Businesses are one step closer to quantum cloud computing, thanks to a breakthrough made in its security and privacy by scientists at Oxford University.

The researchers used an approach dubbed ‘blind quantum computing’ to connect two quantum computing entities (Figure A); this simulates the situation where an employee at home or in an office remotely connects to a quantum server via the cloud. With this method, the quantum server provider does not need to know any details of the computation for it to be carried out, keeping the user’s proprietary work secure. The user can also easily verify the authenticity of their result, confirming it is neither erroneous nor corrupted.

Figure A

Ensuring the security and privacy of quantum computations is one of the most significant roadblocks that has held the powerful technology back so far, so this work could lead to it finally entering the mainstream.

Despite only being tested on a small scale, the researchers say their experiment has the potential to be scaled up to large quantum computations. Plug-in devices could be developed that safeguard a worker’s data while they access quantum cloud computing services.

Professor David Lucas, the co-head of the Oxford University Physics research team, said in a press release: “We have shown for the first time that quantum computing in the cloud can be accessed in a scalable, practical way which will also give people complete security and privacy of data, plus the ability to verify its authenticity.”

What is quantum cloud computing?

Classical computers process information as binary bits represented as 1s and 0s, but quantum computers do so using quantum bits, or qubits. Qubits exist as both a 1 and a 0 at the same time, but with a probability of being one or the other that is determined by their quantum state. This property enables quantum computers to tackle certain calculations much faster than classical computers, as they can solve problems simultaneously.

Quantum cloud computing is where quantum resources are provided to users remotely over the internet; this allows anyone to utilise quantum computing without the need for specialised hardware or expertise.

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Why is ‘blind quantum computing’ more secure?

With typical quantum cloud computing, the user must divulge the problem they are trying to solve to the cloud provider; this is because the provider’s infrastructure needs to understand the specifics of the problem so it can allocate the appropriate resources and execution parameters. Naturally, in the case of proprietary work, this presents a security concern.

This security risk is minimised with the blind quantum computing method because the user remotely controls the quantum processor of the server themselves during a computation. The information required to keep the data secure — like the input, output and algorithmic details — only needs to be known by the client because the server does not make any decisions with it.

“Never in history have the issues surrounding privacy of data and code been more urgently debated than in the present era of cloud computing and artificial intelligence,” said Professor Lucas in the press release.

“As quantum computers become more capable, people will seek to use them with complete security and privacy over networks, and our new results mark a step change in capability in this respect.”

How could quantum computing impact business?

Quantum computing is vastly more powerful than conventional computing, and could revolutionise how we work if it is successfully scaled out of the research phase. Examples include solving supply chain problems, optimising routes and securing communications.

In February, the U.K. government announced a £45 million ($57 million) investment into quantum computing; the money goes toward finding practical uses for quantum computing and creating a “quantum-enabled economy” by 2033. In March, quantum computing was singled out in the Ministerial Declaration, with G7 countries agreeing to work together to promote the development of quantum technologies and foster collaboration between academia and industry. Just this month, the U.K.’s second commercial quantum computer came online.

Due to the extensive power and refrigeration requirements, very few quantum computers are currently commercially available. However, several leading cloud providers do offer so-called quantum-as-a-service to corporate clients and researchers. Google’s Cirq, for example, is an open source quantum computing platform, while Amazon Braket allows users to test their algorithms on a local quantum simulator. IBM, Microsoft and Alibaba also have quantum-as-a-service offerings.

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But before quantum computing can be scaled up and used for business applications, it is imperative to ensure it can be achieved while safeguarding the privacy and security of customer data. This is what the Oxford University researchers hoped to achieve in their new study, published in Physical Review Letters.

Dr. Peter Dmota, study lead, told TechRepublic in an email: “Strong security guarantees will lower the barrier to using powerful quantum cloud computing services, once available, to speed up the development of new technologies, such as batteries and drugs, and for applications that involve highly confidential data, such as private medical information, intellectual property, and defence. Those applications exist also without added security, but would be less likely to be used as widely.

“Quantum computing has the potential to drastically improve machine learning. This would supercharge the development of better and more adapted artificial intelligence, which we are already seeing impacting businesses across all sectors.

“It is conceivable that quantum computing will have an impact on our lives in the next five to ten years, but it is difficult to forecast the exact nature of the innovations to come. I expect a continuous adaptation process as users start to learn how to use this new tool and how to apply it to their jobs — similar to how AI is slowly becoming more relevant at the mainstream workplace right now.

“Our research is currently driven by quite general assumptions, but as businesses start to explore the potential of quantum computing for them, more specific requirements will emerge and drive research into new directions.”

How does blind quantum cloud computing work?

Blind quantum cloud computing requires connecting a client computer that can detect photons, or particles of light, to a quantum computing server with a fibre optic cable (Figure B). The server generates single photons, which are sent through the fibre network and received by the client.

Figure B

The client then measures the polarisation, or orientation, of the photons, which tells it how to remotely manipulate the server in a way that will produce the desired computation. This can be done without the server needing access to any information about the computation, making it secure.

To provide additional assurance that the results of the computation are not erroneous or have been tampered with, additional tests can be undertaken. While tampering would not harm the security of the data in a blind quantum computation, it could still corrupt the result and leave the client unaware.

“The laws of quantum mechanics don’t allow copying of information and any attempt to observe the state of the memory by the server or an eavesdropper would corrupt the computation,” Dr Dmota explained to TechRepublic in an email. “In that case, the user would notice that the server isn’t operating faithfully, using a feature called ‘verification’, and abort using their service if there are any doubts.

“Since the server is ‘blind’ to the computation — ie, is not able to distinguish different computations — the client can evaluate the reliability of the server by running simple tests whose results can be easily checked.

“These tests can be interleaved with the actual computation until there is enough evidence that the server is operating correctly and the results of the actual computation can be trusted to be correct. This way, honest errors as well as malicious attempts to tamper with the computation can be detected by the client.”

Figure C

What did the researchers discover through their blind quantum cloud computing experiment?

The researchers found the computations their method produced “could be verified robustly and reliably”, as per the paper. This means that the client can trust the results have not been tampered with. It is also scalable, as the number of quantum elements being manipulated for performing calculations can be increased “without increasing the number of physical qubits in the server and without modifications to the client hardware,” the scientists wrote.

Dr. Drmota said in the press release, “Using blind quantum computing, clients can access remote quantum computers to process confidential data with secret algorithms and even verify the results are correct, without revealing any useful information. Realising this concept is a big step forward in both quantum computing and keeping our information safe online.”

The research was funded by the UK Quantum Computing and Simulation Hub — a collaboration of 17 universities supported by commercial and government organisations. It is one of four quantum technology hubs in the UK National Quantum Technologies Programme.