Secure service convergence based on scalable media coding

Abstract

In multimedia services, security and privacy issues are urgent to be solved, such as the content security and service protection. To solve these issues, some means have been proposed, such as conditional access and digital rights management. However, for the latest application scenarios in convergent networks, there is still no solution. This paper focuses on the convergent multimedia broadcasting applications: the multimedia content, e.g., TV program, is encoded and packaged by the content provider, and is then transmitted to users through different communication networks, e.g., 3G network, DVB-H, ADSL, etc. Thus, the same multimedia content will be used for various services, i.e., mobile TV, Internet TV and home TV. Since different network channel support different bandwidths, the multimedia content should be transcoded before being transmitted through the networks. To protect the content and service in this application, we propose the content and service protection methods. In content protection, the content provider encrypts the scalable multimedia content with the manner denoted by Encryption Flag. The content distributor has no decryption keys, but can transcode the scalable content with the manner denoted by Layer Flag, and transmit the transcoded content to users. In service protection, the content provider combines the encryption key, Encryption Flag and the user right information, and transmits them, independent from the encrypted content, to certified users. At user side, the content is decrypted with the received key according to the Encryption Flag and Layer Flag. Thus, the content provider needs only to encrypt the content once, which can be transcoded by the content distributor in a secure manner and used for various networks. Additionally, the user rights need not to be changed when the service network is changed. Totally, the proposed scheme is secure and efficient for service convergence.