[cryptography] What the World's First Quantum Satellite Launch Means

Jeffrey Walton noloader at gmail.com
Thu Sep 15 11:32:33 EDT 2016


That’s one small step for man, one quantum leap for China.

China blasted the world’s first quantum communications satellite into
orbit from the Gobi Desert early Tuesday.

The project signals the dawn of a potentially game-changing
communications technology: quantum key distribution—a dependable
system for exchanging secrets (more on this in a bit)—as beamed from
space. If the experiment is successful, it could lead to considerably
more secure global communications.

While many news outlets have followed Chinese state media’s cue and
described the technology as “hack-proof,” a more appropriate
descriptor would be “tamper resistant.” (Nothing is “hack-proof.”)
Quantum crypto-systems achieve this by exploiting the quirky
properties of subatomic particles

Here’s how the science works. The fundamental problem of cryptography
involves exchanging keys—secret alphanumeric strings—that enable
people to encode and decode messages. When two parties swap keys, they
normally have no indication whether anyone has intercepted them; an
interloper with stolen keys can eavesdrop on correspondence or
manipulate it.

When quantum science is applied, the keys can be made to self-destruct
or change if a third party interferes with their transmission. The
keys are sent using pairs of entangled photons, or light particles
that share a special bond, to carry the information.

The Wall Street Journal quoted an executive familiar with the
technology as comparing it to “sending a message written on a soap
bubble.” Touch, and it pops.

The technology is defensive in nature. China, which has increased
funding for basic science research in this area over the past few
years (likely in response to revelations about other countries’
hacking capabilities) played that aspect up by naming the satellite
Micius in honor of an ancient Chinese philosopher who preached a
philosophy of “universal love.”

Dubbed Quantum Experiments at Space Scale, the Chinese experiment is
not the first time quantum key distribution has been attempted.
Ground-based fiber optic networks have successfully transmitted
quantum keys in the United States, Europe, and China. Other countries
like the U.K. and Singapore have smaller experiments in the works.

Bringing this quantum technology to a satellite network will be a
grand feat, however. The team, led by Pan Jianwei, said they would
attempt to transmit quantum keys from Beijing to Vienna to test the
system’s feasibility.

The experiment of beaming finicky particles over vast distances will
be tricky. Yet it could vault China over the international competition
in counter-surveillance tech if it does succeed.

For space-based quantum cryptography, the race is on.

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