Perceptual cryptography on MPEG compressed videos

In this paper, a perceptual cryptography on MPEG encoded video is presented. By confusing different number of DCT coefficients, encrypting different number of coefficients´ signs, confusing DCT blocks in different color planes and encrypting motion vectors according to certain quality factor, the videos can be degraded to different degree. Experimental results show that its encryption strength can be adjusted according to certain quality factor, it supports direct bit-rate control and is of low cost, which makes it suitable for multimedia applications with real-time operation requirement, such as video conference, multimedia network, mobile multimedia and so on.