Quantum crypto busted again

I mentioned an experiment to close Bell loopholes, and now there are a couple of others, as Alain Aspect summarizes:

By closing two loopholes at once, three experimental tests of Bell’s inequalities remove the last doubts that we should renounce local realism. They also open the door to new quantum information technologies.

This is nice to affirm the generally accepted quantum mechanics of 1930, but it has been raised to a very high profile for two reasons. It supposedly proves nature is nonlocal, and it supposedly enables unbreakable quantum cryptography.

It does not prove nonlocality, as I have repeatedly explained. It is also worthless for cryptography, for several reasons.

One reason is that all of these supposedly unbreakable systems have been repeatedly broken. Here is the latest:

Quantum key distribution is supposed to be a perfectly secure method for encrypting information. Even with access to an infinitely fast computer, an attacker cannot eavesdrop on the encrypted channel since it is protected by the laws of quantum mechanics. In recent years, several research groups have developed a new method for quantum key distribution, called "device independence." This is a simple yet effective way to detect intrusion. Now, a group of Swedish researchers question the security of some of these device-independent protocols. They show that it is possible to break the security by faking a violation of the famous Bell inequality. By sending strong pulses of light, they blind the photodetectors at the receiving stations which in turn allows them to extract the secret information sent between Alice and Bob.

This will not kill the subject, because the quantum Bell-heads will suggest work-arounds. They have too much invested in this nonsense. But it will never be something practical and secure enuf to buy goods on Ebay, and there is other technology that solves that problem. Quantum cryptography is useless in principle, and is a big scam.