The development of quantum computers poses different challenges for research and society today: On the one hand, the technical feasibility of development and, on the other hand, the possible global impact on digital security.

**1. Technical challenges of quantum computers**

One of the greatest challenges for scientists lies in the basic technical conditions for making the computing power of a quantum computer usable or controllable in the first place. This is due to the extreme sensitivity of qubits: even the slightest external impact can cause them to lose their specific quantum characteristics. Vibrations, magnetic and electric fields, light, temperatures and many other external influences cause errors and can destroy the computing process. In order to keep the qubits stable, they must be well shielded, but it must also be possible to manipulate them to be able to perform a calculation at all. This is like squaring a circle. To achieve this, superconducting qubits, for example, are cooled to temperatures close to absolute zero of –273.15°C and shielded several times from the environment; but even then, this qubit species only ever remains stable for fractions of a second – a minimal time period during which calculations have to take place.

Other qubit technologies such as ions, on the other hand, are much more stable and retain their properties over minutes or even hours, but they take much longer for a single computing step. The main focus of current development is:

- Reducing the susceptibility to errors, e.g., by merging many qubits into a stable "logical" qubit.
- A significant increase in the number of qubits – which, however, usually increases the susceptibility to errors again.

And of course, there is no established software for something that does not yet exist. Quantum computers function with completely different laws than today's computers, which leads to completely new challenges for the software. At this point quantum algorithms are a field that is often overlooked. The fantastic ability of a quantum computer to calculate simultaneously on an unbelievably large number of states is not so easy to use beyond theory. The goal of a calculation is the correct result. But if all the states of the quantum computer had to be read out for this, not much would be gained, because it is a huge number. Therefore, specific algorithms are needed to ensure that only the correct state with the greatest probability remains at the end of a calculation. This is a task that has so far only been solved for a manageable number of problems.

These challenges make it clear how far quantum computers are from being used in our everyday lives.

**2. The challenge of digital security through quantum computers**

In addition to the technically demanding basic requirements for the development of quantum computers and their application, society will also have to adapt to the capabilities of this technology as soon as quantum computers can be used on a larger scale. For it is precisely in the area of encryption, and thus digital security, that special challenges can arise in both the private and professional spheres.

"The digital lockpick of the future" – that could be a headline when it comes to quantum computers and their ability to crack widespread encryption systems in use today. The crypto procedures that make surfing the net secure today must be strengthened in the future and be able to withstand the computations of quantum computers. And also, because supercomputers are becoming more and more powerful, and today's encryption methods are only secure because it is simply computationally too intense to decrypt them over several years.

Quantum computers can crack older systems in the future. However, only if the older systems remain old and are not replaced by new encryption methods. This is what *post-quantum cryptography* is working on, researching quantum-safe encryption methods. As a pioneer, Infineon is actively pushing this research– you can read more about it in our article on post-quantum cryptography.

*Edward Snowden's* revelations in 2014 showed just how great the interest can be: the National Security Agency (NSA) was already conducting intense research on the use of quantum computers in cryptography. Post-quantum cryptography is already displaying initial solutions and successes for these challenges. As with conventional computers, it is up to us humans to decide what potential quantum computers will develop in the future and what they will be used for.