Quantum Cryptography: 100km Barrier Broken

jdfox writes "Toshiba Research Europe have just demonstrated quantum crypto over 100km fibre links. Sounds like there's still a fair bit of work to be done before it leaves the lab, but it's amazing that they've got as far as they have. There's another article about it, though still not much technical detail, here on the BBC and here on The Register."

Comments

Sounds like the press hasn't thought this through

[fireboy1919]

Any attempt to hack into the link must not be passive as it alters the quantum state of the intercepted photons.

If the sender is capable of generating photons with an arbitrary quantum state, so is the hacker. Obviously this will block attempt to merely split the signal, but why not just observe and then retransmit new photons with the original state?

I'm sure it's just an oversimplification by people who don't know what the researchers where talking about...why does this help anything?

Re:A clarification on Quantum Cryptology being sec

[jfern]

The problem is, if I steal Bob's qubits, and throw him into solitary confinement in some military base in Cuba for being an "enemy combatant", that I can then pretend to be Bob to Alice, unless Alice and Bob had a weird protocal that they had agreed to use, and Bob wouldn't say what it was after being torture.. I mean given a nice friendly conversation.