scholarly journals Quantum Key Distribution with High Loss: Toward Global Secure Communication

2003 ◽  
Vol 91 (5) ◽  
Author(s):  
Won-Young Hwang
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
High Loss

scholarly journals DECOY STATE QUANTUM KEY DISTRIBUTION

2005 ◽  
Vol 03 (supp01) ◽  
pp. 143-143 ◽  
Author(s):  
HOI-KWONG LO
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Generation Rate ◽  
Key Generation ◽  
Long Distance ◽  
Decoy State ◽  
Bb84 Protocol ◽  
High Loss ◽  
Statistical Fluctuations

Quantum key distribution (QKD) allows two parties to communicate in absolute security based on the fundamental laws of physics. Up till now, it is widely believed that unconditionally secure QKD based on standard Bennett-Brassard (BB84) protocol is limited in both key generation rate and distance because of imperfect devices. Here, we solve these two problems directly by presenting new protocols that are feasible with only current technology. Surprisingly, our new protocols can make fiber-based QKD unconditionally secure at distances over 100km (for some experiments, such as GYS) and increase the key generation rate from O(η2) in prior art to O(η) where η is the overall transmittance. Our method is to develop the decoy state idea (first proposed by W.-Y. Hwang in "Quantum Key Distribution with High Loss: Toward Global Secure Communication", Phys. Rev. Lett. 91, 057901 (2003)) and consider simple extensions of the BB84 protocol. This part of work is published in "Decoy State Quantum Key Distribution", . We present a general theory of the decoy state protocol and propose a decoy method based on only one signal state and two decoy states. We perform optimization on the choice of intensities of the signal state and the two decoy states. Our result shows that a decoy state protocol with only two types of decoy states—a vacuum and a weak decoy state—asymptotically approaches the theoretical limit of the most general type of decoy state protocols (with an infinite number of decoy states). We also present a one-decoy-state protocol as a special case of Vacuum+Weak decoy method. Moreover, we provide estimations on the effects of statistical fluctuations and suggest that, even for long distance (larger than 100km) QKD, our two-decoy-state protocol can be implemented with only a few hours of experimental data. In conclusion, decoy state quantum key distribution is highly practical. This part of work is published in "Practical Decoy State for Quantum Key Distribution", . We also have done the first experimental demonstration of decoy state quantum key distribution, over 15km of Telecom fibers. This part of work is published in "Experimental Decoy State Quantum Key Distribution Over 15km", .

scholarly journals Security Analysis of Discrete-Modulated Continuous-Variable Quantum Key Distribution over Seawater Channel

2019 ◽  
Vol 9 (22) ◽  
pp. 4956 ◽  
Author(s):  
Xinchao Ruan ◽  
Hang Zhang ◽  
Wei Zhao ◽  
Xiaoxue Wang ◽  
Xuan Li ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Security Analysis ◽  
Finite Size ◽  
Key Distribution ◽  
Continuous Variable ◽  
Heterodyne Detection ◽  
Secret Key ◽  
Transmission Distance ◽  
Better Than

We investigate the optical absorption and scattering properties of four different kinds of seawater as the quantum channel. The models of discrete-modulated continuous-variable quantum key distribution (CV-QKD) in free-space seawater channel are briefly described, and the performance of the four-state protocol and the eight-state protocol in asymptotic and finite-size cases is analyzed in detail. Simulation results illustrate that the more complex is the seawater composition, the worse is the performance of the protocol. For different types of seawater channels, we can improve the performance of the protocol by selecting different optimal modulation variances and controlling the extra noise on the channel. Besides, we can find that the performance of the eight-state protocol is better than that of the four-state protocol, and there is little difference between homodyne detection and heterodyne detection. Although the secret key rate of the protocol that we propose is still relatively low and the maximum transmission distance is only a few hundred meters, the research on CV-QKD over the seawater channel is of great significance, which provides a new idea for the construction of global secure communication network.

scholarly journals Physical-layer encryption on the public internet: A stochastic approach to the Kish-Sethuraman cipher

2014 ◽  
Vol 33 ◽  
pp. 1460361 ◽  
Author(s):  
Lachlan J. Gunn ◽  
James M. Chappell ◽  
Andrew Allison ◽  
Derek Abbott
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Stochastic Approach ◽  
Physical Layer ◽  
Information Theoretic ◽  
The Public ◽  
Information Theoretic Security ◽  
Transit Times ◽  
The One

While information-theoretic security is often associated with the one-time pad and quantum key distribution, noisy transport media leave room for classical techniques and even covert operation. Transit times across the public internet exhibit a degree of randomness, and cannot be determined noiselessly by an eavesdropper. We demonstrate the use of these measurements for information-theoretically secure communication over the public internet.

