The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Qiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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satellite to ground entanglement based Quantum Key Distribution
Physical Review Letters, 2017Co-Authors: Yuhuai Li, Li Li, Shengkai Liao, Liang Zhang, B Li, Ming Li, Y Huang, Lei Deng, Qiang ZhangAbstract:We report on entanglement-based Quantum Key Distribution between a low-Earth-orbit satellite equipped with a space borne entangled-photon source and a ground observatory. One of the entangled photons is measured locally at the satellite, and the other one is sent via a down link to the receiver in the Delingha ground station. The link attenuation is measured to vary from 29 dB at 530 km to 36 dB at 1000 km. We observe that the two-photon entanglement survives after being distributed between the satellite and the ground, with a measured state fidelity of ≥0.86. We then perform the entanglement-based Quantum Key Distribution protocol and obtain an average final Key rate of 3.5 bits/s at the distance range of 530-1000 km. © 2017 American Physical Society.
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experimental measurement device independent Quantum Key Distribution
Physical Review Letters, 2013Co-Authors: Tengyun Chen, Liujun Wang, Hao Liang, Guoliang Shentu, Jian Wang, Li Li, Jason S Pelc, M M Fejer, Chengzhi Peng, Qiang ZhangAbstract:: Quantum Key Distribution is proven to offer unconditional security in communication between two remote users with ideal source and detection. Unfortunately, ideal devices never exist in practice and device imperfections have become the targets of various attacks. By developing up-conversion single-photon detectors with high efficiency and low noise, we faithfully demonstrate the measurement-device-independent Quantum-Key-Distribution protocol, which is immune to all hacking strategies on detection. Meanwhile, we employ the decoy-state method to defend attacks on a nonideal source. By assuming a trusted source scenario, our practical system, which generates more than a 25 kbit secure Key over a 50 km fiber link, serves as a stepping stone in the quest for unconditionally secure communications with realistic devices.
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Megabits secure Key rate Quantum Key Distribution
New Journal of Physics, 2009Co-Authors: Qiang Zhang, K Wen, Hiroki Takesue, Motohiro Suyama, Yasuhiro Tokura, Toshimori Honjo, Toru Hirohata, Yoshihiro Takiguchi, Hidehiko Kamada, Osamu TadanagaAbstract:Quantum cryptography (QC) can provide unconditional secure communication between two authorized parties based on the basic principles of Quantum mechanics. However, imperfect practical conditions limit its transmission distance and communication speed. Here we implemented the differential phase shift (DPS) Quantum Key Distribution (QKD) with up-conversion assisted hybrid photon detector (HPD) and achieved 1.3 M bits per second secure Key rate over a 10-km fiber, which is tolerant against the photon number splitting (PNS) attack, general collective attacks on individual photons, and any other known sequential unambiguous state discrimination (USD) attacks.
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megabits secure Key rate Quantum Key Distribution
New Journal of Physics, 2009Co-Authors: K Wen, Hiroki Takesue, Motohiro Suyama, Haruhiko Kamada, Qiang Zhang, Toshimori Honjo, Toru Hirohata, Yoshihiro Takiguchi, Yasuhiro TokuraAbstract:Quantum cryptography can provide unconditional secure communication between two authorized parties based on the basic principles of Quantum mechanics. However, imperfect practical conditions limit its transmission distance and communication speed. Here, we implemented the differential phase shift (DPS) Quantum Key Distribution (QKD) with an up-conversion-assisted hybrid photon detector (HPD) and achieved a 1.3 Mbits per second secure Key rate over a 10 km fiber, which is tolerant against photon number splitting (PNS) attack, general collective attacks on individual photons and any other known sequential unambiguous state discrimination (USD) attacks.
