Multimedia systems--Security measures

Intrusion Detection Systems (IDS) are security tools which monitor systems and networks for malicious activity. In saturated network links the amount of data present for analysis can overwhelm them, resulting in potentially undetected attacks. Many of these network links contain significant amounts of multimedia traffic which may seem to contribute to the problem, however our work suggests otherwise. This thesis proposes a novel method to classify and analyze multimedia traffic in an effort to maximize the efficiency of IDS. By embedding multimedia-specific knowledge into IDS, trusted multimedia contents can be identified and allowed to bypass the detection engine, thereby allowing IDS to focus its limited resources on other traffic. The proposed framework also enables IDS to detect multimedia-specific exploits which would otherwise pass under the radar. Results of our experiments confirm our claims and show substantial CPU savings in both streaming and non-streaming scenarios.

The aim of this work is to explore the utilization of permutation-based transformations to achieve compression, encryption and steganography in the domain of digital videos. The main contribution of this dissertation is a novel type of digital video encryption that has several advantages over other currently available digital video encryption methods. An extended classification of digital video encryption algorithms is presented in order to clarify these advantages. The classification itself represents an original work, since to date, no such comprehensive classification is provided in known scientific literature. Both security and performance aspects of the proposed method are thoroughly analyzed to provide evidence for high security and performance efficiency. Since the basic model is feasible only for a certain class of video sequences and video codecs, several extensions providing broader applicability are described along with the basic algorithm. An additional significant contribution is the proposition of a novel type of digital video steganography based on disguising a given video by another video. Experimental results are generated for a number of video sequences to demonstrate the performance of proposed methods.