基于模拟语音的加密技术研究

发布时间：2018-06-01 01:01

本文选题：GSM通信 + 语音加密　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：近年来,随着通信网络的不断发展和移动通信技术的不断完善,人们在日常生活中对手机等通信设备的应用越来越广泛,而语音信息作为移动通信网络中传输的最主要信息,其传输过程中的安全问题引起了越来越多的关注。在传统的语音传输系统中,语音信息采用移动通信网中现有的安全机制进行加密以确保通话信息不被泄露,是否加密以及加密密钥都是由运营商控制的。随着业务量的增加,通信系统愈加复杂,其中一些核心的加密算法也遭到破解,原来的安全机制出现不少漏洞,用户的通信安全得不到较好的保证,因此,为了保证端到端通信安全,需要一种由用户控制是否加密并掌握密钥的加密方法对语音信号进行加密,使得语音信号在进入移动通信网之前就进行加密。本文在研究GSM(Global System for Mobile communication,全球移动通信系统)通信系统工作流程和RPE-LTP(Regular Pulse Excitation-Long Term Prediction,规则脉冲激励长期预测)声码器特性的基础上,设计了一种用于手机声码器之前的模拟语音加密系统,并通过仿真验证了该系统的可行性,所取得的主要研究成果为:1.本文在分析GSM语音传输系统工作流程及RPE-LTP声码器编解码原理的基础上,通过借鉴传统语音加密技术的思想以及满足加密语音在移动话音通道中传输所需要的三个基本条件:加密语音满足声码器输入要求、加密语音对有损压缩编码不敏感以及加密语音可以对抗VAD(Voice Activity Detection,语音活动检测)检测,对加密算法进行理论分析,提出了一种语音加密方案,以保证进入GSM系统前的加密语音在通过声码器后不会出现明显失真。2.设计了一种基于GSM系统的模拟语音加密算法。本算法首先在发送端对模拟语音进行采样、分帧和分组。然后,将语音信号变换到频域对其频谱进行置乱,达到频域加密的目的。最后,将语音信号变换到时域,并打乱组内帧顺序,从而得到可以在移动话音通道中传输的模拟加密语音。在发送端也可在语音信号的频谱中插入伪谱来改变原始信号的频谱以掩盖语音信号的音调特征。在接收端,对解码后的加密语音进行与加密过程相对称的解密。本算直接对模拟的语音信号进行加密,加密后的语音信号能够对抗移动通信网络中的有损压缩,更好的保证了GSM通信系统中端到端的安全通信。3.设计并实现了端到端语音加密系统仿真平台。基于该平台,成功进行了加密语音传输实验,并对实验结果进行了分析。实验结果证实了本文设计的加密算法是有效且安全的,验证了端到端语音加密系统方案的可行性。
[Abstract]:In recent years, with the continuous development of communication network and the continuous improvement of mobile communication technology, people are more and more widely used in mobile phone and other communication devices in daily life, and voice information is the most important information transmitted in mobile communication network. More and more attention has been paid to the security problems in the transmission process. In the traditional voice transmission system, the voice information is encrypted by the existing security mechanism in the mobile communication network to ensure that the call information is not leaked. The encryption and encryption keys are controlled by the operator. With the increase of traffic, the communication system becomes more and more complex, and some of the core encryption algorithms are also broken. There are many vulnerabilities in the original security mechanism, and the communication security of users is not guaranteed well. In order to ensure the security of end-to-end communication, it is necessary to encrypt the voice signal by a encryption method controlled by the user and master the key, so that the voice signal can be encrypted before entering the mobile communication network. In this paper, based on the study of the workflow of GSM(Global System for Mobile communication, global mobile communication system and the characteristics of RPE-LTP(Regular Pulse Excitation-Long Term prediction, regular pulse excitation and long term prediction) vocoder, An analogue voice encryption system for mobile phone vocoder is designed, and the feasibility of the system is verified by simulation. The main research results are: 1: 1. Based on the analysis of the working flow of GSM voice transmission system and the principle of RPE-LTP vocoder, By using the idea of traditional voice encryption technology and three basic conditions to meet the need of transmission of encrypted voice in mobile voice channel, the encrypted voice meets the input requirements of vocoder. Encryption speech is insensitive to lossy compression coding and can resist VAD(Voice Activity detection (voice activity detection) detection. The encryption algorithm is theoretically analyzed, and a speech encryption scheme is proposed. To ensure that the encrypted voice before entering the GSM system will not appear obvious distortion. 2. 2 after passing through the vocoder. An analog voice encryption algorithm based on GSM system is designed. In this algorithm, analog speech is sampled, divided into frames and packets at the transmitter. Then, the speech signal is transformed into frequency domain to scramble the frequency spectrum to achieve the purpose of frequency domain encryption. Finally, the speech signal is transformed into time domain, and the frame sequence in the group is scrambled to obtain the analog encrypted speech which can be transmitted in the mobile voice channel. The pseudo-spectrum can also be inserted in the spectrum of the speech signal at the transmitter to change the spectrum of the original signal to mask the tone characteristics of the speech signal. At the receiving end, the encrypted voice after decoding is decrypted symmetrically with the encryption process. This algorithm encrypts the analog speech signal directly, the encrypted speech signal can resist the lossy compression in the mobile communication network, and better ensure the end-to-end secure communication in the GSM communication system. An end-to-end speech encryption system simulation platform is designed and implemented. Based on this platform, the encrypted speech transmission experiment is successfully carried out, and the experimental results are analyzed. The experimental results show that the encryption algorithm designed in this paper is effective and secure, and the feasibility of the end-to-end voice encryption system is verified.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN912.3;TN918.4

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