Lower and Upper Bounds on the Secret-Key Rate for Quantum Key Distribution Protocols Using One-Way Classical Communication

We propose a simultaneous classical communication and quantum key distribution (SCCQ) protocol based on plug-and-play configuration with an optical amplifier. Such a protocol could be attractive in practice since the single plug-and-play system is taken advantage of for multiple purposes. The plug-and-play scheme waives the necessity of using two independent frequency-locked laser sources to perform coherent detection, thus the phase noise existing in our protocol is small which can be tolerated by the SCCQ protocol. To further improve its capabilities, we place an optical amplifier inside Alice’s apparatus. Simulation results show that the modified protocol can well improve the secret key rate compared with the original protocol whether in asymptotic limit or finite-size regime.

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AUTHENTICATED QUANTUM KEY DISTRIBUTION WITHOUT CLASSICAL COMMUNICATION

Parallel Processing Letters ◽

10.1142/s0129626407003058 ◽

2007 ◽

Vol 17 (03) ◽

pp. 323-335 ◽

Cited By ~ 12

Author(s):

NAYA NAGY ◽

SELIM G. AKL

Keyword(s):

Quantum Channel ◽

Quantum Key Distribution ◽

Communication Channel ◽

Quantum Communication ◽

Key Distribution ◽

Secret Key ◽

Classical Communication ◽

Quantum Communication Channel ◽

High Security ◽

Public Keys

The aim of quantum key distribution protocols is to establish a secret key among two parties with high security confidence. Such algorithms generally require a quantum channel and an authenticated classical channel. This paper presents a totally new perception of communication in such protocols. The quantum communication alone satisfies all needs of array communication between the two parties. Even so, the quantum communication channel does not need to be protected or authenticated whatsoever. As such, our algorithm is a purely quantum key distribution algorithm. The only certain identification of the two parties is through public keys.

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INFEASIBILITY OF QUANTUM CRYPTOGRAPHY WITHOUT EAVESDROPPING CHECK

International Journal of Modern Physics B ◽

10.1142/s0217979211058407 ◽

2011 ◽

Vol 25 (08) ◽

pp. 1061-1067

Author(s):

WEI YANG ◽

LIUSHENG HUANG ◽

FANG SONG ◽

QIYAN WANG

Keyword(s):

Quantum Cryptography ◽

General Model ◽

Quantum Key Distribution ◽

Communication Channel ◽

Key Distribution ◽

Secret Key ◽

Classical Communication ◽

Man In The Middle ◽

Distribution Scheme ◽

Special Case

Secure key distribution is impossible in pure classical environment. Unconditional secure key distribution is available when quantum means are introduced, assisted by a classical communication channel. What is possible when a quantum key distribution scheme is without classical communication? We present a general model with this constraint and show that quantum key distribution without classical eavesdropping check is in principle impossible. For an adversary can always succeed in obtaining the secret key via a special case of man-in-the-middle attack, namely intercept-and-forward attack without any risk of being captured.

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Coherent-State-Based Twin-Field Quantum Key Distribution

Scientific Reports ◽

10.1038/s41598-019-50429-0 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 5

Author(s):

Hua-Lei Yin ◽

Zeng-Bing Chen

Keyword(s):

Coherent State ◽

Communication Networks ◽

Quantum Key Distribution ◽

Large Scale ◽

Key Distribution ◽

Entanglement Swapping ◽

Secret Key ◽

Entanglement Purification ◽

Classical Communication ◽

Security Proof

Abstract Large-scale quantum communication networks are still a huge challenge due to the rate-distance limit of quantum key distribution (QKD). Recently, twin-field (TF) QKD has been proposed to overcome this limit. Here, we prove that coherent-state-based TF-QKD is a time-reversed entanglement protocol, where the entanglement generation is realized with entanglement swapping operation via an entangled coherent state measurement. We propose a coherent-state-based TF-QKD with optimal secret key rate under symmetric and asymmetric channels by using coherent state and cat state coding. Furthermore, we show that our protocol can be converted to all recent coherent-state-based TF-QKD protocols by using our security proof. By using the entanglement purification with two-way classical communication, we improve the transmission distance of all coherent-state-based TF-QKD protocols.

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Geometrical Optics Restricted Eavesdropping Analysis of Satellite-to-Satellite Secret Key Distillation

Entropy ◽

10.3390/e23080950 ◽

2021 ◽

Vol 23 (8) ◽

pp. 950

Author(s):

Ziwen Pan ◽

Ivan B. Djordjevic

Keyword(s):

Free Space ◽

Quantum Key Distribution ◽

Security Analysis ◽

Key Distribution ◽

Geometrical Optics ◽

Secret Key ◽

Satellite Applications

Traditionally, the study of quantum key distribution (QKD) assumes an omnipotent eavesdropper that is only limited by the laws of physics. However, this is not the case for specific application scenarios such as the QKD over a free-space link. In this invited paper, we introduce the geometrical optics restricted eavesdropping model for secret key distillation security analysis and apply to a few scenarios common in satellite-to-satellite applications.

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A novel error correction protocol for continuous variable quantum key distribution

Scientific Reports ◽

10.1038/s41598-021-90055-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kadir Gümüş ◽

Tobias A. Eriksson ◽

Masahiro Takeoka ◽

Mikio Fujiwara ◽

Masahide Sasaki ◽

...

