How can we ensure that data sent over the internet only reaches the recipient? Currently, our data is protected using encryption methods based on the assumption that factoring large numbers is a difficult task. But as quantum computing advances, these encryption methods may become vulnerable and potentially ineffective in the future.

Encryption using physical laws

Tobias Vogl, professor of quantum communication systems engineering, is working on an encryption process based on principles of physics. “Security will be based on information encoded in individual light particles and then transmitted. The laws of physics do not allow this information to be extracted or copied. When information is intercepted, light particles change their properties. Since we can measure these state changes, any attempt to interfere with the transmitted data will be prevented by future technological advances.” Whatever it is, it will be noticed instantly,” says Tobias Vogl.

The biggest problem of the method called quantum cryptography is the transmission of data over long distances. In classical communication, information is encoded in many light particles and transmitted through optical fibers. However, information in a slice cannot be copied. As a result, the light signal cannot be amplified multiple times as with existing optical fibers. This limits the information transfer distance to a few hundred kilometers.

The structure of the atmosphere will be used to transmit information to other cities or continents. At altitudes greater than 10 kilometers, the atmosphere becomes so rarefied that light is neither scattered nor absorbed. This will allow the use of satellites to extend quantum communications over long distances.

Satellites for quantum communications

As part of the QUICK³ mission, Tobias Vogl and his team are developing a complete system containing all the components needed to create a satellite for quantum communication. In the first phase, the team tested every component of the satellite. The next step will be to test the entire system in space.

Researchers will investigate whether the technology can withstand space conditions and how the individual components of the system interact. The launch of the satellite is planned for 2025. But creating a comprehensive quantum communications network would require hundreds, perhaps thousands, of satellites.

Hybrid network for encryption

The concept does not require transferring all information using this method, which is very complex and expensive. It is possible to implement a hybrid network where data can be encrypted physically or mathematically. Antonia Wachter-See, professor of coding and cryptography, is working on the development of algorithms so complex that even quantum computers cannot solve them.

In the future, it will still be sufficient to encrypt most information using mathematical algorithms. Quantum cryptography can only be used for documents that require special protection (for example, in communications between banks).