With the current trend toward nearly-ubiquitous cloud computing, maintaining data security is of paramount concern. To assist with that important goal, a group of Austrian researchers are looking at quantum computing's potential to enable secure data processing on remote servers. A paper based on their work, "Demonstration of Blind Quantum Computing," was recently published in Science, along with additional commentary here.

Encryption has long been considered one of the killer apps of quantum computing. The fundamental unit of quantum mechanics, called a quantum bit or qubit, can exist as both zero and one simultaneously, enabling an extreme level of encryption that cannot be cracked by traditional computers. Using the principles of quantum cryptography, as this field is called, European researchers demonstrated that quantum computation can be performed on a remote server, while remaining securely encrypted. The research was carried out at the Vienna Center for Quantum Science and Technology (VCQ) at the University of Vienna and the Institute for Quantum Optics and Quantum Information (IQOQI).

The details of the experiment were shared in a prepared statement:

The user prepares qubits – the fundamental units of quantum computers – in a state known only to himself and sends these qubits to the quantum computer. The quantum computer entangles the qubits according to a standard scheme. The actual computation is measurement-based: the processing of quantum information is implemented by simple measurements on qubits. The user tailors measurement instructions to the particular state of each qubit and sends them to the quantum server. Finally, the results of the computation are sent back to the user who can interpret and utilize the results of the computation. Even if the quantum computer or an eavesdropper tries to read the qubits, they gain no useful information, without knowing the initial state; they are "blind."

The computation is "blind" in that the quantum server performs its calculations, but does not have the ability to find out what it is doing. At present, this functionality is not thought to be achievable using traditional computation, which relies on classical physics principles.

According to Stefanie Barz, the lead author of the study, "Quantum physics solves one of the key challenges in distributed computing. It can preserve data privacy when users interact with remote computing centers."

While this is an exciting development, it bears mentioning that quantum computers are still in the development stage and when they do come on the scene, their sheer expense, not to mention energy requirements, will put them on par with the highest-echelon supercomputing centers. A process known as "quantum annealing" shows the most promise to date.