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A quantum of privacy
ANALYSIS SUPER-ENCRYPTION
A quantum of privacy HAS the era of unhackable global communication begun? Last week, the world’s first quantum communications satellite blasted into orbit from China’s Gobi desert. Known as the Quantum Science Satellite (QUESS), it is Sputnik for the ultra-paranoid. The mission will test a way of transmitting impenetrable messages across vast distances. If successful, the next decade could see a boom in quantum satellites, resulting in a secure network that will protect its users from even the most savvy eavesdroppers. In an age of cyberwarfare, WikiLeaks and state-sponsored hacks, it’s easy to see the lure of a truly private way to talk to each other – something existing infrastructure just can’t ensure. The new satellite will make its home among the thousands of communications spacecraft that already float in low Earth orbit, pumping out multiple TV
channels and enabling agree a stream of 0s and 1s that international phone calls. But form a secure code or key, which signals beamed from regular can be used to encrypt data sent satellites to the ground via radio via conventional means – over the or microwaves can be intercepted internet or through an ordinary by anyone with the necessary communications satellite. receiving equipment. To get Measuring a quantum object around this, signals are often disturbs its state, so any attempts encrypted. Trouble is, encryption by an eavesdropper to intercept a can be cracked – that’s how photon will be detected and the satellite TV pirates are able to “If the first is a success, watch channels for free. a quantum constellation QUESS is different. It uses a of satellites could provide technique called quantum key global coverage” distribution to encrypt signals. The laws of quantum mechanics are such that they guarantee the key discarded, so there is no risk of message is secure. So if done being hacked (see diagram, below). properly, signals can’t be hacked. Quantum key distribution It’s a bold claim, but one has already been rolled out on backed up by hard science. fibre-optic networks in the US, Quantum key distribution Europe and China, but these are works by transmitting particles limited to just a few hundred of light called photons prepared kilometres – any greater and the in a particular quantum state. light signals become too faint. By measuring these states, the Photons sent through space receiver on the other end can last longer, and QUESS will extend the reach of quantum key distribution even farther by Eavesdroppers thwarted exploiting the quantum property of entanglement, which links the Quantum key distribution allows users to agree on a way of transmitting their data without the worry that someone is listening in quantum states of two particles even when they are separated. 1 Sender instructs satellite to generate The satellite will first test 1 2 entangled photons in particular communications between quantum states ground stations 1200 kilometres apart in China, says Jian-Wei Pan 2 of the University of Science and 2 Photons are beamed to both Technology of China in Hefei. ground stations If successful, his team will look to establish a secure connection 3 Sender and receiver compare the with collaborators in Austria, quantum states of the photons to then in Italy and Germany, before check if they have been intercepted. creating “a quantum constellation If not they use the photons to create for global coverage”, says Pan. a code to encrypt the data 3 Pan’s efforts are likely to spur other launches. “You could 4 Encrypted data can then be sent dream of a network of satellites 4 securely via conventional means providing secure keys,” says 10100010011101011100 Harald Weinfurter of the Ludwig
16 | NewScientist | 27 August 2016
JASPER JAMES/PLAINPICTURE
The launch of a Chinese quantum communication satellite could usher in age of total digital privacy for all, says Jacob Aron
Maximilian University of Munich, Germany. “Within some 10 years we could have a working network.” Given the need for specialised receivers to pick up the faint photon signals, it’s unlikely you or I will be tapping directly into this network right away. Ordinary encryption methods based on difficult mathematical problems work fine most of the time, and underpin everyday activities like buying things online, checking your bank balance or sending WhatsApp messages. The first users of quantum key distribution will therefore be the military, governments and banks wanting security for their most precious data. “With the budget that banks have, it’s a minor investment,” says Weinfurter. Another attraction of quantum key distribution is that it offers
For daily news stories, visit newscientist.com/news
QUESS weighs 600 kilograms and is equipped to run experiments that will push quantum science to its limits (see “Testing times for quantum theory”, right). “If you only want to do secure communication, we can make much smaller and cheaper
“Quantum communication would prevent things like the NSA tapping into Google’s fibre-optic cables”
protection against the march of progress. As computers get faster, there’s no guarantee that a secure message sent today won’t eventually become crackable. And if we ever develop large-scale quantum computers, many of today’s encryption techniques will be busted wide open.
