陳文進臺灣大學：資訊工程學研究所張燕君Cheong, In-KuanIn-KuanCheong2007-11-262018-07-052007-11-262018-07-052004http://ntur.lib.ntu.edu.tw//handle/246246/53783MPEG (ISO Moving Picture Expert Group)是一種影像壓縮標準，目前廣泛地應用在各多媒體應用程式中，如 : VCD, DVD and VOD (Video-on-Demand)。 在網際網路傳輸MPEG影像時，由於要維護機密性及著作權，影像的安全性就變得非常重要。 在本篇論文中，我們提出一種對MPEG影像加密的方法，此方法使用了一個有別於標準的Huffman table來壓縮影像串流，然後對串流中的每個位元組進行旋轉，最後再對串流的位元進行XOR。 我們的方法對影像壓縮過程只增加了微量的計算，因此實作時速度十分快，能符合即時傳輸的要求。 經過我們的分析，它也能抵抗密碼學上的明文及密文的攻撃。 另外，我們的方法也能應用在所有的MPEG壓縮標準中。MPEG (ISO Moving Picture Expert Group) is a compression standard for video processing and is widely used in multimedia applications, for example, VCD, DVD and VOD (Video-on-Demand). When the MPEG streams are transmitted over the public Internet, security becomes very important because of Confidentiality and Copyright protection. In this thesis, we propose an encryption scheme, which uses a permutated Huffman table to encode the input symbols, then rotates and XORs the encoded bit stream. This scheme adds very little computational overhead to the MPEG video compression process, and therefore the implementation is fast enough to meet the real-time requirement of MPEG video applications. In our analysis, it is also robust to both plaintext and ciphertext attacks. In addition, our scheme can be applied to all MPEG compression standards.Table of Contents Page TABLE OF CONTENTS 1 LIST OF TABLES 3 LIST OF FIGURES 5 CHAPTER 1 INTRODUCTION 7 CHAPTER 2 RELATED WORK 9 2.1 Introduction to Cryptanalysis 9 2.2 Introduction to MPEG video compression 10 2.3 MPEG Encryption Algorithms 17 2.3.1 ZigZag-Permutation Algorithm 18 2.3.2 Video Encryption Algorithm (cipher only half bitstream) 22 2.3.3 Realtime Video Encryption Algorithm (cipher sign bits of DCT coefficients) 26 2.3.4 Multiple Huffman Tables Scheme 28 CHAPTER 3 THE PROPOSED SCHEME 35 3.1 High Performance, Low Complexity Encryption Scheme 35 3.1.1 Discussion of the proposed scheme 38 3.2 Security Analysis 41 3.3 Speed and Size 43 CHAPTER 4 EXPERIMENTAL RESULTS AND PERFORMANCE ANALYSIS 45 4.1 Experimental Results 45 4.2 Performance Analysis 47 CHAPTER 5 CONCLUSION 49 BIBLIOGRAPHY 51510409 bytesapplication/pdfen-US影像加密加密encryptionmpegthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/53783/1/ntu-93-R91922020-1.pdf