Quantum mechanics, Carl Sagan once observed, is so strange that “common sense is almost useless in approaching it”. Scientists still don’t understand exactly why matter behaves as it does at the quantum level. Yet they’re getting better at exploiting its peculiar dynamics — in ways that may soon upend the technology business.

One of the most interesting applications is in computing. In theory, quantum computers could take advantage of odd subatomic interactions to solve certain problems far faster than a conventional machine could. Although a full-scale quantum computer is still years off, scientists have lately made a lot of progress on the materials, designs and methods needed to make one.

And that could have some striking benefits. Quantum computers could simulate how atoms and molecules behave, to the great advantage of chemists and drug designers. They could solve optimisation problems — say, how to efficiently route airplane traffic — far faster than current technology can. They could speed advances in artificial intelligence, improve sensors, and lead to the design of stronger and lighter industrial materials.

Unsurprisingly, then, investment in the field is surging. IBM, Microsoft and Google are all building quantum research labs. Start-ups are gearing up. Banks are very interested indeed. Governments see applications for space exploration, medical research and intelligence-gathering. America’s National Security Agency, in fact, has been quietly trying to build a quantum computer for years, in the hope that it would make an unstoppable code-breaker.

And that suggests a looming problem. To simplify a bit, the cryptographic tools commonly used to protect information online rely on very hard maths problems, such as factoring large integers, that normal computers can’t solve in a reasonable time frame. Quantum computers, though, could probably make quick work of such equations.

As a result, they could undermine the security of everything from mobile phones to e-commerce to cloud computing. Within two decades, by some estimates, quantum computers may be able to break all public-key encryption now in use. “The impact on the world economy,” says the nonprofit Cloud Security Alliance, “could be devastating.”

As dire as that sounds, panic isn’t in order just yet. Researchers are already working on “quantum-resistant” encryption. Some companies claim to have made significant progress in the field. Google, among others, is working on a new form of security for its browser that might rebuff a quantum algorithm. Although a lot more research is needed, standards agencies around the world are well aware of the problem.

Yet some vigilance is still advisable.

Businesses, in particular, should pay attention. Many have files that must be stored for years, for legal or commercial reasons. But woefully few have a long-term strategy for protecting them. That’s especially worrisome because, without precautions, sensitive records — medical files, financial data, trade secrets — that are stored using today’s encryption could potentially be exposed by quantum computers.

Governments could also help. Quantum computing requires competence in physics, computer science and engineering, and that makes it hard to find qualified workers. Public investment in basic quantum science research would help build a skilled workforce, boost technical know-how and generally lay the groundwork for a promising new field. It could also speed the development of stronger cryptography. More cooperation between Silicon Valley and the government, not on notable display recently, could be invaluable in this regard.