基于連續(xù)變量量子密鑰分發(fā)的高效LDPC解碼算法
發(fā)布時間：2018-12-08 11:47
【摘要】：當今社會已經(jīng)跨入信息化時代,信息在流通中體現(xiàn)價值,而流通要求高效率、高質(zhì)量。經(jīng)典密碼學在保障信息安全方而起到了關(guān)鍵性作用,然而隨著現(xiàn)代計算機的快速發(fā)展,量子計算機應(yīng)運而生。量子密碼學是量子理論和經(jīng)典密碼學相結(jié)合的新學科,被證明有絕對安全性,量子密鑰分發(fā)(Quantum Key Distribution,簡稱QKD)是量子密碼學的一個重要分支。目前,量子密鑰分發(fā)協(xié)議分為離散變量量子密鑰分發(fā)(DV-QKD)、連續(xù)變量量子密鑰分發(fā)(CV-QKD)和分布式相位參考(DPR-QKD)三種協(xié)議。數(shù)據(jù)協(xié)調(diào)是量子密鑰分發(fā)中必不可少的一個環(huán)節(jié),它可判斷竊聽的存在,糾正通信中大量的誤碼,并通過密性放大實現(xiàn)密鑰蒸餾。數(shù)據(jù)協(xié)調(diào)是利用經(jīng)典通信技術(shù)對在量子信道傳輸中信源和信宿的不一致進行糾正的一種協(xié)議,因此屬于量子通信技術(shù)范疇下的經(jīng)典通信技術(shù)。數(shù)據(jù)協(xié)調(diào)實際是一個信道編碼問題,本文我們選擇具有靈活校驗矩陣,碼率靈活的低密度奇偶校驗碼(LDPC)作為整個系統(tǒng)的糾錯碼。本文主要工作內(nèi)容如下：為了解決隨著分組碼長的增加,利用常規(guī)LDPC碼的編碼方法編碼對于計算機的內(nèi)存難以承擔的問題,提出兩種有效方案：首先,該數(shù)據(jù)協(xié)調(diào)方案不同于傳統(tǒng)校驗位譯碼,而是利用邊信息和原始數(shù)據(jù)產(chǎn)生的校驗子聯(lián)合譯碼,最終得到理想碼字；其次,該方案中將H矩陣以稀疏矩陣的形式存貯,利用雙向十字鏈表只記錄1的位置的方式存貯H矩陣,這樣可極大的節(jié)省內(nèi)存空間,從而提高編碼的時效性與有效性。提出基于LDPC碼的離散變量QKD(即單光子)和高斯連續(xù)變量QKD的協(xié)調(diào)方案,其中連續(xù)變量QKD是以離散變量為基礎(chǔ)。針對高斯量子密鑰分發(fā)的數(shù)據(jù)協(xié)調(diào)問題,對高斯連續(xù)變量進行了最優(yōu)量化,實現(xiàn)了Alice和Bob之間的互信息量最大。在分層錯誤校正協(xié)議(SEC)和多電平編碼／多級解碼(MLC/MSD)協(xié)議的基礎(chǔ)上,各級碼流采用了LDPC碼進行錯誤校正,并推出了一次硬信息級間迭代更新公式參與MSD譯碼算法。在2.4GHz CPU,32G內(nèi)存服務(wù)器平臺上,離散變量實驗中選取碼長為105為最佳碼長,誤碼率收斂于1.0dB,每一分組譯碼時問僅需4s,譯碼收斂后速率達到24.85kbits/s。高斯連續(xù)變量實驗仿真結(jié)果表明該算法可在信噪比4.9dB以上實現(xiàn)2×105個連續(xù)變量序列的可靠協(xié)調(diào),協(xié)調(diào)效率達91.71%,安全密鑰量可達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.
【學位授予單位】：山西大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN918.4;TN911.22
本文編號：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.
【學位授予單位】：山西大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN918.4;TN911.22
【參考文獻】
相關(guān)期刊論文 前1條
1 陳曉峰,王育民;公鑰密碼體制研究與進展[J];通信學報;2004年08期
，本文編號：2368294
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