Before I get into the topic of this post, let me clear a few things up. First, quantum physics is a field of physics that no one, not even quantum physicists can wrap their brains around. It utterly defies common sense. Some day we’ll be able to explain it, but for now it just has to remain something quite like computers are to the elderly; they don’t have to understand it, it just has to work, and be predictable, which it is.
There are several aspects of quantum physics that don’t follow rules that make any sense. But they’ve been demonstrated to follow the math behind the theory in experiment after experiment. The one I’ll focus on for this post is known as quantum non-locality. This one was the one that bothered Einstein the most. He called it “spooky action at a distance,” because it describes information traveling not just faster than light, but instantaneously. Something which clearly defies his own theory of special relativity. Unfortunately, they’re both correct theories. Just on different scales.
This occurs when two particles, no matter what the type, (photons, every type of sub-atomic particle) are “entangled”. So what is entanglement? Well, nothing I can print here will properly explain it, because it’s mostly a mathematical concept that just so happens to be demonstrable in the lab. Two particles can be entangled in nature, or, now, by us. Using lasers on photons. It basically means that the two particles share a quantum bond. If there’s one thing that the universe absolutely does not allow is the destruction of energy. So if two photons are entangled, and one has an up “spin”, then the other one has essentially neither an up or down until it’s observed. Once that happens, it’s forced, instantaneously, to be the opposite. So no energy is lost. How is this relevant to the encryption of information? Well, banks and governments all over the world are already developing this property for practical use.
Now, for those of you not already familiar with how most data encryption works, a brief description. Most advanced encryption has two parts. The data itself, and the key. The key is essentially a mathematical algorithm that gives the recipient the means to decipher it. Since giving the key to the recipient in person not only isn’t practical, it kind of negates the need for encryption in the first place. So they’re sent electronically. Usually separate, but that isn’t always practical. So someone can eavesdrop, acquire both, and then your encryption is defeated. Quantum non-locality encryption is done exactly the same way. But here’s how it’s so truly impenetrable. Bear with me. Let’s go back to the observation part of quantum entanglement. Observation of either the data or the key (and remember, we’re dealing with photons, so only fiber optic transmission would be used), forces the one half of the entangled pair to take its correct, energy static state. If this is done by the recipient, then all is fine. If it’s done by someone who’s trying to intercept the data, both parts of the pair are then correct, but the recipient receives an un-entangled photon which has a random up or down state. This doesn’t completely solve the problem of eavesdropping, but the recipient knows that what they’re getting is just garbage data, and both parties immediately know the communication is compromised. One company developing this offers a pretty good solution for the eavesdropping problem as well. Changing the key 100 times per second. Combine the two and you get just about the closest thing to uncrackable encryption possible. Rapid key changing, plus the fact that the recipient always knows when the communication has been compromised, if someone even manages to do that.
This even has huge importance for space flight. I’m talking about VERY long distance space flight. When we eventually send probes to other star systems, the trip for the probe will take decades, even centuries, but they could use this form of communication to instantaneously transmit their data to Earth. Now of course you can’t have light years of fiber optic cable connecting the probe to Earth. What is possible, and this has also been done, is to entangle a very large amount of photons, place one set of the pair on the probe, while keeping the other set here. Trapping photons requires somewhat large equipment. But things always get smaller as technology advances. Advanced alien species no doubt use this as standard. Why not? It’s instantaneous over a meter, or a billion light years.
Einstein hated and dismissed the math that showed this is possible as “spooky action at a distance”. Sorry Albert, but it’s been tried, and tested in many labs. You and Niels Bohr will have to share your titles of the world’s most intelligent people of the 20th century.