在行動裝置上作視訊及文字之資訊隱藏研究

Abstract

隨著行動無線網路的進步以及手機使用率的普及，越來越多樣化的多媒體資料在網路上供使用者利用行動裝置瀏覽、使用。本論文主要針對行動裝置上普遍使用的3GP影音格式以及文字訊息，利用資訊隱藏和數位浮水印的技術，在行動裝置的平台上作版權保護、秘密通訊、秘密分享與驗證之研究與應用。在版權保護方面，我們提出一個架構，來做到限定一個帳號只能在一個特定的行動裝置上使用以及一個可無失真還原的數位浮水印技術來保護視訊檔案。在秘密傳輸方面，我們將秘密資訊隱藏在視訊檔案中，再透過網路來傳遞秘密資訊。在秘密分享方面，我們改善前人所提出的方法，將系統移植到行動裝置上實現。針對廣泛使用的手機簡訊，我們提出一個方法，可以驗證所接收到的簡訊內容的真偽及發送方。最後，我們提出相關的實驗結果證明所提出的方法的可行性。

With the increase of population having mobile phones as well as the advance of high-speed transmission capability of the wireless network, more and more multimedia data are transmitted through and displayed on public networks for mobile devices. In this study, several methods for information hiding applications, such as copyright protection, covert communication, secret sharing, and text authentication, on mobile devices are proposed. In order to restrict a user account to a specific mobile phone for downloading videos, a copyright protection method is proposed. Because users do not want to see their video productions suffering from downloading by illegal users, a copyright protection method by a lossless visible watermarking technique for videos is proposed. In order to transmit large-volume secret messages on the Internet securely, a covert communication by videos is proposed. Because of the convenience of getting shares by mobile networks, storing shares in mobile devices, and transmitting shares by the SMS, a secret sharing technique by mobile devices is proposed. Furthermore, because of the large number of usages of short messages, an authentication method for short messages is proposed. Good experimental results show the feasibility of the proposed methods.