Research Of Issues In Video Cover Communication And Content Security

As a remedy for the traditional cryptography technology, information hiding plays a more and more important role in the information security research, and becomes the main countermeasure to the network information security threats in the digitalize age. In its infant times, information hiding algorithms are designed with the still image cover commonly. However, with the rapid development of stream media technology, digital audio and video resources are taking the place of text and image to be the dominant information format in present networks. Therefore, video information hiding technology becomes the hotspot of information technology research. The main works of this thesis are as the following:1. Collusion-based video space domain steganalysis: the existence of local motion will disturb the detecting precision of present video steganalysis algorithms. An interframe collusion based video steganalysis framework is proposed for higher hiding message detection exactness. The video steganalysis process is divided into two steps. In the first step, local motion and message embedded in video is treated as a bimodal noise. Suspicious video frames will be recognized by decision module employing features extracted with inter-frame correlation. In the second step, suspicious frames will be analyzed critically by the present powerful image steganalysis schemes.2. Compressed video real time steganography in the VLC codes: When embedding message in the compressed video, the message capacity will be limited by the compress coding standard. A real time video staganography algorithm based on VLC code pairs mapping is proposed. With the less change of compressed video code rate, the capacity of message will be increased by using the proposed algorithm. Moreover, the embedding and extracting operation are wholely performed in the VLC codes, with no need for full or even partial decompression for the real time requirement.3. Optimal strategy on compressed video secure steganogrphy: Present frame by frame approaches to video steganography will bring a serious security pitfall. Temporal dimension is a crucial point in video and it should be taken into account to design efficient algorithms. With the highlight of perceptual shaping research, an optimal strategy on compressed video secure steganography is proposed. With the optimal strategy, an appropriate message embedding scheme is determined in a closed-loop manner with a cost function for minimization, to enhance the antisteganalysis capability and image quality after data embedding.4. Content feature based compressed video hierarchical authentication: For the compressed video authentication, a content feature based hierarchical authentication scheme is proposed. The scheme combined the inter-frame and intra-frame features to ensure the authenticity of video content with two different level. Features selected have semi-fragile property, with which can distinguish malicious attacks such as erasure, insertion and replacement from video processing. The proposed scheme can detect the existence of malicious attacks with a light computer payload and further locate the corrupt areas.5. Anti-collusion digital fingerprint based traitor tracing: How to defense collusive attack is one of the key problems of copyright protection of digital contents. An anti-collusion fingerprint based traitor tracing scheme is proposed. The tracing protocol is based on the trusted third party, which concerns on both security and practicality. The existence of complete anti-collusion fingerprint scheme is proved in a construct manner. The fingerprint coding scheme and corresponding tracing protocol are proposed by using an orthogonal sequence to construct the fingerprint bits. Under the average collusion attack, by the fingerprint algorithm, the owner can trace the traitors quite efficiently.At last, the research work in this thesis is summarized and potential research topics in future are discussed.