Eleni Diamanti - One of the best experts on this subject based on the ideXlab platform.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
Physical Review X, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature-phase-shift-Keying modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature-amplitude-modulation schemes. This result opens the way to establishing the full security of continuous-variable protocols with a discrete modulation, and thereby to the large-scale deployment of these protocols for Quantum Key Distribution.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
arXiv: Quantum Physics, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature phase-shift Keying (QPSK) modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature amplitude modulations (QAM) schemes. This work is a major step towards establishing the full security of continuous-variable protocols with a discrete modulation in the finite-size regime and opens the way to large-scale deployment of these protocols for Quantum Key Distribution.
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Practical challenges in Quantum Key Distribution
npj Quantum Information, 2016Co-Authors: Eleni Diamanti, Hoi-kwong Lo, Bing Qi, Zhiliang YuanAbstract:Quantum Key Distribution (QKD) promises unconditional security in data communication and is currently being deployed in commercial applications. Nonetheless, before QKD can be widely adopted, it faces a number of important challenges such as secret Key rate, distance, size, cost and practical security. Here, we survey those Key challenges and the approaches that are currently being taken to address them.
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experimental demonstration of long distance continuous variable Quantum Key Distribution
Nature Photonics, 2013Co-Authors: Paul Jouguet, Anthony Leverrier, Philippe Grangier, Sebastien Kunzjacques, Eleni DiamantiAbstract:Researchers demonstrate continuous-variable Quantum Key Distribution over 80 km of optical fibre. They develop a detection system based on homodyne detectors to achieve an unprecedented level of stability and implement new codes tailored to perform secure communication optimally in a range of signal-to-noise ratios corresponding to long distances.
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Analysis of Imperfections in Practical Continuous-Variable Quantum Key Distribution
Physical Review A, 2012Co-Authors: Paul Jouguet, Sébastien Kunz-jacques, Eleni Diamanti, Anthony LeverrierAbstract:As Quantum Key Distribution becomes a mature technology, it appears clearly that some assumptions made in the security proofs cannot be justified in practical implementations. This might open the door to possible side-channel attacks. We examine several discrepancies between theoretical models and experimental setups in the case of continuous-variable Quantum Key Distribution. We study in particular the impact of an imperfect modulation on the security of Gaussian protocols and show that approximating the theoretical Gaussian modulation with a discrete one is sufficient in practice. We also address the issue of properly calibrating the detection setup, and in particular the value of the shot noise. Finally, we consider the influence of phase noise in the preparation stage of the protocol and argue that taking this noise into account can improve the secret Key rate because this source of noise is not controlled by the eavesdropper.
Anthony Leverrier - One of the best experts on this subject based on the ideXlab platform.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
Physical Review X, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature-phase-shift-Keying modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature-amplitude-modulation schemes. This result opens the way to establishing the full security of continuous-variable protocols with a discrete modulation, and thereby to the large-scale deployment of these protocols for Quantum Key Distribution.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
arXiv: Quantum Physics, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature phase-shift Keying (QPSK) modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature amplitude modulations (QAM) schemes. This work is a major step towards establishing the full security of continuous-variable protocols with a discrete modulation in the finite-size regime and opens the way to large-scale deployment of these protocols for Quantum Key Distribution.
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experimental demonstration of long distance continuous variable Quantum Key Distribution
Nature Photonics, 2013Co-Authors: Paul Jouguet, Anthony Leverrier, Philippe Grangier, Sebastien Kunzjacques, Eleni DiamantiAbstract:Researchers demonstrate continuous-variable Quantum Key Distribution over 80 km of optical fibre. They develop a detection system based on homodyne detectors to achieve an unprecedented level of stability and implement new codes tailored to perform secure communication optimally in a range of signal-to-noise ratios corresponding to long distances.
