Abstract
Multimedia data security is important for multimedia commerce. Previous cryptography studies have focused on text data. The encryption algorithms developed to secure text data may not be suitable to multimedia applications because of large data sizes and real time constraint. For multimedia applications, light weight encryption algorithms are attractive. In this paper, we present four fast MPEG video encryption algorithms. These algorithms use a secret key randomly changing the sign bits of of DCT coefficients and/or the sign bits of motion vectors. The encryption effects are achieved by the IDCT during MPEG video decompression processing. These algorithms add very small overhead to MPEG codec. Software implementations are fast enough to meet the real time requirement of MPEG video applications. Our experimental results show that these algorithms can achieve satisfactory results. We believe that they can be used to secure video-on-demand, video conferencing and video email applications.
