself, it heralds an imminent practical advantage for these machines.

[00:15:14]>> We wouldn't say that we've as a community have yet got to this point that people call practical quantum advantage where you use a quantum computer to solve a problem that's of genuine commercial utility or you know a utility for a um an end user beyond scientific experimentation.

[00:15:33]But we think that this threshold is is very close now. And what this means is that if you had a large enough quantum computer, you would be able to uh to break these crypto systems and for example, you'd be able to steal quite a lot of Bitcoin.

[00:15:48]>> Hence the Qday problem. Okay, this all sounds pretty freaky so far, but there's a good reason why we're not just pulling the plug on every quantum computer in the world. Because quantum computers may also help us solve problems that ordinary computers never could and even uncover new truths about the universe itself. If you're curious about other imminent technological breakthroughs, there's no better place to uncover them than New Scientist. We're founded in 1956. It's almost our 70th birthday for all those interested in scientific discovery and its social consequences.

[00:16:23]And ever since, we've been asking the big picture questions about technology, the universe, and what it means to be human. And these are just some of the topics we explore each week. From in-depth reporting on quantum computing, how these machines work, when they might change the world, and what's hype versus reality to the bold new era of space exploration and expert analysis of the science behind aging. With a new scientist digital subscription, you'll get access to all of our award-winning journalism, including daily news to keep you up to date and deep dive features.

[00:16:53]Some of them commissioned by me so you're never without something fascinating to explore. So if that sounds like something you'd enjoy, why not try us out and keep discovering? You can get a month's unrestricted digital access for free today at newcientist.com/youtube.

[00:17:07]Chapter 5, the machines that could unlock new physics. As someone once said, with great power comes great responsibility. And although there is dangerous potential, physicists are already using the power of quantum computing for good. A growing pile of quantum algorithms promises to have a huge impact on science and society as soon as the quantum machines are fully up and running. It is no exaggeration to say that seemingly obstruuse theory of quantum physics has already transformed the way we live. Without quantum theory, there wouldn't be any fiber optics, no internet, no smartphones. But physicists have long suspected that another transformation could happen if we were able to take devices that not only benefit from quantum effects, but use them as that main resource in order to perform perfect simulations. It was way back in 1981 that physicist Richard Feman showed that the best way to simulate nature was to change our ideas of what a computer can be made of. Let the computer itself be built of quantum mechanical elements which obey quantum mechanical laws. He said that would mean the simulation was built on exactly the same processes as nature itself and thus had no need for compromising approximations.

[00:18:24]>> So there are things quantum computers we know will do fundamentally more powerfully and better than a conventional one. And those things when we get them working they demonstrate advantage quantum advantage or another phrase now popular is quantum utility.

[00:18:39]The key thing that makes quantum computing incredibly useful for material science and chemistry is that quantum computers can natively model quantum mechanics. So if you want to model a physical system highly accurately at the atomistic level where quantum correlations are really important, quantum computing enables you to do that directly whereas standard computing pays an exponential cost to do that accurately.

[00:19:05]>> There's a vision for true quantum simulation is now becoming a reality.

[00:19:09]It's still bumping up against the temporary problem of errors and the difficulties of scaling up the number of available cubits. But within a few years, they might be able to handle problems in chemistry and material science that classical computers simply can't. For instance, in 2024, quantum algorithm firm Phasecraft, which was founded by Ashley Montro, published a technique for making quantum computing simulations of materials run a million times faster. In the past year or so, several quantum computers have been used to perform computations in the physics of materials, high energy particles in a way that may soon rival or surpass the best traditional computing methods.

[00:19:51]>> If you say, if I've got a machine and inside it can process quantum information, what would it be good for?

[00:19:58]Where should I look in the world to find the things that it' be good for? You should say, well, where where is the quantum stuff happening? It happens at the level of uh material science and chemistry right down at the base level of reality. It's all quantum physics.

