Text Information-Hide Based On Still Color Image

With the rapid development of information-technology especially Internet technology, it is more and more convenient to transmit and exchange the digital information, but the digital information is also faced with the threat being stole and interpolated, so it has become the fucos point of people's attention that how to guarantee the security of the digital information transferring.Currently, the information-hiding technique which serves as a new effectual route for resolving the information safely transferring has become hot topic of researching in information security area. Aiming at the objectively demand of the military covert communication, in this dissertation, the text-information hiding technique that based on the still color image was mainly studied and discussed.Firstly,the difference between the information-hiding and encription was analyzed in this paper, and then discussed the discrepancy and contacts between steganography and digital watermarking which are the greatest branches of the information-hiding. Because of the characteristics of the text-information, combining with the strong randomness and the sensitivity to the initial value of the chaotic sequence, in the course of secret information preprocessing, the text-information was encrypted with the chaotic pseudorandom sequence firstly, and then the cryptographic bit-stream was encoded with convolution-coding, finally, to translate the burst error into stochastic error, the encoded bit-stream was disarranged with interlace-coding.On the foundation of analyzing the classic information-hiding algorithm of LSB(Least Significance Bit),aiming at the weak robustness of the LSB algorithm and the noise andor crop attack that the stego-image probably underwent, a new algorithm based on the Most Significance Bit which can resist the cropping attack was presented. The experimental results show that the new algorithm not only has a good imperceptibility, but also has good performance on resisting the noise and image-cropping. By analyzing the property of Human Visual System(HVS), and combining with the vision model of Watson, a improved algorithm based on the HVS in the DCT(Discrete Cosine Transform)domain was presented. Through comparing the experimental results, the imperceptibility of the embedded information has been improved to some extent. In order to improve the capability of the hidden-image resisting the JPEG compression and according to the principium of the image compressed coding, an algorithm which can effectively enhance the JPEG compressed rate of the stego-image was proposed. The experiments show that the algorithm has great function to improve the imperceptibility and robustness of the concealed information.Finally, a brief and practical information-hiding software was developed by the Matlab GUI program tool.