Bitstream-Oriented Protection for the H.264/Scalable Video Coding (SVC)

The newly standardized H.264/SVC enable multimedia suppliers to provide video bitstream with temporal, spatial and quality scalabilities to meet various needs of end users. Its bitstream scalability characteristic is also especially suitable for multimedia applications under merged heterogeneous networks with different network protocols, capacities and throughputs. Although the network environment, to some extent, provides security protection against the illegal users, it is not enough to protect against the authorized users from digesting contents beyond its authorization. Hence the issue of content protection for the H.264/SVC has aroused researchers’ interests in recent years. In this paper, we present an efficient bitstream-oriented protection scheme for the H.264/SVC in a compression friendly and format compliant manner. The encryption is implemented on the Network Abstraction Layer (NAL) unit level. To improve the computational efficiency as well as to provide sufficient security, selective cryptographic algorithms with different computation cost are employed for different content level of SVC according to its significance. The I slice NAL units from the base layer of SVC bitstream are encrypted with the symmetric AES algorithm in Cipher Block Chaining mode. And the other NAL units are protected by simplified XOR cipher. Furthermore, a robust key management (key generation and distribution) mechanism is also discussed in this paper. The security analysis and simulation results further verify that the proposed methods can effectively protect the H.264/SVC bitstream at low computational cost.