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Ming-Qi Huang

Bio: Ming-Qi Huang is an academic researcher from University of Science and Technology of China. The author has contributed to research in topics: Quantum key distribution & Quantum cryptography. The author has an hindex of 2, co-authored 3 publications receiving 709 citations.

Papers
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Journal ArticleDOI
TL;DR: This record-breaking implementation of the MDIQKD method provides a new distance record and achieves a distance that the traditional Bennett-Brassard 1984 QKD would not be able to achieve with the same detection devices even with ideal single-photon sources.
Abstract: A protocol for secure quantum communications has been demonstrated over a record-breaking distance of 404 km.

737 citations

Journal ArticleDOI
TL;DR: In this paper, a quantum key distribution network spread over a metropolitan area is shown to be secure against untrustworthy relays, where the relays are assumed to be untrusted.
Abstract: Unconditionally secure communication between remote parties has many applications in finance and industry. Now, a quantum key distribution network spread over a metropolitan area is shown to be secure against untrustworthy relays.

166 citations

Journal ArticleDOI
TL;DR: This work constructs a measurement-device-independent quantum key distribution (MDIQKD) network in a star topology over a 200 square kilometers metropolitan area, which is secure against untrustful relays and against all detection attacks.
Abstract: Quantum cryptography holds the promise to establish an information-theoretically secure global network. All field tests of metropolitan-scale quantum networks to date are based on trusted relays. The security critically relies on the accountability of the trusted relays, which will break down if the relay is dishonest or compromised. Here, we construct a measurement-device-independent quantum key distribution (MDIQKD) network in a star topology over a 200 square kilometers metropolitan area, which is secure against untrustful relays and against all detection attacks. In the field test, our system continuously runs through one week with a secure key rate ten times larger than previous result. Our results demonstrate that the MDIQKD network, combining the best of both worlds --- security and practicality, constitutes an appealing solution to secure metropolitan communications.

33 citations


Cited by
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Journal ArticleDOI
09 Aug 2017-Nature
TL;DR: This work reports the development and launch of a low-Earth-orbit satellite for implementing decoy-state QKD—a form ofQKD that uses weak coherent pulses at high channel loss and is secure because photon-number-splitting eavesdropping can be detected.
Abstract: Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. However, the distance over which QKD is achievable has been limited to a few hundred kilometres, owing to the channel loss that occurs when using optical fibres or terrestrial free space that exponentially reduces the photon transmission rate. Satellite-based QKD has the potential to help to establish a global-scale quantum network, owing to the negligible photon loss and decoherence experienced in empty space. Here we report the development and launch of a low-Earth-orbit satellite for implementing decoy-state QKD-a form of QKD that uses weak coherent pulses at high channel loss and is secure because photon-number-splitting eavesdropping can be detected. We achieve a kilohertz key rate from the satellite to the ground over a distance of up to 1,200 kilometres. This key rate is around 20 orders of magnitudes greater than that expected using an optical fibre of the same length. The establishment of a reliable and efficient space-to-ground link for quantum-state transmission paves the way to global-scale quantum networks.

1,216 citations

Journal ArticleDOI
16 Jun 2017-Science
TL;DR: Satellite-based distribution of entangled photon pairs to two locations separated by 1203 kilometers on Earth, through two satellite-to-ground downlinks is demonstrated, with a survival of two-photon entanglement and a violation of Bell inequality.
Abstract: Long-distance entanglement distribution is essential for both foundational tests of quantum physics and scalable quantum networks. Owing to channel loss, however, the previously achieved distance was limited to ~100 kilometers. Here we demonstrate satellite-based distribution of entangled photon pairs to two locations separated by 1203 kilometers on Earth, through two satellite-to-ground downlinks with a summed length varying from 1600 to 2400 kilometers. We observed a survival of two-photon entanglement and a violation of Bell inequality by 2.37 ± 0.09 under strict Einstein locality conditions. The obtained effective link efficiency is orders of magnitude higher than that of the direct bidirectional transmission of the two photons through telecommunication fibers.

917 citations

Journal ArticleDOI
02 May 2018-Nature
TL;DR: This work introduces an alternative scheme for QKD whereby pairs of phase-randomized optical fields are first generated at two distant locations and then combined at a central measuring station, enabling a form of quantum key distribution that can exceed the secret-key capacity without using quantum repeaters and that has security independent of the measuring devices.
Abstract: Quantum key distribution (QKD)1,2 allows two distant parties to share encryption keys with security based on physical laws. Experimentally, QKD has been implemented via optical means, achieving key rates of 1.26 megabits per second over 50 kilometres of standard optical fibre3 and of 1.16 bits per hour over 404 kilometres of ultralow-loss fibre in a measurement-device-independent configuration4. Increasing the bit rate and range of QKD is a formidable, but important, challenge. A related target, which is currently considered to be unfeasible without quantum repeaters5–7, is overcoming the fundamental rate–distance limit of QKD8. This limit defines the maximum possible secret key rate that two parties can distil at a given distance using QKD and is quantified by the secret-key capacity of the quantum channel9 that connects the parties. Here we introduce an alternative scheme for QKD whereby pairs of phase-randomized optical fields are first generated at two distant locations and then combined at a central measuring station. Fields imparted with the same random phase are ‘twins’ and can be used to distil a quantum key. The key rate of this twin-field QKD exhibits the same dependence on distance as does a quantum repeater, scaling with the square-root of the channel transmittance, irrespective of who (malicious or otherwise) is in control of the measuring station. However, unlike schemes that involve quantum repeaters, ours is feasible with current technology and presents manageable levels of noise even on 550 kilometres of standard optical fibre. This scheme is a promising step towards overcoming the rate–distance limit of QKD and greatly extending the range of secure quantum communications. Twin optical fields enable a form of quantum key distribution that can exceed the secret-key capacity without using quantum repeaters and that has security independent of the measuring devices.

787 citations

Journal ArticleDOI
TL;DR: This review begins by reviewing protocols of quantum key distribution based on discrete variable systems, and considers aspects of device independence, satellite challenges, and high rate protocols based on continuous variable systems.
Abstract: Quantum cryptography is arguably the fastest growing area in quantum information science. Novel theoretical protocols are designed on a regular basis, security proofs are constantly improving, and experiments are gradually moving from proof-of-principle lab demonstrations to in-field implementations and technological prototypes. In this paper, we provide both a general introduction and a state-of-the-art description of the recent advances in the field, both theoretical and experimental. We start by reviewing protocols of quantum key distribution based on discrete variable systems. Next we consider aspects of device independence, satellite challenges, and protocols based on continuous-variable systems. We will then discuss the ultimate limits of point-to-point private communications and how quantum repeaters and networks may overcome these restrictions. Finally, we will discuss some aspects of quantum cryptography beyond standard quantum key distribution, including quantum random number generators and quantum digital signatures.

769 citations

Journal ArticleDOI
TL;DR: This review gives both sides of the story, with the current best theory of quantum security, and an extensive survey of what makes quantum cryptosystem safe in practice.
Abstract: Some years ago quantum hacking became popular: devices implementing the unbreakable quantum cryptography were shown to have imperfections which could be exploited by attackers. Security has been thoroughly enhanced, as a consequence of both theoretical and experimental advances. This review gives both sides of the story, with the current best theory of quantum security, and an extensive survey of what makes quantum cryptosystem safe in practice.

761 citations