常见信息隐藏技术..

编号：10013210439南阳师范学院2014届毕业生毕业论文题目：常见信息隐藏技术的研究完成人：刘豪一班级：2010-04学制：4年专业：软件工程指导教师：李争艳完成日期：2014-03-15目录摘要························································································(1)0引言·····················································································(1)1信息隐藏技术的概念及特征··················································(1)1.1信息隐藏技术的概念···························································(1)1.2信息隐藏技术的特征···························································(2)1.3信息隐藏的分类·································································(3)2常见信息隐藏技术介绍·························································(3)2.1隐写术·············································································(3)2.2数字水印技术····································································(4)2.3可视密码技术····································································(5)3常见信息隐藏技术算法实现··················································(5)3.1隐写术算法概述·································································(5)3.1.1时空域算法·································································(6)3.1.2变换域算法·································································(6)3.1.3压缩域算法·································································(7)3.2数字水印技术算法介绍························································(8)3.2.1空域算法····································································(8)3.2.2Patchwork算法···························································(8)3.2.3变换域算法·································································(8)3.2.4压缩域算法·································································(9)3.2.5NEC算法···································································(10)3.2.6生理模型算法·····························································(10)3.3可视密码技术实现方法·······················································(10)3.3.1(k，k)可视密码基本矩阵的构造······································(10)3.3.2(k，n)可视密码基本矩阵的构造······································(11)4信息隐藏技术的应用···························································(11)4.1数字知识产权保护·····························································(11)4.2数据完整性鉴定································································(12)4.3数据保密·········································································(12)4.4资料不可抵赖性的确认·······················································(13)5信息隐藏技术的发展和未来趋势··········································(13)6总结····················································································(13)参考文献················································································(14)Abstract··················································································(15)第1页（共15页）常见信息隐藏技术的研究作者：刘豪一指导老师：李争艳摘要：在信息化时代，随着计算机网络的迅猛发展，信息安全保密工作面临着动态变化的新形势和问题。