Multimedia authentication distinguishes itself from other data integrity security issues because of its unique property of content integrity in several different levels — from signal syntax levels to semantic levels. In this section, we describe several image authentication issues, including the mathematical forms of optimal multimedia authentication systems, a description of robust digital signature, the theoretical bound of information hiding capacity of images, an introduction of the self-authentication-and-recovery image (SARI) system, and a novel technique for image/video authentication in the semantic level. This chapter provides an overview of these image authentication issues.
As the interconnected networks for instant transaction prevail and the power of digital multimedia processing tools for perfect duplication and manipulation increases, forgery and impersonation become major concerns of the information era. This chapter is intended to disseminate the concept of digital watermarking for multimedia authentication. Issues and challenges, such as security, resolution of tamper localization, and embedding distortion, of this technical area are explained first. Three main categories of watermarking approaches, namely fragile, semi-fragile, and reversible schemes, to the issues and challenges are then presented. Merits and limitations of specific schemes of each category are also reviewed and compared.
A Dynamic Threshold Proxy Digital Signature Scheme by using RSA Cryptography for Multimedia Authentication