A successful experiment by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in cooperation with the Ludwig-Maximilians-Universität (LMU) in Munich has opened up new possibilities in cryptography. For the first time, researchers have managed to transmit a quantum key from a fast-moving object. The quantum data was sent from an aircraft to a ground station via a laser beam.
Key exchange based on quantum mechanics is considered to be absolutely secure against eavesdropping. The quantum mechanical states of individual photons are used for the encryption; attempts at interception disturb the behaviour of the particles and so can be detected immediately. However, quantum cryptography has only been put to limited use so far – the data is usually transmitted via glass fibre so that only limited distances can be bridged. The current flight experiment now proves that the encryption technology can also be used with fast-moving objects and can be integrated into existing optical communications systems. In future, quantum data might also be distributed globally via satellite in this way.
The quantum key transmission experiment took place in Oberpfaffenhofen, using the optical ground station at the DLR Institute for Communications and Navigation and the DLR Dornier Do 228-212 research aircraft. DLR was also responsible for flight certification and campaign planning. The aircraft was fitted with a laser system for the experiment, combining a transmitter for data communication with a second transmitter for the quantum cryptography. The laser beam sent from the aircraft was received by the ground station, recorded with specially developed measuring equipment and analysed. The detailed assessments have now been published in the journal ‘Nature Photonics‘.
Read more at: DLR