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How To Build a Quantum Eavesdropper
KentuckyFC writes "Quantum encryption is perfectly secure, in theory. In practice, however, there are loopholes. Now Japanese scientists have designed a quantum eavesdropper that exploits one of these loopholes to listen in to quantum conversations. QC's security arises from the impossibility of making a perfect copy of a quantum object without destroying it — so the sender and receiver can always tell if they've been overheard. But it turns out that an eavesdropper can make imperfect copies and use them to extract information from a quantum message without alerting sender or receiver (abstract). The Japanese design does just this. That should worry banks and government agencies that have begun to use some of the commercial quantum encryption systems now available."
You don't need anything so fancy. The quanta are, like packets, not guaranteed to get tot he destination every time. All you have to do is sidetrack every random(N)'th photon to your receptor.
Not really. The whole point of the South Park defense was to get out of trouble by being humble and flattering the enemy. In the Chinese hacking incident, the big penis joke was more analogous to having Americans being told that they have hardened systems that couldn't be cracked (pun sorta intended). In the case of this article, the Japanese scientists are being perfectly transparent in showing that there is a hole with quantum cryptography. Just having Japanese people in the subject is not sufficient for saying the two articles are equivalent or even relate to the same joke.
As Quantum Modulation (the term ''encryption'' has absolutely no place here) is used for key exchange, any data gained will make attacks on the keys used for the later conventional exchange easier. How bad that is depends on the actual parameters used, it can be anything from ''not a problem'' to ''cpmplete practical system compromise''.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
This is wrong. The eavesdropper gets imperfect copies and so does the receiver. If the quality of the receiver's copies are as bad as the eavesdropper's, any working quantum crypto setup will abort and not try to make a secret key out of it.
That should worry banks and government agencies that have begun to use some of the commercial quantum encryption systems now available.Nobody needs to worry about these kinds of attacks, as the software in all commercial quantum crypto systems automatically checks and takes care of these kinds of attacks. What the paper shows is how to implement in practice a class of attacks that has been known for years how to do in theory.
There are other attacks on quantum crypto systems that actually attack loopholes in the implementation, and some of these have previously been discussed on slashdot here