It’s just that stealth communication has gotten more secure, as far as complexity goes.
Quantum physics provides a way to share secret information that is mathematically proven to be safe from prying eyes. But until now the demonstrations of the art, which is called the distribution of the key quantity, is based on the assumption: The ideas to create and measure the quantity of the known particles must be false. Hidden flaws could allow a stealthy snoop to penetrate unwary security.
Now three-party researchers have demonstrated the ability to securely perform quantum communication without prior confirmation that machines are fooled. Fabrication – independent of the quantum key distribution, the method is based on quantum entanglements, a mysterious relationship between particles that unites their properties even over long distances.
In common communication, such as the transmission of credit numbers over the Internet, a secret code, or key, encrypts information so that it can only be read by another key. But the question is: How can the remote sender and the receiver share that key with each other without anyone else intercepting it?
Quantum physics provides a way to communicate keys by transmitting a series of quantized particles, such as particles of light called photons, and making measurements on them. By comparing notes, users can be sure that no one else has intercepted the key. Those hidden keys, once established, can then be used to encrypt sensitive information.SN: 12/13/17). By comparison, the internet security standard is based on a shaky foundation of math problems that are difficult for today’s computers to solve, which can be vulnerable to new technologies, namely quantum computers (.SN: 6/29/17).
But the amount of sharing typically has a catch. “Glitch” cannot be unexpected, “according to scientist Valerius Scarani of the National University of Singapore”. For example, he says, imagine that your device is supposed to emit one photon but, unknown to you, emits two photons. Any such flaws would mean that the mathematicians would have to endure the security test for longer. A hacker could extract the secret key, even if the transmission seems secure.
Device-independent, as much as the distribution of such keys can dictate. The method builds on the well-known bell-shell technique, which involves measurements of obstructed particles. Such tests can prove the extent to which mechanics really have “spooky” properties, namely the idea that the measurement of a single particle can be correlated with distant particles. In 2015, researchers made the first “stem-free” bell, which proved beyond doubt that the counterintuitive nature of quantum physics is real (SN: 12/15/15).
“The satellite test basically acts as a guarantee,” says Jean-Daniel Bancal of CEA Saclay in France. A faulty device will fail the test, so “we can assume the device is working properly.”
In their study, Bancal and colleagues involved electrically objecting strontium atoms about two meters apart. Measurements of those ions indicated that their devices were performing correctly and that the researchers had generated a secret key, the team reported on July 28. nature.
Typically, the amount of communication over a long distance is indicated by letters. (To share the secret with someone a couple of meters away, it would be easier to walk across the room.) So Scarani and his colleagues studied the entanglement of red atoms 400 meters away. He had a plan that he took to produce a secret key, to report to the researchers in the same event nature. But the team didn’t follow the process all the way: Extra space meant that the key producer had months.
In the third study, published in the month of July on the 29th Physical Review LettersThe researchers argued that photons rather than atoms or ions were involved. Physicist Wen-Zhao Liu of the University of Science and Technology of China in Hefei and colleagues demonstrated the ability to generate keys at distances of up to 220 meters. This is especially challenging when dealing with photons, Liu says, because photons are often lost in the transmission and detection process.
Loophole-free bell tests are no longer easy, and these techniques are becoming increasingly difficult, says Krister Shalm, a scientist at the National Institute of Standards and Technology in Boulder, Colo. “The requirements for this experiment are so absurdly high that it’s just. From what capabilities it can demonstrate something impressive,” says Sham, who wrote a perspective in the same issue. nature.
That means the technology won’t see practical use anytime soon, says scientist Nicolas Gisin of the University of Geneva, who was not involved with the research.
Still, an independent quantum key distribution mechanism is “a totally fascinating idea,” Gisin says. Bell’s evidence was designed to answer a philosophical question about the nature of reality – whether physics really is as strange as it seems. “Now that I see it, it becomes an instrument by which it does something else,” he said, “this is beauty.”
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