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Experimental demonstration of free-space decoy-state quantum key distribution over 144 km 总被引:1,自引:0,他引:1
Schmitt-Manderbach T Weier H Fürst M Ursin R Tiefenbacher F Scheidl T Perdigues J Sodnik Z Kurtsiefer C Rarity JG Zeilinger A Weinfurter H 《Physical review letters》2007,98(1):010504
We report on the experimental implementation of a Bennett-Brassard 1984 (BB84) protocol type quantum key distribution over a 144 km free-space link using weak coherent laser pulses. Optimization of the link transmission was achieved with bidirectional active telescope tracking, and the security was ensured by employing decoy-state analysis. This enabled us to distribute a secure key at a rate of 12.8 bit/s at an attenuation of about 35 dB. Utilizing a simple transmitter setup and an optical ground station capable of tracking a spacecraft in low earth orbit, this outdoor experiment demonstrates the feasibility of global key distribution via satellites. 相似文献
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Quantum key distribution (QKD) systems provide a method for two users to exchange a provably secure key. Synchronizing the users’ clocks is an essential step before a secure key can be distilled. Qubit-based synchronization protocols directly use the transmitted quantum states to achieve synchronization and thus avoid the need for additional classical synchronization hardware. Previous qubit-based synchronization protocols sacrifice secure key either directly or indirectly, and all known qubit-based synchronization protocols do not efficiently use all publicly available information published by the users. Here, we introduce a Bayesian probabilistic algorithm that incorporates all published information to efficiently find the clock offset without sacrificing any secure key. Additionally, the output of the algorithm is a probability, which allows us to quantify our confidence in the synchronization. For demonstration purposes, we present a model system with accompanying simulations of an efficient three-state BB84 prepare-and-measure protocol with decoy states. We use our algorithm to exploit the correlations between Alice’s published basis and mean photon number choices and Bob’s measurement outcomes to probabilistically determine the most likely clock offset. We find that we can achieve a 95 percent synchronization confidence in only 4140 communication bin widths, meaning we can tolerate clock drift approaching 1 part in 4140 in this example when simulating this system with a dark count probability per communication bin width of and a received mean photon number of 0.01. 相似文献
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Wang Xiang-bin Ying Hao Ma Huai-xing Peng Cheng-zhi Yang Tao Pan Jian-wei 《Frontiers of Physics in China》2006,1(3):251-255
In principle, quantum key distribution (QKD) can be used to make unconditionally secure private communication. However, the
security of the existing real system for QKD needs to be carefully examined. Actually, the existing experiments based on weak
coherent states are not secure under photon-number-splitting attack. Fortunately, the decoy-state method and the entanglement-distribution
method can be used to realize the unconditionally secure QKD based on real-life systems with existing technology. 相似文献
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Experimental long-distance decoy-state quantum key distribution based on polarization encoding 总被引:1,自引:0,他引:1
Peng CZ Zhang J Yang D Gao WB Ma HX Yin H Zeng HP Yang T Wang XB Pan JW 《Physical review letters》2007,98(1):010505
We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102 km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75 km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2, and 0.6 for the light sources in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation. 相似文献
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WANG ChaoZe GUO Hui REN JiGang CAO Yuan PENG ChengZhi LIU WeiYue 《中国科学:物理学 力学 天文学(英文版)》2014,57(7):1233-1237
Ground-satellite quantum key distribution(QKD)is a feasible way to implement global-scale quantum communication.Herein we propose an approach to dynamically compensate the polarization of the photons when passing through the optical telescope used in ground-satellite QKD.Our results experimentally demonstrate that the fidelity of any polarization state after dynamic compensation can be achieved by more than 99.5%,which fulfills the requirements of ground-satellite QKD. 相似文献
