Thomas Shaddack wrote...
There are quite many important activities that don't require storage of the transported data.
For example, very very few people record their phone calls.
Storage wasn't my point per se. My point was that quantum cryptography only becomes unsnoopable* when it's in the optical form. With current optical fiber technologies this would limit the useful bandwidth distance product to short distances (ie, 10s of Km for key exchanges). After that, the signal must go O/E and then it's just the same as any normal digital signal.
Where Quantum Crypto might have application is in small metro area deployments, like downtown NYC or the DC Beltway, and where people are completely totally balls-to-the-wall paranoid about security (ie, they assume an attacker is willing to tap into their fiber and has all of the test sets needed to pull out a useful packet exchange--that ain't no pimply-face DoS script bunny, and hell it ain't Al Qaeda either).
Of course, to extend quantum protection beyond mere transport you'd need all sorts of quantum logic gates and processors (in addition to storage), but don't look for that in our lifetimes.
-TD
*: With quantum crypto it is of course possible to 'eavesdrop', depending on the coding, but that will cause the eavesdropper to quickly be revealed.
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