Research On Digital Fragile Watermarking Scheme For Authentication Of JPEG Images

As an important component of information hiding technology, digital watermarking schemes , especially the schemes combined with the prevalent image compression standard, such as JPEG, and used for authentication and integrity proofing of the image content, have aroused great fever in the researchers around the world. The existing JPEG watermarking schemes can be classified into two categories: The semi-fragile ones that can tolerate JPEG compression and accept the JPEG compression as an acceptable manipulation while detecting other malicious manipulations as well; the fragile ones used for authentication of JPEG images coupled the watermarking algorithm and JPEG compression algorithm together. In these schemes, the watermark is embedded in the compression process and extracted in the decompression stage. The fragile authentication watermarking for JPEG images, mainly used for the authentication and integrity proofing of the images needed to be transmitted through the internet, has attracted more attention in the research and industrial communities.This paper introduces image authentication watermarking technology synoptically firstly. And then pay attention to the security aspect of the existing authentication watermarking schemes. For the sake of a better view on the existing schemes, the cryptanalysis is conducted on a pixel-level authentication scheme and a block-wise authentication scheme separately, and various counterfeiting attacks are carried on both of the two schemes. Throughout the analysis on the existing authentication watermarking schemes, the crucial shortcoming inhered in the current schemes can be concluded as follows: accuracy localization and high security cannot be hold at the same time. This paper dedicates to resolve this problem.A novel authentication watermarking scheme for JPEG images is proposed in this paper, which holds accuracy localization and high security at the same time. In this scheme, for the sake of improving the accuracy of localization, the image block's watermark is generated from the block itself; to enhance the security aspect in order to resist collage attack completely, each bit of the block's watermark information is embedded in another block that is selected by its corresponding secret key, so as to establish the non-deterministic dependence among the image blocks. Simulation results show the excellent performance of the scheme which is superior localization and security. In the interest of evaluating the detailed performance so as to demonstrate the superior localization and security of the scheme, the probabilities of tamper detection and false detection are deduced under region tampering and collage attack separately, and then, these probabilities are verified through statistic experiments. The results further confirm the confidence on the security and localization of the proposed scheme.