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Analysis of Imperfections in Practical Continuous-Variable Quantum Key Distribution
Physical Review A, 2012Co-Authors: Paul Jouguet, Sébastien Kunz-jacques, Eleni Diamanti, Anthony LeverrierAbstract:As Quantum Key Distribution becomes a mature technology, it appears clearly that some assumptions made in the security proofs cannot be justified in practical implementations. This might open the door to possible side-channel attacks. We examine several discrepancies between theoretical models and experimental setups in the case of continuous-variable Quantum Key Distribution. We study in particular the impact of an imperfect modulation on the security of Gaussian protocols and show that approximating the theoretical Gaussian modulation with a discrete one is sufficient in practice. We also address the issue of properly calibrating the detection setup, and in particular the value of the shot noise. Finally, we consider the influence of phase noise in the preparation stage of the protocol and argue that taking this noise into account can improve the secret Key rate because this source of noise is not controlled by the eavesdropper.
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strenghtening classical symmetric encryption with continuous variable Quantum Key Distribution
Conference on Lasers and Electro-Optics, 2012Co-Authors: Thierry Debuisschert, Simon Fossier, Rosa Tuallebrouri, Philippe Pache, Philippe Painchault, Anthony Leverrier, Romain Alleaume, Philippe Grangier, Eleni Diamanti, Paul JouguetAbstract:An improved security fast encryption prototype is implemented over field installed fibers. Continuous variable Quantum Key Distribution produces 600 bit/sec secret Keys allowing session Keys renewal of classical symmetric algorithms each 10 seconds.
Philippe Grangier - One of the best experts on this subject based on the ideXlab platform.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
Physical Review X, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature-phase-shift-Keying modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature-amplitude-modulation schemes. This result opens the way to establishing the full security of continuous-variable protocols with a discrete modulation, and thereby to the large-scale deployment of these protocols for Quantum Key Distribution.
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asymptotic security of continuous variable Quantum Key Distribution with a discrete modulation
arXiv: Quantum Physics, 2019Co-Authors: Shouvik Ghorai, Philippe Grangier, Eleni Diamanti, Anthony LeverrierAbstract:We establish a lower bound on the asymptotic secret Key rate of continuous-variable Quantum Key Distribution with a discrete modulation of coherent states. The bound is valid against collective attacks and is obtained by formulating the problem as a semidefinite program. We illustrate our general approach with the quadrature phase-shift Keying (QPSK) modulation scheme and show that distances over 100 km are achievable for realistic values of noise. We also discuss the application to more complex quadrature amplitude modulations (QAM) schemes. This work is a major step towards establishing the full security of continuous-variable protocols with a discrete modulation in the finite-size regime and opens the way to large-scale deployment of these protocols for Quantum Key Distribution.
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experimental demonstration of long distance continuous variable Quantum Key Distribution
Nature Photonics, 2013Co-Authors: Paul Jouguet, Anthony Leverrier, Philippe Grangier, Sebastien Kunzjacques, Eleni DiamantiAbstract:Researchers demonstrate continuous-variable Quantum Key Distribution over 80 km of optical fibre. They develop a detection system based on homodyne detectors to achieve an unprecedented level of stability and implement new codes tailored to perform secure communication optimally in a range of signal-to-noise ratios corresponding to long distances.
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strenghtening classical symmetric encryption with continuous variable Quantum Key Distribution
Conference on Lasers and Electro-Optics, 2012Co-Authors: Thierry Debuisschert, Simon Fossier, Rosa Tuallebrouri, Philippe Pache, Philippe Painchault, Anthony Leverrier, Romain Alleaume, Philippe Grangier, Eleni Diamanti, Paul JouguetAbstract:An improved security fast encryption prototype is implemented over field installed fibers. Continuous variable Quantum Key Distribution produces 600 bit/sec secret Keys allowing session Keys renewal of classical symmetric algorithms each 10 seconds.
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long distance Quantum Key Distribution with continuous variables
arXiv: Quantum Physics, 2010Co-Authors: Anthony Leverrier, Philippe GrangierAbstract:We present a continuous-variable Quantum Key Distribution protocol combining a continuous but slightly non-Gaussian modulation together with a efficient reverse reconciliation scheme. We establish the security of this protocol against collective attacks which correspond to a linear Quantum channel. In particular, all Gaussian attacks are considered in our framework. We show that this protocol outperforms all known practical protocols, even taking into account finite size effects.
