Analysis of the DVB Common Scrambling Algorithm

The Common Scrambling Algorithm (CSA) is used to encrypt streams of video data in the Digital Video Broadcasting (DVB) system. The algorithm cascades a stream and a block cipher, apparently for a larger security margin. In this paper we set out to analyze the block cipher and the stream cipher separately and give an overview of how they interact with each other. We present a practical attack on the stream cipher. Research on the block cipher so far indicates it to be resistant against linear and algebraic cryptanalysis as well as simple slide attacks.