China's quantum satellite: The key to hacker-proof communication?

In a big step forward, China launched the world’s first quantum-communications satellite early Tuesday morning.

First Look

From the vast expanse of the Gobi Desert, China launched a satellite in the early hours of Tuesday that could herald a technological breakthrough.

The satellite, named Micius after an ancient Chinese philosopher who eschewed offensive warfare, is designed to test the limits of quantum communications, an avenue of scientific endeavor that could prove all but immune to hackers.

While China is not the only nation investigating quantum communications, this launch is by far the most ambitious experiment so far, and if it succeeds, it could catapult the country to the forefront of encrypted technology.

“There’s been a race to produce a quantum satellite, and it is very likely that China is going to win that race,” Nicolas Gisin, a professor and quantum physicist at the University of Geneva, told The Wall Street Journal. “It shows again China’s ability to commit to large and ambitious projects and to realize them.”

China is pouring billions of dollars into its scientific research, and quantum technology lies at the heart of its strategic aim to draw parallel with, or surpass, Western expertise. This state sponsorship has allowed China to undertake the ambitious Micius project, whereas scientists in other countries have access to far less funding.

University of Vienna physicist Anton Zeilinger – who was the PhD adviser to Pan Jianwei, the physicist now leading the Micius effort – has been trying to convince the European Space Agency since 2001 to undertake a similar project. He is now assisting on his former student’s mission.

In fact, this cutting edge experiment represents something of a collaboration between Beijing and Vienna, as the satellite seeks to fire photons between both cities.

“Our first mission is to see if we can establish quantum key distribution [the encoding and sharing of a secret cryptographic key using the quantum properties of photons] between a ground station in Beijing and the satellite, and between the satellite and Vienna,” Mr. Pan told Nature in January. “Then we can see whether it is possible to establish a quantum key between Beijing and Vienna, using the satellite as a relay.”

The mind-bending science behind this technology relies on a quantum concept called “entanglement,” something Albert Einstein once described as “spooky action at a distance.” Essentially, the theory states that when two particles are “entangled,” anything that happens to one happens to the other, no matter how far they are from one another.

It is as though you have two pieces of paper, lying as far apart as you can imagine, and when you write on one, that writing immediately appears on the other.

The beauty of this phenomenon in terms of encryption is its “observer effect,” whereby as soon as the quantum exchange is observed, its form is changed, making it nigh on impossible for the signal to be hacked.

While scientists have successfully sent encrypted messages via land using this technology, introducing a satellite opens up far greater distances and speeds of communication. But the Micius project represents just the first step in an ambitious array of proposed experiments.

“In future, we also want to see if it is possible to distribute entanglement between Earth and the Moon,” said Pan. “I think China has an obligation not just to do something for ourselves – many other countries have been to the Moon, have done manned spaceflight – but to explore something unknown.”