本文關(guān)鍵詞： 物理層安全編碼 Wiretap模型 陪集編碼 噴泉編碼 極化編碼 打孔 強安全 錯誤擴散　出處：《解放軍信息工程大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：物理層安全編碼是一種同時保證私密信息可靠和安全傳輸?shù)男诺谰幋a技術(shù)。它利用合法信道與竊聽信道的固有差異,在物理層從信息層面直接防止私密信息被竊聽。但是現(xiàn)階段的研究仍然存在以下問題有待改善:(1)保證私密信息強安全傳輸?shù)碾S機冗余使得碼字間實際漢明距離變小,導(dǎo)致強安全編碼的抗噪能力較差;(2)當(dāng)合法信道與竊聽信道均為二進制刪除信道(Binary Erasure Channel,BEC)時,編碼方式的任何變化對合法接收者和竊聽者的影響相同,導(dǎo)致缺乏強安全且可靠的編碼;(3)在已知信道統(tǒng)計信息時,盡管利用信道極化理論可以得到強安全且可靠的編碼,但是私密信息傳輸效率較低;(4)現(xiàn)有級聯(lián)安全編碼的安全間隙較大,不利于實現(xiàn)私密信息在合法信道和竊聽信道的區(qū)分傳輸。針對上述問題,本文依托國家自然科學(xué)基金項目“無線通信信道特征等效下的物理層安全性研究”,首先基于互信息理論和典型序列理論,分析了編碼可靠性與安全性的關(guān)系,然后以將合法信道與竊聽信道較小的特征差異轉(zhuǎn)化為合法接收者與竊聽者較大的誤比特率差異為主線,面向不同場景,重點研究合法信道有噪時的安全編碼技術(shù)。主要研究成果如下:1.針對合法信道為高斯信道且竊聽信道為BEC時,強安全編碼抗噪能力差的問題,提出了一種基于部分陪集的強安全編碼。該方法利用信道模型的差異,實現(xiàn)私密信息的區(qū)分傳輸。首先,為了保證強安全,文章證明了當(dāng)且僅當(dāng)陪集母碼的對偶碼的最小漢明距離大于信息泄露位數(shù)時,利用部分陪集編碼能夠保證私密信息在BEC竊聽信道的強安全傳輸。然后,為了提高可靠性和有效性,文章通過分析陪集編碼的一系列性質(zhì)將計算陪集間漢明距離的復(fù)雜度簡化為1次查表運算,再證明了勢最大的部分陪集集合一定包含基準陪集,進而根據(jù)最大完全子圖理論提出了一種基于樹形深度優(yōu)先的搜索算法,得到了一定距離冗余下的最大可用陪集集合,從而提高私密信息在高斯合法信道的抗噪能力。最后,給出了典型陪集母碼下所提方法的抗信息泄露和抗噪聲能力,以及相應(yīng)的最大可用陪集集合。理論分析和仿真結(jié)果表明,當(dāng)陪集母碼為BCH(15,11)的對偶碼時,與傳統(tǒng)陪集編碼方案相比,該方法在保證私密信息傳輸?shù)膹姲踩耐瑫r,對合法信道的信道質(zhì)量要求降低了5dB。2.針對合法信道與竊聽信道均為BEC時,無法同時保證強安全且可靠傳輸?shù)膯栴},提出了一種基于爆發(fā)噴泉碼級聯(lián)陪集預(yù)映射的安全編碼方法。該方法利用信道刪除概率的差異,實現(xiàn)私密信息的區(qū)分傳輸。首先,利用噴泉碼的無速率特性,保證私密信息的可靠傳輸。然后,通過優(yōu)化度分布構(gòu)造了具有爆發(fā)譯碼速度的噴泉碼,并利用它隨機生成和爆發(fā)譯碼的特性,保證對竊聽者泄露盡量少的符號。為了進一步保證強安全,文章在噴泉編碼前增加陪集冗余,防止竊聽者從已泄露的符號中獲取私密信息。仿真結(jié)果表明,該方法能夠自適應(yīng)合法信道質(zhì)量,保證信息的可靠傳輸,同時減少符號泄露量,便于配合陪集編碼保證強安全。3.針對極化安全編碼信息速率較低的問題,提出了一種面向私密信息位的極化強安全打孔方案。該方法利用信道極化后邏輯信道傳輸能力的差異,實現(xiàn)私密信息的區(qū)分傳輸。首先,為了保證私密信息的強安全且可靠傳輸,文章根據(jù)信道極化理論提出了一種安全極化母碼構(gòu)造方法。然后,為了提高私密信息傳輸?shù)挠行?文章通過分析極化編碼器的迭代構(gòu)造結(jié)構(gòu),利用3個參數(shù)表征輸出符號與特定輸入位的校驗關(guān)系,并以僅對私密信息輸入位的影響程度最小為原則,提出了一種安全極化碼打孔方案。仿真結(jié)果表明,當(dāng)合法信道和竊聽信道的交叉轉(zhuǎn)移概率分別為0.01和0.15時,在滿足強安全與可靠傳輸?shù)那疤嵯?所提方法的傳輸效率提高了12.7%。4.針對級聯(lián)函數(shù)錯誤擴散能力較弱,不利于通過減小安全間隙將信道編碼擴展應(yīng)用到安全編碼的問題,提出了一種基于平衡擴散多輸出函數(shù)的級聯(lián)安全編碼方法。碼字的安全間隙越小,越容易利用信噪比差異,實現(xiàn)私密信息的區(qū)分傳輸。為此,文章首先指出了現(xiàn)有關(guān)于隨機擾亂方法具有最佳錯誤放大結(jié)論的局限性,然后根據(jù)布爾函數(shù)理論,構(gòu)造了滿足錯誤擴散準則的多輸入多輸出函數(shù),對信道譯碼后低信噪比區(qū)域內(nèi)的誤比特率進行錯誤放大,達到減小安全間隙的目的。同時,為了防止輸入均勻分布時輸出出現(xiàn)集中分布,文章進一步優(yōu)化保證了函數(shù)的平衡性。仿真結(jié)果表明,與現(xiàn)有方法相比,本文所提方法的錯誤擴散能力更逼近理論限,安全間隙縮小了3.5dB。
[Abstract]:The physical layer security encoding is a guarantee of channel encoding technology reliable and secure transmission of private information at the same time. It exploits the inherent differences in the legitimate channel and Wiretap Channel, in the physical layer from the aspect of information directly to prevent private information eavesdropping. But the current study is still the following problems need to be improved: (1) random redundancy strong private information secure transmission makes the smaller Hamming distance between the codewords actually lead to strong security guarantee, encoding anti noise ability is poor; (2) when the legitimate channel and wiretap channel are binary erasure channel (Binary Erasure, Channel, BEC), any change of encoding effect on the legitimate receiver and the eavesdropper, leading to a lack of strong safe and reliable encoding; (3) in the known channel statistics, although the use of channel polarization theory can get strong safety and reliable encoding, but private information transmission efficiency Low; (4) the existing security clearance cascade encoding is large, is not conducive to the realization of private information in the transmission channel and distinguish legal Wiretap Channel. Aiming at the above problems, this paper relies on the National Natural Science Fund Project "the physical layer of wireless communication channel characteristics under equivalent safety study, based on the mutual information theory and typical sequence theory analysis of the relationship between encoding, reliability and safety, and to differences in the characteristics of the legitimate channel and small Wiretap Channel into legitimate receiver and the eavesdropper bit error rate larger difference as the main line, for different scenarios, focusing on the legitimate channel safety encoding technology noise. The main research results are as follows: 1. for the legal a channel for the Gauss channel and the wiretap channel is BEC, strong safety encoding poor anti noise ability, a strong safety Part Based on the coset encoding method using. The difference of channel model, realize the transmission of private information. First of all, in order to ensure strong security, this article proves that when and only when the mother sub code the minimum Hamming distance is greater than the number of information disclosure, the part can ensure the safe transmission of coset encoding strong private