Research On Digital Image Steganography

With the rapid development of Internet technology, human society has entered the Internet age. The Internet, like sunshine, air and water, has penetrated into every aspect of our lives. We can easily use the Internet to download, upload or send a multimedia files. This brings great convenience to people’s lives, but at the same time, also left a serious danger of our society. Steganography as one of the branches of information hiding technology, it is likely to be used by illegal organizations, terrorists or some intelligence personnel for covert communications. And with the advent of the mobile Internet era,smart phones or other intelligent terminal has become a tool for everyone which can not lack of. The Security of a large number of private messages in mobile phones has got lots of people’s attention. so develop the research of Information Steganography and its attack algorithm Has an important meaning. The main work of this paper is as follows:First, taking into account the DCT domain embedding space is small and the weak algorithm security, we propose a new DCT domain embedding space with bigger embedding space and better security based on the JPEG compression principle. also, we proposes a DCT domain steganography algorithm based on low frequency priority with the consideration of characteristic of DCT coeffcient. The test shows that the novel embedding mechanism and low priority ideas can improve the embedding capacity and security algorithms.Second, minimize losses embedded coding technology is relatively mature, but so far, there is not a good model to define the overall embedded pixel loss. Many tests and studies has shown that embed secret message adaptively in richer texture area can get better security. This paper designed a embedding loss function based on local image texture and logisitic function in spatial domain. And then combined Syndrome Trellis Codes algorithm to obtain a minimal embedding distortion. Experiments has shown that this kind of loss function has a certain rationality.Thrid, based on the existing gray image steganography algorithm, the adaptive embedding algorithm is designed combined with the characteristic of color image, We designed and realized a steganographic system which can embed secret message with various algorithm On Android platform.