Research And Implementation Of Steganography Based On Transform Domain Of Digital Image

With the development of network technology and multimedia technology, multimedia information can be conveniently storaged, accessed and distributed. But the following problems are also increasingly serious, such as the illegal interception and view of network information and so on. The intense demands of copyright protection and secure communication have accelerated the development of information hiding technology. In the field of information security, information hiding is a hot research direction too. Traditional encryption technology can protect the information content, but it exposed the communication process. Compared with the encryption technology, information hiding technology can hide the communication process, thereby providing a higher level of security. Steganography is an important branch of information hiding, mainly used in the covert communications. This paper researches the steganography based on image transform domain, the principal tasks are as follows:1. An algorithm is proposed based on hybrid transform domain of color image, which is based on research and analysis about DWT, DCT and color models of color image, and the transformation between the color models. The algorithm first extracts a component from a kind of color model of color image as carrier image, then making discrete wavelet transform of the carrier image, and doing discrete cosine transform of the result from the DWT. Lastly, embedding the secret information into the coefficients of hybrid transform domain by using quantization embedding idea. The experimental results show that the proposed algorithm based on hybrid transform domain has strong capability in resisting common image attacks. At the mean time, comparing with the different color models, the performance of the algorithm will vary.2. Through research the theory of wavelet package transform, an algorithm based on wavelet package transform on multi-section is proposed. The wavelet package transform is the expansion and extension of the wavelet transform, it can provide more sophisticated analysis method and decompose the high frequency that not decompose in wavelet transform, thereby widening the embedded space. The algorithm first making best wavelet package transform of the carrier image, and then choose some sub-band frequency as embedded sections, then embedding the secret information into the extracted sections using repeat manners. Information extracting taking the method of double extracting. The experimental results show that the algorithm has good performance on imperceptible. At the same time, the algorithm has good robustness in resisting common image attacks.3. According the algorithms introduced in this paper, we design and implement an information hiding prototypical system based on digital image.