I just read something about quantum cryptography in a newsletter I (got) subscribed (to). It is interesting to have some more secure forms of communication in the not-so-distant future... and I am not quite awake right now so I did only read the newsletter summary. But what I gather is that use of these fiber-optics for transmitting encrypted data would "prevent eavesdropping" - by giving you a notification the very instant somebody does it. Sooo... unless it stops right at the "bit" level, that is pretty useless, isn't it? I mean if I have sensitive data (like bank transactions) I wouldn't want to have anybody to receive more than one or possibly two bits of information :) A "handful" bits would already be way too much because it just *might* be the important ones.
I'm also not quite sure how this would help against classical "man in the middle" attacks - granted they would have to take place at the fiber level but still... as long as my infrastructure and the remote infrastructure are thinking that they talk with each other somebody in the middle might relay the information already. Not talking about "inspecting" or "copying" here. Plain and simple "proxy mode". [A] -> [(X pretending to be B) (X pretending to be A)] -> [B]
To me, "quantum security" sounds wonky from the get-go: "a tiny little bit security"? Who thought that name was a good idea?
Also, preventing eavesdropping would be more like "quantum communication" than "quantum cryptography" wouldn't it? It doesn't really affect the encryption but rather prevents theft of data. Also neat but not the same.
It's the same with "quantum computing". Right now all that "university tech talk" sounds pretty much like Trekkies discussing the warp drive. Interesting and cool but will it work? Can anybody actually tell what it would hold for "us" - i.e. the people using computers? So far all I ever got as an answer was "it will be 100000 times faster!" - whoop-de-doo!
Oh, and something else I associate with "quantum"... the Heisenberg principle. I know that much :) So, does quantum computing mean that I can either know where my data is or where it is going to but not both at the same time? Rather scary actually :D - come to thing about that... isn't that what "cloud computing" is all about?
Just my 0.02$ on that subject. If anybody here has an explanation of the subject that doesn't require multiple degrees in physics to understand, please link me!