An efficient MPEG video encryption algorithm

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 constraints. For multimedia applications, light weight encryption algorithms are attractive. We present an efficient MPEG video encryption algorithm. This algorithm uses a secret key randomly changing the sign bits of encoded differential values of DC coefficients of I pictures and the sign bits of encoded differential values of motion vectors of B and P pictures. The encryption effects are achieved by the IDCT during MPEG video decompression processing. This algorithm adds very small overhead to MPEG codec. A software implementation is fast enough to meet the real time requirement of MPEG video applications. Experimental results show that this algorithm achieves satisfying results. We believe that it can be used to secure video-on-demand, video conferencing and video email applications