[00:20:12]Some of the most important applications of quantum computing in material science are likely to be in clean energy. So developing better batteries, better solar cells, maybe better catalysts. Um, and in all of these cases, the idea will be that we'll use quantum computing to screen hundreds of potential materials for their desirable properties, meaning that we don't need to actually test them out in the lab. Um, we can just rule them out or rule them in at a very early stage and maybe even design breakthrough materials that have properties we didn't even imagine in advance. So, basically, places where we're held back because the problems are quantum in their nature. If we build a machine that has controlled quantum physics inside it, then we can we can have those things. So, a golden age of discovery powered by quantum computers. That's the dream.

[00:21:05]>> So, quantum computers could find use in figuring out the properties of molecules that could upgrade the catalyst and fuel cells, improve chemical battery performance, provide better ingredients for the next generation of solar panels.

[00:21:19]In the field of material science, they could help us model and create better high temperature superconductors that don't have to be cooled. Quantum computers could also boost drug discovery. In fact, they're already being used for calculations that help us identify the best ways for drugs to find a biological molecules and to predict which potential drug molecules may ultimately prove to be toxic. While the deep impact of those kinds of advances may be a way off still, quantum computers are actually already helping basic science. In fact, I recently wrote a very cruel article where particle physicists use quantum computers to observe particles emerging out of empty space for the first time. So, if these machines are already powerful enough to shed light on the fundamentals of the universe, what's stopping them from changing everything in society right now? Chapter 6, the race against Qday?

[00:22:18]The answer to that question is not much.

[00:22:21]The remaining barriers to full quantum computing are what researchers would refer to as engineering challenges. It's all about scaling up and correcting errors. And here researchers are already making progress.

[00:22:34]>> Quantum computing and quantum computers are now scaling up to really impressive sizes which are beyond the capacity of even the world's best supercomputers to reliably simulate. And I think that it's it's certain now that there's no fundamental limit that stops us from scaling up quantum computing to a larger size. Dutch startup Quantare has a quantum processor unit architecture that promises to incorporate 10,000 cubits in a working machine within 2 and 1/2 years. Several other firms such as IBM and Quantum aim to build large quantum computers on a similar time scale. QR plans on 10,000 cubits made from ultra cold atoms within just a year. Error correction is a rapidly advancing field and a recent surge in progress has made researchers super optimistic. At the International Quantum Academy in China, a team has recently demonstrated that just two superconducting cubits can be combined with a tiny resonator to make one larger cubit that both makes fewer errors and can automatically flag an error when it happens. They then went a step further to show how three such cubits can be grouped together through quantum entanglement for building up computational power without surreptitious errors. And there's no shortage of funding to make this future happen. The quantum computing industry is already projected to keep growing from $1.07 billion in global investment in 2024 to about $2.2 billion in 2027, according to one survey. All of this leads experts to plead for urgent replacements to our vulnerable encryption systems before Qday comes over the horizon.

[00:24:20]>> So really now's the time to move away from standard cryptographic schemes to ones which are designed to be secure against quantum attack. And the good news is that these schemes exist and there many um organizations have already done this.

[00:24:32]>> Even some internet browsers already offer encryption impervious to quantum attacks. This is known as postquantum cryptography.

[00:24:41]Google has recently urged a migration to postquantum cryptography by 2029. The US National Institute of Standards and Technology in Maryland has also developed several postquantum cryptography algorithms and the US federal government is aiming to migrate to using them by 2035. But the advice is that organizations should begin their transition as soon as possible.

[00:25:05]>> It's a bit like it's been likened to the millennium bug, right? the the idea that everything was going to stop working when the millennium flicked around and it didn't. But perhaps the reason it didn't stop working is that people had been panicking about it for like two or three years and upgrading all the software in the airplanes and the nuclear power stations and the hospitals. So we're in that regime of trying now to make sure that everything that really matters is quantum safe before we get to Qday.

[00:25:29]>> Qday is coming and no one knows exactly when. The deep revelation from all of this is that computation is not the solid well-defined process we once thought because it's based on the laws of quantum physics. Quantum computation can be much more subtle and interesting and dangerous than we had ever imagined.

[00:25:49]But quantum computers are just one consequence of a much bigger discovery.

[00:25:54]Because quantum mechanics didn't just change the future of technology, it changed our understanding of reality itself. Check out our video where we explore the bizarre quantum world where particles can exist in multiple states at once and reality may be split into parallel worlds and even time itself might not work the way we think it This