A Study on Digital Watermarking Techniques

• Main Authors: Kuo-Feng Hwang, 黃國峰
• Other Authors: Min-Shiang Hwang
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/90282434410039645719

碩士 === 朝陽大學 === 資訊管理系碩士班 === 87 === Nowadays, the Internet revolution is in full swing, and commercial interests abound. Many commercial vendors and developers try to use Internet to deliver media products or transactions for profit. Such as video on demand service, electronic data exchange, online shopping and so on. To utilize Internet is convenient for both vendors and customers. However, there are many problems when provide these services via Internet. The identification of intellectual property owner is one of that problems. Digital watermarking is a technique used to solve this problem. In this thesis, we use cryptography, image processing, and information security techniques to develop digital watermarking scheme. In addition, a time-stamping protocol for digital watermarking also proposed in this thesis. For practical use, the digital watermark scheme has the following requirements: 1) Alterations introduced in the image or video should be perceptually invisible. 2) Watermark must be undetectable by a perpetrator. 3) The detection of the watermark should be no correlative with original image or video. 4) Watermark should be robust as much as possible image processing which preserves desired quality for the image. 5) Like information securing technique, the details of digital watermark technique must be opening. In this thesis, we propose two new digital watermarking technique. The first scheme is based on Rabin's public-key cryptosystem, which has highly security of embedded watermark. The second scheme is based on neural network, one-way hash function, and discrete cosine transform (DCT). Our schemes can achieve the following two goals. One is that the illegal users do not know the locations of an embedded watermark in the image. The other is that a legal user can retrieve the embedded watermark from an altered (filtering, lossy compression, and scaling) image. Finally, a new time-stamping protocol for all digital watermarking algorithms is proposed. This protocol is added a time-stamp on digital watermarking algorithms through a trusted-third party.