基于连续变量量子密钥分发的高效LDPC解码算法
发布时间：2018-12-08 11:47
【摘要】：当今社会已经跨入信息化时代,信息在流通中体现价值,而流通要求高效率、高质量。经典密码学在保障信息安全方而起到了关键性作用,然而随着现代计算机的快速发展,量子计算机应运而生。量子密码学是量子理论和经典密码学相结合的新学科,被证明有绝对安全性,量子密钥分发(Quantum Key Distribution,简称QKD)是量子密码学的一个重要分支。目前,量子密钥分发协议分为离散变量量子密钥分发(DV-QKD)、连续变量量子密钥分发(CV-QKD)和分布式相位参考(DPR-QKD)三种协议。数据协调是量子密钥分发中必不可少的一个环节,它可判断窃听的存在,纠正通信中大量的误码,并通过密性放大实现密钥蒸馏。数据协调是利用经典通信技术对在量子信道传输中信源和信宿的不一致进行纠正的一种协议,因此属于量子通信技术范畴下的经典通信技术。数据协调实际是一个信道编码问题,本文我们选择具有灵活校验矩阵,码率灵活的低密度奇偶校验码(LDPC)作为整个系统的纠错码。本文主要工作内容如下：为了解决随着分组码长的增加,利用常规LDPC码的编码方法编码对于计算机的内存难以承担的问题,提出两种有效方案：首先,该数据协调方案不同于传统校验位译码,而是利用边信息和原始数据产生的校验子联合译码,最终得到理想码字；其次,该方案中将H矩阵以稀疏矩阵的形式存贮,利用双向十字链表只记录1的位置的方式存贮H矩阵,这样可极大的节省内存空间,从而提高编码的时效性与有效性。提出基于LDPC码的离散变量QKD(即单光子)和高斯连续变量QKD的协调方案,其中连续变量QKD是以离散变量为基础。针对高斯量子密钥分发的数据协调问题,对高斯连续变量进行了最优量化,实现了Alice和Bob之间的互信息量最大。在分层错误校正协议(SEC)和多电平编码／多级解码(MLC/MSD)协议的基础上,各级码流采用了LDPC码进行错误校正,并推出了一次硬信息级间迭代更新公式参与MSD译码算法。在2.4GHz CPU,32G内存服务器平台上,离散变量实验中选取码长为105为最佳码长,误码率收敛于1.0dB,每一分组译码时问仅需4s,译码收敛后速率达到24.85kbits/s。高斯连续变量实验仿真结果表明该算法可在信噪比4.9dB以上实现2×105个连续变量序列的可靠协调,协调效率达91.71%,安全密钥量可达8.645kbits/s。
[Abstract]:Nowadays the society has stepped into the information age, the information embodies the value in the circulation, and the circulation requires high efficiency and high quality. Classical cryptography plays a key role in ensuring information security. However, with the rapid development of modern computers, quantum computers emerge as the times require. Quantum cryptography is a new subject combining quantum theory and classical cryptography. It has been proved to have absolute security. Quantum key distribution (Quantum Key Distribution,) is an important branch of quantum cryptography. At present, quantum key distribution protocols include discrete variable quantum key distribution (DV-QKD), continuous variable quantum key distribution (CV-QKD) and distributed phase reference (DPR-QKD). Data coordination is an essential link in quantum key distribution. It can judge the existence of eavesdropping, correct a large number of error codes in communication, and realize key distillation through dense amplification. Data coordination is a kind of protocol which uses classical communication technology to correct the inconsistency between source and receiver in quantum channel transmission, so it belongs to the classical communication technology under the category of quantum communication technology. Data coordination is a channel coding problem. In this paper, we choose the low density parity check (LDPC) code with flexible check matrix and flexible bit rate as the error correction code of the whole system. The main work of this paper is as follows: in order to solve the problem that the coding method of conventional LDPC code is difficult to bear the memory of computer with the increase of block code length, two effective schemes are put forward: first, The data coordination scheme is different from the traditional parity-bit decoding, but uses the parser generated by the edge information and the original data to decode, and finally obtains the ideal codeword. Secondly, the H matrix is stored in the form of sparse matrix in this scheme, and the H matrix is stored only in the position of 1 by using the bidirectional cross linked list, which can save the memory space greatly and improve the efficiency and efficiency of coding. A concordant scheme of discrete variable QKD (single photon) and Gao Si continuous variable QKD based on LDPC code is proposed, in which the continuous variable QKD is based on discrete variable. Aiming at the problem of data coordination of Gao Si's quantum key distribution, the optimal quantization of Gao Si continuous variables is carried out, and the maximum amount of mutual information between Alice and Bob is realized. On the basis of layered error correction protocol (SEC) and multilevel coding / multilevel decoding (MLC/MSD) protocol, LDPC codes are used for error correction in all levels of code streams, and an iterative updating formula between hard information levels is proposed to participate in the MSD decoding algorithm. On the platform of 2.4GHz CPU,32G memory server, the best code length is 10 ~ 5 code length in discrete variable experiment. The BER converges to 1.0 dB, and only 4 ss is required for each block decoding. The convergent rate of decoding is 24.85 kbit / s. The simulation results of Gao Si continuous variable experiment show that the proposed algorithm can achieve reliable coordination of 2 脳 105 sequence of continuous variables above SNR 4.9dB, and the coordination efficiency is 91.71, and the amount of secure key can reach 8.645 kbits / s / s.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.4;TN911.22
