scholarly journals Shannon-limit approached information reconciliation for quantum key distribution

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Bang-Ying Tang ◽  
Bo Liu ◽  
Wan-Rong Yu ◽  
Chun-Qing Wu
Keyword(s):  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Polar Codes ◽  
Frame Error Rate ◽  
Quantum Bit ◽  
Information Reconciliation ◽  
Successive Cancellation ◽  
Two Phases ◽  
List Decoder

AbstractInformation reconciliation (IR) corrects the errors in sifted keys and ensures the correctness of quantum key distribution (QKD) systems. Polar codes-based IR schemes can achieve high reconciliation efficiency; however, the incidental high frame error rate decreases the secure key rate of QKD systems. In this article, we propose a Shannon-limit approached (SLA) IR scheme, which mainly contains two phases: the forward reconciliation phase and the acknowledgment reconciliation phase. In the forward reconciliation phase, the sifted key is divided into sub-blocks and performed with the improved block checked successive cancellation list decoder of polar codes. Afterward, only the failure corrected sub-blocks perform the additional acknowledgment reconciliation phase, which decreases the frame error rate of the SLA IR scheme. The experimental results show that the overall failure probability of SLA IR scheme is decreased to $$10^{-8}$$ 10 - 8 and the efficiency is improved to 1.091 with the IR block length of 128 Mb. Furthermore, the efficiency of the proposed SLA IR scheme is 1.055, approached to Shannon limit, when the quantum bit error rate is 0.02 and the input scale of 1 Gb, which is hundred times larger than the state-of-the-art implemented polar codes-based IR schemes.

scholarly journals The Influence of Signal Polarization on Quantum Bit Error Rate for Subcarrier Wave Quantum Key Distribution Protocol

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1393
Author(s):  
Andrei Gaidash ◽  
Anton Kozubov ◽  
Svetlana Medvedeva ◽  
George Miroshnichenko
Keyword(s):  
Optical Fiber ◽  
Bit Error Rate ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Stokes Parameters ◽  
Second Phase ◽  
Quantum Bit ◽  
Quantum Bit Error Rate ◽  
Quantum Key Distribution Protocol

In this paper, we consider the influence of a divergence of polarization of a quantum signal transmitted through an optical fiber channel on the quantum bit error rate of the subcarrier wave quantum key distribution protocol. Firstly, we investigate the dependence of the optical power of the signal on the modulation indices’ difference after the second phase modulation of the signal. Then we consider the Liouville equation with regard to relaxation in order to develop expressions of the dynamics of the Stokes parameters. As a result, we propose a model that describes quantum bit error rate for the subcarrier wave quantum key distribution depending on the characteristics of the optical fiber. Finally, we propose several methods for minimizing quantum bit error rate.

An Efficient Reconciliation in Removing Errors Using Bose, Chaudhuri, Hocquenghem Code for Quantum Key Distribution

2012 ◽  
pp. 13-19
Author(s):  
Riaz Ahmad Qamar ◽  
Mohd Aizaini Maarof ◽  
Subariah Ibrahim
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Error Probability ◽  
Key Distribution ◽  
Secret Key ◽  
Post Processing ◽  
Quantum Bit ◽  
Quantum Bit Error Rate ◽  
Quantum Key Distribution Protocol

A quantum key distribution protocol(QKD), known as BB84, was developed in 1984 by Charles Bennett and Gilles Brassard. The protocol works in two phases which are quantum state transmission and conventional post processing. In the first phase of BB84, raw key elements are distributed between two legitimate users by sending encoded photons through quantum channel whilst in the second phase, a common secret-key is obtained from correlated raw key elements by exchanging messages through a public channel e.g.; network or internet. The secret-key so obtained is used for cryptography purpose. Reconciliation is a compulsory part of post processing and hence of quantum key distribution protocol. The performance of a reconciliation protocol depends on the generation rate of common secret-key, number of bits disclosed and the error probability in common secrete-key. These characteristics of a protocol can be achieved by using a less interactive reconciliation protocol which can handle a higher initial quantum bit error rate (QBER). In this paper, we use a simple Bose, Chaudhuri, Hocquenghem (BCH) error correction algorithm with simplified syndrome table to achieve an efficient reconciliation protocol which can handle a higher quantum bit error rate and outputs a common key with zero error probability. The proposed protocol efficient in removing errors such that it can remove all errors even if QBER is 60%. Assuming the post processing channel is an authenticated binary symmetric channel (BSC).