Keyword(s):

Error Correction ◽

Quantum Key Distribution ◽

Ldpc Codes ◽

Key Distribution ◽

Continuous Variable ◽

Early Termination ◽

Parity Check ◽

Secret Key ◽

Ldpc Decoder ◽

And Performance

AbstractReconciliation is a key element of continuous-variable quantum key distribution (CV-QKD) protocols, affecting both the complexity and performance of the entire system. During the reconciliation protocol, error correction is typically performed using low-density parity-check (LDPC) codes with a single decoding attempt. In this paper, we propose a modification to a conventional reconciliation protocol used in four-state protocol CV-QKD systems called the multiple decoding attempts (MDA) protocol. MDA uses multiple decoding attempts with LDPC codes, each attempt having fewer decoding iteration than the conventional protocol. Between each decoding attempt we propose to reveal information bits, which effectively lowers the code rate. MDA is shown to outperform the conventional protocol in regards to the secret key rate (SKR). A 10% decrease in frame error rate and an 8.5% increase in SKR are reported in this paper. A simple early termination for the LDPC decoder is also proposed and implemented. With early termination, MDA has decoding complexity similar to the conventional protocol while having an improved SKR.

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Computing conditional entropies for quantum correlations

Nature Communications ◽

10.1038/s41467-020-20018-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Peter Brown ◽

Hamza Fawzi ◽

Omar Fawzi

Keyword(s):

Quantum Key Distribution ◽

Detection Efficiency ◽

Conditional Entropy ◽

Key Distribution ◽

Quantum Correlations ◽

Upper Bounds ◽

Cryptographic Protocols ◽

Quantum States ◽

Security Proofs

AbstractThe rates of quantum cryptographic protocols are usually expressed in terms of a conditional entropy minimized over a certain set of quantum states. In particular, in the device-independent setting, the minimization is over all the quantum states jointly held by the adversary and the parties that are consistent with the statistics that are seen by the parties. Here, we introduce a method to approximate such entropic quantities. Applied to the setting of device-independent randomness generation and quantum key distribution, we obtain improvements on protocol rates in various settings. In particular, we find new upper bounds on the minimal global detection efficiency required to perform device-independent quantum key distribution without additional preprocessing. Furthermore, we show that our construction can be readily combined with the entropy accumulation theorem in order to establish full finite-key security proofs for these protocols.

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

Applied Sciences ◽

10.3390/app9224956 ◽

2019 ◽

Vol 9 (22) ◽

pp. 4956 ◽

Cited By ~ 2

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.

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Full daylight quantum-key-distribution at 1550 nm enabled by integrated silicon photonics

npj Quantum Information ◽

10.1038/s41534-021-00421-2 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

M. Avesani ◽

L. Calderaro ◽

M. Schiavon ◽

A. Stanco ◽

C. Agnesi ◽

...

Keyword(s):

Optical Fibers ◽

Silicon Photonics ◽

Free Space ◽

Quantum Key Distribution ◽

Cost Effective ◽

Key Distribution ◽

Global Scale ◽

Secret Key ◽

Quantum Bit ◽

Integrated Silicon Photonics

AbstractThe future envisaged global-scale quantum-communication network will comprise various nodes interconnected via optical fibers or free-space channels, depending on the link distance. The free-space segment of such a network should guarantee certain key requirements, such as daytime operation and the compatibility with the complementary telecom-based fiber infrastructure. In addition, space-to-ground links will require the capability of designing light and compact quantum devices to be placed in orbit. For these reasons, investigating available solutions matching all the above requirements is still necessary. Here we present a full prototype for daylight quantum key distribution at 1550 nm exploiting an integrated silicon-photonics chip as state encoder. We tested our prototype in the urban area of Padua (Italy) over a 145 m-long free-space link, obtaining a quantum bit error rate around 0.5% and an averaged secret key rate of 30 kbps during a whole sunny day (from 11:00 to 20:00). The developed chip represents a cost-effective solution for portable free-space transmitters and a promising resource to design quantum optical payloads for future satellite missions.

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The attack strategy for a quantum key distribution protocol based on Bell’s theorem

Journal of Physics Conference Series ◽

10.1088/1742-6596/2056/1/012011 ◽

2021 ◽

Vol 2056 (1) ◽

pp. 012011

Author(s):

Chan Myae Hein ◽

T F Kamalov

Keyword(s):

Quantum Key Distribution ◽

Key Distribution ◽

Bell’S Theorem ◽

Bell's Theorem ◽

Secret Key ◽

Theoretical Concepts ◽

Information Theoretic ◽

Information Theoretic Security ◽

Quantum Key Distribution Protocol ◽

Attack Strategy

Abstract A new eavesdropping strategy is proposed for the Quantum Key Distribution (QKD) protocol. This scheme represents a new kind of intercept/resend strategy based on Bell’s theorem. Quantum key distribution (QKD) provides the foremost reliable form of secure key exchange, using only the input-output statistics of the devices to realize information-theoretic security. In this paper, we present an improved QKD protocol that can simultaneously distribute the quantum secret key. We are already using the QKD protocol with simulated results matched completely with the theoretical concepts.

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