Research On Fragile Watermarking Of Text Image Based On Hash Function And Chaos

With the rapid development of digital technology,the text image application is becoming more and more popular.The text images are often malicious tampered with in network transmission,it is likely to cause all kinds of issues.Therefore,the identification of the text image's integrity and authenticity is an important problem to be solved.Fragile watermarking tecgnology is one of the most effective ways to solve the problem of image authentication.The text image is special compared with other digital image,and its regions of before and after is clear,and has low redundancy.It is difficult to hid information in the text image.In view of the existing research base,this paper amis to study the fragile watermark of text image based on the hash function.First,this paper studies the theory knowledge of hash function and related algorithms of chaos,and analyzes the application in text images of these basic tories.MD5-Hash amd Henon mapping was applied to the study of text image fragile watermarking,which makes the text image fragile watermarking is designed has good computationl,confidentiality and security.Secondly,this paper designs the text image fragile watermarking algorithm based on the hash function and Henon chaotic mappong,including the watermark generation and watermark embeding,watermark extraction and tamper localization.The algorithm uses the md5-hash algorithm to generate the digest and encrypt it with Henon chaos seguence,which can improve the encryption and security of the algoritjm.Then,encrypted watermark is embedded into the flippable pixels,and this algorithm has good fragility and invisibility.Carrier image is detected whether been tampered with and located the tampered area by comparing the extracted watermark and refactored watermark.Finaly,this paper simulatesn the algorithm through Matlab platform.To simulation of algorithm in this paper,results show that the watermark invisible effect is good,the algorithm is highly sensitive to gaussian noise,filtering,JPEG compression and rotation operations,and it has a good ability to locate the tampered area of the watermark imaeg.Thus,this algorithm can effectively dentify the integrity and authenticity of the text image.