Research Of Information Hiding Algorithm Based On Image DCT Domain

Information hiding technology based on image uses the HVS masking effects and the redundancy of the digital signal and transforms secret information through embedding them into the cover-images. In order to communicate secretly, both the existence of communication process and the communication sides are hided. Therefore the illegal user will not judge the secret information from the abundant web resources.The basic concepts and theories of information hiding technology are studied and the typical algorithms of image scrambling and information hiding are analyzed. An adaptive embedding algorithm based on the image DCT domain is improved by using the DCT coefficients and HVS characteristic. Regarding the secret image scrambled by magic as bit streams and categorizing the sub blocks selected by random interval method, different embedding strategies are adapted to embed secret information. As for smooth sub blocks, secret bits are embedded by adjusting the relationship of intermediate frequency coefficients those have the same quantization coefficients. As for others, how many bits to embed are decided by the logarithm of the intermediate frequency coefficients. The secret bits are embedded in the DCT coefficients that being quantized and inverse quantized.The algorithm is realized in MATLAB7.0 environment. Experiment results show that the method is easy to implement, and that a large capacity of hiding information and a goodish robustness are achieved under the condition of imperceptibility. Moreover, the secret information can be extracted from the stego-image without referencing the original cover image.