How can we guarantee that data transmitted over the internet can only be read by the intended recipient? Currently, our data is encrypted using mathematical methods based on the idea that factoring large numbers is a difficult task. However, with the increasing power of quantum computers, these mathematical codes are likely to become insecure in the future.
Encrypted 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 the fact that the information is encoded in individual light particles and then transmitted. The laws of physics do not allow this information to be extracted or copied. When the information is intercepted, the light particles change their characteristics. Since we can measure these changes of state, any attempt to intercept the transmitted data will be immediately detected, regardless of future technological advances," says Tobias Vogl.
The major challenge of so-called quantum cryptography lies in long-distance data transmission. In classical communications, information is encoded in many light particles and transmitted through optical fibers. However, the information contained in a single particle cannot be copied. Consequently, the light signal cannot be repeatedly amplified, as is the case with current fiber optic transmissions. This limits the transmission distance to a few hundred kilometers.
To send information to other cities or continents, the structure of the atmosphere will be used. At altitudes above about 10 kilometers, the atmosphere is so thin that light is neither scattered nor absorbed. This will allow the use of satellites to extend quantum communications over longer distances.
Satellites for Quantum Communications:
As part of the QUICK³ mission, Tobias Vogl and his team are developing a complete system that includes all the components needed to build a quantum communications satellite. As a first step, the team tested each of the satellite's components. The next step will be to test the entire system in space. The researchers will study whether the technology can withstand the conditions of outer space and how the individual components of the system interact. The satellite is scheduled to launch in 2025. However, creating a global quantum communications network will require hundreds, or perhaps thousands, of satellites.
Hybrid network for encryption
The concept doesn't necessarily require that all information be transmitted using this method, which is very complex and expensive. It's conceivable that a hybrid network could be implemented in which data can be encrypted either physically or mathematically. Antonia Wachter-Zeh, Professor of Coding and Cryptography, is working on developing algorithms so complex that even quantum computers cannot solve them. In the future, encrypting most information using mathematical algorithms will remain sufficient. Quantum cryptography will only be an option for documents requiring special protection, such as those used in communications between banks.
Publication:
Najme Ahmadi, Sven Schwertfeger, Philipp Werner, Lukas Wiese, Joseph Lester, Elisa Da Ros, Josefine Krause, Sebastian Ritter, Mostafa Abasifard, Chanaprom Cholsuk, Ria G. Krämer, Simone Atzeni, Mustafa Gündoğan, Subash Sachidananda, Daniel Pardo, Stefan Nolte, Alexander Lohrmann, Alexander Ling, Julian Bartholomäus, Giacomo Corrielli, Markus Krutzik, Tobias Vogl. "QUICK3 - Design of a Satellite-Based Quantum Light Source for Quantum Communication and Extended Physical Theory Tests in Space". Adv. Quantum Technol. (2024). https://doi.org/10.1002/qute.202300343
- Tobias Vogl was appointed as professor of Quantum Communication System Engineering at the School of Computation, Information and Technology in July 2023. His research focuses on optical quantum technologies in crystalline solids. In particular, he investigates fluorescent defects in the 2D hexagonal material boron nitride, which are combined with resonant nanostructures and photonic circuits for use as components for quantum information processing and in quantum networks.
- The QUICK³ mission is an international research project involving researchers from the Friedrich Schiller University Jena, the Humboldt University of Berlin, Technische Universität Berlin, Ferdinand-Braun-Institut für Höchstfrequenztechnik, the Institute for Photonics and Nanotechnologies in Italy and the National University of Singapore
