Research On Fragile Watermarking Algorithms For Image Authentication

In a networked environment, digital multimedia brings us great convenience such as enrich our lives, simplify our work and make our work easy.But we can’t accept the risk of being easily modified, copied and spread.Fragile watermarking technology greatly satisfy our requirements in the field of digital multimedia data integrity verification: Complete fragile watermark algorithm can make an accurately image authentication,and semi fragile watermarking algorithm is robust to common image processing.Malicious tampering can hardly cause distress for the users of digital multimedia,and copyright owners can better themselves.Research on fragile watermarking is a long and deep process,this paper introduces the research of complete fragile watermarking and semi fragile digital watermarking technique in the field of image authentication. This paper introduces the basic concept of the two watermarking technology, main characteristics, classification and the common attack method.The paper design the fragile watermarking scheme with two different functions combined analysis the existing scheme and technology route from image authentication angle, with the four fork tree decomposition, wavelet transform, chaotic system and Hash algorithm. The main contents of this paper are as follows:First, the paper explores the current technology of fragile digital watermarking, discusses the background and significance of the project. Furthermore, it analyzes and compares the typical watermarking algorithms, and provides a way for the research of this paper.Secondly, it studies the four fork tree decomposition, chaotic system, Hash algorithm,wavelet transform technique and so on. The paper designed two different fragile watermarking scheme. The first one is a complete fragile watermark with using temporalspatial domain algorithm, by dividing the image into blocks and combines the Hash algorithm and Logistics for image authentication, it has good transparency, security and authentication ability; Second is a semi fragile watermarking with using the transform domain algorithm,used for image tamper detection and recovery. The arithmetic can distinguish the difference between the common image processing and malicious tampering, and has the ability to recover the tamper. It has a very good practical value.Finally, the experimental results show that, using the two algorithm effect little on image quality, both of them have good abilities on tamper and localization.