The quantum internet is coming sooner than you think â€” even sooner than quantum computing itself. When things change over, you might not even notice. But when they do, new rules will protect your data against attacks from computers that donâ€™t even exist yet.
Despite the fancy name, the â€œquantum internetâ€ wonâ€™t be some futuristic new way to navigate online. It wonâ€™t produce any mind-blowing new content, at least not for decades. The quantum internet will look more or less the same as the internet youâ€™re using now, but scientists and cryptographers hope it could provide protection against not only theoretical threats but also those we havenâ€™t dreamed up yet.
â€œThe main contribution of a quantum internet is to allow encrypted communication in a perfectly secure fashion that canâ€™t be broken in principle, even if in the future we develop a more fundamental theory of physics,â€ CiarÃ¡n Lee, a researcher at University College, London, explained to Gizmodo. In short, the quantum internet would hopefully protect us from planned new computers, along with every theoretical computer for the foreseeable future.
So whatâ€™s the quantum internet? Itâ€™s what happens when you apply the weird rules of quantum mechanics to the way computers communicate with one another.
Quantum mechanics says that the smallest things, like subatomic particles, are restricted to a list of distinct values for certain properties (their energy, for example). When youâ€™re not looking at them, they might enter a superposition of states, meaning taking on several values simultaneously â€” both the lowest and the second-lowest energy states, for example.
But once they are measured, they assume only one of the values. The value you see is determined based on some innate probability. But you can also entangle these particlesâ€™ states, meaning when you repeat the measurements many times, they seem more related than youâ€™d expect from two independent things following the usual rules of probability.
Researchers are working toward incorporating these weird rules into computing and networking. Computers that rely on quantum processors, based on quantum bits that can take on a superposition of states or entangle, might quickly create accurate simulations of molecules, enhance artificial intelligence, and solve other problems faster than regular computers can. No company has yet experimentally demonstrated that quantum computers can beat classical computers at anything, though theyâ€™re trying and may do so soon. A quantum computer worth worrying about is likely decades away.
Some of the potential problems that researchers think a quantum computer would excel at solving form the very basis of present-day encryption. And that is concerning.
â€œIf quantum computers are on the horizon, then we need to prepare the internet to be secure against quantum computers,â€ Lily Chen, project leader at the National Institute of Standards and Technology (NIST)â€™s Cryptographic Technology Group, told Gizmodo.
Today, internet communications are secured by algorithms like (Diffieâ€“Hellman) key exchange or the RSA (Rivestâ€“Shamirâ€“Adleman) system. These algorithms scramble the message using a mathematical formula with some non-secret key number plugged in. Unscrambling the message requires plugging the ciphered text back into a formula and plugging in a private key, known only by the message recipient. The private key and the public key are mathematically related, but itâ€™s incredibly difficult to figure out what the private key is.
Todayâ€™s encryption schemes would not be secure to quantum attacks, thanks to a quantum algorithm called Shorâ€™s algorithm.Â No quantum computer exists thatâ€™s big enough to run Shorâ€™s algorithm in a way that would crack present-day encryption, and there probably wonâ€™t be one for decades.
But the fact that it could exist, in theory, means that itâ€™s time for cryptographers to devise a new way to encrypt data so that weâ€™re prepared. The first step toward a quantum internet will barely be visible to you; maybe, instead of secure web pages beginning with https, theyâ€™ll begin with httpq. But on the back end, a new algorithm not believed to be solvable by quantum computers will encrypt online communications.
These changes, called post-quantum cryptography, are coming soon. NIST received its first submissions for post-quantum cryptography strategies in late 2017. A month later, NIST scientists selected 69 â€œcomplete and properâ€ candidates, and then announced 26 second-round candidates in January of this year. Round 3 (or the final algorithm selection process) is scheduled for 2020 to 2021, and the new post-quantum standards will be available before 2024.
Youâ€™ll notice that this isnâ€™t especially â€œquantumâ€. NIST is just looking for a classical algorithm that a quantum computer canâ€™t crack. If this seems disappointing, just know that post-quantum cryptography could be the most important and relevant change that quantum computing will bring to your life. Even bitcoinâ€™s encryption faces threats from quantum attacks.Â The change will be good for cybersecurity overall.
â€œOn the one side, itâ€™s like, gosh, weâ€™re doing all of this work just to reestablish the status quo,â€ Michele Mosca, faculty and university research chair at the University of Waterlooâ€™s Institute for Quantum Computing, told Gizmodo. â€œWell, yeah, thatâ€™s life. We better do it or else. But there really is a positive aspect and it could be a blessing in disguise. What cryptographers are doing is rebuilding some of the foundational pieces [of cybersecurity]. This process of retooling our very fundamental cryptography across all of our digital platforms is good for our cyber health.â€
Post-quantum cryptography is only the first step. Researchers have already put together a roadmap detailing what the addition of quantum technology to computer networks will actually entail.
The Micius quantum satellite has already allowed researchers to pass encrypted messages by sending entangled photons between two locations, and upon confirming the entanglement, generating a quantum key for researchers to decode encrypted messages. One day, quantum repeaters might send entangled particles of light, called photons, to the computers on a network in order to set up a quantum link.
This might allow users to access something akin to quantum-secured private Slack channels, where every entangled computer in the network can pass secret messages, with an icon based on entanglement measurements on the screen showing users that no one is eavesdropping into the network. Lee is working on a way to test such a network without having to trust its manufacturer or the manufacturer of the repeaters.
Ultimately, researchers hope a quantum internet will mean more than just a secure network. Anne Broadbent is a university research chair in quantum information processing at the University of Ottawa. Broadbentâ€™s most recent research demonstrates a way for a server to certify that it really deleted a file using quantum mechanics.
Broadbent explained to Gizmodo that once quantum processors are more mature, the quantum internet would allow a way to access their power via a secure quantum link over the cloud. This is important because, as far as anyone can tell, quantum processors must be stored in conditions that make them impractical for home use (such as temperatures near absolute zero).
Quantum links to quantum processors could allow the public to reap the hypothetical benefits in the far future. Thereâ€™s lots of speculation as to what those benefits might be, including some very cool things like quantum algorithms that would make searching for information online faster or maybe advances in gaming thanks to quantum computersâ€™ potential improvements to AI.
Maybe it will lead to a quantum blockchain where itâ€™s impossible (as defined by the laws of physics) to doubt the authenticity of something thanks to the quantum no-cloning theorem, which says it is physically impossible to create a copy of an unknown quantum state. None of these are a given, and maybe theyâ€™ll never happen, but they definitely wonâ€™t happen without a quantum internet.
Quantum computers today donâ€™t have any killer apps, yet, and probably wonâ€™t pose a threat to your computer experience for decades. But the internet will slowly incorporate quantum-inspired security protocols, then maybe actual quantum links. And then maybe one day, youâ€™ll be running programs incorporating quantum algorithms. You might not realise once itâ€™s already happening.