利用有意義圖像之視覺密碼

Visual Cryptography Using Meaningful Shares

陳俐伶(Li-Ling Chen)

指導教授 ： 汪順祥

大同大學/電機資訊學院/通訊工程研究所/碩士(2007年)

摘要

視覺密碼是一種有效的影像加密方法。本篇論文中，我們提出了新的視覺密碼演算法，以達成不需像素擴展為目標，必且運用的有意義的圖像以作為分享影像。為了能達到原始秘密影像的視覺效果，我們定義了四個對比參數PSHb、PSHw、PSIb以及PSIw以控制分享影像及解密後影像的黑白對比。此外，我們亦利用不同的區塊大小選擇來控制所得分享影像的亮度及細節品質。針對(2, 2)、(2, n)以及(n, n)的視覺密碼演算法我們都提出了推導，並提供實驗結果驗證其效果。

關鍵字

秘密共享 ； 視覺密碼

並列摘要

Visual cryptography (VC) has been developed as an efficient image encryption method. In the thesis, we proposed a new visual cryptography algorithm to achieve non-pixel expansion VC using meaningful shares. To maintain the visibility of object in shares and secret image, we use four parameters PSHb, PSHw, PSIb and PSIw to set the contrast in the share images and the decrypted image. Also, we use different block sizes to control the brightness and quality of shares and decrypted image. The schemes of (2, 2), (2, n) and (n, n) are developed and experimental results shows the effectiveness of our visual cryptography algorithm.

並列關鍵字

secret sharing ； visual cryptography

參考文獻

[3] G. Ateniese, C. Blundo, A. D. Santis, and D. R. Stinson, “Visual cryptography for general access structures,” Electronic Colloquium on Computational Complexity (ECCC), vol 3, pp. 86 – 106, 1996.

[4] C. N. Yang, “New visual secret sharing schemes using probabilistic method,” Pattern Recognition Letters, vol. 25, pp. 481 – 494, 2004.

[6] Z. Zhou, G. R. Arce, and G. D. Crescenzo, “Halftone visual cryptography,” Image Processing International Conference, vol. 1, pp. I-521 -524, September 2003.

[1] M. Naor and A. Schamir, “Visual cryptography,” Advances in Cryptology-EUROCRYPT ’94, pp. 1 – 12, 1995.

[2] C. Blundo, A. D. Santis, and M. Naor, “Visual cryptography for gray level images,” Proceedings of 2000 Conference on Computer Vision, Graphics and Image Processing, pp. I-221 -226, August 2000.