Digital Image Secure Authentication Watermarking Algorithms And Their Performance Analysis Of Statistical Detection

As a branch of information security, digital image authentication watermarking aims to verify the integrality and authenticity of a host image and provide the tamper proofing by tamper localization and tamper recovery. The research achievements on secure digital image authentication watermarking are classified into the following five categories.The first is a study on three basic problems in digital image authentication watermarking techniques. (1) three common issues in digital image authentication watermarking are generalized and formally described. (2) the false acceptance probability, the false rejection probability and the security strength are introduced for performance evaluation; and (3) new encryption methods for authentication watermarking are proposed.The second is to propose a secure hash block-wise watermarking scheme for image authentication based on statistical distribution. In proposed schemes, the watermark of each block is randomly distributed and hidden into the least significant bit of whole host image based on secret key. The statistical distributions corresponding to tampered and valid blocks and threshold decision can be used to determine the validity of image blocks. Furthermore, we discuss the relationship between the security strength and block size. Theoretical and experimental results demonstrate that the proposed scheme not only satisfactorily resists the Holliman-Memon attack and collage attack, but also improves the localization accuracy without sacrificing security.The third category is secure authentication watermarking schemes based block-neighborhood tampering characterization. The main object of this chapter is to improve localization accuracy, robustness against noise and the tamper detection performance. In proposed algorithm, the security watermark data are generated by quantizing and scrambling the low-frequency wavelet coefficients of the original image content. The validity of the test block is detected by taking the blocks in a 3×3 block-neighborhood of it. Moreover, we discuss the block-neighborhood distributions of tampered and original blocks and the choice of predefined threshold. In addition, we design a neighborhood-characteristic (NC) based statistical detection model, and gives analytical analysis of the false acceptance and false rejection probabilities of the proposed and conventional statistical detection model.The fourth is a security analysis of existing self-recovery watermarking schemes. First, we generalize four key issues to be resolved in self-recovery watermarking schemes. And then, we analyze the security of the current self-recovery watermarking schemes from the four aspects, and proposed two new counterfeiting attacks: the XOR-equivalent attack and the synchronous counterfeiting attack.The last is to propose a secure self-recovery authentication watermarking scheme based on neighborhood-comparison of the test block and its mapping one, and gives analytical analysis of its false acceptance and false rejection probabilities under various maliciously tampering. The proposed scheme embeds the encrypted feature comprising 6-bit recovery data and 2-bit key-based data of the image block into its mapping block, which is randomly generated based on secret key. The legitimacy of a test block is determined by comparing the number of inconsistent blocks in the 3×3 block-neighborhood of the test block with that of its mapping block. Analytical and experimental results demonstrate that the proposed method outperforms conventional self-recovery watermarking algorithms in tamper detection and recovery under various maliciously attacks such as the collage attack and the constant-average attack. In addition, the encrypted feature and the non-linear block-mapping sequence make it difficult to obtain the information of the block-mapping sequence. Thus security of the proposed fragile watermarking scheme is enhanced.In summary, the thesis mainly focuses on the research of secure digital watermarking for image authentication and performance analysis of statistical detection. The quantitative evaluation of security, tamper detection performance and tamper recovery quality will be helpful to design the algorithm for different applications and consummate authentication digital watermarking technique.