The Digital Image Information Hiding Technology

The digital information revolution has brought about profound changes in our society and our lives, and generated new challenges and new opportunities for innovation. This thesis discusses the technologies and application of multimedia information security in the area of digital image scrambling, digital image Steganography and digital watermarking. First, we introduce the history and some applications of information hiding technology, then propose two image scrambling schemes and a Steganography scheme based bmp file header, and apply information hiding to safe transmission of email, finally, we suggest a dual- watermark scheme.The main contributions of this paper are as follows:1. We introduce an image scrambling method based on smpling technology. The sampling theory is introduced as a method for digital image scrambling, we prove the period of sampling theory for digital image scrambling, and provide some periods of useful image sampling. At the same time, we analyze scrambling effect and improve the scheme.2. We extend the baker transform to K-th system, give the digital image scrambling algorithm based on it and test the algorithm robust (for example, key space, two adjacent pixels correlation and tolerance of image processing). Experiments show that our algorithm can endure some common image attack, such as loss of data, compression and Gaussian noises, etc.3. We bring forward a Steganography scheme based on Bitmap File Header. We analyze the redundancy of file header and embed the secret information using scrambling, which doesn't affect image content. It provides multi-protection combined with other Steganography algorithm.4. We discuss the security of email and reach a conclusion: encryption of email cannot provide the absolute security because cipher text shows the existence of secret and is attacked easily. But the safe transmission scheme based on information hiding technique is different, which embeds email into public image and hides the existence of email. So it can provide deeper protection than email encryption.5. Dual digital watermarking. By using the human psychology and vision model, we embed visible and invisible watermarking into an image, which can provide dual protection for digital image copyright.