The primary driver of the race to create quantum computers is their ability to solve problems that today’s classical computers can’t. One such problem is the factoring of large prime numbers – the basis of common encryption protocols used on the internet today. Crack the problem and you crack the internet’s security.
That’s one reason there’s now a push to create a ‘quantum internet’. It will exploit quantum properties to deliver unbreakable security and, ultimately, create a cloud of networked quantum computers capable of addressing problems of immense complexity.
We have long been aware of the threat quantum computers would pose to digital security. In the 1980s, mathematician Peter Shor demonstrated that a quantum algorithm could factor large primes, but at that time quantum computers were purely theoretical. Today, rapid advances in the field mean quantum computers running Shor’s algorithm could, as IBM warned in early 2018, break much of the security in routine use on the internet in just a few years from now.
Security researchers are already working on various technologies that quantum algorithms couldn’t crack, such as Lattice Cryptography and the associated homomorphic encryption. There are strong drivers for this, such as the current need to store highly sensitive military data on commercial cloud infrastructure.
This arms race between quantum computers and unbreakable security will create a new era of communication.
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The quantum internet relies on the same fundamental properties as quantum computing. It uses qubits to encode information as ones, zeroes and a superposition state of both that encompasses a near infinite spectrum of possibilities. It also uses the phenomenon of entanglement that links the quantum state of qubits so that acting on one will affect another.
It’s these characteristics that deliver the advantages to security and speed. The superposition state of qubits means they can convey much more information than traditional bits and run calculations in parallel. While entanglement can send data between qubits instantly, with no chance to steal the information as any attempt would change the properties of the qubits and scramble the data.
Quantum network security exploits this fact – that ‘reading’ the quantum state of an object changes it. A ground-breaking intercontinental videoconference over a satellite laser network demonstrated the un-hackable nature of quantum networks. But at the same time, this property creates a challenge because it’s hard to copy or amplify qubits – essential characteristics in conventional networks.
To solve this, engineers will need to develop quantum ‘repeaters’ that stop quantum signals degrading over distance. Initially, this will be trusted repeater networks that can encode and decode qubits and send them on across fibreoptic or satellite networks. Ultimately, there will be true quantum repeaters that exploit quantum entanglement to ‘teleport’ information and remove the need for any trusted intermediaries.
Overcoming such technical challenges will be essential to achieving a large-scale quantum internet that complements and enhances the existing global network. A prominent research team based at Delft University of Technology has set out a roadmap for the evolution of the quantum internet. Beginning with enhancing security through quantum key distribution, its proposed end state is a global network of quantum-connected quantum computers resembling today’s digitally-connected digital computers. The team proposes six phases of development:
1. A network of trusted nodes letting users receive quantum-generated codes (but not send and receive actual quantum states) and share encryption keys that service providers will also know.
2. A ‘prepare and measure’ phase where users can receive and measure quantum states, letting them share private keys and making it possible to verify passwords without directly reading or revealing them – potentially a massive boon in the battle against fraud.
3. Entanglement distribution networks where any two users can receive, but not store, states of quantum entanglement that enable the strongest possible encryption. Prototype demonstrators of this technology already exist, such as the satellite videoconferencing example above.
4. Quantum memory networks where users can receive and store entangled qubits and can effectively teleport information to each other. Quantum memory networks make quantum cloud computing possible.
5 & 6. Quantum computing networks that link multiple advanced quantum computers (capable of error correction on data transfers) to create distributed quantum computing and sophisticated quantum sensing applications. These phases will also need quantum equivalents of today’s internet communications protocols and standards that are entirely absent today.
The potential threat posed to traditional internet security by quantum computers means quantum internet technology should be on the radar of most organisations. In 2015, the NSA highlighted the scale of the threat and the need for security-critical businesses to start thinking about ‘quantum safe’ technology.
The technology described in the first two phases of the Delft roadmap is already available to businesses today and in use in nationally-critical sectors such as financial services, defence, energy and oil and gas exploration.
Other organisations can start experimenting too. Companies such as IDQ, Toshiba and Qubitekk offer commercial and prototype quantum key generation and distribution technology so business can test next-generation security today.
The Delft roadmap goes beyond security. It aims to create an array of quantum computers directly linked by quantum networks to form a quantum cloud able to solve previously impossible calculations, sharing the results instantly and securely anywhere in the world. This quantum internet will usher in a wealth of potential applications.
It would turbo-charge scientific research in areas such as pharmaceuticals and material sciences by running complex molecular simulations that go far beyond the capabilities of classical or individual quantum computers.
It could also create networks of synchronised quantum clocks that would significantly improve the precision of measurements. Researchers say this could have applications in astronomy and astrophysics, such as measuring gravitational waves or connecting arrays optical telescopes to see the universe in unprecedented detail.
Or the quantum internet could give rise to voting systems that exploit the properties of superposition to let voters give preferences across a range of candidates or issues.
Researchers have already demonstrated the first two phases of the Delft roadmap and progress continues at pace. So, organisations should start exploring how quantum computing will affect them and how they can capitalise on the quantum internet when it arrives.