Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Tuesday October 03 2017, @08:47PM   Printer-friendly
from the yes-and-no dept.

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!


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 0) by Anonymous Coward on Wednesday October 04 2017, @09:15AM (1 child)

    by Anonymous Coward on Wednesday October 04 2017, @09:15AM (#576953)

    And entanglement-based quantum key distribution is non-local OTP generation (well, OK, whether you actually use your shared non-locally generated random data as OTP or as key for other classical cryptographic algorithms is up to you; I suspect the key generation rate of the satellite photons is not large enough for a video stream OTP, so I guess in that case they used another encryption method, or maybe "diluted" the QKD using a PRNG, similar to how /dev/urandom "dilutes" the entropy collected in /dev/random).

    Basically, QKD eliminates the one weakness of OTP: You have to somehow transmit the key (where "written on a CD and carried in a suitcase" is also just one way of transmission), and if anyone manages to intercept that transmission (get hold of the CD to make a copy), he can read the message encrypted with it. With entanglement-based QKD, the key is never transmitted. What is transmitted is entangled states (which are no secret; everyone knows what they look like). Both ends can verify that the states they get are indeed entangled (by measuring Bell inequality violations). And they can use them to non-locally generate the key.

    There's one loophole: AFAICT you cannot use the very same pairs you checked entanglement on to also generate the key (because the check requires communication of measurement results, while those results you use for the key should of course not be transmitted). But exploiting that would require the eavesdropper to know in advance which pairs you use for Bell tests, and which for actual key generation.

  • (Score: 2) by wonkey_monkey on Wednesday October 04 2017, @08:54PM

    by wonkey_monkey (279) on Wednesday October 04 2017, @08:54PM (#577176) Homepage

    There's one loophole: AFAICT you cannot use the very same pairs you checked entanglement on to also generate the key (because the check requires communication of measurement results, while those results you use for the key should of course not be transmitted). But exploiting that would require the eavesdropper to know in advance which pairs you use for Bell tests, and which for actual key generation.

    Doesn't simply checking whether the key ultimately works - encrypt and send something - tell you whether or not entanglement was uncompromised?

    --
    systemd is Roko's Basilisk