BOFFINS AT THE University of Ottawa claim that quantum computing may not provide the virtually 'unbreakable' security that it has been claimed the technology could offer.

Physicists at the University claim that they were able to build a "quantum cloning machine" that was able to intercept a "secure quantum message".

Their research suggests that initiatives such as China's dedicated quantum encryption network, which will supposedly provide secure communications between Beijing, Shanghai and a number of cities in between when it is finished at the end of the year, might not provide the security that its designers had planned.

"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.

"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, 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 to protect against such hacking.

"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 Frdric Bouchard, a University of Ottawa doctoral student.

"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.

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Boffins create quantum cloning machine to intercept 'secure' messages - The INQUIRER