在影像與文字檔案中進行資料隱藏的技術與應用之研究

Abstract

本博士論文冀能領先全球研究，發展出將資料隱藏於影像及本文文字檔的技術及其應用。本論文總共提出了10種新方法，分別適用於黑白，灰階及彩色影像，以及電子郵件，CP++P軟體程式，PDF和網頁等檔案類型。首先，本論文提出二種新方法分別針對黑白及灰階影像，基於人眼視覺模型及動態規劃技術去降低影像扭曲程度並增加資料被隱藏的容量。接著，本論文提出一種新方法可將大量資料藏於BMP彩色影像中，本方法係利用色彩立體方塊及色彩叢集的觀念來隱藏資料。然後，本論文提出一種利用特殊的ASCII控制碼將秘密訊息隱藏於電子郵件中的新方法，這些特殊的ASCII碼顯示在Outlook Express與IE 網路郵件的瀏覽視窗中是使用者看不見的。接著本論文提出二種將資料隱藏於原始程式的新方法。其中一種方法係利用資訊分享與驗證的技巧及人眼看不見的ASCII控制碼來保護軟體程式的安全。另一種技術是應用於秘密通訊，同時可驗證隱藏訊息真偽的新方法。更進一步，本論文提出二種利用特殊的ASCII碼將資訊隱藏於通用的PDF檔中的新方法。其中之ㄧ應用於秘密通訊，另一個應用於驗證PDF檔的真偽。最後，本論文提出二種新方法將資訊隱藏於大家常瀏覽的網頁中。其中之ㄧ應用於秘密通訊，另一個應用於驗證網頁的真偽。二種方法皆是利用HTML檔中各種不同的編碼系統的特殊空白碼。以上本論文提出之10種方法,皆為創新之作, 且已投稿於國內外重要期刊。實驗結果顯示本論文提出的方法皆具有可行性及實用性。

In this study, data hiding techniques for image files and text documents and their applications are investigated, and totally ten methods are proposed for binary, grayscale, and color images, as well as email, software CP++P program, PDF, and webpage files. First, two methods are proposed respectively for binary and grayscale images based on human vision modeling and dynamic programming to reduce the image distortion and increasing data hiding capacities. Also, a method is proposed for hiding large-volume data in BMP color images, based on the use of color cubes and the idea of color clustering. Then, a method is proposed for hiding secret messages in emails using some special ASCII codes which are invisible in the window of Outlook Express and IE Webmail browsers. Also proposed are two methods for data hiding in software programs. One is used for security protection of software programs by information sharing and authentication techniques using invisible ASCII control codes. And the other is applicable to covert communication with the additional capability of authenticating the hidden secret message. Furthermore, two methods are proposed for data hiding in PDF files which are popular nowadays. One is useful for covert communication and the other for PDF file authentication, both using certain special ASCII codes. Finally, two methods are proposed for data hiding in web pages which are browsed by lots of people in the world. One method is proposed for covert communication and the other for authentication of web pages, both utilizing certain space codes of various coding systems applicable in HTML files. Experimental results show the feasibility and practicality of all the proposed methods.