scholarly journals Security of quantum key distribution with intensity correlations

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 602
Author(s):  
Víctor Zapatero ◽  
Álvaro Navarrete ◽  
Kiyoshi Tamaki ◽  
Marcos Curty

The decoy-state method in quantum key distribution (QKD) is a popular technique to approximately achieve the performance of ideal single-photon sources by means of simpler and practical laser sources. In high-speed decoy-state QKD systems, however, intensity correlations between succeeding pulses leak information about the users' intensity settings, thus invalidating a key assumption of this approach. Here, we solve this pressing problem by developing a general technique to incorporate arbitrary intensity correlations to the security analysis of decoy-state QKD. This technique only requires to experimentally quantify two main parameters: the correlation range and the maximum relative deviation between the selected and the actually emitted intensities. As a side contribution, we provide a non-standard derivation of the asymptotic secret key rate formula from the non-asymptotic one, in so revealing a necessary condition for the significance of the former.

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 950
Author(s):  
Ziwen Pan ◽  
Ivan B. Djordjevic

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.


2019 ◽  
Vol 9 (22) ◽  
pp. 4956 ◽  
Author(s):  
Xinchao Ruan ◽  
Hang Zhang ◽  
Wei Zhao ◽  
Xiaoxue Wang ◽  
Xuan Li ◽  
...  

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.


Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 571
Author(s):  
Yuang Wang ◽  
Shanhua Zou ◽  
Yun Mao ◽  
Ying Guo

Underwater quantumkey distribution (QKD) is tough but important formodern underwater communications in an insecure environment. It can guarantee secure underwater communication between submarines and enhance safety for critical network nodes. To enhance the performance of continuous-variable quantumkey distribution (CVQKD) underwater in terms ofmaximal transmission distance and secret key rate as well, we adopt measurement-device-independent (MDI) quantum key distribution with the zero-photon catalysis (ZPC) performed at the emitter of one side, which is the ZPC-based MDI-CVQKD. Numerical simulation shows that the ZPC-involved scheme, which is a Gaussian operation in essence, works better than the single photon subtraction (SPS)-involved scheme in the extreme asymmetric case. We find that the transmission of the ZPC-involved scheme is longer than that of the SPS-involved scheme. In addition, we consider the effects of temperature, salinity and solar elevation angle on the system performance in pure seawater. The maximal transmission distance decreases with the increase of temperature and the decrease of sunlight elevation angle, while it changes little over a broad range of salinity


2020 ◽  
Vol 18 (06) ◽  
pp. 2050031
Author(s):  
Ali Mehri-Toonabi ◽  
Mahdi Davoudi Darareh ◽  
Shahrooz Janbaz

In this work, we introduce a high-dimensional polarization-phase (PoP)-based quantum key distribution protocol, briefly named PoP[Formula: see text], where [Formula: see text] is the dimension of a hybrid quantum state including polarization and phase degrees of freedom of the same photon, and [Formula: see text] is the number of mutually unbiased bases. We present a detailed description of the PoP[Formula: see text] protocol as a special case, and evaluate its security against various individual and coherent eavesdropping strategies, and in each case, we compare it with the BB84 and the two-dimensional (TD)-PoP protocols. In all the strategies, the error threshold and the effective transmission rate of the PoP[Formula: see text] protocol are far greater than the other two protocols. Unlike most high-dimensional protocols, the simplicity of producing and detecting the qudits and the use of conventional components (such as traditional single-photon sources and quantum channels) are among the features of the PoP[Formula: see text] protocol.


2008 ◽  
Vol 100 (9) ◽  
Author(s):  
Qin Wang ◽  
Wei Chen ◽  
Guilherme Xavier ◽  
Marcin Swillo ◽  
Tao Zhang ◽  
...  

2017 ◽  
Vol 34 (12) ◽  
pp. 120301 ◽  
Author(s):  
Jia-Ji Li ◽  
Yang Wang ◽  
Hong-Wei Li ◽  
Peng Peng ◽  
Chun Zhou ◽  
...  

2011 ◽  
Vol 19 (20) ◽  
pp. 19562 ◽  
Author(s):  
M. Fujiwara ◽  
A. Tanaka ◽  
S. Takahashi ◽  
K. Yoshino ◽  
Y. Nambu ◽  
...  

Quantum ◽  
2017 ◽  
Vol 1 ◽  
pp. 14 ◽  
Author(s):  
Marco Tomamichel ◽  
Anthony Leverrier

In this work we present a security analysis for quantum key distribution, establishing a rigorous tradeoff between various protocol and security parameters for a class of entanglement-based and prepare-and-measure protocols. The goal of this paper is twofold: 1) to review and clarify the stateof-the-art security analysis based on entropic uncertainty relations, and 2) to provide an accessible resource for researchers interested in a security analysis of quantum cryptographic protocols that takes into account finite resource effects. For this purpose we collect and clarify several arguments spread in the literature on the subject with the goal of making this treatment largely self-contained. More precisely, we focus on a class of prepare-and-measure protocols based on the Bennett-Brassard (BB84) protocol as well as a class of entanglement-based protocols similar to the Bennett-Brassard-Mermin (BBM92) protocol. We carefully formalize the different steps in these protocols, including randomization, measurement, parameter estimation, error correction and privacy amplification, allowing us to be mathematically precise throughout the security analysis. We start from an operational definition of what it means for a quantum key distribution protocol to be secure and derive simple conditions that serve as sufficient condition for secrecy and correctness. We then derive and eventually discuss tradeoff relations between the block length of the classical computation, the noise tolerance, the secret key length and the security parameters for our protocols. Our results significantly improve upon previously reported tradeoffs.


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