Future proof If the signal has been encrypted using a quantum satellite, these issues go away. “While quantum key distribution is considered difficult to implement, it does provide very high, long-term security for communications,” says Thomas Jennewein at the University of Waterloo, Canada. Such a network could change the rules of financial fraud and cyberwarfare. Thanks to the
satellites,” says Weinfurter. A team at the Centre for Quantum Technologies in Singapore is working to put quantum key distribution equipment on CubeSats – small spacecraft that cost a fraction of their larger cousins to build and launch. The team launched its first test photon generators earlier this year, and will be watching how the Chinese mission aims photons at a ground station from a fast-moving satellite, says team member Alexander Ling. And Jennewein and his colleagues are working on a quantum CubeSat for the Canadian Space Agency, but –I’d like anonymity, please- haven’t yet got full funding. QUESS could change that, he says. Snowden revelations, we know Future satellites may go higher that the US National Security as well as smaller. QUESS is about Agency and its spying partners 500 kilometres up, and whizzes have tapped into the fibre-optic around the globe every networks of firms like Yahoo and 90 minutes, so can be in contact Google, allowing them to slurp up with ground stations for only a data at will. With quantum key short period of time. Christoph distribution, that data would be Marquardt of the Max Planck encrypted in an unbreakable form. Institute for the Science of Light And much like the internet in Erlangen, Germany, thinks began as a military tool, there’s quantum satellites should be no reason why this shouldn’t placed 36,000 kilometres up, in become the default encryption geostationary orbit, so they are of communications for everyone above the same point on the in a few decades. Firms may start ground at all times and thus offering customers ultimate always in contact. His team has security as a premium product, shown that this is technically a move Apple has already made and economically feasible. with ordinary encryption after Whatever its form, the quantum its battle against the FBI. network is coming soon. “Five For this to happen, a quantum years ago, I wouldn’t have thought network will have to be made up it would be working so fast,” says of satellites designed differently Marquardt. “Now, it’s likely in the to China’s pioneering effort. next 10 or 15 years.” n
Testing times for quantum theory The laws of quantum mechanics govern how atoms and sub-atomic particles behave. Although it is one of our most successful theories, we still don’t know whether its predictions hold in some situations – such as over very long distances or beyond Earth’s gravitational pull. As well as showcasing the feasibility of a secure global communications network (see main story), China’s satellite QUESS will put quantum mechanics to the test. ENTANGLEMENT The satellite is equipped with a crystal that produces entangled photons. If the theory holds, their quantum states should remain intertwined even when they are physically separated. QUESS will fire one of these photons at a ground station in Delingha, China, and another to a station in Lijiang, more than 1200 kilometres away. If all goes to plan, measuring the state of one photon will instantly put the other in the opposite state, despite the vast separation. The record for demonstrating entanglement currently stands at 143 kilometres, the distance between the Canary Islands of La Palma and Tenerife, where such experiments are often done thanks to the still atmosphere. TELEPORTATION The QUESS team will perform quantum teleportation over 1000 kilometres between the satellite and a ground station, which involves transferring or “teleporting” the quantum state of one photon to another. Although this happens instantly, the result is only apparent once the satellite and ground stations have communicated their readings via normal channels, so this can’t send messages faster than light. HIDDEN VARIABLES The team will also carry out what’s known as a Bell test – essentially, a statistical check that reality must be based on quantum mechanics, and not some other hidden theory. 27 August 2016 | NewScientist | 17
A quantum of privacy HAS the era of unhackable global communication begun? Last week, the world’s first quantum communications satellite blasted into orbit from China’s Gobi desert. Known as the Quantum Science Satellite (QUESS), it is Sputnik for the ultra-paranoid. The mission will test a way of transmitting impenetrable messages across vast distances. If successful, the next decade could see a boom in quantum satellites, resulting in a secure network that will protect its users from even the most savvy eavesdroppers. In an age of cyberwarfare, WikiLeaks and state-sponsored hacks, it’s easy to see the lure of a truly private way to talk to each other – something existing infrastructure just can’t ensure. The new satellite will make its home among the thousands of communications spacecraft that already float in low Earth orbit, pumping out multiple TV
channels and enabling agree a stream of 0s and 1s that international phone calls. But form a secure code or key, which signals beamed from regular can be used to encrypt data sent satellites to the ground via radio via conventional means – over the or microwaves can be intercepted internet or through an ordinary by anyone with the necessary communications satellite. receiving equipment. To get Measuring a quantum object around this, signals are often disturbs its state, so any attempts encrypted. Trouble is, encryption by an eavesdropper to intercept a can be cracked – that’s how photon will be detected and the satellite TV pirates are able to “If the first is a success, watch channels for free. a quantum constellation QUESS is different. It uses a of satellites could provide technique called quantum key global coverage” distribution to encrypt signals. The laws of quantum mechanics are such that they guarantee the key discarded, so there is no risk of message is secure. So if done being hacked (see diagram, below). properly, signals can’t be hacked. Quantum key distribution It’s a bold claim, but one has already been rolled out on backed up by hard science. fibre-optic networks in the US, Quantum key distribution Europe and China, but these are works by transmitting particles limited to just a few hundred of light called photons prepared kilometres – any greater and the in a particular quantum state. light signals become too faint. By measuring these states, the Photons sent through space receiver on the other end can last longer, and QUESS will extend the reach of quantum key distribution even farther by Eavesdroppers thwarted exploiting the quantum property of entanglement, which links the Quantum key distribution allows users to agree on a way of transmitting their data without the worry that someone is listening in quantum states of two particles even when they are separated. 