CRYPTOGRAPHY 2006 THE RISE AND FALL OF DVD ENCRYPTION by Kim Rauff Schurmann, 20033033 (
[email protected]) Claus Andersen, 20030583 (
[email protected]) Jacob Styrup Bang 20030585 (
[email protected]) Jakob Løvstad Funder 20033047 (
[email protected]) Department of Computer Science - Daimi University of Aarhus December 15, 2006 Abstract The motivation for this project is to understand the failures made in the past in order to avoid repeating them. There were two main reasons for the fall of DVD encryption. One is a very insecure cryptosystem and the other is poor key management. Our focus will be on the former and we will spend a great deal of time describing and analyzing CSS, and the attacks on it. To fully understand and demonstrate those attacks, we will implement two of the attacks.. These are not the only two, but should be enough to understand the weaknesses in CSS This paper is for a large part based on information retrieved by reverse engineering CSS. This is because the DVD encryption was supposed to be a closed source encryption scheme. As a closure we will take a short look on the succeeding encryption schemes for HD-DVD and Blu-ray and what have been learned from the failures of CSS. Contents 1 About DVD 1 1.1 Securing the DVD .............................. 1 1.2 The hidden sector .............................. 2 2 Mutual authentication 3 3 Description of CSS 5 3.1 Keys ..................................... 5 3.2 Linear Feedback Shift Registers ...................... 7 3.2.1 LFSR-17 .............................. 7 3.2.2 LFSR-25 .............................