臺灣博碩士論文加值系統

在這篇論文裡，我們依據黃日良學長和王聖智老師在2001年提出的加解密架構，做改良以提高其安全度。他們的加解密架構的主要概念在於加密可變長度碼表。為了提高安全度，我們利用隨機位元插入法和隨機位元轉換法來打亂密文的統計特性；另外，我們也打亂RLC(run-length coding)的對應關係，以增加被攻擊的困難度。我們的加解密架構係以MPEG-4實現，並能達到即時傳輸。在論文中，我們也討論到我們的加解密架構的安全度及所可能遭受到的攻擊。值得一提的是，我們的加解密架構抵抗雜訊的能力並不因為加解密的訴求而降低。

In this paper, we propose a new video encryption algorithm, which is based on the encryption scheme proposed by Huang and Wang in 2001. In Huang’s approach, the encryption operation is fulfilled via the modification of VLC tables. Based on this encryption scheme, we made a few modifications to greatly enhance its security level. The modifications include the use of randomized bit-insertion and bit-flipping to complicate the statistics of ciphertexts and the use of RLC (run-length coding) disarrangement to increase the difficulty in cryptanalysis. This algorithm can be easily employed over an MPEG-4 codec to achieve real-time encryption. The security levels of this proposed algorithm against various types of attacks are also discussed. Moreover, the encrypted data have about the same level of noise sensitivity as the original MPEG-4 bit-stream.

CHAPTER 1 INTRODUCTION 1
Chapter 2 Background 3
2.1 Secret-Key Cryptosystem 4
2.1.1 Data Encryption Standard - DES 4
2.1.2 Advanced Encryption Standard - AES 8
2.2 Public-Key Cryptosystem 12
2.3 MPEG-4 standard 14
2.4 Methods for the encryption of video data 20
2.4.1 Complete Encryption 20
2.4.2 Partial Encryption 20
2.4.3 Mixture of Compression and Encryption 23
2.5 Attacks 25
Chapter 3 Proposed Encryption Algorithm 27
3.1 Huang’s encryption algorithm 29
3.2 Basics of the proposed algorithm 31
3.3 Experimental results 37
3.3.4 Comparisons of coding efficiency 43
3.3.5 Noise sensitivity of the proposed algorithm 44
Chapter4 Possible attacks against the proposed algorithm 47
4.1 Security level against exhaustive attacks 47
4.1.1 Security offered by the disarrangement of RLC indices 47
4.1.2 Security offered by randomized bit-insertion 49
4.1.3 Security offered by the modification of VLC table 49
4.1.4 Security offered by the disturbance of CBPY VLC table 50
4.2 Resistance against ciphertext-only attacks 51
4.3 Resistance against Known-Plaintext Attacks 55
4.4 Resistance against Chosen-Plaintext Attacks 55
4.5 Resistance against Chosen-Ciphertext Attacks 55
Chapter 5 Conclusion 57
Reference 58

REFERENCE
[1] Report on the Development of the Advanced Encryption Standard(AES)
[2] Federal Information Processing Standards Publication 197
[3]近代密碼學及其應用，賴溪松、韓亮及張真誠合著，松崗電腦圖書資料股份
[4] Lintian Qiao and Klara Nahrstedt , “Comparison of MPEG encryption algorithms,” International Journal on Computers & Graphics, Special Issue: "Data Security in Image Communication and Network", Permagon Publisher, Vol. 22, No. 3, 1998.
[5] Lei Tang ,”Methods for encrypting and decrypting MPEG video data efficiently,” Proceedings of the fourth ACM international conference on Multimedia, 1996
[6] Wenjun Zeng and Shawmin Lei ,”Efficient frequency domain selective scrambling of digital video,” Multimedia, IEEE Transactions on , Volume: 5 Issue: 1 , March 2003 Page(s): 118 -129
[7] Jiangtao Wen, Michael Severa, Wenjun Zeng, ”A format-compliant configurable encryption framework for access control of video,” Circuits and Systems for Video Technology, IEEE Transactions on , Volume: 12 Issue: 6 , Jun 2002
Page(s): 545 -557
[8] X. Liu, P. G. Farrell, and C. A. Boyd, “Resisting the Bergen-Hogan attack on adaptive arithmetic coding,” Proc. 6th IMA Int. Conf. Cryptography Coding 1997
[9] Howard Cheng and Xiaobo Li, “Partial encryption of compressed images and videos,” Signal Processing, IEEE Transactions on [see also Acoustics, Speech, and Signal Processing, IEEE Transactions on] , Volume: 48 Issue: 8 , Aug 2000
Page(s): 2439 -2451
[10] Mohan S. Kankanhalli and Teo Tian Guan, ”Compressed-domain scambler/descrambler for digital video,” IEEE Transactions on Comsumer Electronics, Vol. 48, No. 2, May 2002
[11] Changgui Shi and Bharat Bhargava, “An Efficient MPEG Video Encryption Algorithm,” Proceedings Seventeenth IEEE Symposium on Reliable Distributed Systems 1998
[12] Franco Chiaraluce, Lorenzo Ciccarelli, Ennio Gambi, Paola Pierleoni and Maurizio Reginelli, “A new chaotic algorithm for video encryption,” Consumer Electronics, IEEE Transactions on , Volume: 48 Issue: 4 , Nov. 2002
Page(s): 838 -844
[13] Huang, Jih-Liang ,”The encryption/ decryption of video data via the modification of VLC table,” Inst. Of Electronics NCTU, 2001
[14] Douglas R. Stinson , Cryptography Ttheory and Practice, 2002
[15] FIPS PUB 46-3, 1999
[16] ISO/IEC JTC1/SC29/WG11 N4668 March 2002
[17] www.cmlab.csie.ntu.edu.tw/cml/ dsp/training/coding/mpeg1/
[18]http://www.cs.sfu.ca/undergrad/CourseMaterials/CMPT365/material/notes/Chap4/Chap4.2/Chap4.2.html