| The digital information revolution has brought about profound changes in our society and our lives. The many advantages of digital information have also generated new challenges and new opportunities for innovation. This thesis discusses the issues regarding multimedia data hiding and its application to multimedia security and communication, addressing both theoretical and practical aspects, and tackling both design and attack problems.; In the fundamental part, we identify a few key elements of data hiding through a layered structure. Data hiding is modeled as a communication problem where the embedded data is the signal to be transmitted. Various embedding mechanisms target different robustness-capacity tradeoffs. We study this tradeoff for two major categories of embedding mechanisms. In addition, we have found that the unevenly distributed embedding capacity brings difficulty in data hiding. We propose a comprehensive solution to this problem, addressing the considerations for choosing constant or variable embedding rate and enhancing the performance for each case.; In the design part, we present new data hiding algorithms for binary images, grayscale and color images, and videos, covering such applications as annotation, tamper detection, copy/access control, fingerprinting, and ownership protection. The designs provide concrete examples regarding the choice of embedding mechanisms, the selection of modulation/multiplexing technique(s) for hiding multiple bits, and the handling of uneven embedding capacity. Data hiding can also be used in video communication to convey side information for additional functionalities or better performance. This is demonstrated by the novel approaches for real-time transcoding and error concealment.; Because many data hiding applications are in a competitive environment where an adversary has an incentive to obliterate the embedded data, testing the systems' robustness and security via attacks is important. In the attack part, we discuss a number of attacks and countermeasures for data hiding systems. Our investigation begins with three specific types of watermarking schemes, in which full knowledge of the watermarking algorithms is available. We then study the attack problems for digital music under a unique competitive environment, in which the watermarking algorithms are unknown to analysts. |