Two-way quantum key distribution in a uniformly distributed quantum space via a special mapping and its analytical security proofs

2019 ◽  
Vol 17 (01) ◽  
pp. 1950010
Author(s):  
Guodong Kang ◽  
Qingping Zhou ◽  
Maofa Fang
Keyword(s):  
General Model ◽  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Reduced Model ◽  
Quantum Space ◽  
Security Proofs ◽  
Main Work ◽  
Security Proof ◽  
Special Mapping

Within the field of quantum cryptography, two-way direct quantum secure communication is a relatively new proposal for sharing secret information that is not fully explored yet. We propose a general model for two-way deterministic quantum key distribution, and a special mapping from integers to a uniformly distributed quantum space is introduced for qubit pad preparation. A reduced model, more practical, is also proposed by relaxing the security assumption of the qubit pad preparation. The main work of this paper focuses on the security proofs of these two models. Under collective attacks, we fully analyze the security basis of the general model, and, in a relatively simple way, we provide an analytical security proof for the reduced model in a depolarization quantum channel. Our results show exactly the analytical upper-bound of the amount of useful key that a powerful eavesdropper could extract in both models, and the security of the reduced model is not reduced. One advantage of this work is that the special mapping guarantees the random distribution property of the qubit pad in a uniformly distributed quantum space, thus guaranteeing the security of the two models, and the other advantage is the simplicity of the analytical derivations of security proofs.

SECURITY OF QUANTUM KEY DISTRIBUTION WITH STRONG PHASE-REFERENCE PULSE

2005 ◽  
Vol 03 (supp01) ◽  
pp. 75-86
Author(s):  
MASATO KOASHI
Keyword(s):  
Coherent State ◽  
Quantum Key Distribution ◽  
Single Photon ◽  
Key Distribution ◽  
Secret Key ◽  
Single Photon Source ◽  
Reference Pulse ◽  
High Loss ◽  
The One ◽  
Photon Source

In the BB84 protocol with a perfect single photon source, the key rate decreases linearly with the transmission η of the channel. If we simply replace this source with a weak coherent-state pulse, the key rate drops more rapidly (as O(η2)) since the presence of multiple photons favors the eavesdropper. Here we discuss the unconditional security of a quantum key distribution protocol in which bit values are encoded in the phase of a weak coherent-state pulse relative to a strong reference pulse, which is essentially the one proposed by Bennett in 1992 (the B92 scheme). We show that in the limit of high loss in the transmission channel, we can construct a secret key with a rate proportional to the transmission η of the channel.

High performance reconciliation for continuous-variable quantum key distribution with LDPC code

2015 ◽  
Vol 13 (02) ◽  
pp. 1550010 ◽  
Author(s):  
Dakai Lin ◽  
Duan Huang ◽  
Peng Huang ◽  
Jinye Peng ◽  
Guihua Zeng
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
High Speed ◽  
High Performance ◽  
Graphics Processing Unit ◽  
Ldpc Code ◽  
Key Distribution ◽  
Continuous Variable ◽  
Processing Unit ◽  
Secret Key

Reconciliation is a significant procedure in a continuous-variable quantum key distribution (CV-QKD) system. It is employed to extract secure secret key from the resulted string through quantum channel between two users. However, the efficiency and the speed of previous reconciliation algorithms are low. These problems limit the secure communication distance and the secure key rate of CV-QKD systems. In this paper, we proposed a high-speed reconciliation algorithm through employing a well-structured decoding scheme based on low density parity-check (LDPC) code. The complexity of the proposed algorithm is reduced obviously. By using a graphics processing unit (GPU) device, our method may reach a reconciliation speed of 25 Mb/s for a CV-QKD system, which is currently the highest level and paves the way to high-speed CV-QKD.

scholarly journals Quantum Key Distribution Based-on Refraction and Polarization Entanglement

2020 ◽  
Vol 8 (6) ◽  
pp. 2911-2918
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Public Key ◽  
Entangled State ◽  
Key Generation ◽  
Secret Key ◽  
The Public ◽  
Encryption And Decryption ◽  
Refraction Factor

