The Studying Of Steganalysis In Digital Images

It is an information time today. All kinds of communication are very well-developed. The network had walked into our lives. More and more we depend on the compute and indulge in the efficiency and convenience of the compute. In order to have a safe data transfer in the internet, information hiding technology was developed rapidly. It can hide the encrypt data in any kind of media packet. Then the encrypt data become common data which everyone can read. For the attackers generally don't notice the common media data, we can avoid attacking. Even if the attacker knows there is something hidden information, it is hard to decrypt. The information hiding is not always the same as the information encrypt. The encrypt work for hiding the content of the information, while the information hiding work for hiding the existence of the information.The information hiding technology is a double-edged sword. It can be used by criminal, when it gives us convenience. They can facilitate specifically through the steganography tool the content which must exchange to hide in the ordinary carrier document, then has the secret information secret document to pass to opposite party through the network, the receiving end through the same steganography tool from the secret document the secret information extraction. These looked that resembles the ordinary correspondence; this middle possible to hide has the harm national security significant plan. If it is negligent in the control, it will give the country and the society creates the serious destruction.In this paper we meet the need of the public security, analyze the popular technology based on image about steganography algorithm, airspace steganography algorithm, transform-domain steganography algorithm, compression-domain steganography algorithm steganography and spread-spectrum technology. We also introduce the steganography detection technology correspond to all mentioned above. The steganography detection is the base of the steganalysis technology and others such as crack and attack technology. It is the technology that detects the document whether there is secret information. In this paper we research steganalysis technology based on Support Vector Machine (SVM). Then we design an image steganography detection system model for public security.The main works are described as follows: (1) This article says from information hiding's history, analyzed the information shelter dependence humanity to feel the system, and thus has drawn out the information hiding concept, the fundamental model and the characteristic.(2)We analyze the popular steganography algorithm, focusing on the visual detection technology, feature detection technology and the most important statistical detection technology. Furthermore, we compare the application scope and detection result of some typical algorithm.(3)We design a steganography algorithm based on SVM. The high-frequency of image wavelet decomposition is DCT transformed for getting the coefficient histogram vector. The algorithm uses the vector as feature vector. And then we input carries on the training to SVM, use this training model to carry on the examination for the test image, The result shows that this algorithm can achieve the very high detection rate, and it can get very high detection rate using the linear kernel function. The parameters of the linear kernel function were checked in five cross-validations.(4)The steganography algorithm designed in this paper is designed as the image steganography system model for public security. We designed system's major function, the construction and the movement overall environment. It can be the foundation of the image steganography detection system based on SVM.We summarize our work at the end of the paper and outlook the development of the research about the attack technology of hiding information.