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Quantum Cryptography Is Safe Again

sciencehabit writes "In theory, so-called quantum cryptography provides a totally secure way of sending information. In practice, maybe not. But now physicists have demonstrated how to close a technological loophole that could have left secrets open to eavesdroppers. '[I]n 2010, an international team of researchers showed that [an attacker] could hack the system by exploiting a weakness in the so-called avalanche photodiodes (APDs) used to detect the individual photons. The problem is that APDs react differently to intense pulses of light than they do to single photons, so that the energy of the pulse must exceed a threshold to register a hit. As a result, all [the attacker] has to do is intercept the single photons, make her best-guess measurements of their polarizations, and send her answers off to Bob as new, brighter pulses. ... Last year, physicist Hoi-Kwong Lo at the University of Toronto and colleagues claimed to find a way around the problem. In the new protocol, Alice and Bob would begin the creation of a quantum key by sending randomly polarized signals to Charlie, a third party. Charlie would measure the signals to determine not their actual polarization, but only whether the polarizations were at right angles. ... Now, in papers in press at Physical Review Letters, two independent groups of physicists have shown that the new protocol works.'"

7 of 34 comments (clear)

  1. Schrödinger protocol by Smidge204 · · Score: 5, Funny

    Quantum Cryptogaphy exists in a superposition of simultaneously being secure and not-secure.

    (Eh, somebody was gonna...)
    =Smidge=

    1. Re:Schrödinger protocol by letherial · · Score: 2

      Perfectly secure when nobody is looking at it, not so good when its being analyzed

  2. Re: so-called summary by Anonymous Coward · · Score: 2, Interesting

    Wake me up in 10 years when they're only 5-10 years away from bringing this to market.

  3. I love news without a use by themushroom · · Score: 3, Insightful

    Yes, you can reason that quantum cryptography is going to protect this and that thing that isn't at the consumer level. Good on it. But you're still going to have people typing "password" as their password at their bank or "Jeremy85", the boy in the photo on their desk and his year of birth, in sensitive work email.

    1. Re:I love news without a use by InfiniteLoopCounter · · Score: 4, Funny

      No, no. Banks have secure passwords of at least 12 characters, with mix of upper and lower case, symbols, and numbers, and completely hidden from view on a sticky note on the back of the keyboard.

    2. Re:I love news without a use by manu0601 · · Score: 2

      Actually, "Jeremy was born in 1985" is a rather good password. Add a typo and it is even better: "Jeremi was born in 1985"

  4. Re: so-called summary by quax · · Score: 2

    You can already buy commercial quantum encryption devices. That was the point of the hacking to begin with. Only caveat: The existing tech is point to point protocol. That's why this was such big news earlier this year.