The internet of the future will be quantum, and this is what it will look like

We've been talking about it for at least two years: in research labs around the world, scientists are currently working on a new generation of computers: quantum computers. While classic PCs reach the end of the performance achievable with their microprocessors and their data encoded in binary digits, their quantum version uses "qubits", a superconductor which does not comply with classical physical laws, and which can be in several places in same time, thus making it possible to perform parallel calculations, simultaneously, and not sequentially. In other words, they would make it possible to solve equations that are almost insoluble for traditional computing, with confusing speed.

Quantum computing and cryptography

By multiplying the computing potential of AI systems, future quantum computers could well revolutionize many industrial sectors, from health to chemistry, including industry, IT security, self-driving cars, energy, transport and traffic management.

Quantum computing should also make it possible, according to expert Renaud Lifchitz, to break asymmetric encryption and RSA algorithms, used in almost all areas of web security. RSA encryption is indeed based on the difficulty of factoring large numbers into prime numbers, but with quantum calculations, it would become possible to break the asymmetric algorithm. Cryptocurrencies and their backbone, the blockchain, could not resist such technology either. That's why mathematicians are turning to quantum cryptography to design encryption codes that can withstand hacks based on quantum computers, and to allow us to securely exchange private keys - "quantum keys".

The “quantum key distribution” (Quantum Key Distribution or QKD), on which researchers around the world are working, is presented as a “functional equivalent of the usual asymmetric key negotiation mechanisms used in most communication protocols deployed over the Internet or in private networks”. The particularity of the QKD would be to have a “higher level of security”, notes ANSSI, the National Agency for the Security of Information Systems.

Quantum teleportation

From this stems the idea that quantum computing could allow us to create a whole new communication system, a kind of quantum internet, on which information would be coded and shared in qubits. Like the current internet, it should allow computers around the world to interact with each other. The difference would be that it would network quantum computers. Machines capable of working together simultaneously, to try to solve problems in all areas, but also to communicate in an ultra-secure way; with significantly higher speed and performance in data transport.

Concretely, communications would be, which is not always the case with current networks, unalterable. The exchange of information between your computer and any other device would indeed be secure and completely safe from hackers, because the QKD would make the information confidential, but also “integral” (unmodifiable by a hacker). A quantum internet would also be able to transmit quantum information over long distances, without resorting to vulnerable “trusted nodes”, but through a “secure cloud”, where server users would be unable to see the data of others. . Thanks to qubits, data would be transported from one point to another without alteration, and almost instantaneously; to the point that researchers speak of “quantum teleportation”.

Experiments have been conducted for at least 10 years around quantum entanglement. This phenomenon intimately links the properties of two particles, regardless of the distance between them. They somehow form an indivisible whole, even if they are separated by light years. But it suffices to observe one of the two particles for its properties to change. In 2019, British and Canadian physicists managed, on their own, to carry out the first teleportations of “quantum states” between qubits. The British used silicon chips, which send “entangled” pairs of photons (light particles) to each other. These pairs of photons follow each other until the connection is established and the information is transferred; which would prevent the modification of the data.

On the other hand, the mere act of an intruder intercepting and observing this information in a potential “quantum network” would alter it. Since the properties of a qubit cannot be measured without changing its state, it would indeed be impossible to make exact “copies” of it. This limitation, known as quantum non-cloning, would then prevent a hacker from extracting quantum information without leaving a trace. In addition, thanks to the laws of quantum physics, the machines exchanging this information would be immediately informed of any modification. Thus, on the quantum internet, a third-party intrusion would be systematically detectable and an attempt at interception would be detected instantly: communication would then be interrupted before sensitive information is lost.

A quantum internet well and truly underway

Quantum networks would therefore make it possible to easily create, store and move information, without the constraints of conventional networks: slowness, transmission errors, and packet loss. Canadian researchers from the University of Toronto, who for their part used a photonic "quantum repeater" (a device capable of transmitting quantum information over very long distances via optical fibers), thus created the prototype of a “quantum communication network”, where data is transmitted at close to the speed of light, without any alteration.

At the QuTech research center in Delft, scientists, Dutch this time, are working on a “quantum memory network” transporting qubits and connecting four cities in the Netherlands (Amsterdam, Leiden, The Hague and Delft). A quantum version of Arpanet, the ancestor of the internet. In parallel, a larger European project called Quantum Internet Alliance, aims to expand the Dutch experience on a continental scale. It brings together computer scientists, network and telecom engineers, as well as security experts, with the aim of creating a real “quantum internet”. Other researchers, at MIT and Harvard, are designing “quantum nodes” intended to avoid any loss of quantum signals.

Finally, in China, several teams have been working since 2017 on quantum teleportation from space, using satellites and laser beams. They have already succeeded on several occasions in sending, over very long distances (between 1200 and kilometres), instantaneous, indecipherable and inviolable information. The researchers describe their future network, already operational between Beijing and Shanghai, as a device “that will eventually combine fiber and satellite links”, in order to provide Chinese companies with “trusted technology”.

In short: all this to say that this is not a utopia, but rather a network under construction. Most scientists imagine a first version of this Net with qubit sauce for 2024-2025.

Applications of the quantum internet

The current internet is far from secure. The flaws are numerous, and hackers are constantly exploiting them. With an ultra-secure quantum internet, there is therefore no more risk of hacking (a priori). No more loss or corruption of data, no more slowness, no bugs, no crashes. A revolution, in short. What uses could then arise?

Researchers and proponents of a quantum internet argue that such a network should enable a host of applications not possible with conventional communications. For example, the interconnection of quantum computers, the convergence of high-performance telescopes located in distant observatories, or the development of new methods for detecting gravitational waves. Obviously, the possibility of linking quantum computers together could make it possible to create real “distributed quantum computing architectures”; France, in any case, believes in it, and has been preparing a “national plan” since January 2020 so as not to miss this “technological shift”.

The QKD should also make it possible, according to Stéphanie Wehner, member of the scientific team of the Quantum Internet project at QuTech, “to make new forms of remote computing possible”; for example, access to a quantum computer from its non-quantum machine. “Thanks to the quantum network, you could from home use a very simple quantum device and carry out simulations”.

On the consumer side, a multitude of applications could also emerge, “such as auctions, elections, contract negotiations and accelerated commerce – which could exploit quantum phenomena to make them faster or safer than their traditional counterparts”, observes Jean-Philippe Carville, IT project director at the Paris City Hall, on the website of his association, LUNIL.

The quantum entanglement characteristic of this new communication system should also promote collaborative work, by facilitating tasks that require remote coordination. Synchronizing clocks using quantum entanglement could also improve the accuracy of navigation and geolocation networks, such as GPS.

Finally, the quantum internet would perhaps make it possible to create a truly secure, decentralized and why not close web. ideals of its beginnings: “an open, collaborative and emancipatory tool”, as Tim Berners-Lee, its founder, dreamed. Dreaming is always allowed, right?