Wednesday, June 17, 2020

China puts quantum keys in space

The NY Times reports:
China Reports Progress in Ultra-Secure Satellite Transmission

Researchers enlisted quantum physics to send a “secret key” for encrypting and decrypting messages between two stations 700 miles apart.

The world of artificial satellites, silent in the void of space, might seem pacific. In fact it’s a high-flying battlefield rife with jamming, snooping, blinding, spoofing, hacking and hostility among the planet’s growing array of spacecraft and space powers. Now, Chinese scientists report new progress in building what appears to be the first unbreakable information link between an orbiting craft and its terrestrial controllers, raising the odds that Beijing may one day possess a super-secure global communications network.

In the journal Nature on Monday, the team of 24 scientists describe successfully testing the transmission of a “secret key” for encrypting and decrypting messages between a satellite and two ground stations located roughly 700 miles apart.

The method enlists quantum entanglement, an idea of modern physics that seems ridiculously at odds with common sense. It posits that a pair of widely separated subatomic particles can still seem instantaneously linked: Measuring a property of one will simultaneously affect the measured results on its companion, even if the two are millions of light-years apart. Albert Einstein called quantum entanglement “spooky action at a distance.”
This is absurd. We already have super-secure communications is space. It is done using end-to-end encryption. It doesn't matter if an adversary listens in, because the messages are computationally indistinguishable from random bits.

What the Chinese quantum physics supposedly accomplishes is that there is a probability that an eavesdropper could be detected, so that the communication link could be shut down.

However, if the cryptography is done right, then there is no need to worry about eavesdroppers or to shut down the link.
In a research summary, Nature said the team had demonstrated that the system “produces a secure channel that is resistant to attacks.”
But not as resistant as conventional end-to-end cryptography.
NASA has drawn up plans to rival the Chinese advance. Known as the National Space Quantum Laboratory program, it intends to use a laser system on the International Space Station to relay quantum information between two ground stations. The program was initiated in 2018.

Generally, Dr. Earl said, Beijing seems far ahead of Washington in the race to master the quantum riddles and their practical applications in space.
That is how you get funding in Washington. Claim that we have a Doomsday Gap.

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