Research Of Information Hiding Technology Based On Cryptogram And Its Application

Information Hiding is a secret communication way by hiding secret information in other secure media. Effective information hiding should have better sightlessness, robustness, security and larger hiding capacity.In this article, it describes the background, the status, the methods, the classification of Information Hiding, the application of cryptogram in image encryption and so on. Then it studies an information hiding algorithm which bases on symmetrical encryption algorithm-DES and the public key encryption algorithm-RSA. DES encrypts information fastly, and RSA encrypts information with high safety. The information hiding algorithm in this article uses two embedding methods-improved LSB and DCT. In LSB algorithm, it splits the original image into 4×4 picture element blocks with not coverd by each other. Calculates the gray level variation of every block and embeds more datas into complex blocks. In DCT algorithm, it embeds information into the middle and second-low frequency coefficients of discrete cosine transformation. This algorithm ensures good invisibility, capability of information. It improves the security of information and the ability of anti-interference.We use various attack methods to test the feasibility and accuracy of this algorithm and the results show that this algorithm can resist many attacks (addion of noise, contrast enhancement, median filtering, shearing and so on).In this article we design and realize an image information hiding system based on the DES and RSA. A number of experiments indicate that this system behaves well in robustness, capacity, and it will be useful in application.