Canadian physicists claim to have developed "quantum cloning machine" capable of hacking quantum computers

Research provides clues on securing quantum computers

Researchers at the University of Ottawa claim to have built what they call a "quantum cloning machine", capable of intercepting a "secure quantum message".

The research, they add, could provide some ideas of how to secure quantum computers if and when they go mainstream.

Their research comes at a time of rapidly increasing interest in the potential of quantum computing, as conventional computing technology approaches the limits of copper on silicon.

"Our team has built the first high-dimensional quantum cloning machine capable of performing quantum hacking to intercept a secure quantum message," said University of Ottawa Department of Physics professor Ebrahim Karimi.

He added: "Once we were able to analyse the results, we discovered some very important clues to help protect quantum computing networks against potential hacking threats."

Quantum systems were believed to provide secure data transmission because until now, according to the University, attempts to copy the transmitted information resulted in an altered or deteriorated version of the original information, thereby defeating the purpose of the initial hack.

In conventional computing anyone can simply copy-and-paste information and replicate it exactly. But this doesn't hold true in the quantum computing world, where attempts to copy quantum information - or qudits* - result in what Karimi refers to as "bad" copies.

Professor Karimi's team was able to clone the photons that transmit information, namely the single carriers of light known as qubits, as well as quantum theory allows, meaning that the clones were almost exact replicas of the original information.

At the same time, though, the researchers' analyses also revealed some clues as to how quantum computers in the future might be protected against such attacks.

"What we found was that when larger amounts of quantum information are encoded on a single photon, the copies will get worse and hacking even simpler to detect," said Frédéric Bouchard, a University of Ottawa doctoral student.

He continued: "We were also able to show that cloning attacks introduce specific, observable noises in a secure quantum communication channel. Ensuring photons contain the largest amount of information possible and monitoring these noises in a secure channel should help strengthen quantum computing networks against potential hacking threats."

Interest in quantum computing has been escalating for years as advances in conventional computing power slows down. Last week, a University of Surrey scientist published a blueprint for a large-scale quantum computer, while commercial developer D-Wave Systems has started to sell its 2000 qubit device to organisations that need to perform particular calculations at speed.

* The term "qudit" is used to denote a unit of quantum information in a d-level quantum system.

Article edited on 8 February 2017 following feedback from readers