基于信道相位响应的物理层密钥分发技术研究

发布时间：2018-04-06 22:13

本文选题：物理层安全　切入点：信道相位响应　出处：《解放军信息工程大学》2014年硕士论文

【摘要】：利用无线信道的唯一性与互易性实现密钥的分发,是一种基于物理层的安全保障方法。将无线信道特征作为随机的信号源,对合法用户的信道进行测量得出相似的密钥序列,并通过密钥协商与保密性增强技术消除密钥序列的不一致,最终获得一致的密钥。现有方法存在的问题有:1)较低的量化精度导致密钥分发的安全性不足;2)一致化方法需要多轮通信且计算复杂度高;3)在慢衰落信道条件下,低的密钥分发速率限制了系统的实用性。针对上述问题,本文依托国家自然科学基金项目,对基于信道相位响应的物理层密钥分发技术进行研究。首先,针对较低的量化精度导致密钥分发安全性不足问题,提出了基于信道相位差异的密钥分发方法;然后,针对一致化方法需要多轮通信且计算复杂度高的问题,提出了信道相位响应加密与网格编码调制技术联合的密钥分发方法;最后,针对慢衰落信道条件下密钥分发速率低的问题,提出了一种基于信道相位响应估计的协作密钥分发方法。主要研究内容包括:1.提出了一种基于信道相位差异的密钥分发方法。首先,在单入单出系统模型下,将合法用户信道与窃听信道化为相位旋转信道与加性噪声信道的级联,计算得出密钥的各态历经安全容量;然后,利用合法用户与窃听用户的信道相位差异性进行密钥提取,可以确保密钥分发的安全性。同时,将信道相位的提取精度转换为密钥长度,可以通过提高提取精度来增大密钥空间;最后,利用连续密钥分发策略逼近密钥容量,并以二进制信源为例说明本方法。仿真结果表明,当相位的估计误差为0.001时,误码率会迅速上升为0.5。2.提出了一种信道相位响应加密与网格编码调制技术联合的密钥分发方法。首先,对随机生成的密钥序列进行网格编码调制得到带有冗余的密钥信息,发送方利用对信道相位响应量化后的保密序列对密钥信息进行隐藏得到校验信息,并公开发送给接收方;然后,接收方利用消除信道相位响应的量化噪声后的保密序列将校验信息中的密钥信息恢复出来,同时利用密钥信息的冗余纠正两端保密序列不一致导致的恢复误差的影响,最终获得一致的密钥。仿真结果表明,在误比特率为10-4时,该方法比现有方法有将近5dB的增益。3.提出了一种基于信道相位响应估计的协作密钥分发方法。首先,构造了协作中继密钥分发模型;然后,密钥节点与中继节点相互发送初始相位为零的单音信号进行信道相位估计,明确考虑了最大似然估计方法对密钥提取的影响,并对估计后的信息进行等间隔量化;最后,中继节点将量化后的信息发送给密钥节点,密钥节点之间采用基于网格编码调制的密钥协商方法获得一致的密钥。仿真结果表明,随着中继个数的增加,密钥生成速率呈线性增加,并且当中继个数为5时,密钥生成速率达到1500bits/s。
[Abstract]:Using the uniqueness and reciprocity of wireless channel to realize key distribution is a physical layer based security method.The wireless channel feature is used as a random signal source to measure the channel of the legitimate user to obtain the similar key sequence, and to eliminate the inconsistency of the key sequence by key agreement and privacy enhancement technique, and finally to obtain the consistent key.The existing methods have the following problems: the low quantization accuracy of 1) leads to the lack of security of key distribution. The consistency method requires multiple rounds of communication and high computational complexity in slow fading channels.The low key distribution rate limits the practicability of the system.In view of the above problems, this paper studies the physical layer key distribution technology based on channel phase response based on the National Natural Science Foundation project.Firstly, a key distribution method based on channel phase difference is proposed to solve the problem that low quantization precision leads to insufficient security of key distribution.A key distribution method based on the combination of channel phase response encryption and trellis coding modulation is proposed. Finally, the problem of low key distribution rate in slow fading channels is discussed.A cooperative key distribution method based on channel phase response estimation is proposed.The main research contents include: 1.A key distribution method based on channel phase difference is proposed.First of all, under the model of single input and single output system, the legitimate user channel and eavesdropping channel are converted into the cascade of phase rotation channel and additive noise channel, and the security capacity of each state of the key is calculated.The security of key distribution can be ensured by extracting the key by using the channel phase difference between legitimate user and eavesdropping user.At the same time, the precision of the channel phase is converted to the length of the key, which can increase the key space by improving the precision of the extraction. Finally, a continuous key distribution strategy is used to approximate the key capacity, and the binary source is taken as an example to illustrate the method.The simulation results show that when the phase estimation error is 0.001, the bit error rate will rise rapidly to 0.5.2.In this paper, a key distribution method based on channel phase response encryption and trellis coding modulation is proposed.Firstly, the key information with redundancy is obtained by trellis coding modulation of the randomly generated key sequence, and the key information is hidden by the secret sequence after quantization of the channel phase response.The receiver then recovers the key information in the check information using a secret sequence of quantized noise that eliminates the phase response of the channel.At the same time, the redundancy of the key information is used to correct the effect of the restoration error caused by the inconsistency between the two ends of the secret sequence, and finally the consistent key is obtained.The simulation results show that when the bit error rate is 10-4, the gain of this method is close to that of 5dB. 3.A cooperative key distribution method based on channel phase response estimation is proposed.First of all, a cooperative relay key distribution model is constructed, and then the channel phase estimation of single tone signal with zero initial phase is carried out by the key node and relay node, and the influence of the maximum likelihood estimation method on the key extraction is explicitly considered.The estimated information is quantized at equal intervals. Finally, the relaying node sends the quantized information to the key node, and the key agreement method based on trellis coding modulation is used to obtain the consistent key.Simulation results show that the key generation rate increases linearly with the number of relays, and when the number of relays is 5, the key generation rate reaches 1500 bits / s.
【学位授予单位】：解放军信息工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.4

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