Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 195-202.

Thesis (PhD)--Macquarie University, Division of Information and Communication Sciences, Department of Computing, 2008. / Bibliography: p. 144-153.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Dr. Lee, Hsien-Hsin S.; Committee Member: Dr. Lim, Sung-Kyu; Committee Member: Dr. Yalamanchili, Sudhakar.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 88-92). Also available in electronic version.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 61-64). Also available in electronic version.

Due to the rapid development of 3D display market, the protection and authentication of the intellectual property rights of 3D multimedia has become an essential concern. As a consequence, the digital watermarking for 3D image and video is attracting considerable attention. The depth-image-based rendering (DIBR) technique has been playing a critical role in 3D contents representation because of its numerous advantages. A good digital watermarking algorithm should be robust to various possible attacks, including geometric distortions and compressions. And di erent from ordinary 2D digital watermarking, there are more speci c requirements for 3D watermarking, especially for DIBR 3D image watermarking. Not only the center view, but also the virtual left and right views can be illegally distributed. Therefore, the embedded watermark information should be accurately extracted from these three views individually for content authentication, even under attacks. In this thesis, we focus on the research of digital watermarking and watermarking based quality evaluation for DIBR 3D images. We first present a 2D image and video watermarking method based on contourlet transform, which is then extended to a robust contourlet-based watermarking algorithm for DIBR 3D images. The watermark is embedded into the center view by quantizing certain contourlet coe cients. The virtual left and right views are synthesized from the watermarked center view and the corresponding depth map. One advantage of our algorithm is its simplicity and practicality. However, the performance on watermark extraction needs to be further improved. As an improvement, a blind watermarking algorithm for DIBR 3D images based on feature regions and ridgelet transform is proposed. The watermarked view has good perceptual quality under both the objective and subjective image quality measures. Compared with other related and state-of-the-art methods, the proposed algorithm shows superiority in terms of watermark extraction and robustness to various attacks. Furthermore, as one of the most promising techniques for quality evaluation, a watermarking based quality evaluation scheme is developed for DIBR 3D images. The qualities of the watermarked center view and the synthesized left and right views under distortions can be estimated by examining the degradation of corresponding extracted watermarks. The simulation results demonstrate that our scheme has good performance of quality evaluation for DIBR 3D images under the attacks.

This paper presents co-resident watermarking, a traffic analysis attack for cloud environments that allows a malicious co-resident virtual machine to inject a watermark signature into the network flow of a target instance. This watermark can be used to exfiltrate co-residency data, compromising isolation assurances. While previous work depends on virtual hypervisor resource management, our approach is difficult to defend without costly underutilization of the physical machine. We evaluate co-resident watermarking under many configurations, from a local lab environment to production cloud environments. We demonstrate the ability to initiate a covert channel of 4 bits per second, and we can confirm co-residency with a target VM instance in less than 10 seconds. We also show that passive load measurement of the target and behavior profiling is possible. Our investigation demonstrates the need for the careful design of hardware to be used in the cloud. This thesis includes unpublished co-authored material.

Abstract Nowadays, content is increasingly in digital form and distributed in the Internet. The ease of making perfect copies of the digital content has created a need to develop a means to protect it. Digital rights management (DRM) relates to systems designed to protect the intellectual property rights of the digital content. The DRM systems try to enable a secure distribution of digital content to the users and to prevent the unauthorized copying, usage, and distribution of the content. This is usually done in practice using encryption and digital watermarking techniques. This thesis concentrates on the problem of protecting and distributing multimedia content securely in mobile environment. The research objectives are: (1) to design an overall DRM architecture which allows an easy content distribution to the user in mobile environment; (2) to develop protection methods that can be used in mobile devices with limited computational capabilities to prevent unauthorized usage of the audio content; (3) to create methods for managing and enforcing the user’s rights and restrictions to the content usage; (4) to study a method for providing the users with an easy access to new digital content and services. The research is carried out by first developing an overall DRM platform to mobile environment. The experimental prototype of the platform is implemented on server side to PC environment and the client runs on a mobile phone. The platform is used to test the functionality and complexity of the content protection methods developed which are based on digital watermarking and encryption techniques. The main results of the thesis are: (1) a DRM platform for mobile devices that supports peer-to-peer networking and license negotiation; (2) audio protection methods utilizing digital watermarking and encryption techniques which support content superdistribution and content preview; (3) methods for counting offline how many times content has been played on the user’s terminal using watermarking and hash chains; (4) a method for adding metadata, such as a web link, into audio content, so that it survives digital to analog to digital transformation and recording with a mobile phone.

