Physics is hardly the most popular course in school and within that field quantum mechanics certainly ranks last among students. Subatomic particles behave in such bizarre ways that even Albert Einstein, the man who paved the way for quantum, kept his distance throughout his life. In fact, he hated the whole idea. For him, the last straw was the concept that two identical particles, when created as pairs, could remain connected for all time, even if separated by huge distances.

Physics is hardly the most popular course in school and within that field quantum mechanics certainly ranks last among students. Subatomic particles behave in such bizarre ways that even Albert Einstein, the man who paved the way for quantum, kept his distance throughout his life. In fact, he hated the whole idea. For him, the last straw was the concept that two identical particles, when created as pairs, could remain connected for all time, even if separated by huge distances.

No one has ever succeeded in providing mathematical proof of this phenomenon, which is known as quantum entanglement. In 1975, a Russian scientist even demonstrated that, in the world of quantum physics, it would be impossible to build a functioning computer. However, in 1982, the brilliant US physicist Richard Feynman suggested a solution to the problem: turn around and let the quantum particles themselves do the computing!

Quantum computers would then be so powerful that no encryption method would be safe from being cracked.

**Bernd Schöne**

is a veteran German Internet journalist and an expert on cybersecurity

If he hadn’t been a Nobel Prize winner, probably no one would have listened. How on earth could particles be taught to perform computing tasks? To do so would mean locking them up in tiny cages, a kind of test tube constructed out of magnetic fields, in which they would “compute” with the help of laser bursts or microwaves. The interference patterns created would constitute the results. Impossible – or at least everybody thought so at the time.

Nevertheless, the concept took hold in the minds of a handful of very intelligent people and, over time, it started to assume the nature of a viable research project. Since 1985, we have known that it is in fact possible, at least in theory, for a quantum machine to perform everyday computing tasks. The tricky part was translating theory into practice and actually building one.

Where a classical computer uses binary digits, or bits, to perform calculations, a quantum computer uses qubits – and it works incredibly faster than the classical model. Qubits can be created using any quantifable material that can be isolated; materials could comprise individual atoms or ions in magnetic fields, electrons in solids, or the spin of an atom’s core.

Bits can exist in two states (either one or zero). Qubits, on the other hand, can exist in a number of diﬀerent states simultaneously, thanks to the superposition principle. Superposition means a number of quantum states can be added together, akin to a child stacking toy bricks, and the result will be another valid quantum state. Therein lies the enormous power of the quantum computer because it needs far fewer steps to calculate its results than a traditional electromechanical computing machine. In 2001, IBM presented the world’s first quantum computer. It contained seven qubits and was capable of answering simple mathematical questions. Should the number of qubits actually reach 1,000 or more, it will be the last time data security experts will be able to enjoy an undisturbed night’s rest. Quantum computers would then be so powerful that no encryption method would be immune to being cracked.

The situation gets worse because the public/private key architecture, core to current cryptographic systems, would also come under attack. Quantum methods would provide the simplest way to break encryption. As far back as 1994, a Massachusetts Institute of Technology (MIT) professor, Peter Shor, developed an algorithm to break numbers down into their prime factors. If the Shor algorithm ran on a quantum computer it would be able to decode the strongest crypto keys in minutes – if not seconds.

In 2015, the US National Security Agency (NSA) announced that, in future, it would only use encryption systems capable of withstanding attacks by quantum computers. In response, the National Institute of Standards and Technology (NIST) made a call for systems that could meet NSA’s demands. Early in 2017, German processor manufacturer Infineon announced it had the first quantum-proof security chip. Dubbed New Hope, it is currently among the submissions being evaluated and the firm’s hopes are high it will be the one to turn the tables on quantum-age threats. The submission deadline was in November 2017 and eggheads at NIST and NSA are currently evaluating the entries.

Time is running out. While hackers may not be able to buy a working quantum computer at their local hardware store yet, a simpler, cheaper solution is just around the corner. Quantum simulators will soon be tailored to address a single computing function (such as cracking crypto keys). Who knows, maybe these simulators are already here in the deep recesses of some government’s security agency.