用於影像篡改偵測與定位的易碎浮水印技術

由於網際網路及數位科技的快速發展，現今的數位影像處理系統提供良好的影像處理能力，數位影像可能很容易的被篡改，甚至透過網際網路散佈該數位影像。為了解決數位影像在傳輸的過程中可能遭受未經授權的篡改，所以需要一個安全的認證機制來驗證可能遭受篡改的數位影像，並檢驗其內容的一致性。　　在本論文中，我們提出一種能對影像做認證與驗證的浮水印技術。我們所提出的浮水印方法是以區塊為基礎的易碎浮水印技術，擁有良好的偵測影像篡改機率並具備定位篡改區域的能力。我們所提出的方法，其安全性是基於嵌入浮水印時所使用的密鑰；即使攻擊者獲得原始的浮水印和浮水印演算法，但在未經授權，且未持有原始密鑰的情況下，並無法擷取出正確的浮水印。此外，在擷取浮水印的過程中，並不需要到原來的影像和浮水印。我們所提出的方法，提供了高度的安全性和良好的執行效能，與其他方法比較，擁有相對較低的計算復雜度。這個方法是不只安全、快速，並且能夠偵測與定位影像中被篡改區域，還能抵抗向量量化攻擊。最後的實驗結果顯示，我們所提出的演算法具有的良好的效率與可靠性。

關鍵字

數位浮水印；影像驗證；篡改偵測；區塊驗證；易碎浮水印；不可視浮水印

並列摘要

Because of the rapid growth of Internet and development of digital technologies, Nowadays, digital imaging systems provide skillful processing capabilities, the digital images can be tampered easily and transmitted over the Internet. As the result, there is a need for secure image authentication techniques in applications where verification of integrity and authenticity of the questionable image content is essential. 　　In this thesis, we develop a watermarking scheme for image authentication and verification. The watermarking scheme for tamper detection of an image is fragile and block-based. Such a scheme has good tamper localization and high tamper detection rate. The security of our scheme depends on a secret key, even though the attacker got the original watermark pattern and watermarking algorithm. The watermark extraction process does not need the original image and original watermark. The proposed scheme provides higher level of security and high performance with low computational complexity. This scheme is secure, fast, and able to detect and localize tampered areas against the well-known vector quantization attack. Experimental results indicate the effectiveness and efficiency of the algorithm.

並列關鍵字

digital watermarking ； image authentication ； tamper detection ； block-based authentication ； fragile watermark ； invisible watermark

參考文獻

[1] S. S. Bedi and S. Verma, “A Design of Secure Watermarking Scheme for Images in Spatial Domain,” Annual India Conference, 2006 Sept. 2006 Page(s):1 - 6

[6] I. J. Cox, J. Killian, T. Leighton and T. Shamoon, “Secure spread spectrum watermarking for Multimedia,” IEEE Trans. On Image Processing, vol.6, pp.1673-1687, Dec.1997.

[7] Richard Durstenfeld, “Algorithm 235: Random permutation,” Communications of the ACM Volume 7, Issue 7, July 1964, table of contents Page: 420

[8] R. Fisher and F. Yates, “Statistical Tables for Biological, Agricultural and Medical Research,” 2nd edition, London, Oliver and Boyd, p. 23-24, 1943

[10] M. Holliman and N. Memon, “Counterfeiting attacks on oblivious block-wise independent invisible watermarking schemes,” Image Processing, IEEE Transactions on Volume 9, Issue 3, March 2000 Page(s):432 – 441

國際替代計量

用於影像篡改偵測與定位的易碎浮水印技術

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