Overview of DVD Copy Protection Methods, With Emphasis on Digital Watermarking James Painter EGR 230.

Overview of DVD Copy Protection Methods, With

Emphasis on Digital Watermarking

James PainterEGR 230

Movie Piracy

• About $3 billion lost annually

• Difficult in days of VHS

• Relatively easy now, since DVD encryption has been cracked (1999)

• Series of decryption keys

• Relatively simple 40-bit encryption compared to today’s standard 128-bit

• Short lived, but lessons learned

Method 1: Content Scrambling System

Method 1: CSS

Method 2: Copy Generation Management System

• Two bits embedded in DVD video indicating one of four “copy states”

• DVD recorder reads copy state, terminates burn if necessary

Method 2: CGMS

• Two bits = 22 = 4 possible copy states:

CGMS Bits Meaning

0 , 0 Copying is permitted without restriction

0 , 1Condition not to be used (“No more copies” in EIA-805)

1 , 0 One generation of copies may be made

1 , 1 No copying is permitted

Method 2: CGMS

• CGMS bits transmitted through television broadcasts– PVR, DVD recorder

• Problems– Non-compliance leads to CGMS bit deletion– Loose regulation

• Information (literally text) embedded in every video frame– Owner identification– License information– Misc. video details– Indicators of previous copy attempts– CGMS “copy states”

Method 3: Digital Watermarking

Method 3: Watermarking

• DVD recorder searches for watermarks, blocks burn if copyrighted material

• Also used for tracking “ripped” DVDs– Search engines

Method 3: Watermarking

• Implementation in camcorders prevent piracy within the theater

• Digital watermarks can be embedded in television broadcast signals (similar to station logos)

Method 3: Watermarking

• Watermarks of varying focus levels

Flat mask vs. Gradual mask

• Allows brightness increases of up to 16% while preserving invisibility

Method 3: Watermarking

Original image with no watermark (left), watermarked image (center), difference between the original and watermarked images (right)

Method 3: Watermarking

Images without watermark (top), images with watermark (bottom)

Method 3: Watermarking

• Effects of “false positives”

• False positive probability minimized to less 4.7x10-23

Method 3: Watermarking

• Attempts to remove watermarks will cause severely garbled pictures

• Possible future implementation in other consumer electronics

• Though CGMS (Method 1) is ineffective by itself, “copy states” embedded within a watermark can accomplish CGMS’s goal

– Difficulty of removal– Survives digital-to-analog conversion

Combination of Methods

Concluding Remarks

• Cooperation among industries with differing interests

• Nothing will stop the determined hacker

• Keeping honest people honest

References• www.up.ac.za/academic/electron/cd.jpg • m%20reel2.gif• D. Avioli, “Hollywood Ups Ante In Copy Protection Fight,” IEEE Spectrum, vol. 39, pp. 24-27, Jul. 2002.• J. A. Bloom, I. J. Cox, T. Kalker, J.-P. M. G. Linnartz, M. L. Miller, and C. B. S. Traw, “Copy Protection for DVD Video,”

Proceedings of the IEEE, vol. 87, pp. 1267-1276, Jul. 1999.• G. Kresden, Carnegie Mellon University, Dec. 6, 2000, “Content Scrambling System (CSS): Introduction,”

http://www.cs.cmu.edu/~dst/DeCSS/Kesden/index.html.• Wikipedia contributors, Wikipedia: The Free Encyclopedia, Mar. 31, 2006, “Content-scrambling system,”

http://en.wikipedia.org/wiki/Content-scrambling_system.• Macrovision Corporation, Mar. 2003, “Preserving an Effective DVD Copy Protection System,” http://www.

macrovision.com/pdfs/Preserving-an-effective-DVD-Copying-System_0303.pdf.• B. Markwalter, Consumer Electronics Association, April 20, 2004, “Copy Generation Management System - Analog,”

http://www.cptwg.org/Assets/TEXT FILES/ ARDG/CEA ARDG CGMS-A 3-6-03.ppt.• Wikipedia contributors, Wikipedia: The Free Encyclopedia, Mar. 19, 2006, “CGMS-A,” http://en.

wikipedia.org/wiki/CGMS-A.• F. Hartung and B. Girod, “Watermarking of Uncompressed and Compressed Video,” Signal Processing, vol. 66, pp.

283-301, May 1998.• N. F. Johnson, Z. Duric, and S. Jajodia, “A Role for Digital Watermarking in Electronic Commerce,” ACM Computing

Surveys, 1999.• M. Maes, T. Kalker, J.-P. Linnartz, J. Talstra, G. Depovere, and J. Haitsma, “Digital Watermarking for DVD Video Copy

Protection,” IEEE Signal Processing Magazine, vol. 17, pp. 47-57, Sept. 2000.• D. Kirovski, M. Peinado, and F. A. P. Petitcolas, “Digital Rights Management for Digital Cinema,” presented at the

International Symposium On Optical Science and Technology, Security in Imaging, Theory and Applications, San Diego, Calif. July, 2001.

• Geek.com Geek News, May 10, 2005, “UMD format cracked, pirate games available,” http://www.geek.com/ news/geeknews/2005May/bga20050510030385.htm.

• M. J. Geier, “Lights, Camera, Controls!,” IEEE Spectrum, vol. 40, pp. 28-30, May 2003.• T. S. Perry, “DVD Copy Protection: Take 2,” IEEE Spectrum, vol. 42, pp. 38-39, Jan. 2005.• A. M. Eskicioglu and E. J. Delp, “An Overview of Multimedia Content Protection in Consumer Electronics Devices,”

Signal Processing: Image Communication, vol. 16, pp. 681-699, Aug. 10, 2000.