Re: interesting article on quantum cryptography


"Douglas A. Gwyn" <DAGwyn@xxxxxxxx> wrote in message
news:4631165B.5127496A@xxxxxxxxxxx
There are several issues involved; generally saying "XOR is involved"
is pointless, since there are a large number of arithmetic and
logical operations involved in implementing the crypto algorithm.

i did say 'many of todays encryption schemes' which they do, XOR was just an
example of a logical function. so i'll broaden the question, how would a
quantum cryptographic scheme work with any logical function.

There is "quantum computing" (QC), which should apply to any algorithm,
with known advantages over conventional computing (once QC is available
on a large scale) in the case of *some* kinds of algorithms. QC could
be applied to any crypto algorithm, "XOR-based" or not.

that is a given, the same as saying the sky is blue.

However, "quantum cryptography" (alas, also "QC") usually denotes the
exploitation of quantum coherence to implement secure communication
channels. The basic principle is that any eavesdropping is detectable
by the legitimate communicants. Alternatively, the eavesdropper may
only be able to obtain "information" that does him no good with respect
to recovering the plaintext or key.

Photons are used in implementations because they are much easier to
work with at the quantum-coherence level than any other phenomenon
(e.g. electrons).

this is just background information and basic particle physics, it does
nothign to address the original question posed. how would a logical function
(XOR for example) be carried out using quantum cryptography.


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