An Uncrackable Lock

ok, so in order to hack the system, the light signal would have to be intercepted and rebroadcast so it would seem like it wasn't intercepted (is this impossible?). Then the intercepted signal would need to be interpreted using the intercepted failsafe key.

Are we saying that because nobody has done it therefore it is unhackable? I think the DVD format was unhackable too.

Where there is a will, there is a way. If one person can access the data, then hackers will always find a way to get in.

It's 'uncrackable' because it would violate laws of physic.

Quantum cryptography uses single photons to negotiate a key. A hacker would need to watch them and make sure they receive as they were, which is impossible, Heisenberg said.
Watching the photon you would destroy it.

Then you use the negotiated key with some standard-encryption like AES or RSA, which theoretically is crackable.

anything is hackable. if it's man made, then it's possible. from an insider revealing secrets or from just plain brute force attacking or experienced 'techs', anything is hackable.

back in the early '80s, videocipher II was unhackable, broken. dss 'h' cards unhackable, broken. dss 'hu' cards unhackable, broken. most other forms of encryption, broken.

it just takes time. fiber optics were once thought to be untappable, but its possible to tap a fiber line to eaves drop. due to u.s government regulations, any form of encryption must be registered for legal consumer uses.

so once the info is in a 'humans' hands, all it takes is time.

Why even go through all the trouble of trying to hack a system anyway. It is much easier to hack people. Bribery seems to work in most cases. All you need is to find an underpaid or unappreciated employee with access to the information you need. A much easier and cheaper solution.

As someone_ said, it's not crackable because it violates the laws of physics. If you even look at it you destroy it. So tapping into the line won't work, as soon as you do, the information is destroyed, per the laws of physics.

True quantum encryption would be uncrackable. The question is whether they are using try quantum encryption from point to point, through the ecryption, transmission, and reception.

As thnder57 said people are the real weak link, not the ecryption in any case.

I wish Richard Feynman were still around to take a crack at this.

If it is indeed possible which I doubt I believe it would require that you understand the math behind quantum mechanics & be able to perform complex equations rather fast rendering it I believe impossible until there are cyborgs (not quit star trek style).
Now of course I'm no scientist so please be mature if I'm incorrect about any of my assumptions.