Unlike encryption, steganography hides the very existence of secret information rather than hiding its meaning only. Image based steganography is the most common system used since digital images are widely used over the Internet and Web. However, the capacity is mostly limited and restricted by the size of cover images. In addition, there is a tradeoff between both steganographic capacity and stego image quality. Therefore, increasing steganographic capacity and enhancing stego image quality are still challenges, and this is exactly our research main aim. Related to this, we also investigate hiding secret information in communication protocols, namely Simple Object Access Protocol (SOAP) message, rather than in conventional digital files. To get a high steganographic capacity, two novel steganography methods were proposed. The first method was based on using 16x16 non-overlapping blocks and quantisation table for Joint Photographic Experts Group (JPEG) compression instead of 8x8. Then, the quality of JPEG stego images was enhanced by using optimised quantisation tables instead of the default tables. The second method, the hybrid method, was based on using optimised quantisation tables and two hiding techniques: JSteg along with our first proposed method. To increase the steganographic capacity, the impact of hiding data within image chrominance was investigated and explained. Since peak signal-to-noise ratio (PSNR) is extensively used as a quality measure of stego images, the reliability of PSNR for stego images was also evaluated in the work described in this thesis. Finally, to eliminate any detectable traces that traditional steganography may leave in stego files, a novel and undetectable steganography method based on SOAP messages was proposed. All methods proposed have been empirically validated as to indicate their utility and value. The results revealed that our methods and suggestions improved the main aspects of image steganography. Nevertheless, PSNR was found not to be a reliable quality evaluation measure to be used with stego image. On the other hand, information hiding in SOAP messages represented a distinctive way for undetectable and secret communication.

Rapid evolution of digital technology has improved the ease of access to digital information enabling reliable, faster and efficient storage, transfer and processing of digital data. It also leads to the consequence of making the illegal production and redistribution of digital media easy and undetectable. Hence, the risk of copyright violation of multimedia data has increased due to the enormous growth of computer networks that provides fast and error free transmission of any unauthorized duplicate and possibly manipulated copy of multimedia information. One possible solution may be to embed a secondary signal or pattern into the image that is not perceivable and is mixed so well with the original digital data that it is inseparable and remains unaffected against any kind of multimedia signal processing. This embedded secondary information is digital watermark which is, in general, a visible or invisible identification code that may contain some information about the intended recipient, the lawful owner or author of the original data, its copyright etc. in the form of textual data or image. In order to be effective for copyright protection, digital watermark must be robust which are difficult to remove from the object in which they are embedded despite a variety of possible attacks. Several types of watermarking algorithms have been developed so far each of which has its own advantages and limitations. Among these, recently Singular Value Decomposition (SVD) based watermarking algorithms have attracted researchers due to its simplicity and some attractive mathematical properties of SVD. Here a number of pure and hybrid SVD based watermarking schemes have been investigated and finally a RST invariant modified SVD and Discrete Cosine Transform (DCT) based algorithm has been developed. A preprocessing step before the watermark extraction has been proposed which makes the algorithm resilient to geometric attack i.e. RST attack. Performance of this watermarking scheme has been analyzed by evaluating the robustness of the algorithm against geometric attack including rotation, scaling, translation (RST) and some other attacks. Experimental results have been compared with existing algorithm which seems to be promising. / Phone number: +88041730212