information in the BEC Wiretap Channel. Then, in order to improve the reliability of and the validity, through the analysis of the computational complexity of the Hamming distance between cosets is simplified into 1 look-up operations and a series of properties of coset encoding, and then prove the potential part of the largest collection of coset must contain reference coset, then according to the maximum complete subgraph theory proposed a tree search algorithm based on depth first, get the maximum available coset of a certain distance from the redundancy set, so as to improve the private information on the legitimate channel Gauss anti noise ability. Finally, gives the typical mother code under the proposed coset The method of anti information leakage and anti noise ability, and the corresponding maximum available coset set. Theoretical analysis and simulation results show that when the mother code is BCH (15,11) dual code, compared with the traditional coset encoding scheme, the method to ensure the safety of the strong private information transmission at the same time, the channel quality of the legitimate channel the requirements for the legitimate channel and reduces the 5dB.2. Wiretap Channel was BEC, at the same time to ensure the strong safety and reliable transmission, proposes a secure encoding method outbreak of fountain codes based on cascaded coset pre mapping. This method uses erasure probability differences, distinguish between the transmission of private information. First of all, no use the rate characteristics of the fountain codes, ensure the reliable transmission of private information. Then, through the optimization of degree distribution is constructed with the outbreak of the decoding speed of fountain codes, and the random generation and decoding the outbreak The characteristics, to ensure the eavesdropper leak less symbols. In order to guarantee the strong safety, increase the redundancy in the fountain before the coset encoding, prevent an eavesdropper access to private information from the leaked symbols. The simulation results show that this method can adaptively legitimate channel quality, ensure the reliable transmission of information, while reducing the amount of leakage of symbols. To ensure the strong security of.3. with coset encoding for the polarization information security encoding rate is low, we propose a new private information a strong polarization safety puncturing scheme. The method uses the difference of channel polarization after logical channel transmission capacity, realize transmission of private information. First of all, in order to ensure the private information safe and strong reliable transmission, the method to construct a safe mother codes according to the channel polarization polarization theory. Then, in order to improve the efficiency of private information transmission, the Through iterative structure analysis of polarization encoder, using 3 parameters characterizing the output symbols with a particular input bit parity relations, and only on the influence of private information input bit principle, proposes a secure polarization code puncturing scheme. The simulation results show that when the cross transfer probability of the legitimate channel and the Wiretap Channel were 0.01 and 0.15, in order to meet the strong security and reliable transmission, the transmission efficiency of the proposed method improves the 12.7%.4. function for the concatenated error diffusion ability is weak, is not conducive to the channel encoding is applied to safety problems by reducing the encoding of security clearance, proposes a security encoding method multi equilibrium diffusion cascade based on the output function. The safety clearance code is smaller, more easily by the signal-to-noise ratio difference, realize the transmission of private information. Therefore, this article firstly points out about now Random perturbation method with the limitations of the optimal error amplification results, then according to the theory of Boolean function, constructed for the multiple input multiple output error propagation criterion function for decoding the low SNR and bit error rates within the area of the error amplifier, to reduce the security gap. At the same time, in order to focus on the distribution of output to prevent the input of uniform distribution, the paper further optimized to ensure balanced function. The simulation results show that compared with the existing methods, the error diffusion ability of the proposed method in this paper is more close to the theoretical limitation of security gap narrowed 3.5dB.

【學(xué)位授予單位】：解放軍信息工程大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TN911.22

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