Quantum computers are coming. Or, at least, that’s what current predictions say. These machines harness the power of quantum mechanics, the set of rules governing how physics operates at atomic and sub-atomic scales.
Because of this, they operate in radically different ways to current machines. Tasks requiring trillions of years on existing supercomputers might be reduced to days on future quantum computers. They could tackle a range of challenges that are out of reach for existing technology.
These potential challenges include code-breaking. In 1994, the American computer scientist Peter Shor came up with a quantum algorithm capable of breaking the form of encryption that would later underpin routine email messaging and internet security. Shor’s advance drew interest from the US military and intelligence community, which began investing in the emerging field.
While decryption is often touted as a potential use for quantum computers, there are now protections against attempts to use them in this way. And in recent decades, other exciting applications have emerged. So is the threat to secure communications being overstated?
Currently, nobody knows for sure which quantum computing technologies will prevail, when the obstacles to their production will be overcome, or who will build one first.
But we can make educated guesses. Quantum computers built for specialised tasks will probably arrive before machines for more generalised uses. Between 10 and 20 years is a plausible guesstimate for the emergence of practical machines – amid considerable uncertainty. The US and China appear to be market leaders, so the big breakthrough could come from one of them.
It’s perhaps understandable why decryption is the poster child for quantum computing applications. The security of our digital world relies on cryptography, which provides a toolkit of mathematical techniques that underpin cyber security.
Digital secrets are protected by encryption, which converts meaningful data into an unintelligible form. If quantum computers could unscramble current encryption, they could expose highly sensitive data. Useful, perhaps, for nation states tracking terror cells or spying on strategic competitors – but bad news for everyone else.
Cryptography apocalypse
If we fail to act, this digital disaster might indeed happen. But researchers in this field have not been sitting on their hands. In the last decade, they have developed standards for new encryption techniques offering protection against quantum code-breaking. This area is known as post-quantum cryptography.
Many governments have announced timelines designed to motivate organisations to migrate from existing cryptography to the new post-quantum encryption standards. If everyone moves swiftly, by the time cryptographically-relevant quantum computers are built, our data should be sufficiently protected.
Yet stories of a pending cryptography apocalypse – sometimes referred to as “Q day” – still abound. So why, as we manoeuvre towards a future protected by post-quantum cryptography, are headlines still obsessed with decryption?
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Is a quantum-cryptography apocalypse imminent?
Well, everyone loves an origin story. The quantum algorithm developed in 1994 by Peter Shor caused a sensation. Cryptographers immediately commenced the hunt for new types of encryption invulnerable to Shor’s algorithm. More significantly, this theoretical breakthrough helped drive the actual development of quantum computers, since Shor’s algorithm was arguably the first convincing application for these machines.
There’s a tangibility to this quantum threat. The (often overblown) idea of a Q-Day posits that we awake one morning and our cyber security has suddenly been lost. In contrast, most constructive use cases for quantum computers seem more abstract. They might greatly assist mathematical modelling of scientific problems such as climate change, along with complex simulations of how physics works.
Other end uses sound fantastical. For example, quantum computers might help us find a cure for cancer or harness vast clean energy from nuclear fusion. In the absence of a proven killer app, decryption often prevails as a prominent, imagined end use. And the prospect of doomsday always focuses human minds.
Other uses
Quantum computing has also become firmly embedded in great power competition. China, the US and Russia, among others, are all pushing the development of quantum computers. To some in government, the consequences of losing a quantum computing race are unthinkable. What if your strategic rival can decrypt your secrets, but you can’t decrypt theirs?
The question is, are these anxieties really driving the stacks of cash being pumped into the field?
Setting aside political advantages, as well as criminal gains, the real money from quantum computing is not going to be made from decryption.
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A range of quantum computing companies are now promoting their technologies and there’s barely a mention of decryption. Instead, other compelling uses are being trumpeted. Quantum computers would excel at optimisation, which is all about finding the most efficient solutions to complex problems that classical computers struggle with.
This could transform parts of the finance industry that deal with large-scale, complex transactions, and intricate investment strategies. It could also make supply chain logistics easier to manage. Quantum computers could supercharge drug discovery and lead to the development of new industrial materials.
They may be capable of greatly enhanced predictive modelling, leading to more accurate weather prediction and geopolitical risk analysis. Quantum computers might also boost artificial intelligence technology.
Most of these remain unrealised visions, but the prospect of breakthroughs and enrichment fuels investment.
Andrey_Popov
So, there’s a genuine geopolitical power struggle in play, but it’s no longer solely or even primarily about decrypting secrets. Quantum competition between great powers concerns first-mover advantage across a broad base of technological domains. Ultimately, it’s about who’s going to make money.
Early progress seems most likely in industrial materials and optimisation. Later opportunities may involve advanced mathematical modelling and predictive simulations.
If quantum computers surpass the sceptics’ doubts to become capable of breaking current encryption, this will probably be a much later development. And if everyone’s done their post-quantum cryptography migration, it will hopefully be largely irrelevant.
But given how long cryptographic upgrades can take, cybersecurity slowpokes may still have a lot to lose.
Keith Martin receives funding from the EPSRC.
Briana Bowen receives funding from the EPSRC and has previously received funding from the US Government.