1 Sender instructs satellite to generate The satellite will first test 1 2 entangled photons in particular communications between quantum states ground stations 1200 kilometres apart in China, says Jian-Wei Pan 2 of the University of Science and 2 Photons are beamed to both Technology of China in Hefei. ground stations If successful, his team will look to establish a secure connection 3 Sender and receiver compare the with collaborators in Austria, quantum states of the photons to then in Italy and Germany, before check if they have been intercepted. creating “a quantum constellation If not they use the photons to create for global coverage”, says Pan. a code to encrypt the data 3 Pan’s efforts are likely to spur other launches. “You could 4 Encrypted data can then be sent dream of a network of satellites 4 securely via conventional means providing secure keys,” says 10100010011101011100 Harald Weinfurter of the Ludwig
16 | NewScientist | 27 August 2016
JASPER JAMES/PLAINPICTURE
The launch of a Chinese quantum communication satellite could usher in age of total digital privacy for all, says Jacob Aron
Maximilian University of Munich, Germany. “Within some 10 years we could have a working network.” Given the need for specialised receivers to pick up the faint photon signals, it’s unlikely you or I will be tapping directly into this network right away. Ordinary encryption methods based on difficult mathematical problems work fine most of the time, and underpin everyday activities like buying things online, checking your bank balance or sending WhatsApp messages. The first users of quantum key distribution will therefore be the military, governments and banks wanting security for their most precious data. “With the budget that banks have, it’s a minor investment,” says Weinfurter. Another attraction of quantum key distribution is that it offers
For daily news stories, visit newscientist.com/news
QUESS weighs 600 kilograms and is equipped to run experiments that will push quantum science to its limits (see “Testing times for quantum theory”, right). “If you only want to do secure communication, we can make much smaller and cheaper
“Quantum communication would prevent things like the NSA tapping into Google’s fibre-optic cables”
protection against the march of progress. As computers get faster, there’s no guarantee that a secure message sent today won’t eventually become crackable. And if we ever develop large-scale quantum computers, many of today’s encryption techniques will be busted wide open.
Future proof If the signal has been encrypted using a quantum satellite, these issues go away. “While quantum key distribution is considered difficult to implement, it does provide very high, long-term security for communications,” says Thomas Jennewein at the University of Waterloo, Canada. Such a network could change the rules of financial fraud and cyberwarfare. Thanks to the
satellites,” says Weinfurter. A team at the Centre for Quantum Technologies in Singapore is working to put quantum key distribution equipment on CubeSats – small spacecraft that cost a fraction of their larger cousins to build and launch. The team launched its first test photon generators earlier this year, and will be watching how the Chinese mission aims photons at a ground station from a fast-moving satellite, says team member Alexander Ling. And Jennewein and his colleagues are working on a quantum CubeSat for the Canadian Space Agency, but –I’d like anonymity, please- haven’t yet got full funding. QUESS could change that, he says. Snowden revelations, we know Future satellites may go higher that the US National Security as well as smaller. QUESS is about Agency and its spying partners 500 kilometres up, and whizzes have tapped into the fibre-optic around the globe every networks of firms like Yahoo and 90 minutes, so can be in contact Google, allowing them to slurp up with ground stations for only a data at will. With quantum key short period of time. Christoph distribution, that data would be Marquardt of the Max Planck encrypted in an unbreakable form. Institute for the Science of Light And much like the internet in Erlangen, Germany, thinks began as a military tool, there’s quantum satellites should be no reason why this shouldn’t placed 36,000 kilometres up, in become the default encryption geostationary orbit, so they are of communications for everyone above the same point on the in a few decades. Firms may start ground at all times and thus offering customers ultimate always in contact. His team has security as a premium product, shown that this is technically a move Apple has already made and economically feasible. with ordinary encryption after Whatever its form, the quantum its battle against the FBI. network is coming soon. “Five For this to happen, a quantum years ago, I wouldn’t have thought network will have to be made up it would be working so fast,” says of satellites designed differently Marquardt. “Now, it’s likely in the to China’s pioneering effort. next 10 or 15 years.” n
Testing times for quantum theory The laws of quantum mechanics govern how atoms and sub-atomic particles behave. Although it is one of our most successful theories, we still don’t know whether its predictions hold in some situations – such as over very long distances or beyond Earth’s gravitational pull. As well as showcasing the feasibility of a secure global communications network (see main story), China’s satellite QUESS will put quantum mechanics to the test. ENTANGLEMENT The satellite is equipped with a crystal that produces entangled photons. If the theory holds, their quantum states should remain intertwined even when they are physically separated. QUESS will fire one of these photons at a ground station in Delingha, China, and another to a station in Lijiang, more than 1200 kilometres away. If all goes to plan, measuring the state of one photon will instantly put the other in the opposite state, despite the vast separation. The record for demonstrating entanglement currently stands at 143 kilometres, the distance between the Canary Islands of La Palma and Tenerife, where such experiments are often done thanks to the still atmosphere. TELEPORTATION The QUESS team will perform quantum teleportation over 1000 kilometres between the satellite and a ground station, which involves transferring or “teleporting” the quantum state of one photon to another. Although this happens instantly, the result is only apparent once the satellite and ground stations have communicated their readings via normal channels, so this can’t send messages faster than light. HIDDEN VARIABLES The team will also carry out what’s known as a Bell test – essentially, a statistical check that reality must be based on quantum mechanics, and not some other hidden theory. 27 August 2016 | NewScientist | 17