Protecting video streams while incurring minimal impact on the compression performance is very important for practical video distribution. Selective encryption is one of the most promising techniques that can offer the required security while maintaining format compliance after encryption with no or little impact on the compression performance. Also, selective encryption techniques can be employed in video surveillance systems to alleviate concerns over privacy invasion by applying the encryption to specific regions of interest. This thesis presents advanced selective encryption techniques for a range of video applications and new methods to effectively and efficiently protect privacy 111 video surveillance systems by applying selective encryption. Background knowledge on video encryption is introduced and previous work is reviewed. Two improved video encryption methods are first demonstrated: one randomly selects one of two equivalent zig-zag scan orders for video preview applications; the other is based on encrypting the sign bits of motion vectors to enhance the scrambling effect. Then, two recently proposed fast selective encryption methods for H.264/AVC are analyzed to show that they are not as efficient as only encrypting the sign bits of nonzero coefficients. A tunable selective encryption scheme for H.264/AVC is developed to provide a tunable scrambling effect by simply adjusting three parameters, so that for different scenarios the user can easily adjust the scrambling effect according to specific requirements. Finally, to more effectively protect privacy in video surveillance systems, it is proposed to el1crypt intra prediction modes within regions of interest in addition to encrypting sign bits of nonzero coefficients, as only encrypting sign bits produces a relatively weak scrambling effect. A re-encoding method is presented to remove the drift error in the non-privacy region caused by the encryption. A spiral binary mask mechanism is also proposed to more efficiently signal the position of the privacy region.

The effectiveness of tour destination selection is dependent on pre-visit information sources. As competition increases in the tourism industry, destination organisations need to improve current destination selection processes. Research on current processes indicate that information sources accessed by potential tourists when making travel decisions may not be a true reflection of what the destination is offering. Any negative difference between perceived images during pre-visit and real images during the actual visit may result in poor destination reputation and dissatisfied customers. This research addresses this gap by improving the process of destination selection using a real-time data streaming mediation technique as an additional pre-visit information source. The researcher adopted a social-technologist research paradigm and a design-science approach. The research process was executed in three phases; the first phase focused on gathering knowledge on destination selection and pre-visit information sources. The findings in Phase 1 were used in Phase 2 to develop and test the performance of a prototype. Phase 3 involved the evaluation of the prototype tool in a real-world setting. One of the main outcomes of this research is the development of a destination selection framework using real-time data streaming mediation and a tool (http://www.tourcamportal.com) as proof of concept. This research has shown that real-time images are valuable pre-visit information sources when making travel decisions. Real-time images authenticate destination attractions, provide real-time availability of destinations, reduce speculations on destination attractions, and provide actual representations of destinations. The findings of this study contribute the body of knowledge and practice in the tourism sector and provide new areas for further research. / Computing / D. Phil. (Information Systems)