IN JANUARY 2017, Chinese scientists officially began experiments using the world’s first quantum-enabled satellite, which will carry out a series of tests aimed at investigating space-based quantum communications over the course of the next two years. The satellite is the first of its kind and was officially launched in August 2016 from the Gobi Desert. The satellite—named Micius after the Chinese scientist and philosopher—was developed by Chinese and Austrian scientists within the Quantum Experiments at Space Scale (QUESS) project. The project has drawn attention from experts and media outlets across the globe, as quantum-enabled satellites could provide the infrastructure for future hack-proof communication networks. At a moment when cyberattacks are carried out with increasing ease, improving the security of communications is crucial for guaranteeing the protection of sensitive information for states, private entities and individuals. For states, securing communications also entails strategic geopolitical advantages. What are the possible implications of quantum-enabled satellite technology, in the context of current global security issues and China’s expanding engineering capabilities in space and elsewhere?
Until now, most technology has been based on classical laws of physics (Newtonian and others). Modern communication technology uses radio waves, which transfer data encrypted with complex mathematical algorithms. The complexity of these algorithms ensures that third parties have a hard time cracking them. However, with stronger computing power and the increasing sophistication of hacking technologies, such methods of communication are increasingly vulnerable to interference.
This is where quantum physics comes in. According to quantum theory, subatomic particles can act as if they are in two places at once. This property can be manipulated by scientists, so that a particle can adopt either one of two states (for example spinning upwards or spinning downwards). If the particle is not observed, it will be in a state of “superposition.” That is, it will be a combination of both states. However, if the particle is observed, the act of observing it will invariably alter its state, thus collapsing the “superposition.” This phenomenon is known as the “observer effect.” Scientists are able to manipulate several particles into a state of “superposition,” in which they are fused and dependent on each other—known as “quantum entanglement.”
Previous experiments with quantum encryption had some success, yet the medium was not appropriate. Quantum-entangled messages were sent through optical fibers; however, the problem was that the signal would end up being absorbed by the medium and therefore was not feasible to do over long distances. Sending a quantum-entangled message over long distances would require “quantum repeaters”: devices that capture and retransmit the quantum information. The alternative was pioneered by China, and it involves beaming entangled photons through the vacuum of space, where nothing can absorb them.
The Chinese satellite functions by firing a laser through a crystal, creating a pair of photons (miniscule subatomic particles) in a state of “entanglement.” One half of each pair is then sent to two separate stations on Earth. The goal is to generate communication keys encrypted with groups of entangled photons, in which the information is encoded by a set of random numbers generated between two users. If a third party attempts to observe or interfere with one of the beams of entangled photons, quantum theory dictates that the encryption key will be altered and it will be rendered unreadable, due to the aforementioned “observer effect.” In this case, the user may change the message or cancel it.
The QUESS program is divided into three phases. The first stage of the experiment, recently achieved by scientists, involved teleporting a photon from a ground station in China to the satellite, establishing a satellite-to-ground quantum network. The second and third stages are more ambitious, as they aim to achieve quantum entanglement between Beijing and Graz (near Vienna). In 2017, it was reported that the QUESS had had its first success, when it beamed photons between the satellite and two ground stations and showed that the particles could remain in a linked quantum state at a distance of 1,200 km—dwarfing the previous distance record of 144 km, set on the Canary Islands. This experiment used laser beams mounted on a satellite. The beam was split and generated pairs of photons which stayed in an entangled state. The entangled photons were then funneled into two telescopes which projected them at two separate stations: one was in Delingha (in the Tibetan Plateau), and the other one 1,203 km away, at the Gaomeigu Observatory in Lijiang.
After establishing reliable communications links using this technique—the most technically challenging element of the experiments—it would then be possible to create “super-secure” quantum-enabled communication networks, simply by adding satellites.
Within the next five years, Chinese scientists hope to conduct a follow-up experiment, in which a quantum-communications satellite would be placed in a higher orbit of 20,000 km.
The implications for global security are plentiful. If quantum-encryption technology is eventually employed on a wide scale, hacking, wire-tapping or code cracking in both the communication and military domains would be rendered obsolete—as quantum-encrypted keys cannot theoretically be observed by third parties. This issue is of great significance, given the increasing influence of cyberattackers in domestic affairs. In the United States, attacks and cyberespionage from Russian cyberattackers—allegedly in collaboration with the Kremlin—effectively revealed private information (including many e-mails) of Democratic party officials, damaging their credibility during the 2016 presidential election campaign. This tactic has also been tested during elections in Ukraine. Quantum technology could also be used to prevent large-scale breaches of public and private information, preventing events like the 2013 Yahoo data breach, which affected over one billion users.