Over the last three years, several encryption algorithms, applied to M
PEG video streams, emerged. Most of the algorithms tried to optimize t
he encryption process with respect to the encryption speed due to the
temporal properties of video retieval and display process. In this pap
er, we Will describe, evaluate, and compare five representative MPEG e
ncryption algorithms, Naive Algorithm, Selective Algorithm, Zig-Zag Pe
rmutation Algorithm, Video Encryption Algorithm, and Pure Permutation
Algorithm, with respect to not only their encryption speed metric, but
also their security level and stream size metrics. We will show that
there are trade-offs among these metrics and the choice of encryption
algorithm will depend on security requirements of the considered multi
media applications. (C) 1998 Elsevier Science Ltd. All rights reserved
.