Image Authentication Technology Based On Self-Embedding Digital Watermaeking

With the rapid development of computer network and communication technology, digital media has been widely used. Information security, Intellectual property protection and certification issues on digital media become increasingly prominent. As a branch of information security, digital image authentication watermarking aims to verity the integrality and authenticity of a host image and provide the tamper proofing by tamper localization and tamper recovery. Nowadays digital image authentication watermarking technology has gradually become an effective method for multimedia copyright protection and integrity authentication.The digital image is focused in this thesis. At first, the basic theory and technology of digital watermarking, especially the digital image watermarking technology is introduced. Then to realize the copyright protection and authentication of digital image, several improved algorithms are proposed, which are detail as follow:1. We propose a novel image watermark scheme for both tamper detection and tampered image recovery. The basic principle of this scheme is to compress per block of the original image using SPIHT, then scramble and embed the bit stream into LSBs of corresponding offset block. Experimental results show that the proposed scheme can detect and locate tamper accurately, and recover tampered block data with satisfied image visual quality.2. We propose a novel dual watermark scheme for image tamper detection and recovery. In the proposed watermarking algorithm, we embed the watermark information into the original image using the algorithm of the LSB (Least Significant Bit) and the DWT (Discrete Wavelet Transform). The basic principle of this scheme is to compress each block of the using SPIHT. First of all, we embed the bit stream into the watermark image using the DWT. Secondly, scrambling and embedding the bit stream into LSBs of corresponding offset block. By using our algorithm, if the attackers destroy the watermark information, which is embedded the least bit of the watermarked image in case, we could extract the watermark information using DWT to tamper recovery. Experimental results demonstrate that our proposed dual watermark technique is efficient, and recover tampered block data with satisfied image visual quality.3. We propose a fragile watermark scheme with the ability of self-restoration and discrimination of tampers on image content or watermark. The basic principle of this scheme is to compress the original image using SPIHT, then scramble and embed the bit stream into two bits place of gray image. During image authentication, the proposed method is able to detect the tampered location and discriminate tampers on image or watermark from the difference image. Experimental results show that the proposed scheme can detect, locate and discriminate tamper accurately, and recover tampered block data with satisfied image visual quality.4. We propose a novel color image watermark scheme based on image self-embedding techniques. The basic principle of this scheme is to use bilinear interpolation for the original image. Then we use the discrete wavelet transform (DWT) to embed the watermark image. Experimental results show that the proposed scheme can self-embed the original image, and extract the watermark information with satisfied image visual quality.Finally, we just make a conclusion of the whole paper and propose future research directions.