the Austrian researchers have reached a decisive step to secure Internet communication: The Team were the first to connect four of the participants in a network with quantum encryption so that everyone could communicate with each tap-proof. The scientists, Rupert Ursin from the Vienna Institute for quantum optics and quantum information of the Austrian Academy of Sciences and their network architecture in the British journal "Nature". As the number of participants easy to expand, could pave the method to a wide application of the so-called quantum cryptography in the Internet the way, say the researchers.
The quantum cryptography a for physical reasons, tap-proof communication promises. For this purpose it uses a phenomenon of quantum physics, according to the rules of two particles in a joint state can make, even if they are subsequently separated over long distances. In this state, the entanglement properties of the two individual particles are undetermined. Is then measured in one of the two particles is a property like, for example, the vibration direction, the other particle instantaneously a corresponding property, and the entanglement ends.
In this way, it is possible to produce bug-proof key at the transmitter and the receiver. To be exchanged because of this purpose, only single light particles (photons), can not be intercepted by the key - because according to the laws of quantum physics, it is impossible to copy the quantum state of a single light particle without error. An eavesdropper cannot disguise his presence, therefore, would immediately reveal. The encrypted message is then exchanged in the traditional way.
made in the past, in this way, according to the researchers most, however, only two participants with a guaranteed secure line to connect. Further Connections are complicated, vulnerable, and with communication constraints. The Team provided four participants from a Central source with entangled photons, so that all four of cryptographic keys generated and used for tap-proof communication could use.More about
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"A key advantage of this architecture is its flexibility," emphasizes Ursin, in a communication to the Academy. "We are in the position to integrate new communication partner in the quantum network, and with only minimal intervention. Thus, it is shown that Quantum networks can become a reality - for Everyone.“ (dpa)