Quantum hacking: Experimental demonstration of time-shift attack against practical quantum-key-distribution systems

By Yi Zhao, Chi-Hang Fred Fung, Bing Qi, Christine Chen, Hoi-Kwong Lo. 2007

479 citations recorded by the source corpus.

Quantum-key-distribution (QKD) systems can send quantum signals over more than $100\phantom{\rule{0.3em}{0ex}}\mathrm{km}$ standard optical fiber and are widely believed to be secure. Here, we show experimentally a technologically feasible attack---namely, the time-shift attack---against a commercial QKD system. Our result shows that, contrary to popular belief, an eavesdropper, Eve, has a non-negligible probability $(\ensuremath{\sim}4%)$ to break the security of the system. Eve's success is due to the well-known detection efficiency loophole in the experimental testing of Bell's inequalities. Therefore, the detection efficiency loophole plays a key role not only in fundamental physics, but also in technological applications such as QKD systems.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/eb6ea7b66e15e0507e107c393ba91a8b3053b1e9

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Quantum Cryptography (2006, unknown): “This way Eve can get information about the sent bits without measuring the quantum signal [8] [9].”
Micius quantum experiments in space (2022, methodology): “For time-shift attacks (Zhao et al., 2008) and dead-time attacks (Weier et al., 2011), the countermeasure was to operate the detector in freerunning mode, in which the detector records all the detection events and postselects the detection windows such that the detection efficiency is guaranteed to…”
Measurement-Device-Independent Quantum Key Distribution Over a 404 km Optical Fiber. (2016, methodology): “We also incl ude simulations for balanced basis passive BB84 protocol using ideal SP sources, the practical SP withg((2))(0) = 0.”
Quantum eavesdropping without interception: an attack exploiting the dead time of single-photon detectors (2011, background): “Recently, considerable effort has been made to reveal those potential threats [11–15] and to find countermeasures against them [16–22].”
Secure quantum key distribution (2014, unknown): “[77]; b , Ref.”
Quantum technology for military applications (2021, background): “Especially in relation to quantum networks and in particular to QKD, we speak about quantum hacking [151, 152, 153, 154, 155], which has developed hand in hand with QKD itself.”
Quantum random number generators (2016, background): “…attacks take advantage of different detection efficiencies with time to make measurement in a chosen basis more or less likely introducing a bias (Zhao et al., 2008) and attacks based on imperfect beam splitters perform a similar feat by introducing unbalances in the way the quantum states are…”
Hacking commercial quantum cryptography systems by tailored bright illumination (2010, methodology): “Experimentally however, this attack only gave a small information-theoretical advantage for Eve when applied to a modified version of a commercial QKD syste”
Distributing Secret Keys with Quantum Continuous Variables: Principle, Security and Implementations (2015, background): “This approach has been pursued extensively for discrete-variable QKD, where powerful side-channel attacks have been demonstrated, in particular against commercial systems [70–72].”