Digital Image Encryption Technology And Watermarking Technology

At present, the security and copyright protection of the digital production under Networks are a hot and difficult problem in information security. In this paper, a research on encryption and watermarking of digital image is done, which includes these follow four aspects:Firstly, an algorithm of digital image scrambling based on queue transformation is proposed. The periodicity , reversibility and security are analyzed and the appraisal formula of the scrambling degree is also given. Theory proving and imitate Experiment show that this algorithm is more safety than other scrambling algorithm such as Arnold.Secondly, A digital image watermark algorithm based on lineal relation among the DCT coefficients is improved, which enhances the adaptation, imperceptibility and security of the watermarking. It has a good performance when be used in the tiny watermark and big carrier image with strong texture.Thirdly, A new kind of multi digital watermarking algorithm based on image scrambling is proposed. Multiple watermarks can be embedded to mark different owners (such as originator, issuer, user, etc.). This algorithm is robust to most signal processing except lossy compression. It also has good imperceptibility , high security and big watermark capacity..Finally, a zero-watermark scheme based on time stampauthentication is proposed, In order to solve the contradiction between invisibility and robustness. The experiment is practiced in DCT and the results show that this algorithm has high security and robust to signal processing operations and attacks (such as JPEG compression, the use of noise, filtering, LSB, cropping, rotating, scaling, etc.), which is absolutely imperceptible.