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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 JoeMerchant on Tuesday October 03 2017, @10:51PM (11 children)
I think the point of the quantum channel is that if anyone MITMs the conventional channel, the result obtained from the quantum channel is rubbish - and as such your video should be rubbish too. But, it has been a long time... seems like physics (our understanding thereof) may have changed a bit since then.
🌻🌻 [google.com]
(Score: 4, Interesting) by Anonymous Coward on Wednesday October 04 2017, @12:02AM (1 child)
no, i think you got it. sat bridges the distance and sends entangled photons to each party. they gather and test (that was explained in an article when that sat first went up) (sat does not know which of the thousands of pairs it sent wound up in the final key!) and off they go to the races, having proved to themselves that they have no 3rd party listeners.
the real question is how long we'll keep up dissing and questioning the breakthrough before realizing that this is beyond 'us' today. can't wait for this to go mainstream!
(Score: 2) by wonkey_monkey on Wednesday October 04 2017, @08:02PM
It doesn't matter if it does. It can't know the results of the measurements.
systemd is Roko's Basilisk
(Score: 2) by wonkey_monkey on Wednesday October 04 2017, @08:16PM (8 children)
They can MITM the conventional channel all they want. It's when they MITM the quantum channel that it turns the results into gibberish, for everyone.
systemd is Roko's Basilisk
(Score: 2) by JoeMerchant on Wednesday October 04 2017, @08:32PM (7 children)
Well, I thought that after I posted, but then let it stand because interference on either channel should corrupt the outcome into gibberish.
The "selling point" of quantum is that if they MITM the quantum channel they've destroyed the information, so the receiving party will know that tampering has taken place, or more simply: it's impossible for two parties to receive the information.
Now, what I've wondered is that since this is a statistical process, could they just siphon off a few of the photons - degrading the quantum channel quality for the legitimate receiver but maybe not enough to detect, and possibly siphon off enough to be able to recover the key themselves (assuming they also had access to the conventional channel, etc...) Like these guys shooting lasers out of apartment windows - lasers diverge, what if the snooping party manages to plant a surreptitious receiver next to the legitimate one?
🌻🌻 [google.com]
(Score: 2) by wonkey_monkey on Wednesday October 04 2017, @08:45PM (6 children)
The bits that make up the key are made up of the measured states of individual photons. You can't slice a bit off.
systemd is Roko's Basilisk
(Score: 2) by JoeMerchant on Wednesday October 04 2017, @09:03PM
So every single photon has to be received?
Any time I've seen entanglement experiment details, it's been a statistical thing involving hundreds of photons, or more...
🌻🌻 [google.com]
(Score: 2) by JoeMerchant on Thursday October 05 2017, @02:43AM (4 children)
Also, seems improbable that not a single photon would get lost between the satellite and ground stations...
🌻🌻 [google.com]
(Score: 2) by wonkey_monkey on Thursday October 05 2017, @04:20PM (3 children)
They don't need to receive every photon. They'll ignore any moments when only one, or neither, of them receives a photon.
systemd is Roko's Basilisk
(Score: 2) by JoeMerchant on Thursday October 05 2017, @04:58PM (2 children)
Then they will get an incomplete key. Most keys schemes are not tolerant of missing bits.
🌻🌻 [google.com]
(Score: 2) by wonkey_monkey on Friday October 06 2017, @03:40PM (1 child)
In QKD you end up discarding half the photons anyway. You only make the key out of the measured states of the photons that you both confirm to have received, and to have measured in the same way, which you confirm over the classical channel.
systemd is Roko's Basilisk
(Score: 2) by JoeMerchant on Friday October 06 2017, @05:37PM
Ah, that's workable...
🌻🌻 [google.com]