Researchers at Vienna's Quantum Science and Technology Center have reported that 'blind' quantum computing could be carried out securely in the cloud.
The first secure quantum computer has been made by combining quantum entanglement with the power of apparent randomness.
The technique is similar to quantum cryptography, which guarantees the secrecy of a message sent from one place to another, but in this instance guarantees the privacy of data-processing. It could enable code-breakers, governments or private individuals to harness the power of a quantum server remotely without having to worry that the owner can snoop on their data or calculations.
Quantum computers exploit the ability of quantum particles to be in more than one state at the same time. This allows the computer to check many possible solutions to a problem simultaneously. If this capability can be scaled up, it could allow quantum computers to solve problems that are beyond the power of classical computers.
For the first time Stefanie Barz at the University of Vienna in Austria and colleagues have demonstrated blind quantum computing using a photon-based quantum computer.
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| Stefanie Barz |
They created strings of photons that looked random but were actually encoded versions of two programs: Deutsch's algorithm, which looks for regularities in certain mathematical functions, and Grover's algorithm, which searches an unsorted database.
They beamed these strings at the quantum computer. It ran the algorithms but because of encryption there was no way to detect it. Only when the results were returned could they be decoded and checked. "It's a new level of security," says Barz.
The secrecy is two-way. The technique also ensures that the user cannot know anything about the quantum computer. "You don't learn anything about their technology or how it works. It's a kind of double-blindess," says Vlatko Vedral, a quantum physicist at the University of Oxford, who was not involved in the work.
This may seem like an extreme form of secrecy, but Vedral says that various government and military organisations need to guarantee the secrecy of their data and calculations on timescales of 30 to 50 years, and the only way of doing that is to use blind computing,
