Due to the spread of internet and the technological advance of digital technology, many contents are produced, processed and distributed in digital forms. As such internet businesses thrive, the dependence on digital technology is increasing in forming relationships among the producers, distributors, and consumers of digital documents. Before the internet and digital information was as important, intellectual properties could be protected by copyrights laws. However, now producing a copy that is identical to the original is easily done as well as sharing it. Because of these characteristics, copyright protections for digitally produced contents have become a huge problem. Also, various new media such as networks and internet makes unauthorized distribution easier, causing piracy to be a serious social issue.
As digital TVs are developed and popularized more rapidly, the digital TV markets are showing a robust increase at the present. However, the fact that the 30% of viewers of digital TVs are illegal users implies the need for technology development. Developing the DRM module with powerful security algorithm applied will block illegal users from the start. This is expected to help not only contents producers, but also the broadcasting industry and any other related industries as a whole.
In this thesis, three points are presented. First of all, encryption and decryption algorithm for digital broadcasting contents is designed here. By using 3DES and AES encryption algorithm, digital broadcasting contents are efficiently encrypted and decrypted.
The second is algorithm designed to restrict and grant access for digital broadcasting contents. DRM technology that is used is more advanced than CAS which already has functions of certifying and limiting access. It is designed to control access by each contents, rather than by the channels.
Last is the key function that is suggested here for the first time. To increase efficiency, encryption and decryption is not applied to the whole video file, but to some bits here and there. Also, depending on the applied encryption algorithm, the number of bit that is encrypted is designed to differ. By these means, 80% to 90% of resources that is used for encryption and decryption in the existing system are reduced.
The digital broadcasting companies will increase in revenue by managing channels and organizing the payment system efficiently and preventing illegal copying and distribution. On the other hand, consumers will enjoy lower cost due to the payment system destined by each contents, and higher practicality due to easier interface for payment system and certification. As illegal piracy is getting more prominent, we can lead the development of digital contents market by coming up with more safe system for certification and payment.