Integated Digital Watermark In Digital Right Management Of Digital Cinema

The security problem of Digital Cinema mainly includes : (1) Secure Transfer ;(2)conditional access ;(3)copyright protection ;(4)content authentication. The first two problem can be solved by classical cryptography . But it is different with the common encryption /decryption or scramble because the media data is so large and the equipment is limited always .Furthermore .compression must be combined with .The later two mainly depend on digital watermark technology combined with cryptography .The initiative of watermark is to support copyright protection for digital content .So many robust watermark algorithm merged .But it is not mature up to now.Digital right management of the digital cinema is the whole system which aim to resolve those security matter . Based on the D. R. M system given by Microsoft Research Darko Kirovski et al . , we study the possible application of watermark and discuss access control and copyright aspect . Digital watermark is the technology which embed secret information in the digital content with robustly and imperceptibly in order to prove the copyright. The open Internet is the main obstacle of the D. R. M ,because anything can be spread through it. So we analyze the basic problem of digital watermark : the balance among robustness, imperceptibility and capacity and describe a watermark based access control model for preventing illegal movie spreading through Internet.