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毕业设计

学 院： 信息工程学院 系(专业)： 通信工程

题 目： 语音加密解密算法研究、仿真和实现

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毕业设计（论文）中文摘要

语音加密解密算法研究、仿真和实现 摘要： 语音信号的传输在当代通信中作用很大，几乎涉及生活的方方面面，例如每天用手机打电话，语音命令操作以及歌曲的录制与播放。在语音应用的某些方面我们并不希望信息外泄，因此我们将语音信号在发送端进行加密后再传输并根据发送端的加密方式在接收端进行解密恢复原先的语音信号。这样就算在传输过程中所传输的信息被截获，由于不知道如何解密也不能获知对应的语音信息，从而起到了语音信息的保护作用。为了加强语音信号的传输安全，采用混沌特性将语音信号进行加密，并利用对称密码体制进行解密。混沌系统对初始值和系统参数非常敏感,即使是两个相同的混沌系统,如果初始值存在微小的差异,经过多次迭代后,系统会变得差距很大。加密过程使用离散混沌映射加密系统的logistic映射。通过观察对比原语音信号、加密后的语音信号与恢复后语音信号的波形图，了解混沌系统在语音加密方面的优缺点。 关键词： 语音传输 混沌系统 logistic映射 对称密码体制

毕业设计（论文）外文摘要

Title VOICE ENCRYPTION AND DECRYPTION ALGORITHMS,SIMULATION AND IMPLEMENTATION Abstract（三号黑体，居左） The transmission of the voice signal which involves almost all aspects of life plays an important role in modern communication，such as calling everyday with the mobilephone ,voice command operation and playing the songs which is recorded in. Sometimes we do not want to leak the voice information so we encrypt it before transmission and decrypt it after reception according to encryption at the transmit side. Therefore, the information can not be obtained even if the information is intercepted in the transmission for decryption is unknown to the attacker, thus protecting the information. In order to enhance the safety of the transmission of voice information, we adopt the system of chaos to encrypt it and the system of symmetrical cipher to decrypt. The characteristic of chaos is extremely sensitive to initial value and the system parameters. It will be a large gap between two chaos systems even if they are identical when there is a slightly difference in initial value or system parameter after several iteration. The encryption process uses logistic mapping of discrete chaotic encryption system. By observing the waveform comparison of the original voice signal, encrypted voice signal and decrypted voice signal, we can voice encryption and decryption. Keywords： the transmission of the voice system of chaos logistic mapping symmetrical cipher system

目 录

1 引言（或绪论） ............................................... - 1 - 1．1 课题来源及意义 .......................................... - 1 - 1.2 混沌加密简介及研究现状 .................................... - 1 -

1.2.1 混沌简介 ............................................ - 1 - 1.2.2 混沌加密研究现状 ..................................... - 2 - 1.3加密解密介绍 ............................................... - 2 - 1.4 本论文的主要工作及内容安排 ................................ - 3 - 2 语音信号读取与预处理 ......................................... - 4 - 2.1 语音信号的特点与选取 ..................................... - 4 - 2.2 语音信号的预处理 ......................................... - 6 -

2.2.1 语音信号的频谱与倒频谱分析 .......................... - 6 - 2.2.2 语音信号的matlab分析 ............................... - 8 - 3

语音信号加密解密设计 ...................................... - 10 -

3.1 加密方案设计 ............................................ - 10 -

3.1.1 加密方案的选用分析 .................................. - 11 - 3.1.2 混沌加密方案的具体流程 ............................. - 12 - 3.2 解密方法 ................................................ - 15 - 4 语音信号加密解密算法程序设计 ................................ - 16 - 4.1算法步骤 .................................................. - 16 - 4.2 算法流程图 ............................................... - 16 - 结 论 ......................................................... - 18 - 参 考 文 献 .................................................... - 22 - 致 谢 ......................................................... - 23 - 附录 ........................................................... - 24 -