Norbert Lütkenhaus - One of the best experts on this subject based on the ideXlab platform.
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Worldwide standardization activity for Quantum Key Distribution
2014 IEEE Globecom Workshops (GC Wkshps), 2014Co-Authors: Romain Alleaume, Vincente Martin, Alan Mink, Norbert Lütkenhaus, Ivo Pietro Degiovanni, Momtchil Peev, Marco Lucamarini, Christopher J. Chunnilall, Martin WardAbstract:We discuss the on-going worldwide activity to develop forward looking standards for Quantum Key Distribution (QKD) in the European Telecommunications Standards Institute (ETSI) QKD industry specification group (ISG). The long term goal is to develop a certification methodology that bridges the gap between theoretical proofs and practical implementations with imperfect devices. Current efforts are focused on the handling of side channels and characterization of the most relevant components.
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the security of practical Quantum Key Distribution
Reviews of Modern Physics, 2009Co-Authors: Valerio Scarani, Norbert Lütkenhaus, Nicolas J Cerf, Helle Bechmannpasquinucci, Miloslav Dusek, Momtchil PeevAbstract:Quantum Key Distribution (QKD) is the first Quantum information task to reach the level of mature technology, already fit for commercialization. It aims at the creation of a secret Key between authorized partners connected by a Quantum channel and a classical authenticated channel. The security of the Key can in principle be guaranteed without putting any restriction on an eavesdropper's power. This article provides a concise up-to-date review of QKD, biased toward the practical side. Essential theoretical tools that have been developed to assess the security of the main experimental platforms are presented (discrete-variable, continuous-variable, and distributed-phase-reference protocols).
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sequential attacks against differential phase shift Quantum Key Distribution with weak coherent states
Quantum Information & Computation, 2007Co-Authors: Norbert Lütkenhaus, Marcos Curty, Lucy Liuxuan ZhangAbstract:We investigate limitations imposed by sequential attacks on the performance of differential-phase-shift Quantum Key Distribution protocols that use pulsed coherent light. In particular, we analyze two sequential attacks based on unambiguous state discrimination and minimum error discrimination, respectively, of the signal states emitted by the source. Sequential attacks represent a special type of intercept-resend attacks and, therefore, they provide ultimate upper bounds on the maximal distance achievable by Quantum Key Distribution schemes.
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unconditional security of practical Quantum Key Distribution
European Physical Journal D, 2007Co-Authors: Hitoshi Inamori, Norbert Lütkenhaus, Dominic MayersAbstract:We present a complete protocol for BB84 Quantum Key Distribution for a realistic setting (noise, loss, multi-photon signals of the source) that covers many of todays experimental implementations. The security of this protocol is shown against an eavesdropper having unrestricted power to manipulate the signals coherently on their path from sender to receiver. The protocol and the security proof take into account the effects concerning the finite size of the generated Key. This paper is identical to the preprint arXiv:quant-ph/0107017, which was finalized in 2001. Therefore, some of the more recent developments, including the question of composability, are not addressed.
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entanglement verification for Quantum Key Distribution systems with an underlying bipartite qubit mode structure
Physical Review A, 2006Co-Authors: Johannes Rigas, Otfried Guhne, Norbert LütkenhausAbstract:We consider entanglement detection for Quantum-Key-Distribution systems that use two signal states and continuous-variable measurements. This problem can be formulated as a separability problem in a qubit-mode system. To verify entanglement, we introduce an object that combines the covariance matrix of the mode with the density matrix of the qubit. We derive necessary separability criteria for this scenario. These criteria can be readily evaluated using semidefinite programming and we apply them to the specific Quantum Key Distribution protocol.
