Quantum Cryptography Now Fast Enough For Video

cremeglace sends in news of a major advance in the speed of quantum key distribution. "Researchers at the Cambridge Lab of Toshiba Research Europe have solved the problem of transferring highly sensitive data at high speed across a long distance network. The team were able to demonstrate the continuous operation of quantum key distribution (QKD) — a system that allows the communicating users to detect if a third party is trying to eavesdrop on the data communication — at a speed greater than one megabit/sec over a 50 km fibre optic network, thanks to the use of a light detector for high bit rates and a feedback system which maintains the high bit rates during data transfer. ... The faster one megabit/sec data handling will allow the one-time pad to be used for the encryption of video — a vast step forward over the current ability to only encrypt voice data."

Comments

Re:And if there's a man in the middle?

[Chrisq]

That's absolutely correct. For some purposes it is better that you terminate the video session than have someone listening in undetected

Re:sigh, the "quantum" buzzword

[FuckingNickName]

(1) Neither of your scenarios covers the case where both the quantum and the secondary channel are created by Eve, not just the secondary channel;

(2) How is the relationship between quantum and classical channels informed to Bob by Alice?

(3) If your solution is to transport a one time pad at some earlier point "by some other means", then you're copping out twice over, as now we need another classical channel to transmit one time pads long enough for message exchanges.

Encryption will only do so much

[itsdapead]

(1) Neither of your scenarios covers the case where both the quantum and the secondary channel are created by Eve, not just the secondary channel;

In other news, no encryption system, even some hypothetical mathematically perfect cypher, will guarantee that Bob is not actually Eve with a pair of socks stuffed down her jeans. No encryption system will tell Alice that Bob really is Bob. No encryption system will warn Alice that Bob is shagging Eve and talks in his sleep. No encryption system will warn you that Eve has tampered with your hardware. No encryption system will magically turn Alice and Bob into experienced cryptographers who will spot tampering.

Of course, you can use encryption to set up something like a trust network to validate identity, but at some point in the chain a human being has to positively identify Bob and Alice and hand them their "credentials". Likewise, no encryption system can be secure against arbitrarily sophisticated hardware/software tampering.

When you have a sexy cypher which the math says is uncrackable its easy to forget that the math depends on a whole raft of assumptions and assertions.