1 DVD Copyright Management Schemes Tanveer Alam CVN

2 Project Goals Compare high level schemes: –CSS (Content Scrambling System) –Advance access ctrl system (AACS) –Content Protection for Recordable Media (CPRM) & Pre-Recording Media (CPPM- Audio) Some methods: –Scrambling –Vertical synch –Watermarking

3 DVD Content Scrambling System (CSS)

4 Content Scrambling System (CSS) Strengths –Proprietary code - harder to break –Key controlled by a few in expert group –Unique key for each DVD during etching Weakness –Existing method already circumvented DeCSS –DVD manufacturers don’t want to pay loyally –Currently easy to bypass. –Newer more secure & robust methods needed.

5 Advanced Access Control System (AACS)

6 AACS Strengths –different levels of access possible –time limits, number of viewings, number of copies controlled –individual distributor can decide what types of protection to offer to consumer –centralized key server for authentication, individual keys for each player Weakness –decoder must be a authorized unit for scheme to work

7 Content Protection for Recordable Media (CPRM)

8 CPRM Applies to DVD-R, DVD-RAM, DVD-RW Features –Cryptomeria Cipher (C2) for content encryption –4 layers of encryption using 56-bit keys –Unique device key for each recording/playback device –Media Key Block (MKB) to allow for revoking a hacked device –Unique Media ID to prevent copying bit-for-bit. –Mutual identification process for PC based systems, which must be performed before CPRM protected data is transferred from DVD drive to the PC.

9 Content Protecting from Pre- Recorded Media (CPPM) DVD Audio Encryption

10 CPPM Features –Born from the failure of CSS, CSS-II –Targeted to DVD- Audio –4C consortium (IBM, Intel, MEI, Toshiba) –56 bit keys instead of 40 bit in CSS –Uses Media Key Blocks (MKB) that can be revoked according to need. –Audio Watermarking included by Verance.

11 Conclusion Compare methods for the following: –Transparency –Robustness –Security / Vulnerability –Resilience Quality Metrics –Visual –Error Rate –Watermark response –False Positive Rate –Market response –Resistance to attacks over time

12 Papers & References Intel Corp, Warner Bros et al., AACS Technical Overview, July Bloom, Jefferey A. et al; Copy Protection for DVD Video; Proceedings of IEEE, July deo/dvdvid_copyprot.htm deo/dvdvid_copyprot.htm f02/notes/content-prot f02/notes/content-prot n/