Slashdot Mirror

← Back to Stories (view on slashdot.org)

Quantum Cryptography: 100km Barrier Broken

Posted by timothy on from the speaking-of-crypto dept.

jdfox writes "Toshiba Research Europe have just demonstrated quantum crypto over 100km fibre links. Sounds like there's still a fair bit of work to be done before it leaves the lab, but it's amazing that they've got as far as they have. There's another article about it, though still not much technical detail, here on the BBC and here on The Register."

6 of 194 comments (clear)

  1. assumptions by Photon01 · · Score: 4, Insightful

    From the Register article:

    Ultimately, quantum cryptography seeks to deliver a method of communication whose secrecy does not depend upon any assumptions.

    Dosent quantum cryptography depend on the assumption that it is impossible to copy this stream of encoded photons without leaving a trace?

    1. Re:assumptions by djpig · · Score: 4, Insightful

      Hmm, physical laws are actually not facts...

      They are more best explanations for which no counterevidence exists yet or explanations that describe the problem as good as needed

  2. The US Gov is going to LOOOVE this! by Eric_Cartman_South_P · · Score: 2, Insightful
    If the US(TM) Government(R) goes ape shit over the fact that its citizens can use 128bit encryption, what are they going to do about unhackable photons!

    This is great news for privacy. Sure, if Scully and Mulder want your box, they put a camera in your house, sniff the keyboard for the pw, or just take it via a warrent issued from a Judge who stamps his approval on anything that involves encryption and terrorism.

    Overall, great for privacy. I sure as hell want Citibank using this on all their ATMs, Visa on the card readers, etc.

    1. Re:The US Gov is going to LOOOVE this! by jez9999 · · Score: 3, Insightful

      Actually, I think this means fuck all for the individual citizen's privacy. As it requires an unbroken fibre all the way from party A to party B, it would indeed only be appropriate for things like banks to use. Big deal. Think the government wants to spy on the minutia of your bank account? Think that, if they did, they'd have to hack the bank's network to do so, rather than just requiring it in law?

      Where it may have helped is over something like the internet... if an 'unhackable' transport method could be developed, privacy would greatly be benefitted. But as the internet inherently requires data streams to be intercepted and forwarded, usually many times over, this method will do nothing to help regular privacy.

      --
      == Jez ==
      Do you miss Firefox? Try Pale Moon.
  3. No use for anything real by avorpa · · Score: 2, Insightful

    I know quantum encryption is supposed to be the next big thing in cryptography, and make up for all the damage that quantum computers are supposed to do, but I just don't see it. Who has fibre all the way from them to their friend?

    And encrypting each hop from me to my friend seems to hardly help at all. Now instead of the evesdropper being able to put a probe on any of the wires, they have to break into one of the routers. But really, who ever heard of someone stealing credit card numbers by digging up cables and putting a probe on them?

    And besides, this still doesn't solve the authentication issue. You still need to be confident that the person at the other end is who you think they are. And it seems that solving that is at least as hard as doing the encryption once you know who you're talking to. Specifically, it seems likely that quantum computers will break all our current authentication schemes, but we have no reason to believe that they will break our symmetric ciphers. So even for people with fibre all the way to their friend, a provably secure symmetric cipher replacement is not very useful just yet.

  4. Re:Sounds like the press hasn't thought this throu by Ryan+Amos · · Score: 3, Insightful

    Barring what the other poster said, you can also predict transmission times over fiber VERY accurately. Any time spent processing the photon information to create a new photon to retransmit would be longer than the total transmission time. This would be easily detected.

    I have another interesting question though.. Would it be possible to combine this with the "laser teleportation" technology demonstrated earlier this year to have a REALLY secure wireless link? If so, 30 years from now, all communications might be so secure that we wouldn't have to worry about eavesdroppers.