How data can be protected from attacks by quantum computers

The secure encryption of data, which prevents access and manipulation by unauthorized persons, is a central requirement for many digital applications - whenever sensitive, confidential and sensitive information is involved. This ranges from online banking to the exchange of secret data between state institutions.

There are a number of methods that can be used to encode data in such a sophisticated way that even supercomputers cannot decode them in a reasonable amount of time. This is generally considered safe.

However, some of the encryption methods commonly used today will probably no longer be secure in the foreseeable future. Namely when quantum computers are able to break these codes. Nobody can say with certainty whether and when the performance of quantum computers will be sufficient for this. But theoretically they have this power and, according to experts, it seems to be only a matter of time before the technology of these exotic computers will be ready.

It is therefore advisable to prepare for the era of quantum computers today and to develop alternative encryption methods that can also withstand the attack of a quantum computer.

One way is to strike back with the weapons of quantum physics and use them for rock-solid encryption. The so-called quantum encryption uses the entanglement of light particles. A pioneer of this technology is the Viennese physicist Anton Zeilinger, who was the first to transmit encrypted data using entangled light particles, initially in the laboratory, then also through kilometers of glass fibers and finally also wirelessly through the air.

Zeilinger successfully conducted the first experiment back in 1999. Five years later, his research team exchanged entangled photons via a 600-meter-long fiber optic cable between Vienna City Hall and a bank branch.

In 2012, entangled photons were transmitted over a distance of 143 kilometers from the Canary Island of La Palma to neighboring Tenerife. Zeilinger was awarded the Nobel Prize in Physics in 2022 for this groundbreaking work.

So far, the Chinese have been in the lead in the practical application of this technology. In 2017, they launched a quantum satellite that enables tap-proof communication between several base stations.

In Europe, the importance of quantum communication has also been recognized. The European Union is now funding the QUDICE project with 4.3 million euros, in which space-compatible hardware for highly secure quantum communication via satellites is to be developed.

At the heart of this is a miniaturized source for entangled photons, which is said to be only about the size of a tetrapak milk carton. It will be developed by an international team of researchers over the next three years. Institutes and companies in Italy, Spain, France, Malta and Germany are involved. In Germany, it is scientists at the Fraunhofer Institute for Applied Optics and Precision Engineering in Jena.

The common goal is the development of a photon source that provides one billion entangled light particles per second. This enables a correspondingly high bit rate. According to the researchers, the current state of the art is several orders of magnitude below the target rate.

The new hardware should one day become the basis for a European satellite network with which data can be exchanged securely. The first step towards developing a highly secure pan-European infrastructure for more data security was taken in 2019 with an agreement between the EU Commission and the European Space Agency Esa.