New Data Hiding and Authentication Techniques with Distortion Reduction Effects for Protection and Secure Transmission of Digital Information
|關鍵字:||資訊隱藏;安全傳輸;驗證;降低失真;數位資訊;Data hiding;Security transmission;Authentication;Distortion reduction;Digital information|
With the advance of hardware and software technologies, digital information can be easily created, seamlessly manipulated, and widely distributed. Therefore, information security has become one of the most critical and challenging problems in recent years. This dissertation is dedicated to solving the problems of protection and secure transmission of digital information. One way to protect various types of digital information is to hide them in images. In this approach, reduction of embedding distortion is one of the major concerns. To design imperceptible data hiding methods, three techniques for distortion reduction are proposed in this study. First, the first technique is based on the new concept of embeddability proposed in this study, which is defined as a measure for checking the quality of stego-images yielded from embedding secret data in cover images. Only embeddable pixels are used to embed data. The other two techniques are proposed for minimizing embedding distortion from a global view. One is based on the use of error-correcting coding to create correctable errors corresponding to the data to be hidden, with the effect of minimizing embedding distortion. These errors can be detected, corrected, and so extracted to recover the hidden data. The other technique is based on providing multiple code holders as candidates for embedding data. An optimal code holder which results in the least embedding distortion is selected to embed data. On the other hand, also proposed are five new techniques for data embedding and four new techniques for solving various digital information hiding and authentication application problems have been developed. More specifically, two methods of data hiding in binary and palette images, and two methods of authentication of binary and palette images are proposed. In the proposed data hiding methods, not only can general digital information be embedded into binary and palette images without introducing noticeable distortion, but also can the credibility of the hidden information be verified. Besides, some tradeoffs between design requirements, including that between image quality and embedding capacity as well as that between the accuracy of authentication and the portability of authentication information, are addressed and solutions for balancing these requirements are proposed. Furthermore, a new method for embedding binary images into cover noise images is proposed. It is argued that there is no need to find a meaningful cover image for data hiding. Instead, a cover noise image which has larger embedding capacity can be used to hide a secret binary image. Nevertheless, a general approach to data hiding based on the employment of error-correcting coding is also proposed. Both embedding of digital information into images and authentication of the results are achieved by the error-correcting as well as error-detection abilities of an error-correcting scheme. On the other hand, a novel content-based authentication method based on the use of digital signatures is proposed. The concept is to extract visual color and edge features, which are invariant to content-preserving manipulations, from image blocks, as digital signatures. The authenticity of each image block can be verified by comparing its features with the corresponding ones recorded in the digital signature. The performances of all the above proposed methods have been evaluated extensively by theoretical analyses and experiments. The results indicate that they are feasible for practical applications.