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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: 2) by takyon on Tuesday October 03 2017, @11:31PM (2 children)
It's better than a one-time pad because it should also be unbreakable if done right [wikipedia.org], but doesn't have the practical issues [wikipedia.org] of the one-time pad.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Informative) by edIII on Wednesday October 04 2017, @12:43AM (1 child)
You need to slow down there a little :)
QKD is not quantum encryption, of which I know of no at-rest quantum encryption anywhere for that matter. So only the key distribution method is quantum, of which they say as much in the article and state that it isn't unbreakable. Furthermore, even in fully quantum based communications, the streamed content is plain text not cypher text. The security is established by more or less knowing that the link is being eavesdropped on so that you can stop transmitting plain text. Quantum is never unbreakable, it's just a plain text conversation snapping shut the instance you open the door to the room so speak. Similar to the refrigerator light paradox. Is it on? :)
In the end, you are still using conventional non-quantum encryption algorithms. None of those have been proven to be unbreakable like OTP has. This QKD cannot be better than OTP, if it requires to OTP to work. It's QKD-OTP.
I'm with Frojack on the "sciency stuff". You might not be able to measure something without changing it, but is that really the sum totality of the attack vector? I remember reading something interesting in a science article some time back where dimensionally speaking information was leaking at a "higher harmonic" and that events happening in one dimension were causing an event in another. Probably explained that awkward as hell, but the bottom line was that the information may be leaking through in other dimensions in ways we don't understand yet.
I'm not convinced that a quantum based side channel attack isn't possible on quantum communications.
OTP is different. At rest it is purely, and mathematically proven to be, unbreakable. Like traditional methods, its greatest vulnerability is the implementation of the key exchange. Others were, again, fairly unwise use of the key. The encryption method itself though is perfect, so as long as the input is high entropy, and zero bits of the key are used more than once, it is completely unbreakable. That, and OTP works at rest, and that is highly valuable.
The Wikipedia article you've referenced points out that QKD+OTP is incredibly secure. Redundant for communications, but provides the at-rest capability you need for many encryption use cases. However, it is also extremely unlikely to provide the required bandwidth. You would be sending one bit to receive it back as cypher text. Which would be unreliable, so add on some methods to make it reliable, and that's where it starts to get expensive to send a bit. You may need to add a bit (no pun intended) more to overcome OTP's stream cipher vulnerability. I sincerely doubt that the satellites have that much bandwidth and can escape the costs that force us to use lesser algorithms to squeeze more out of keys.
There is one more thing about OTP... You could use it with bad actors intercepting your data, where with quantum methods you just need to shut up. Quantum on its own doesn't have it what it takes.
Technically, lunchtime is at any moment. It's just a wave function.
(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.