Image Tamper Detection And Self-recovery Based On Fragile Watermarking Algorithm

Nowadays,digital images have been widely used in all walks of life.In some important industries,such as the judicial evidence of judicial proceedings and the image of the press media industry,if they were tampered,it would have a great impact on the society.Thus,the problem of how to ensure the validity of the image contents and make full use of image are needed to be addressed.Fragile watermarking technology can effectively solve the problem by embedding the watermark into the digital image in advance to ensure the effectiveness of the image.In this paper,the image tamper detection and recovery methods have been studied,and the drawbacks of the existing methods are pointed out.And then a hierarchical tamper detection and recovery algorithm based on fragile watermarking is proposed.The following is the main work done in this article.The tamper detection accuracy of the methods with insufficient watermark capacity is not satisfactory.To deal with this problem,a mixed block-dividing technique for accurate tamper detection and self-recovery is proposed.4×4 pixel blocks are utilized to enlarge the watermark payload,and 2×2 pixel blocks are used for self-recovery.To resolve the problem of the algorithms cannot resist all the attacks,two different methods are adopted to generate the watermark.The combination of two different watermark make the malicious attackers are difficult to implement pseudo authentication,which improves the security of the proposed scheme.To solve the problem that the methods based on block-wise independency are vulnerable to collage attack and the security of linear block mapping is low,a chaotic map is used to obtain the block mapping sequence to ensure the safety of the method.Based on the GUI development environment of MATLAB,an image simulation system is designed and implemented.The system can be used for image tamper detection and self-recovery.The experimental results demonstrate that the proposed method not only has good tamper detection accuracy,but also can effectively resist all kinds of pseudo-authentication attacks.The proposed scheme has the superiority of high tamper detection accuracy and excellent recovery quality under various attacks compared with other fragile watermarking methods.