quantum hype

[Ian Grigg]

"R. Hirschfeld" wrote on QKD:

> The eavesdropper Eve doesn't know with which basis to measure the
> polarity of the each intercepted photon.  When she guesses right, she
> gets the correct information and can send it on undetectably.  When
> she guesses wrong, she gets a zero or one with equal probability (*)
> and half the time sends on the wrong bit (which is again randomized
> when Bob reads it with the correct basis).  By eavesdropping Eve thus
> introduces a 25% error rate, which is detectable.


If I understand this correctly, this is both
an eavesdropping scenario and an MITM scenario.

In the above, Eve is acting as Mallory, as she
is by definition intercepting the bits and re-
sending them on?

That is, the "Quantum Property" is that Eve can
be detected because she destroys photos in the
act of listening, and Mallory, who can resend
the photons, has only a 50% chance of reading
each bit correctly in advance, so he can be
detected after the fact as well, as 25% of his
bits are wrong.


iang

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