scholarly journals Security of quantum key distribution with state-dependent imperfections

2011 ◽  
Vol 11 (11&12) ◽  
pp. 937-947
Author(s):  
Hong-Wei Li ◽  
Zhen-Qiang Yin ◽  
Shuang Wang ◽  
Wan-Su Bao ◽  
Guang-Can Guo ◽  
...  
Keyword(s):  
Error Rate ◽  
Distribution System ◽  
Quantum Channel ◽  
Quantum Key Distribution ◽  
Phase Error ◽  
Key Distribution ◽  
The State ◽  
Secret Key ◽  
Quantum Bit ◽  
State Dependent

In practical quantum key distribution system, the state preparation and measurement have state-dependent imperfections comparing with the ideal BB84 protocol. If the state-dependent imperfection can not be regarded as an unitary transformation, it should not be considered as part of quantum channel noise introduced by the eavesdropper, the commonly used secret key rate formula GLLP can not be applied correspondingly. In this paper, the unconditional security of quantum key distribution with state-dependent imperfections will be analyzed by estimating upper bound of the phase error rate in the quantum channel and the imperfect measurement. Interestingly, since Eve can not control all phase error in the quantum key distribution system, the final secret key rate under constant quantum bit error rate can be improved comparing with the perfect quantum key distribution protocol.

scholarly journals A Comparison of Several Implementations of B92 Quantum Key Distribution Protocol

2021 ◽  
Author(s):  
Catalin Anghel
Keyword(s):  
Quantum Mechanics ◽  
Bit Error Rate ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Detection Method ◽  
Key Distribution ◽  
Quantum Bit ◽  
Comparison And Analysis ◽  
Quantum Key Distribution Protocol ◽  
B92 Protocol

This paper presents the development, comparison and analysis of several implementations of the B92 Quantum Key Distribution (QKD) protocol. In order to achieve this objective a prototype which consists of traditional (non-quantum) simulators was created, one for B92 protocol, one for B92 protocol with eavesdropper and one for B92 protocol with Quantum Bit Travel Time (QBTT) eavesdropper detection method. The principles of quantum mechanics were studied, as a foundation of quantum cryptography, for the realization of simulation programs that were written in C ++, focusing mainly on the B92 protocol and QBTT eavesdropper detection method. We compared the Quantum Bit Error Rate (QBER) for implementation of B92 protocol without eavesdropper, B92 protocol with eavesdropper and B92 protocol with QBTT eavesdropper detection method and found that QBTT eavesdropper detection method significantly reduces the QBER from the final key.

HỆ THỐNG PHÂN PHỐI KHÓA LƯỢNG TỬ ĐA KÊNH TỪ VỆ TINH SỬ DỤNG SCM-WDM

2021 ◽  
pp. 35-43
Author(s):  
Hiền
Keyword(s):  
Wavelength Division Multiplexing ◽  
Bit Error Rate ◽  
Error Rate ◽  
Free Space ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Secret Key ◽  
Quantum Bit ◽  
Wavelength Division ◽  
Free Space Optic

