Semantically secure digital multimedia cryptosystem;

For implementing the encryption/decryption and information hiding for digital multimedia,and aiming to generate enough large cipher key space,the accurate period of high dimension random matrix scrambling transformation is studied with the help of number theory and algebraic theory.

Starting from a general introductio n of the concepts of information hiding and digital watermarking technology and the fundamental principles,if focuses on representing some typical applications and useful algorithms of information hiding technology to digital multimedia includ ing text, image, audio and video.

Watermark for R-database developed which was based on multimedia digital watermark in recent years.

The architecture and key technology of satellite mobile digital multimedia broadcasting system is introduced, and the prospect of digital multimedia broadcasting is analyzed

With analysis of international and domestic mainstream standards on digital multimedia broadcasting and recently released DMB-TH and CMMB standards, key techniques such as signal synchronization, channel coding & modulation and single frequency network are discussed, and some predictions of its development are made based on our research.

Digital Multimedia Broadcasting Electronic Programme Guide (DMB EPG), is an important application of digital TV and an indispensably tools for users to know about programs by mobile telephone.

Main superiority of DAB is: no matter portable or mobile reception, DAB can provide CD-like quality radio programmes, aside from sound, the improving DAB can carry not only audio, but also text, pictures, data and even videos-all on your radio! This is real DMB (Digital Multimedia Broadcasting).