Perceptual video encryption using multiple 8×8 transforms in H.264 and MPEG-4

It has been demonstrated in our earlier works that perceptual video encryption can be effectively achieved by using multiple transforms where the block size 4×4 has been considered. In this paper, we study the extension to the transforms of size 8×8. In this case, a more complex flow-graph structure is resulted, thus leading to a larger room for encryption. In addition, special technique on controlling the encrypted video quality is presented by carefully selecting the number of rotations in the flow-graph structure of an 8×8 transform. The proposed scheme is first evaluated using the high profile of H.264. It is then further tested for the MPEG-4 standard that completely relies on 8×8 transform. Both cases show that promising results can be achieved with our proposed scheme.