Russian physicists have successfully tested airborne quantum cryptography in an urban environment: they combined quantum information security equipment with laser data transmission technology and evaluated the influence of weather conditions on the quality of their synchronization.
Russian physicists have successfully tested the technology of distributing a quantum key over the air in an urban environment. During the experiment they connected points separated by a distance of 180 and 3,100 meters.
As a result of the work, the researchers obtained data on the operation of quantum channel timing systems under various interference conditions, which will allow the technology to be brought to commercial implementation in the future.
Quantum technologies have significantly expanded the possibilities of modern cryptography, explains N+1. If before it was necessary to physically transmit the key necessary to decrypt the message, now the Quantum Key Distribution (QKD) method allows them to be generated simultaneously for both remote users connected by some optical channel. The method is also good because it is sensitive to attempts to intercept a message and is therefore absolutely protected.
state of the art
However, many obstacles remain on the road to mass distribution of this technology. Firstly, the problem is the fragility of the state of quantum entanglement, basis of QKD, since it must be conserved between two photons separated by a large distance. The solution to this problem depends on the optical link. In the most common of them -optic fiber- a distance record of 830 kilometers was recently achieved.
However, it is not always possible to use fiber optics for communication. Although there are examples of quantum communication via satellites, such an expensive technology is justified for long-distance communications, while for points between which there is a direct line of sight, an atmospheric optical channel would be preferable.
On the other hand, in the case of quantum key distribution in free space, achievements have been much more modest and there are no commercially available solutions. In fact, only laboratory facility designs are described in the scientific literature. Therefore, systematic work has been started to find effective solutions to the problem of the distribution of quantum keys in open spaces, in which the experiment of the Russian physicists is framed.
Quantum keys in the air
A group of Russian researchers from the Moscow Technical University of Communications and Informatics (MTUCI), Mostcom (a world leader in the creation of wireless optical communication systems) and QRate (a subsidiary of the Russian Quantum Center) developed an experiment on the transmission of a quantum key over the air in urban areas at a distance of 180 and 3,100 meters, according to a statement.
They were able to combine laser data transmission through the atmosphere with quantum key generation, as well as assess how the quality of communication is affected by various weather conditions.
During the experiment, the researchers placed M1-40GE atmospheric optical communication terminals developed by Mostcom on the roofs of the MTUCI buildings. The terminals transmitted packets at wavelengths in the range of 1550.92 to 1554.13 nanometers. An additional laser at a wavelength of 785 nanometers was used only to obtain service information on air leaks.
As a result, they obtained data on the operation of quantum communication channel synchronization systems in real urban conditions, as well as in the presence of various types of atmospheric (fog, snow, smog) and optical (sunlight and street lighting) effects. town).
Good prospects
Scientists are pleased about the prospects for wireless transfer of the quantum key. Before the end of the year, they plan to conduct another test, the results of which will help finalize the technology to the stage of commercial use.
In August 2021, these researchers conducted the first experiment on the compatibility of quantum cryptography equipment and laser data transmission technology. Then, under laboratory conditions, the scientists tested the possibility of transmitting quantum keys through an atmospheric channel at a distance of 10 meters. The current experiment far exceeds this previous result.
In the future, these developments will be applicable in the implementation of smart city programs and the creation of unmanned vehicles.
They will also help solve the problems of the last mile and the limited amount of radio frequency spectrum in the telecommunications business, the military industry and the public sector, the researchers note.
Quantum Key Distribution Keys
With quantum technologies, it is possible to apply quantum principles to exchange a key between the ends of a communication channel, so that the key is secure against any attack.
Quantum Key Distribution (QKD) is one of these technologies: it not only solves the problem of the threat that quantum computing poses to the cryptographic algorithms in use, but also provides a much higher level of security to any data exchange . This technology requires a high quality fiber optic physical infrastructure.
The viability of QKD has so far been demonstrated in laboratories and in controlled field tests, but there have always been problems in being able to deploy it on commercial infrastructures and in its integration with the operating mechanisms of these infrastructures.
Trends21, 14 June 2018