Date and Time Apr 10, 2013, 3:00 PM - 4:00 PM
Location Bahen Centre, Room 7180
Host Alex Wong

From Quantum Hacking to Quantum Security

Feihu Xu

Qian and Lo Groups, Photonics



Quantum cryptography or quantum key distribution (QKD) can provide unconditional (i.e. information-theoretic) security based on the laws of quantum physics. It has been identified as the first technology in quantum information science to reach practical applications. During the past decade, commercial QKD products have appeared in the market; various field-test QKD networks have already been built in the USA, Europe, China, and Japan. However, owing to the imperfections in real-life implementations of QKD, a large gap between its theory and practice remains unfilled. In particular, an eavesdropper may exploit these imperfections and launch quantum hacking not covered by the original security proofs of QKD.

In this presentation, I will firstly give an introduction to QKD and review the recent developments of the field. Specifically, I will discuss the quantum hacking activities by using some well-known quantum attacks for illustration. Then, I will present a novel countermeasure scheme, namely measure-device-independent QKD (MDI-QKD), which removes all attacks in the detection system, the most serious loophole of QKD implementations. Finally, I will show how the entanglement-photon source (such as parametric down-conversion source) can be used in MDI-QKD to improve its performance.


Feihu Xu received his B.S. degree (Hons.) from the University of Science and Technology of China in 2009. After that, he went to the Department of Electrical and Computer Engineering, University of Toronto for graduate study, where he received M.A.Sc degree in 2011. Currently, he is a Ph.D. candidate in photonics and communications groups under the supervision of Prof. Li Qian and Prof. Hoi-Kwong Lo.