Design And Implementation Of Image Authentication Algorithm Based On Fragile Watermarking

As the rapid development of information science technology and the popularity of highperformance computers, digital image processing technology is more and more advanced, anddigital image processing tools are more and more powerful. Editing and processing of digitalimages has become extremely easy. The digital images can be easily modified, and the humaneyes can not distinguish their authenticity, consequently, image authentication hasincreasingly become a serious and urgent problem. The fragile watermark is a special kind ofdigital watermark, due to its strong sensitivity for image tampering, it has become an effectivemeans to solve the problem of image authenticity certification. Now fragile watermark hasbecome a hot research field of information security at home and abroad.The paper first introduces the problem of digital image tampering or forgery, and givesan overview of digital image authentication techniques. Then it describes the basic theory andmethod of fragile digital watermarking technology, and reviews the development process andresearch status of digital image authentication based on fragile watermarking. In this paper,fragile watermarkings for different characteristics are researched, and respectively, threefragile watermarking algorithms are proposed as follow:1、For the problem of low tampering detection rate and weak resistance to vectorquantization attack and pseudo authentication attack, this paper proposes a fragilewatermarking algorithm with tampered-pixels localization used in precise digital imageauthentication. Message authentication code of Image and chaos are used to generateauthentication watermark information and look-up table, and authentication watermarking areembedded in the two lowest bit planes of the image according to certain rules, as a result, thealgorithm can effectively resist vector quantization attack and pseudo-authentication attack.Tamper detection is divided into two hierarchy, which have a high tamper detection efficiency.The experiment results show that the algorithm completely meets the requirements ofwatermark imperceptibility, has higher detection accuracy rate which is almost free fromtampering rate.2、For the problem of weak resistance to vector quantization attack and pseudoauthentication attack due to fixed mapping or fixed certification chain of fragile watermarking,this paper proposes a fragile watermarking with tampered-blocks localization. The algorithmuses image singular value to generate watermarking, and using chaotic to embed one block’swatermaking in its mapping block. Experiment results show that the proposed algorithm notonly has good tamper localization capability and security, but alse can effectively resist theattack of vector quantization attack and pseudo certification attack.3、Combined with the a hierarchical watermark and multiple watermark, this paper proposes a fragile watermarking algorithm with tampering localization, tempering typedistinguishing and tempering recovery. The watermarking of proposed algorithm arecomposed of recovery watermarking, image content authentication watermarking andwatermarking authentication watermarking. Experiment results show that the proposedalgorithm meets the visibility requirements of watermarking, has the ability of tamperinglocalization, tempering type distinguishing and tempering recovery, and keeps a goodperformance in case of large tampering.