Cryptography is the specialty of encoding and decoding messages and exists as extended as the individuals have doubted from one another and need secure correspondence. The traditional techniques for encryption naturally depend on any among public key or secret key approaches. In general, the public key encryption depends on two keys, for example, public key and private key. Since encryption and decryption keys are different, it isn't important to safely distribute a key. In this approach, the difficult of the numerical issues is assumed, not demonstrated. All the security will be easily compromised if proficient factoring algorithms are found. In secret key encryption two clients at first create secret key, which is a long string of arbitrarily selected bits and safely shares between them. At that point the clients can utilize the secret key along with the algorithms to encryption and decryption information. The procedures are complicated and also planned such a way that every bit of output is based on every bit of input. There are two fundamental issues with secret key encryption; first one is that by breaking down the openly known encoding algorithms, it gets simpler to decrypt the message. The subsequent one is that it experiences key-conveyance issue. As a result of the ongoing improvements in quantum processing and quantum data hypothesis, the quantum computers presents genuine difficulties to generally utilized current cryptographic strategy. The improvement of quantum cryptography beat the deficiencies of old style cryptography and achieves these huge accomplishments by using the properties of infinitesimal articles, for example, photon with its polarization and entangled state. In this paper, Polarization by refraction based quantum key distribution (PR-QKD) is proposed for quantum key generation and distribution. The proposed work considers three basis of polarization such as rectilinear (horizontal and vertical), circular (left-circular and right-circular), ellipse (left-ellipse and rightellipse) and refraction factor. This quantum key can be used for secure communication between two users who are spatially separated and also offer intrusion detection ability to detect attackers. The theoretical approach and conceptual results are discussed in this paper.

scholarly journals CV-MDI quantum key distribution via satellite

2017 ◽  
Vol 17 (5&6) ◽  
pp. 361-379
Author(s):  
Nedasadat Hosseinidehaj ◽  
Robert Malaney
Keyword(s):  
Fading Channels ◽  
Quantum Key Distribution ◽  
Positive Impact ◽  
Key Distribution ◽  
Continuous Variable ◽  
Key Generation ◽  
Measurement Device ◽  
High Loss ◽  
The Status ◽  
The Cost

In this work we analyze a measurement-device-independent (MDI) protocol to establish continuous-variable (CV) quantum key distribution (QKD) between two ground stations. We assume communication occurs between the ground stations via satellite over two independent atmospheric-fading channels influenced by turbulence-induced beam wandering. In this MDI protocol the measurement device is the satellite itself, and the security of the protocol is analyzed through an equivalent entanglement-based swapping scheme. We quantify the positive impact the fading channels can have on the final quantum key rates, demonstrating how the protocol is able to generate a positive key rate even over high-loss atmospheric channels provided that the maximum transmission coefficient of the channel is sufficiently large. This is somewhat counter-intuitive given that the same outcome is only possible in the low-loss regime for a measurement device centrally positioned in a fiber-optic channel. Our results show that useful space-based quantum key generation rates between two ground stations are possible even when the relay satellite is held by an adversary. The cost in key rate incurred by altering the status of the satellite from trustworthy to untrustworthy is presented.

scholarly journals Optimization of ATP System Based on Quantum Secure Communication and Its Tracking Control Strategy

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jin Liu ◽  
Fan Zhang ◽  
Carlo Cattani ◽  
Haima Yang ◽  
Song Wanqing
Keyword(s):  
Ground Motion ◽  
Control Strategy ◽  
Tracking Control ◽  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Normal Operation ◽  
Technical Solution ◽  
Tracking Accuracy ◽  
Motion Platform

In quantum key distribution experiments, ground motion is usually used to simulate satellite-based motion. The posture fluctuation of the platform affects the normal operation of the acquisition, tracking, and pointing (abbreviated as ATP) system seriously. To achieve the verification of the ground motion platform, the ATP parameters of the ground simulation motion system cannot be designed only according to the satellite-based ATP parameters. To solve this problem, a set of initial pointing system and inertial stabilization system is added to the simulation ATP system. This provides a technical solution for the ground simulation ATP system similar to the satellite-based motion platform. In the meanwhile, a tracking control strategy based on the identification method is proposed by establishing identification symbols. Compared with traditional proportion, integral, and differential (abbreviated as PID) control, this method overcomes the shortcoming of tentative modification of the control parameters and improves the stability and adaptability of the tracking control process. Tracking accuracy of ±0.1° is achieved under heavy-load conditions. This guarantees the success of the quantum key distribution (QKD) verification test of the ground motion platform.

Study on Quantum Key Distribution

2013 ◽  
Vol 275-277 ◽  
pp. 2515-2518
Author(s):  
Xiao Qiang Guo ◽  
Cui Ling Luo ◽  
Yan Yan
Keyword(s):  
Quantum Mechanics ◽  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Secret Key ◽  
Bb84 Protocol

Quantum key distribution (QKD) uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages. QKD is a research hotspot of international academia in recent years. We introduce some protocols: BB84 protocol, E91 protocol, SARG04 protocol.

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