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Private information retrieval (PIR) is a database query protocol that provides user privacy in that the user can learn a particular entry of the database of his interest but his query would be hidden from the data centre. Symmetric private information retrieval (SPIR) takes PIR further by additionally offering database privacy, where the user cannot learn any additional entries of the database. Unconditionally secure SPIR solutions with multiple databases are known classically, but are unrealistic because they require long shared secret keys between the parties for secure communication and shared randomness in the protocol. Here, we propose using quantum key distribution (QKD) instead for a practical implementation, which can realise both the secure communication and shared randomness requirements. We prove that QKD maintains the security of the SPIR protocol and that it is also secure against any external eavesdropper. We also show how such a classical-quantum system could be implemented practically, using the example of a two-database SPIR protocol with keys generated by measurement device-independent QKD. Through key rate calculations, we show that such an implementation is feasible at the metropolitan level with current QKD technology. 相似文献
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Simultaneous two-way classical and quantum (STCQ) communication combines both continuous classical coherent optical communication and continuous-variable quantum key distribution (CV-QKD), which eliminates all detection-related imperfections by being measurement-device-independent (MDI). In this paper, we propose a protocol relying on STCQ communication on the oceanic quantum channel, in which the superposition-modulation-based coherent states depend on the information bits of both the secret key and the classical communication ciphertext. We analyse the encoding combination in classical communication and consider the probability distribution transmittance under seawater turbulence with various interference factors. Our numerical simulations of various practical scenarios demonstrate that the proposed protocol can simultaneously enable two-way classical communication and CV-MDI QKD with just a slight performance degradation transmission distance compared to the original CV-MDI QKD scheme. Moreover, the asymmetric situation outperforms the symmetric case in terms of transmission distance and optical modulation variance. We further take into consideration the impact of finite-size effects to illustrate the applicability of the proposed scheme in practical scenarios. The results show the feasibility of the underwater STCQ scheme, which contributes toward developing a global quantum communication network in free space. 相似文献
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自由空间量子密钥分布系统是全球性量子保密通信的关键组成部分之一。因此研究湍流大气信道对量子密钥分布系统性能的影响就非常重要。使用光束近场传播和统计分析的方法定量分析了湍流大气信道对基于BB84协议的自由空间量子密钥分布系统的误码率的影响。数值计算结果表明,大气衰减系数超过-3dB/km时,大气衰减对量子密钥分布系统的误码率影响很大;在大气传输因子小于0.5的区域,系统误码率比无湍流影响时的系统误码率高出一个数量级。 相似文献
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Optical communication technology shows promising prospects to fulfill the large bandwidth communication requirements of future deep-space exploration missions that are launched by NASA and various other international space agencies. At Earth, a telescope with a large aperture diameter is required to capture very weak optical signals that are transmitted from distant planets and to support large bandwidth communication link. A single large telescope has the limitations of cost, single point failure in case of malfunction, difficulty in manufacturing high quality optics, maintenance, and trouble in providing communication operations when transmitting spacecraft is close to the Sun. An array of relatively smaller-sized telescopes electrically connected to form an aggregate aperture area equivalent to a single large telescope is a viable alternative to a monolithic gigantic aperture. In this paper, we present the design concept and analysis of telescope array receivers for an optical communication link between Earth and Mars. Pulse-position modulation (PPM) is used at the transmitter end and photon-counting detectors along with the direct-detection technique are employed at each telescope element in the array. We also present the optimization