Many years ago, it was predicted that quantum computers would soon turn previous computers into scrap iron, but this has never materialised. Like doomsday prophets, experts have regularly had to postpone „doomsday“ to the future. As with other foreseeable events that will only become relevant in the long term — climate change or demographics — politics, business, and the public gradually become numb. The warnings fizzle out.

This also explains why the latest warnings from the German Federal Office for Information Security (BSI) about the „post-quantum threat“ often fall on deaf ears. However, it would be better if at least the economy, and the financial sector in particular, were all ears this time. After all, the associated dangers for established data and communication structures are now genuine: Universal quantum computers are now close to being ready for use. They can crack current encryption technologies in no time at all. This applies not only to data storage but also to all forms of financial transactions, payment and communication processes. Cryptography can be found everywhere on computers, smartphones, chip cards, payment terminals, and the Internet.

Until now, quantum computer researchers have faced the almost impossible task of constructing a computer that is virtually based on light, works at extremely low temperatures and is capable of measuring and reading out quantum mechanical shifts. In the meantime, the first devices are already working in particular applications, and some algorithms can actually be used and minimize the previously large margin of error.

Even though Winfried Hensinger, a physicist at the University of Sussex in Brighton, says that computers are still „useless at the moment“, he is also co-founder of the start-up Universal Quantum, which can already report several breakthroughs. In Germany, too, large corporations such as IBM and Google, as well as research institutes in Munich, Jülich, Leipzig, Stuttgart and Darmstadt, are developing such devices. German scientists are well-represented in cutting-edge research. At the same time, the start-up scene is also highly active, and some of their devices are already being trialled. This is extremely important for the future structure of quantum computers, their stability and their scalability.

Management consultants McKinsey see a market worth between 394 and 700 billion dollars by 2035. IBM expects the first computers that are superior to traditional computers as early as 2026, while the Helsinki-based company Algorithmiq predicts that quantum computers will even be used on a large scale in five years.

However, quantum computers also pose significant challenges for businesses and society because they cause tectonic fractures due to their enormous computing power. On the one hand, this property is beneficial because new materials can be researched, better medicines can be designed, and infrastructure optimisation can be facilitated. Not to mention that research can be catapulted forward in all areas if there is sufficient computing time and computing power available.

However, the established digital infrastructure must be completely revised and adapted, which is already a challenge under normal circumstances. This is because quantum computers remove a central security on which the infrastructure is based: That the encryption techniques are actually secure. However, while conventional mainframe computers would take up to 30 years to crack standard encryption, quantum computers with the Shore algorithm can do this in a fraction of a second — a piece of cake.

It's hard to imagine what it would mean if this technology fell into the wrong hands! Encryption techniques must, therefore, be hardened, new standards developed, and better hardware supplied in order to guarantee data security in the post-quantum age. Post-quantum cryptography already exists, such as crystal cyber technology, which quantum computers are also struggling with. But it also needs to be implemented. However, companies, authorities and infrastructure operators are apparently finding it difficult to prepare for this right now.

BSI President Claudia Plattner, therefore, recently warned of this „genuine danger“. Cyber experts are predicting an imminent „cryptocalypse“, the collapse of confidential communication. The Global Risk Institute currently estimates the risk of this at 1 in 7, but by 2031, it will be 1 in 2. A new encryption standard for post-quantum cryptography has been available since the beginning of August. The American National Institute of Standards (NIST) has published a specification that European standard setters are also likely to follow.

But the changeover should happen now because cyber criminals are not waiting until quantum computers are available on a large scale. For one thing, we don't know whether companies are already more advanced than they admit. For another, bad guys are already collecting encrypted material in petabyte dimensions according to the motto: Harvest now, decrypt later. Much of the information obtained in this way is likely to still be explosive in a few years.