本文编号：2368294
[Abstract]:Nowadays the society has stepped into the information age, the information embodies the value in the circulation, and the circulation requires high efficiency and high quality. Classical cryptography plays a key role in ensuring information security. However, with the rapid development of modern computers, quantum computers emerge as the times require. Quantum cryptography is a new subject combining quantum theory and classical cryptography. It has been proved to have absolute security. Quantum key distribution (Quantum Key Distribution,) is an important branch of quantum cryptography. At present, quantum key distribution protocols include discrete variable quantum key distribution (DV-QKD), continuous variable quantum key distribution (CV-QKD) and distributed phase reference (DPR-QKD). Data coordination is an essential link in quantum key distribution. It can judge the existence of eavesdropping, correct a large number of error codes in communication, and realize key distillation through dense amplification. Data coordination is a kind of protocol which uses classical communication technology to correct the inconsistency between source and receiver in quantum channel transmission, so it belongs to the classical communication technology under the category of quantum communication technology. Data coordination is a channel coding problem. In this paper, we choose the low density parity check (LDPC) code with flexible check matrix and flexible bit rate as the error correction code of the whole system. The main work of this paper is as follows: in order to solve the problem that the coding method of conventional LDPC code is difficult to bear the memory of computer with the increase of block code length, two effective schemes are put forward: first, The data coordination scheme is different from the traditional parity-bit decoding, but uses the parser generated by the edge information and the original data to decode, and finally obtains the ideal codeword. Secondly, the H matrix is stored in the form of sparse matrix in this scheme, and the H matrix is stored only in the position of 1 by using the bidirectional cross linked list, which can save the memory space greatly and improve the efficiency and efficiency of coding. A concordant scheme of discrete variable QKD (single photon) and Gao Si continuous variable QKD based on LDPC code is proposed, in which the continuous variable QKD is based on discrete variable. Aiming at the problem of data coordination of Gao Si's quantum key distribution, the optimal quantization of Gao Si continuous variables is carried out, and the maximum amount of mutual information between Alice and Bob is realized. On the basis of layered error correction protocol (SEC) and multilevel coding / multilevel decoding (MLC/MSD) protocol, LDPC codes are used for error correction in all levels of code streams, and an iterative updating formula between hard information levels is proposed to participate in the MSD decoding algorithm. On the platform of 2.4GHz CPU,32G memory server, the best code length is 10 ~ 5 code length in discrete variable experiment. The BER converges to 1.0 dB, and only 4 ss is required for each block decoding. The convergent rate of decoding is 24.85 kbit / s. The simulation results of Gao Si continuous variable experiment show that the proposed algorithm can achieve reliable coordination of 2 脳 105 sequence of continuous variables above SNR 4.9dB, and the coordination efficiency is 91.71, and the amount of secure key can reach 8.645 kbits / s / s.
【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.4;TN911.22
【参考文献】
相关期刊论文 前1条
1 陈晓峰,王育民;公钥密码体制研究与进展[J];通信学报;2004年08期
，本文编号：2368294
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