Philips Digital and Analog Protection System (Philips DNA)
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Transcript of Philips Digital and Analog Protection System (Philips DNA)
Philips Digital and Analog Protection System (Philips
DNA)
Michael EpsteinRaymond KrasinskiMartin RosnerOctober 22-23, 2003
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Outline
• Problem Statement– D-A-D of video content– Special case: Broadcast content
• Solution Concept– Two proposals A and B
• Proposal B is the simples subset of proposal A• Other subsets or combinations are possible
• Tools– Watermarking– Zone coding– Re-conversion detection
• Remote verification
• Summary
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Problem Statement
• D-A-D conversion carriage of content protection
states
– Prevent the copying of “copy never” (CN) content
– Prevent improper copying of “one generation” content
(COG)
– Prevent the Internet re-transmission to the public (NIR)
• To allow personal use when appropriate
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Features• Prevents redistribution of video content via the
Internet– Preserves compatibility with legacy equipment– Permits reasonable transmission of content over the
Internet between appropriate locations• Provides protection after content is placed on the
Internet without authorization– Does not fail catastrophically after secured content is
compromised• Permits manufacture of computers free of any
legal mandate • Becomes more effective with the passage of
time, as the population of compliant equipment grows
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Solution Concept• Encryption systems
– Protect content insides a compliant world– When content is lost to the non-compliant world
• Content is played in the non-compliant world• Content is played in the compliant world
• DNA system – a holistic solution– Assume that content will leak to the non-compliant
world– Assume content will want/need to return to the
compliant world– This will work for all types of content (CN, COG, NIR)
STOP CONTENT FROM RETURNING TO THE COMPLIANT WORLD
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Assumptions
• It remain difficult to transmit video
across the Internet without using
lossey compression technologies
• It will be desirable to use compliant
devices to record/play/watch video
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Watermark Detection
• Watermark detectors will exist in:
– Optical/magnetic player or recording
drives which will check well known video
formats on command
– Video generators
• e.g. computer graphics cards
– Displays
• Televisions or monitors
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Tools
• Watermarks– Base watermark– Remark
• Zone coding– Tagging content with geographic information
• Reconversion detection– Detect D-A-D – Detect compression
• Remote verification– Information at one device aids in decisions of a
second device
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Watermark Fundamentals
• An indelible mark that carries information– Typically applied by the owner/distributor of
content
• Does not interfere with the use of content• Should be difficult to remove
– Without destroying the content
• Should be difficult to write• Should be inexpensive to find
– If you know the secrets
• A remark is a watermark that is applied by consumer equipment according to certain rules
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Zone Coding
• Zone coding for NIR and COG content– Set at the broadcast station
– Internal Zone code set in devices by inputs• Quick reset allowed once in a while
• Devices play content that matches the internally stored zone– Adjacent zones are also allowed
• Boundary areas
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Zone Coding
InternetInternet
D/A
NIR-ADVD Recorder
zone Azone B
NIR-B
NIR content zone B
NIR content zone A
DisplayComputer
Unregulated Demodulator
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End Proposal B-Simplified Proposal
• Protects only NIR content
– Prevents retransmission to remote locations
• Most basic proposal using our tools
– Zone coding is a portion of the A proposal
• Combining zone coding with reconversion
detection provides a more complete
approach to NIR content
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Reconversion Detection
• Hash the bits of a “sector” and use the hash to construct a watermark (or remark) for a subsequent “sector”
• Verify content against the watermark (or remark)– If the content changes verification will
fail• D-A-D conversion inevitably changes content
• So does compression
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Reconversion Detection-Recording
1 2
HASH
Content
Recorded Content
3
HASH
4
HASH
5
HASH
6
HASH
21 3 4 5 6
mark mark mark mark mark
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Reconversion Detection-Checking
HASH
markequal?
Recorded Content
HASH HASH HASH HASH
21 3 4 5 6
markequal?
markequal?
markequal?
markequal?
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NIR Example – Hashed Remark
NIR
DVD Recorder NIR-RM
DVD Player
DVD Recorder
TelevisionReceiver
NIR – No Internet Retransmission to public
NIR-RM – NIR-remarked NIR-RM
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Failure to Traverse the Internet
NIR-RM
InternetInternet
NIR-Altered content
DVD Recorder
DVD Player
A/D
(compression)
Non-compliant DVD Recorder
DVD PlayerNIR-Altered content
NIR-RM – NIR-remarked
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Remote Verification
• There will be situations where content is altered prior to watermark detection for valid reasons– e.g. software sharpening
• Content source sends verification data to the watermark detecting device– e.g. graphics card works with DVD drive
• Checking device uses source-generated verification data in conjunction with the detected watermark
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Drive DisplayVideo
Generator
Computer
content
NIR-RM
Content +verification data
Verificationrequest
Remote Verification
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Mandates
• All displays must have a watermark detector• Video generators with uni-directional outputs
must have a watermark detector– e.g. analog outputs or DVI
• Video generators with bi-directional outputs may license a watermark detector
• Disk drives (magnetic/optical) may license a watermark detector
• Thus, a computer that has only bi-directional outputs need have no watermark detectors at all– but such a computer will not be able to play marked
content
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Summary
• Prevent improper content from coming into the compliant world– It is a given that content will leak from the
compliant world to the non-compliant world
• Attach rights to content – Pervasive protection
• More compliant equipment increases the efficacy of the solution– But increases or maintains consumer
functionality