How quantum computers threaten cybersecurity

Tokyo Quantum computers promise a major technological leap: They can run through the most complex simulations in seconds and thus replace years of laboratory studies on new drugs, decisively advance the development of artificial intelligence (AI) – or even reliably predict the weather.

The Japanese IT group Fujitsu is developing such a quantum computer. In an interview with the Handelsblatt, however, technology chief Vivek Mahajan also warns of risks for cyber security: once the quantum computers are powerful and stable enough, they could easily crack many common encryption systems.

German companies should therefore also think about the challenges and, for example, switch the encryption of their data to “quantum-safe” methods. Because the quantum computers are still too small and unreliable to become a danger. But Fujitsu CTO Mahajan warns: “The thing about quantum computing is that it could be as far away as six months or as long as six years.”

The probability of Breakthroughs are increasing because more and more companies are doing intensive research on quantum computers. The demand has increased significantly, because “enormous computing power is required for the digitization of business and life and the AI ​​boom,” says Mahajan.

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Quantum computers could bring the next big leap in performance, although they only calculate solutions that a normal computer can also come up with. The decisive factor is speed: Even conventional supercomputers sometimes need many years for the complex calculations, while quantum computers only need a few seconds.

Vivek Mahajan

Fujitsu’s Chief Technology Officer also warns of cyber risks from quantum computing.

(Photo: Martin Kolling)

Many encryption systems are based on the fact that their algorithms exceed the conceivable computing power of future computers so much that it would take hundreds of years to crack them. To put it simply: Today’s computers take too long to guess passwords, quantum computers could try thousands of possible passwords at the same time. Blockchain technology is also vulnerable in this way.

More states, more power

Conventional computer chips were developed from ever smaller circuits and work electronically: each computing unit, called a bit, has either the value “0” or “1”, either the status “on” or “off” – current flows or not. Quantum computers, on the other hand, calculate on the subatomic quantum level, where other physical laws apply.

A quantum bit, called a qubit, can also have both states at the same time during the calculation. As a result, qubits can calculate much more complex data, the performance of a quantum computer doubles with each qubit and thus grows exponentially.

This growth makes progress in development so unpredictable: If a researcher finds the crucial piece of the puzzle to connect qubits in large numbers, the performance immediately increases by leaps and bounds. If a quantum computer surpasses the power required to decrypt common security systems, most codes in the world are theoretically cracked in one fell swoop.

>> Read here: Quantum Computers – The Science Fiction Technology of Google and Co.

A controversial scientific paper from China shows just how explosive the problem is. A group of experts claimed in December that they had used a quantum computer to crack RSA algorithms used, for example, for online banking and data backup.

However, they only deciphered a relatively short code using a small quantum computer with ten qubits. The researchers explained that they had not yet transferred the method to larger computers. As a result, it is not yet clear whether the quantum computer with their method is actually faster than a conventional computer.

Many experts still doubt the statements. André König, head and co-founder of Global Quantum Intelligence, judged in an interview with the online medium “Decrypt”: “The paper itself announces nothing really new.”

The Chinese researchers claimed that only 372 qubits were needed to jump to code-breaking with their method. And although many researchers assume significantly higher numbers, it is clear that the developers of quantum computers are already very close to this leap.

According to Fujitsu, the technological leap comes at 10,000 qubits

But when will quantum computers actually cross the critical threshold to become powerful code breakers? According to the Fujitsu researchers, this goal is not quite that close: a fault-tolerant quantum computer with 10,000 qubits is required to crack the RSA encryption system.

The researchers concluded this from an experiment with the in-house quantum simulator. This is a conventional supercomputer that calculates 39 stable qubits virtually. “It gives you a bug-free environment that simulates a lot of what quantum computers do,” says Mahaja. “I think you can solve 70 percent of the problems you want to solve with quantum computers with them.”

However, cracking encryption algorithms is still part of the remaining 30 percent. Especially since a real quantum computer with 39 stable qubits would need 104 days for this – but that doesn’t exist.

>> Read here: Comment – ​​Quantum computing is not hype, but heralds a new era

The problem is not only the number of qubits, but also their short lifetime and high susceptibility to errors. If our competitors say they have 400 or 500 qubits, but they are all unstable, what good is that to them?” says Fujitsu Chief Technology Officer Mahajan. Because it is very difficult to make the computing units more reliable and to interconnect them in large numbers. In addition, for most methods, the qubits have to be extremely cooled down, close to absolute zero of minus 273 degrees Celsius.

Fujitsus is working with the Riken research institute on its own quantum computer. Yasunobu Nakamura, who is considered one of the inventors of the first stable qubit, is also involved here. Fujitsu’s computer currently has 64 qubits. Fujitsu plans to make the model available to other companies to try out before the end of this year. By 2026, the team wants to increase the device to 1000 qubits.

The race of the great powers

Geopolitically, too, the great powers are in a race to see who will be the first to break through with quantum computers. China is intensively researching the technology, in the USA Google and IBM are pushing ahead and allowing companies access to their research results. In 2021, for example, IBM exported its Q One system to both Germany and Japan in a high-profile manner.

Europe is also involved in research: the German-Finnish company IQM received a capital injection of 128 million euros last year. This week Pasqal from France announced an investment of 100 million euros.

>> Read here: Chip industry in Germany wants to play an important role in quantum computers

Japan is also a serious competitor in the young field of research. Government and industry want to use Japan’s technological strength to establish the country as a quantum player and important supplier of key technologies.

The Indian Mahajan, who switched from IBM to Fujitsu, gives his adopted country a chance to keep up in the global race. “I think Japan has done a good job of keeping basic research alive, not just in the quantum realm, but also in photonics and cellular technology.”

More: Japan is making the race for quantum computers exciting – thanks to a special industrial policy

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