New Cryptography Scheme Secured By Quantum Physics

Image Caption: The experiment's Alice and Bob communicated with entangled photons produced in this setup. Such apparatus could be miniaturized using techniques from integrated optics. Credit: IQC, University of Waterloo

Centre for Quantum Technologies

The way we secure digital transactions could soon change. An international team has demonstrated a form of quantum cryptography that can protect people doing business with others they may not know or trust a situation encountered often on the internet and in everyday life, for example at a banks ATM.

Having quantum cryptography to hand is a realistic prospect, I think. I expect that quantum technologies will gradually become integrated with existing devices such as smartphones, allowing us to do things like identify ourselves securely or generate encryption keys, says Stephanie Wehner, a Principal Investigator at the Centre for Quantum Technologies (CQT) at the National University of Singapore, and co-author on the paper.

In cryptography, the problem of providing a secure way for two mutually distrustful parties to interact is known as two-party secure computation. The new work, published in Nature Communications, describes the implementation using quantum technology of an important building block for such schemes.

CQT theorists Wehner and Nelly Ng teamed up with researchers at the Institute for Quantum Computing (IQC) at the University of Waterloo, Canada, for the demonstration.

Research partnerships such as this one between IQC and CQT are critical in moving the field forward, says Raymond Laflamme, Executive Director at the Institute for Quantum Computing. The infrastructure that weve built here at IQC is enabling exciting progress on quantum technologies.

CQT and IQC are two of the worlds largest, leading research centres in quantum technologies. Great things can happen when we combine our powers, says Artur Ekert, Director of CQT.

The experiments performed at IQC deployed quantum-entangled photons in such a way that one party, dubbed Alice, could share information with a second party, dubbed Bob, while meeting stringent restrictions. Specifically, Alice has two sets of information. Bob requests access to one or the other, and Alice must be able to send it to him without knowing which set hes asked for. Bob must also learn nothing about the unrequested set. This is a protocol known as 1-2 random oblivious transfer (ROT).

ROT is a starting point for more complicated schemes that have applications, for example, in secure identification. Oblivious transfer is a basic building block that you can stack together, like lego, to make something more fantastic, says Wehner.

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New Cryptography Scheme Secured By Quantum Physics