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"Quantum supercomputers promise to be exponentially faster and more powerful than traditional computers, Yu said, and can communicate with immunity to hacking o

• kristopolous 11y ago
  are you familiar with the potentials of "quantum cryptography"? If not, just do a web search ... that was the reference here. I'm not a physicist so I can't speak with any authority on the claims but Bruce Schneier in Applied Cryptography claimed that a system which used the principles of quantum cryptography as the transport of the data had already been developed and deployed at great cost between a few key organizations, and this was in a 1996 book. I'll use this as a basis for a [fallacious] appeal to authority argument here and claim that the "less hackable" claim can't be dismissed outright. But again, I'm not even going to attempt to make any physics claim here --- I simply don't have such credentials.
  • dogma1138 11y ago
    Those systems afaik currently do not encrypt data but ensure that no one is tapping into the fiber and retransmitting the signal as they cannot reproduce the photons in their original quantum state. It's pretty standard these days for government point to point links that use existing laid fibers or go through existing metro ducts. http://www.lanl.gov/projects/feynman-center/technologies/information-technology-communications/quantum-enabled-security-qes.php http://www.lanl.gov/projects/feynman-center/technologies/inf...
    • vectorjohn 11y ago
      The quantum part simply allows perfect distribution of keys. So person A can tell person B what key to use, and person B can know with certainty that nobody else saw it. Then they just use regular encryption.
      • kristopolous 11y ago
        Does asymmetric key exchange handle this problem, or am I missing some attack vector?
        • vectorjohn 11y ago
          Well, I'm not actually sure if there's any problem with asymmetric keys, now. I think, since asymmetric keys depend on factors of big prime numbers, they are vulnerable to quantum computers actually. Whenever those start working, keys become easily breakable. https://en.wikipedia.org/wiki/Post-quantum_cryptography https://en.wikipedia.org/wiki/Post-quantum_cryptography
          • kristopolous 11y ago
            No it doesn't. It depends on the existence of asymmetric algorithms. There's as far as I know, a number of classes of algorithms that have a good potential to satisfy this.
            • vectorjohn 11y ago
              That sounds neat, but we're not using any of those. And I don't see a [0] with a link anywhere in your comment. What I read, cited above, said that all existing asymmetric key algorithms are easily broken with quantum computers.
• spooningtamarin 11y ago
  There are algorithms that can have an exponential speedup on a quantum computer, there are plenty that have a quadratic speedup, for example, searching an unsorted/unindexed database takes O(sqrt(n)) instead of O(n) (with high probability of success). Which means that any optimization problem (with a search tree) can have this quadratic speedup too. Quantum cryptography has some pretty lovely nature tricks that enable no chance of spying/hacking, measuring the state plays so weirdly with the quantum system.