Transcript Document

DVD Copyright Management
Schemes
Tanveer Alam
CVN
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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
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DVD Content Scrambling System
(CSS)
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Content Scrambling System (CSS)
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Strengths
– Proprietary code - harder to break
– Key controlled by a few in expert group
– Unique key for each DVD during etching
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Weakness
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Existing method already circumvented DeCSS
DVD manufacturers don’t want to pay loyally
Currently easy to bypass.
Newer more secure & robust methods needed.
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Advanced Access Control System
(AACS)
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AACS
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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
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Weakness
– decoder must be a authorized unit for scheme
to work
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Content Protection for Recordable
Media (CPRM)
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CPRM
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Applies to DVD-R, DVD-RAM, DVD-RW
Features
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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.
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Content Protecting from PreRecorded Media (CPPM)
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DVD Audio Encryption
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CPPM
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Features
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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.
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Conclusion
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Compare methods for the following:
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Transparency
Robustness
Security / Vulnerability
Resilience
Quality Metrics
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Visual
Error Rate
Watermark response
False Positive Rate
Market response
Resistance to attacks over time
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Papers & References
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Intel Corp, Warner Bros et al., AACS
Technical Overview, July 2004.
Bloom, Jefferey A. et al; Copy Protection for
DVD Video; Proceedings of IEEE, July 1999.
http://www.disctronics.co.uk/technology/dvdvi
deo/dvdvid_copyprot.htm
http://www.cs.berkeley.edu/~daw/teaching/cs
261-f02/notes/content-prot
http://www.apim.ens.fr/Watermark99/oostvee
n/
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