Research On Technique Of Information Hiding And Digital Watermarking

There are two key problems in watermarking technique of digital images. One is how to improve the security of hiden information which is based on the method of digital watermarking technique and the other is how to deal with the conflict of robustness and transparency.The dissertation focuses on the security fragility of digital watermarking system based on LSB, develops the method based on DES algorithm to encrypt for the hiden information. With the analysis of many spatial domain watermark algorithms, a new spatial domain digital watermarking method based on DES is presented, which is implemented by VC++ 6.0.On the other hand, there are many problems in the current watermarking technique, such as the weakness of robustness and imperceptibility of algorithms and so on. The dissertation does some studies on DCT domain and a new watermarking algorithm based on the property of DCT coefficients is proposed. Then the design principles are simulated and the performances are validated through some common attack experiments of images. Furthermore, PN series is used to ensure watermarking security.With the periodic property of DCT coefficients and the digital image scrambling transformation namely Zig-Zag scan, we proposes a meaningful binary watermarking image embedding algorithm on block DCT intermediate frequency AC coefficients of the original image. The proposed algorithm is more practical and better than others at robustness and imperceptibility. All processes, including watermarking embedding, attacking, extracting and verifying, are simulated in MATLAB environment.