Video Encryption Based on Data Partitioning and Scalable Coding - A Comparison

Many of today's multimedia applications require con dential video transmission over the Internet. Appropriate encryption methods require a high computational complexity and are likely to become a performance bottleneck within software-only applications. To reduce the computational encryption e ort, partial video encryption methods have been proposed in the past. Promising approaches are based on data partitioning where the encoded video stream is partitioned into two streams, one containing the most important data, the other one containing the least important data. Encrypting the most important data only can reduce the required computational complexity to 10 50 % compared to encryption of the whole data stream. Besides the known standardized DCT based video codecs, scalable codecs become more and more popular. Scalable codecs have the advantage that no additional e ort is needed to obtain the required data partitioning. In this paper, a novel approach to partial video encryption based on data partitioning applicable to every DCT-based video codec is presented. It is compared to base layer encryption of a video stream encoded with a scalable codec based on a spatio-temporal resolution pyramid. Besides partial encryption, transparent encryption is discussed as well.