Lightweight secure multimedia distribution based on homomorphic operations

A secure media distribution scheme is proposed in this paper, which distributes different media copy to different customer in a secure and efficient manner and is able to trace illegal redistribution. At the sender side, media data are scrambled with a random sequence under the control of a secret key. At the receiver side, the scrambled media data are descrambled with a new random sequence under the control of a unique customer code besides the secret key. The scrambling and descrambling strength can be adjusted by the parameter named quantization factor. Generally, the bigger factor is used in scrambling and the smaller one is used in descrambling. After descrambling, the recovered media copy that contains a unique customer sequence, named fingerprint, is slightly different from the original one. This difference is imperceptible to human eyes, while can be detected by computers and used to trace the redistribution of the media copy. Additionally, the unique customer sequence is produced by the collusion-resistant code, which can survive the attacks that combine several copies by averaging. The scheme's performances, including security, imperceptibility, robustness and efficiency, are analyzed and tested in detail. Its good performances make it a suitable choice for lightweight secure multimedia distribution, such as music download, image sharing, live TV or video-on-demand, etc., especially over Mobile terminals.