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Hackers, take notice: Ultrasecure quantum video chats are now possible across the globe.
In a demonstration of the world's first intercontinental quantum link, scientists held a long-distance videoconference on September 29 between Austria and China. To secure the communication, a Chinese satellite distributed a quantum key, a secret string of numbers used to encrypt the video transmission so that no one could eavesdrop on the conversation. In the call, chemist Chunli Bai, president of the Chinese Academy of Sciences in Beijing, spoke with quantum physicist Anton Zeilinger, president of the Austrian Academy of Sciences in Vienna.
"It's a huge achievement," says quantum physicist Thomas Jennewein of the University of Waterloo in Canada, who was not involved with the project. "It's a major step to show that this approach could be viable."
I can't wait to use this!
(Score: 1, Interesting) by Anonymous Coward on Wednesday October 04 2017, @10:03AM
The problem with at-rest quantum encryption is that we don't know how to preserve quantum states over extended periods of times (an encryption method where you have to decrypt and re-encrypt your document every few milliseconds, or even every few seconds, isn't exactly useful). If we had long-term quantum memory (where long-term means something like months or even years), at-rest quantum encryption would be feasible.
Indeed, it would be rather easy: Just generate entangled pairs of qubits, where one side is the key, and the other is the memory. You can encode the data into the memory qubits, even without having the key qubits, but you cannot read them out without the key qubits; moreover, the key qubits cannot be copied (the no-cloning theorem of quantum mechanics); any attempt to do so would destroy them. And as bonus, every qubit could store two classical bits in that scheme (it's basically just superdense coding).
What this scheme would not do is to make the data tamper-proof (while you cannot read it out, you can easily flip some bits if you know where they are). But give that this is the most immediate method that comes into mind, I'm sure that more sophisticated schemes could fix that, too (and probably smart people already did think of such schemes). But then, without long-term quantum information storage, this is all very theoretical anyway.