Copyright Protection Schemes for Digital Multimedia

• Main Authors: Tzung-Her Chen, 陳宗和
• Other Authors: Gwoboa Horng
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/41198803464846197046

博士 === 國立中興大學 === 資訊科學研究所 === 93 === As easiness and rapidness of distribution for digital multimedia data over communication networks enrich the daily lives of people, the challenges of multimedia security are rising such as confidentiality, authentication, integrity, non-repudiation and copyright protection. The first four issues can be well addressed mainly by means of cryptographic tools. However, even well-defined cryptographic tools can not be adopted to settle copyright protection directly. Digital copyright protection in multimedia data has not only drawn a lot of attention in recent years but also, unfortunately, obstructed the rapid development of computer and communication networks at the same time. This dissertation deals with digital copyright protection in terms of watermarking techniques with public verification and watermarking protocols with asymmetry and anonymity. In the first part, a copyright message is embedded in digital images, audio and video in an imperceptible way so as not to interfere with the normal usage of the protected media while its existence can discourage the manner of violating rightful copyright. This technique, so-called digital watermarking, should at least satisfied four essential requirements: transparency, robustness, security and blindness. In our research, robustness enhancement, public verification and multiple watermarking have been found as main three trends of digital watermarking for copyright protection. Based on this observation, a multiple watermarking scheme is firstly proposed in Chapter 2 to enhance the robustness of a watermark by simultaneously benefiting public verification and several valuable advantages from introducing visual secret sharing. Taking account of some malicious attacks, a lossless copyright-protection scheme, distinct from conventional watermarking techniques, is secondly proposed in Chapter 3 to resist against StirMark attacks, counterfeit attacks, copy attacks, BPM attacks, etc. It’s worthwhile to note that the protected media is lossless, i.e., it is the same as the original. This property is considerably important for the situations, high-quality art, medical application and military application, in particular. This scheme not only meets all of the watermarking properties but also answer the above three trends: robustness enhancement, public verification and multiple watermarking. Next, we also observe that watermarking alone is not sufficient to resolve rightful copyright of digital media. Therefore, Chapter 4 and 5 present two watermarking protocols with asymmetry and anonymity. Firstly, a buyer-reseller watermarking protocol, which is based on a public key cryptosystem that is a privacy homomorphism with respect to the watermark insertion operator, supports the digital media redistribution in the first-hand and second-hand markets over the Internet. Secondly, a lightweight watermarking protocol, which is based on a secret key cryptosystem and a tamper-resistant device, is proposed to adjust itself to the device equipped with a low computation capability. Finally, the dissertation ends with some future research topics as an extension of our current research. Our goal, in sum, is to position digital watermarking as a complement of cryptography. We believe that the security and reliability of copyright protection can benefit from a combination of cryptography and watermarking techniques.