小波变换在网络信息安全中的应用研究

【作者】 李鑫；

【导师】 余生晨；

【作者基本信息】 北方工业大学 ， 计算机应用技术， 2004， 硕士

【摘要】 随着计算机技术和网络多媒体技术的广泛应用和发展，人们对计算机的依赖性越来越高，国际互联网也已成为知识经济时代重要传播途径之一。多媒体信息极大地丰富了计算机信息的表现能力，已经成为计算机信息中的一个重要部分，因此对多媒体信息的安全保密工作变得越来越重要。多媒体信息具有信息量大及易复制的特点，因此早期的加、解密算法在多媒体信息的安全保密方面已经显得力不从心。于是，数字世界里便出现了多种能够保护多媒体信息安全的新技术。信息隐藏便是这样一种技术。 小波分析是一种有效的分析工具，已经引起了各领域、各学科的科学家和研究人员的高度重视并取得了显著成绩。以小波分析为工具进行数字图像处理已经是小波研究与应用的热点之一。 本文首先简述了小波发展历史和小波的基本理论知识后，接着介绍了信息隐藏技术的概念及应用，并以小波为工具对数字图像处理进行了有益的探索。利用小波变换的多分辨率特性并结合人眼的视觉特性来进行图像的小波域分解，这样可以获得更好的图像保真度并且比在空域中的隐藏信息嵌入算法更稳健。针对待隐藏文件为图像的情况，由于直接按待隐藏图像的扫描顺序将其嵌入原始图像中时，在嵌入信息后的图像经过图像处理后会对提取信息的质量影响比较大，因此本文提出了一种隐藏算法，考虑在嵌入信息之前对待隐藏图像进行预处理，将待隐藏图像进行置乱。采用面包师变换的方法对图像进行置乱，以求得到更好的提取图像。实验结果表明，采用本文提出的算法，可以得到不可见性与鲁棒性较好的隐藏图像。本文为可执行文件与文本文件及其他各种格式的文件提供了一种通用的小波域隐藏方式，采用整数小波变换对原始图像进行处理，实验结果表明，可以达到较好的不可见性。更多还原

【Abstract】 With the wide application and the fast development of the computer and multimedia, people depend more on the computer. And the Internet has been an important spread means of the knowledge and economy time. The multimedia enrich the behaving of computer information, and it has become a signify part of the computer information. So how to protect the safe of the multimedia is eager. The multimedia usually contains more information and it is copied easily, so it is difficult that we protect the safe of the multimedia through encryption and its converse arithmetic. Just so, there are some new kinds of technology can protect the safe of theimultimedia in the digital world. Information Hiding is one of them.Wavelet is a useful analysis tool. It has gotten notable success. More and more scientists and investigators pay attention to wavelet in all kinds of fields and subjects. The digital image process on wavelet has been a hotspot in the study and application of wavelet.This thesis describes the development history and the basis theory of wavelet briefly. Then we introduce the conception and application of information hiding. And we explore the digital image process with wavelet. With the multi-resolution analysis of wavelet and the vision character of the human eyes we decompose the image inwavelet domain, which can get better image and is more robust than the arithmetic embedded with hid information in airspace. When the hid file is a image, common image process will affect the attracted information if we hide the hid image into the original image by its own scan order. So we scramble the hid image before it is embedded to the original image. Here we use the baker transposition to scramble the hid information to get better attracted image. The experiment result indicates it can get a invisible hid image and it is also robust through our arithmetic. With the integer wavelet transform to the original image we apply a general hid means in wavelet domain for all kinds of files especially for the executable files and text files. The result shows that we can get an invisible image.更多还原