Why you might trust a quantum computer with secrets – even over the internet

Here's the scenario: you have sensitive data and a problem that only a quantum computer can solve. You have no quantum devices yourself. You could buy time on a quantum computer, but you don't want to give away your secrets. What can you do?

Writing in Physical Review X on 11 July, researchers in Singapore and Australia propose a way you could use a quantum computer securely, even over the internet. The technique could hide both your data and program from the computer itself. Their work counters earlier hints that such a feat is impossible.

The scenario is not far-fetched. Quantum computers promise new routes to solving problems in cryptography, modelling and machine learning, exciting government and industry. Such problems may involve confidential data or be commercially sensitive.

Technology giants are already investing in building such computers – and making them available to users. For example, IBM announced on 17 May this year that it is making a quantum computer with 16 quantum bits accessible to the public for free on the cloud, as well as a 17-qubit prototype commercial processor.

Seventeen qubits are not enough to outperform the world's current supercomputers, but as quantum computers gain qubits, they are expected to exceed the capabilities of any machine we have today. That should drive demand for access.

Read more at Centre for Quantum Technologies at the National University of Singapore

Image: It may be possible to control a quantum computer over the internet without revealing what you are calculating, thanks to the many possible ways that information can flow through a computation. That's the conclusion of researchers in Singapore and Australia who studied the measurement-based model of quantum computing, reported 11 July in the open-access journal Physical Review X. (Credit: Timothy Yeo / Centre for Quantum Technologies, National University of Singapore)