本文主要介绍了信息隐藏的基本概念，主要特征，研究方法，技术分类等；研究了各种信息隐藏技术的算法实现；对信息隐藏技术的发展及未来趋势进行了分析和评述。关键字：信息隐藏技术；数字水印；可视密码技术；隐写术0引言信息是人类社会和国家发展的重要战略资源。随着科学技术的快速发展，传统媒体内容正在向数字化转变。数据的交换与传输也变得更加快捷。但随之而来的日益严重的知识产权侵犯行为和基于加密的安全措施面临的严峻挑战，使得信息隐藏技术重新焕发活力。信息隐藏是与数学、密码学、信息论、计算机视觉以及其他计算机应用技术等多学科交叉的学科，是各国研究者所关注和研究的热点[1]。在信息隐藏研究中，可以分为基础理论研究、应用基础研究和应用研究。其中基础理论研究是建立图像信息隐藏的理论框架和若干理论模型，解决安全性度量、通信量分析等基本理论问题，以揭示信息隐藏中若干基本矛盾。信息隐藏的应用基础研究主要针对典型应用需求，研究各种信息隐藏算法和评估体系。信息隐藏的应用研究以图像信息隐藏技术的实用化为目的，研究针对各种应用的实用系统。本文通过对信息隐藏的理论研究学习，浅谈下常见信息隐藏技术的应用。1信息隐藏技术的概念及特征1．1信息隐藏技术的概念信息隐藏主要研究如何将某一机密信息秘密隐藏于另一公开的信息(载体)中，然后通过公开信息的传输来传递机密信息。第三方则难以从公开信息中判断机密信息是否存在，难以截获机密信息，从而第2页（共15页）能保证机密信息的安全。信息隐藏学是一门新兴的交叉学科，在计算机、通讯、保密学等领域有着广阔的应用前景。信息隐藏是20世纪90年代开始兴起的信息安全新技术，并成为信息安全技术研究的热点；传统通信领域为了保证传递的信息能够不被窃听或破坏，常采用密码来保护信息，即让窃听者无法看到或听懂，但是这种技术的缺点是告诉窃听者这就是秘密信息，特别是随着计算机技术的发展，密码的安全性受到很大挑战[2]。而新的信息隐藏技术是将需要传递的秘密信息，隐藏在一个普通的非秘密消息当中，再进行传输，这样即使窃听者窃听了传输的信息，也只会将其当成普通的消息，而不会怀疑或者无法得知是否有秘密信息的存在。一般而言，信息隐藏是为四个阶段：预处理阶段、嵌入阶段、传输阶段和提取阶段。为了使每个阶段都达到安全，所以必须在预处理阶段，引入加密术中的加密算法。在嵌入阶段，使用基于小波的隐藏信息的算法，在传输阶段，进行隐蔽通信，从而使用传输阶段也是安全的。所以这套信息隐藏的处理方案，将形成一个安全的体系，因此既能隐藏秘密信息的内容，也能隐蔽通信的接收方和发送方，从而建立隐藏通信。信息隐藏的原理如下图1所示。图1信息隐藏原理图1．2信息隐藏技术的特征根据信息隐藏的目的和技术要求，该技术存在以下特性。(1)鲁棒性：指不因图像文件的某种改动而导致隐藏信息丢失的能力。这里所谓“改动”包括传输过程中的信道噪音、滤波操作、重采样、有损编码压缩、D／A或A／D转换等。(2)不可检测性：指隐蔽载体与原始载体具有一致的特性，如具密钥秘密信息载体信息嵌入算法通信信道检测器秘要信息密钥第3页（共15页）有一致的统计噪声分布等。使非法拦截者无法判断是否有隐蔽信息。(3)透明性：利用人类视觉系统或人类听觉系统属性，经过一系列隐藏处理，使目标数据没有明显的降质现象，而隐藏的数据却无法人为地看见或听见。(4)安全性：指隐藏算法有较强的抗攻击能力，即它必须能够承受一定程度的人为攻击，而使隐藏信息不会被破坏。(5)自恢复性：由于经过一些操作或变换后可能会使原图产生较大的破坏，如果只从留下的片段数据，仍能恢复隐藏信号，而且恢复过程不需要宿主信号，这就是所谓的自恢复性。1．3信息隐藏的分类信息隐藏的主要学科分支包括掩蔽信道、匿名通信技术、隐写术和数字水印技术。按密钥分类：若嵌入和提取采用相同密钥，则称为对称隐藏算法，否则称为公钥隐藏算法。按隐藏的载体分类：可分为基于图像、音频、视频、文本等技术的信息隐藏。按隐藏目的分类：可分为秘密消息隐藏和数字水印，其中秘密消息是用来进行秘密传输，数字水印是用来版权保护。按嵌入域分类：可分为空域和变换域隐藏。空域法是用待隐藏消息位替换载体中的冗余部分，变换域法是把待隐藏的信息嵌入到载体的某个变换空间中。按提取要求分类：若在提取隐藏信息时不需要利用原始载体，称为盲隐藏；否则为非盲隐藏。按保护对象分类：主要可分为隐秘术和水印技术。隐秘术主要用于保密通信，它所要保护的是隐藏的信息；水印技术主要用于版权保护及真伪鉴别等，它最终所要保护的是载体[3]。2常见信息隐藏技术介绍2.1隐写术隐写术(Steganography):这个术语来自希腊词汇steganos和graphia，前者的含义是“秘密的”，后者的含义是“书写”。隐写术是一种隐蔽通信技术，其主要目的是将重要的信息隐藏起来，以便不引起人注意地进行传输和存储。隐写术在其发展过程中逐渐形成了两大分支，即语义隐写和技术隐写。语义隐写术利用了语言文字自身及其修辞方面的知识和技巧，通第4页（共15页）过对原文按照一定规则进行重新排列或剪裁，从而隐藏和提取密文。语义隐写术包括符号码、隐语以及虚字密码等。所谓符号码是指一次非书面形式的秘密通信。例如，第二次世界大战中，有人曾经利用一幅关于圣安东尼奥河的画传递了一封密信。画中的圣