无线信道密钥生成中近端窃听及抵御方法的研究

论文总字数：35900字

摘 要

信息安全在现代社会中越来越受到重视，尤其是网络安全，更是全社会关注的热点话题。近年来，物理层安全成为了国内外越来越关注的领域。物理层安全主要分为无密钥安全和无线密钥安全两个方向。在无线密钥安全方向中，密钥的生成主要依靠信道的互易性和唯一性，通过采集信道特征，把信道特征作为密钥生成的随机源，从而生成无线密钥。

近端窃听可能为物理层密钥生成方法带来严重安全威胁。而在实际中半波长以外的窃听者信道信息不相关的假设往往并不成立。本文仿真了One-Ring、Two-Ring、E-Ring和Far-Ring典型室内外模型下的近端窃听者与合法接收者信道的相关系数，并给出了不同天线位置下的安全距离。

针对近端窃听问题，本文提出一种幅度取余的算法，对接收信号强度进行模X（mod X）运算，以余数作为特征进行量化等后续密钥生成步骤的输入。在模值选取方面，本文综合考虑了密钥的随机性、密钥的一致性、窃听密钥去相关三大准则，提出一种基于遍历取余的模值选取方法。该方法可以提高取余后信道幅度特征的随机性，同时拉大窃听者与合法接收者间的信道差距。此外，该方法还可以很好的解决接收信号强度作为特征随机性差，生成密钥的密钥熵太低的问题。

本文使用QuaDriga信道模型，仿真验证了幅度取余在不同信噪比下对除窃听信道去相关的有效性。此外，本文还在基于Zigbee的跳频通信平台上进行了实验研究，实验结果同样有效。

关键词：物理层安全，无线密钥，RSS，取余

Abstract

Information security has been paid more and more attention in modern society, especially network security, which is a hot topic of the whole society. In recent years, physical layer security has become an increasingly concerned filed. Proximal eavesdropping may bring serious security threats to physical layer key generation methods. However, in practice, the assumption that eavesdropper channel information other than half wavelength is irrelevant is often not true. In this paper, the correlation coefficients between the near-end eavesdropper an-d the legitimate receiver channel under typical indoor and outdoor models of One-Ring, Two-Ring, E-Ring and Far-Ring are simulated, and the safe distances under different antenna positions are given.

In order to solve the problem of near-end eavesdropping, this paper proposes an algorithm of amplitude remainder, which performs modulo X (mod X) operation on the received signal strength and quantizes the remainder as the input of subsequent key generation steps such as feature quantization. In the aspect of module selection, this paper comprehensively considers the randomness of keys, consistency of keys and decorrelation of eavesdropping keys, and proposes a module selection method based on ergodic remainder. This method can improve the randomness of the channel amplitude characteristics after taking the remainder, and at the same time widen the channel gap between eavesdroppers and legitimate receivers. In addition, the method can also well solve the problem that the received signal strength is poor in randomness as a characteristic and the key entropy for generating the key is too low.

In this paper, the QuaDriga channel model is used to simulate and verify the effectiveness of amplitude residue decorrelation for eavesdropping channels under different SNR. In addition, this paper also carried out experimental research on the Zigbee experimental platform, and the experimental results are also valid.

KEY WORDS: Physical layer security, Wireless key security, RSS, Taking remainder

目 录

摘 要 3

Abstract 4

第一章 绪论 1

1.1 选题背景 1

1.2 研究的问题与意义 2

1.3 本文内容与结构安排 3

第二章 无线密钥生成中的近端窃听 4

2.1 无线密钥生成 4

2.1.1 信道测量 4

2.1.2 量化 5

2.1.3 信息调和与隐私放大 8

2.2 近端窃听 9

2.2.1 One-Ring模型 10

2.2.2 Two-Ring模型 13

2.2.3 E-Ring模型 15

2.2.4 Far-Ring模型 16

第三章 基于幅度取余的密钥生成方法 19

3.1 密钥生成的指标 19

3.2 遍历取余后对不同指标的研究 20

3.2.1 随机性与均匀性 22

3.2.2 量化后的一致性 25

3.2.3 窃听信道的去相关性 26

3.3 综合指标的密钥生成 27

第四章 仿真与实验结果 34

4.1 仿真结果 34

4.2 实验结果 37

第五章 总结与展望 42

参考文献 43

附录 毕业论文期刊发表成果 46

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