06.03.2024
How satellites protect our data
Secure Telecommunications and Secure Encryption
How Satellites Protect Our Data
Digitalization and globalization require secure telecommunications, and this, in turn, requires secure encryption. Ernst Piller of St. Pölten University of Applied Sciences has been researching data encryption using satellites as part of a research project funded by the Austrian Research Promotion Agency (FFG).
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Previous encryption methods, also known as cryptography, rely exclusively on mathematical methods. In contrast, physical methods, particularly in key management, offer a new dimension in security.
These physical methods began with "quantum cryptography," as presented by Nobel Laureate Prof. Zeilinger. It is now available in practice as a highly secure solution. However, this method is very complex and expensive, especially over long distances. However, since data encryption must be end-to-end secure, a large number of communication partners quickly emerge in international deployments, which is not feasible with quantum cryptography on a mass scale.
In contrast, research has been underway for around 15 years on a new method based on the reciprocity of radio transmission and the measurement of radio channel properties, which is suitable for mass use and cost-effective. With high-frequency radio transmission in both directions, similar measurement results are achieved on both sides (sender and receiver). The pattern of the main signal and delayed echoes is random and only the same at both receiver sides, allowing random data to be generated that cannot be intercepted by an attacker (who measures different values). The measured values form the basis for determining an identical cryptographic key on both sides in a further processing step. Since the measurements practically do not change without changes in the environment, the greatest challenge is the required dynamic range of the measurements, which in practice can only be sufficiently achieved with moving objects. However, this method is only suitable for short distances, up to approximately 20 km.
In the KIF research project, funded by the Austrian Research Promotion Agency (FFG) as part of the KIRAS security research program, the St. Pölten University of Applied Sciences has succeeded in making the technology applicable for long distances, i.e., using satellites. It is therefore called "satellite cryptography." The aforementioned challenge of "measurement dynamics" is easily solved here by the movement of the satellites.
A complete satellite cryptography system consists of two terminal devices from the two communication partners and several satellites. The two terminal devices communicate with each other by sending and receiving signals to and from satellites, performing measurements (propagation time, phase angle, etc.). The satellites can be LEO satellites (approx. 1,000 km altitude) with a transparent transponder, like hundreds already orbiting the Earth, or geostationary satellites (approx. 35,700 km altitude).
The research results have already received multiple awards, including first place at the riz up GENIUS competition in the "Ingenious Research" category, the Lower Austria Innovation Award in the Research category, and the patent pending was recognized as a patent of the century at the 100th anniversary celebration of Lower Austria.
Work is currently underway to develop a commercial solution.
From February 4, 2024, to May 26, 2024, satellite cryptography will be part of the current exhibition on innovations in aerospace at the Vienna Technical Museum.