Quantum key distribution (QKD) protocols have been proven to be information theoretically secure based on fundamental laws in quantum mechanics. However, practical QKD systems often deviate from idealized models employed in standard security proofs and have imperfections that may lead to fatal security loopholes. Indeed, quantum hacking against practical QKD systems, particularly via detector side channel attacks, has emerged as a hot topic. One important research direction in QKD is to examine potential security loopholes in practical systems and develop QKD protocols with the best balance between security and practicality.
We have been exploring in this direction by taking the view of both the code-makers and code-breakers. In this talk, I will review a few successful quantum hacking schemes, including the “time-shift” attack and the “detector blinding” attack. I will also present the measurement device independent QKD (MDIQKD) protocol proposed by us recently (arXiv:1109.1473v1), which “looks like an elegant solution for the untrusted detector problem” (Charlie Bennett, on the Quantum Pontiff).
Dr. Bing Qi received his B.A. in Physics from Nanjing University in 1990, and Ph.D. in Optical Instrument from Dalian University of Technology in 1996. Currently, he is a senior research associate in the Dept. of Electrical and Computer Engineering, University of Toronto, Canada.
Dr. Qi has been working on practical quantum cryptography since 2003. He made important contributions to the first experimental implementation of the decoy state quantum key distribution (QKD) protocol and the design and implementation of time-shift attack, which is the first successful attack against a commercial QKD system. His current research interests include measurement device independent QKD (MDIQKD), continuous variable QKD through existing fiber optic network, QKD based on energy-time uncertainty principle, high rate random number generation from quantum phase noise of a laser, etc.