Nature reports that Quantum Cryptography has been completely broken in “Hackers blind quantum cryptographers.” Researcher Vadim Makarov of the Norwegian University of Science and Technology
constructed an attack on a quantum cryptography system that “gave 100% knowledge of the key, with zero disturbance to the system,” as Makarov put it.
There have been other attacks on quantum cryptography, but this is the first in which there is no indication that the key has been stolen. In those attacks, the operator of the system would see the transmission error rate go up, but in Makarov’s attack, the operator sees nothing. In short, they are completely, utterly defeated. The attacker gets everything with impunity.
As usual, the quantum crypto crowd doesn’t see that a 100% loss of key with no inkling of the loss is a problem. Makarov himself said to Nature, “If you want state-of-the-art security, quantum cryptography is still the best place to go.”
Perhaps the kicker is this in Nature’s article:
Ribordy [CEO of ID Quantique] and Zavriyev [Director of R&D at MagiQ] stress that the open versions of their systems that are sold to university researchers are not the same as those sold for security purposes, which contain extra layers of protection. For instance, the fully commercial versions of IDQ’s system also use classical cryptographic techniques as a safety net, says Ribordy.
Huh? We can trust commercial versions of quantum crypto because it uses classical crypto as a safety net? That’s saying that the quantum coolness is really just icing over a VPN. Isn’t it? Am I missing something?
Now it’s time for a rant. Quantum cryptography is really, really cool technology, but the whole point of it is, well, security, and if the state of the art is that the system is breakable, then the art is in a sorry state. It’s a state of being a research toy, not a real security system.
The whole point of quantum crypto is that it isn’t even really crypto. It’s communications that can’t be eavesdropped on. It’s a magical tour-de-force of science and technology. But if it can be silently thwarted, it’s no good. If there is no way that it can be tested to be good, it’s no good. Moreover, the latter is more important than anything else.
For quantum crypto to be viable and trusted, we have to have some way that we know that the boxes were designed and manufactured in such a way that we can be confident that there’s no silent quantum backdoor in the box, then it has no value. You might as well just get a VPN router from the usual suspects and be done with it. If you’re really paranoid, just lay down some glass fiber and put it in a conduit.
Quantum information science as a discipline needs to start taking security seriously. It can’t just brush off a break of this magnitude, and remain credible. Come on, at least admit this is serious and has to be reflected in the manufacturing and testing. Come up with countermeasures, something.