Phân phối khoá lượng tử QKD (Quantum Key Distribution) là giải pháp có khả năng đảm an ninh vô điều kiện nhờ áp dụng luật cơ lượng tử để phân phối khóa an toàn giữa hai bên hợp pháp với sự hiện diện của kẻ nghe lén. Sử dụng vệ tinh để phân phối khóa lượng tử tới các trạm mặt đất qua kênh quang không gian tự do FSO (Free Space Optic) là giải pháp hứa hẹn tạo ra một mạng QKD phạm vi toàn cầu. Tuy nhiên, do ảnh hưởng của kênh FSO, đặc biệt là nhiễu loạn khí quyển, tốc độ truyền khóa bí mật SKR (Secret Key Rate) của các hệ thống QKD hiện tại bị hạn chế. Do đó, nghiên cứu này đề xuất mô hình hệ thống QKD đa kênh dựa trên ghép kênh phân chia theo bước sóng WDM (Wavelength Division Multiplexing) và ghép kênh sóng mang phụ SCM (Sub Carrier Multiplexing) nhằm tăng SKR. Sử dụng phương pháp phân tích lý thuyết với các công cụ giải tích và xác suất, nhóm tác giả đã xây dựng các công thức tính toán SKR và tỉ lệ lỗi bit lượng tử của hệ thống đề xuất. Kết quả khảo sát hiệu năng cho thấy, hệ thống QKD đa kênh cho phép cải thiện SKR so với hệ thống đơn kênh trong khi vẫn đảm bảo yêu cầu về QBER (Quantum Bit Error Rate).

PRACTICAL QUANTUM KEY DISTRIBUTION USING POLARIZATION ENTANGLED STATES

2005 ◽  
Vol 03 (01) ◽  
pp. 141-146 ◽  
Author(s):  
FABIO A. BOVINO ◽  
PIETRO VARISCO ◽  
ANNA MARTINOLI ◽  
PAOLO DE NICOLO ◽  
SANDRA BRUZZO ◽  
...  
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Distribution System ◽  
Quantum Key Distribution ◽  
Current System ◽  
Key Distribution ◽  
Industrial Applications ◽  
Entangled States ◽  
Quantum Bit ◽  
Cryptographic Keys

We present the architecture and recent experimental results for a quantum key distribution system realized at Elsag spa Quantum Optics Laboratory with a key distribution rate suitable for practical industrial applications. The current system can reliably distribute secure cryptographic keys at a rate of 1,500 bit per second and higher at a few hundred meters, with a quantum bit error rate lower than 1%.

scholarly journals Improved reconciliation with polar codes in quantum key distribution

2018 ◽  
Vol 18 (9&10) ◽  
pp. 795-813
Author(s):  
Sunghoon Lee ◽  
Jooyoun Park ◽  
Jun Heo
Keyword(s):  
Quantum Key Distribution ◽  
Block Size ◽  
Ldpc Codes ◽  
Key Distribution ◽  
Block Codes ◽  
Polar Codes ◽  
Information Reconciliation ◽  
Linear Block Codes ◽  
Small Block ◽  
Cryptographic System

Quantum key distribution (QKD) is a cryptographic system that generates an information-theoretically secure key shared by two legitimate parties. QKD consists of two parts: quantum and classical. The latter is referred to as classical post-processing (CPP). Information reconciliation is a part of CPP in which parties are given correlated variables and attempt to eliminate the discrepancies between them while disclosing a minimum amount of information. The elegant reconciliation protocol known as \emph{Cascade} was developed specifically for QKD in 1992 and has become the de-facto standard for all QKD implementations. However, the protocol is highly interactive. Thus, other protocols based on linear block codes such as Hamming codes, low-density parity-check (LDPC) codes, and polar codes have been researched. In particular, reconciliation using LDPC codes has been mainly studied because of its outstanding performance. Nevertheless, with small block size, the bit error rate performance of polar codes under successive-cancellation list (SCL) decoding with a cyclic redundancy check (CRC) is comparable to state-of-the-art turbo and LDPC codes. In this study, we demonstrate the use of polar codes to improve the performance of information reconciliation in a QKD system with small block size. The best decoder for polar codes, a CRC-aided SCL decoder, requires CRC-precoded messages. However, messages that are sifted keys in QKD are obtained arbitrarily as a result of a characteristic of the QKD protocol and cannot be CRC-precoded. We propose a method that allows arbitrarily obtained sifted keys to be CRC precoded by introducing a virtual string. Thus the best decoder can be used for reconciliation using polar codes and improves the efficiency of the protocol.

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