of various system parameters, such as detector size (i.e., receiver field of view), PPM slot width, and the PPM order M, to mitigate the atmospheric turbulence and background noise effects, and to maximize the communication system performance. The performance of different array architectures is evaluated through analytical techniques and Monte-Carlo simulations for a broad range of operational scenarios, such as, Earth-Mars conjunction, Earth-Mars opposition, and different background and turbulence conditions. It is shown that the performance of the telescope array-based receiver is equivalent to a single large telescope; and as compared to current RF technology, telescope array-based optical receivers can provide several orders of magnitude greater data rates for deep-space communication with Mars. 相似文献
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针对实用的量子密钥分配(QKD)系统是基于强衰减的弱激光脉冲作为单光子源, 光子数分束攻击极大限制了通信双方在非理想条件下QKD的传输距离和密钥生成率,采用大数定律对诱惑态协议中单光子的计数率、单光子增益和误码率分别进行统计涨落分析, 利用双诱惑态比较了1310 nm和1550 nm条件下,编码脉冲的长度为(N = 106-N = 1012)实际QKD协议中密钥的生成率与安全传输距离之间的关系、安全传输距离随编码长度的变化的关系, 得出脉冲编码长度增大到N = 1012时,密钥的最大安全传输距离为135 km. 相似文献
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We report on the first demonstration of a two way Quantum Key Distribution (QKD) protocol with decoy state. The experiment was conducted over free space medium and exhibits a significant increase in the maximum secure distance of a two way QKD protocol specifically the LM05 protocol. 相似文献
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量子通信是一个量子密钥分发过程,目前采用的通信技术严重制约了量子密钥分发的比特率.将多输入多输出(MIMO)技术应用于量子通信系统,提高量子密钥分发的比特率,促进量子通信向高速大容量发展.然而,量子场本身不可避免地存在量子噪声约束容量的增长,限制了可利用空间资源,即空间自由度.文中采用光子场的量子化和满足Schrdinger方程条件的电磁场波动方程推导出MIMO量子信道的空间自由度上限,为开发稳健的MIMO量子通信空时处理算法和优化设计高性能MIMO量子通信系统提供理论基础和技术支持.
关键词:
多输入多输出
量子密钥分发
Schrdinger方程
光子场的量子化 相似文献
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通过比较被动系统与主动系统的特性, 得出可信光源、不可信光源主动系统和不可信光源被动系统的密钥生成率随距离的变化关系; 采用标准误差分析法, 得到相应变量的偏离量; 基于诱骗态方案分析不可信光源被动系统暗计数率和光源强度参数波动对系统安全特性的影响, 得出在1310 nm 和1550 nm通信窗口下, 系统最大安全通信距离范围分别为[73.2 km, 96.5 km] 和[104.5 km, 137.9 km]. 这可为实用量子通信实验提供重要的理论参数.
关键词:
量子密钥分配
不可信光源
被动系统
统计波动 相似文献
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To increase dramatically the distance and the secure key generation rate of quantum key distribution (QKD), the idea of quantum decoys--signals of different intensities--has recently been proposed. Here, we present the first experimental implementation of decoy state QKD. By making simple modifications to a commercial quantum key distribution system, we show that a secure key generation rate of 165 bit/s, which is 1/4 of the theoretical limit, can be obtained over 15 km of a telecommunication fiber. We also show that with the same experimental parameters, not even a single bit of secure key can be extracted with a non-decoy-state protocol. Compared to building single photon sources, decoy state QKD is a much simpler method for increasing the distance and key generation rate of unconditionally secure QKD. 相似文献
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By combining the idea of quantum secure direct communication (QSDC) and BB84 quantum key distribution (QKD), we propose a secure quantum dialogue protocol via single photons. Comparing with the previous bidirectional quantum secure communication scheme [24] in which the EPR pairs are used, our protocol is not only feasible in practice but also can overcome the drawback “information leakage” or “classical correlation”. Our scheme possesses the characters of security and high efficiency. 相似文献
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A long-distance quantum key distribution scheme based on pre-detection of optical pulse with auxiliary state 下载免费PDF全文
《中国物理 B》2015,(5)
We construct a circuit based on PBS and CNOT gates, which can be used to determine whether the input pulse is empty or not according to the detection result of the auxiliary state, while the input state will not be changed. The circuit can be treated as a pre-detection device. Equipping the pre-detection device in the front of the receiver of the quantum key distribution(QKD) can reduce the influence of the dark count of the detector, hence increasing the secure communication distance significantly. Simulation results show that the secure communication distance can reach 516 km and 479 km for QKD with perfect single photon source and decoy-state QKD with weak coherent photon source, respectively. 相似文献