Research On Information Hiding Of The Image

The technique of information hiding which has developed since mid to late 1990s is one of the new cross subjects in information security field. In this thesis, the main contents are techniques of information hiding, in which the digital images are applied as carriers.This paper analyzes and discusses the concept, theories, characteristics, development history and current situation domestic and overseas of the information hiding technology. To improve the security of secret information after hiding, it has described the image scrambling theory and recovery based on Arnold in detail, and discussed the measurement methods of the image scrambling degree.On base of consulting a great deal of literature on the information hiding technology domestic and overseas, it mainly put forward three kinds of information hiding algorithms:(1) Based on introducing about the theory, its advantages and disadvantages of the traditional LSB hiding algorithm, it proposed an improvement method. Experiment showed, compared with the traditional LSB method, it can resist Salt & Pepper Noise attacks better.(2) The application of the discrete cosine transform(DCT) on the information hiding technology is general increasingly. According to the statistical characteristics of image pixel values, combined with the characteristics of the DCT coefficients, it put forward an information hiding algorithm based on DCT, which blocks the DCT coefficients and classifies them combined with the statistical characteristics of image pixel values to obtain the best hiding positions in the embedding process. The experimental results indicate that: it can resist series of attacks pretty well, such as Salt & Pepper Noise, white noises,, filtering, shearing, compression and rotating etc.(3) In recent years, the wavelet transform becomes the hotspot of information hiding technology study. It proposed a wavelet transform hiding method based on chaotic sequences encrypting, which embeds secret information in the most important low-frequency subgraph of the image secondary wavelet decomposition. Compared to the other two hiding methods in the paper, it can conclusion that the properties of the method based on DCT is best, and the one based on DWT second, and the last one is poor.