Transcript Technical Aspects of Digital Rights Management - uni

Technical Aspects of
Digital Rights
Management
Emilija Arsenova
MI, RWTH-Aachen
Digital Intellectual Property

Digital media properties
Digital content (audio, video, graphics, images)
can be easily copied, transmitted and distributed
 Exact copies of the original data
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Problem for content owners/providers?
Digital Rights Management I
System for protecting the
copyrights of data circulated
via the Internet or other digital
media by enabling secure
distribution and/or disabling
illegal distribution of the data
RIGHTS

OWN
USERS
OVER
CREATE/
USE
CONTENT
http://lib.colostate.edu/lingo/d.html
What Does DRM Really Mean?
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You can play your new audio CD on your stereo system,
but when you insert it into the CD drive on your
Macintosh computer, the CD doesn't work. Worse still,
the machine crashes and refuses to reboot. The disc
remains stuck in the drive until you force the tray open
by inserting a paper clip.
You buy an e-book and discover you can read it onscreen but can't print a chapter, even though the book is
by Dickens and entered the public domain more than a
century ago.
http://www.pcmag.com/article2
Digital Rights Management II

DRM = digital restriction management ?
Digital Rights Management III
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DRM - commonly advertised as the technology
that can restore the value of content
‘DRM is a system of IT components and
services, corresponding law, policies and
business models which strive to distribute and
control IP and its rights’
(www.eu.int )
DRM Focus

"DRMs' primary role is not about keeping
copyrighted content off P2P networks. DRMs
support an orderly market for facilitating efficient
economic transactions between content
producers and content consumers."
Dan Glickman, Motion Picture Association of America, to BBC
NEWS
DRM Architecture
http://www.dlib.org/dlib/june01/iannella/06iannella.html
DRM Goals
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Protection of digital
content
Secure distribution
Content authenticity
Transaction nonrepudiation (digital
signature)
Market participant
identification (digital
certificates)
DRM Techniques
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Encryption
Public / private keys
Digital certificates
Watermarking
Access control
Secure communications protocols
Fingerprinting
Rights specification language
Trust infrastructure
Hashing
Security goals
SECURITY GOAL
TECHNIQUES
PREVENTION
CONDITIONAL ACCESS
COPY
DETECTION
ENCRYPTION
TAMPER
RESISTANT
HW DEVICES
FINGERPRINTING
INTEGRITY PROTECTION
PROTECTION OF
OWNERSHIP
WATERMARKING
http://www.inf.tu-dresden.de/~hf2/
Protection of digital content

Encryption
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scramble data to make it unreadable to everyone
except the recipient
Decryption

recovering the original bits
Encrypting the file – is it enough?
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Managing the decryption key:
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creating it
transferring it to the customer
enforcing any time limitations
changing user rights
preventing theft or transfer of the key
Watermarking
Steganography (covered writing)
 Digital Watermarking
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Why Use Watermarking?
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Ease of replication
Ease of transmission and multiple use
Exact copies of digital data
Permanently mark the data
Watermark Applications
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Proof of ownership
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Broadcast monitoring
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Prove ownership in a court of law
Keep track of when and where a clip is played
Owner identification
Transactional watermarks (Fingerprinting)
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Identifying the source of an illegal copy
www.digimarc.com
Watermark Applications
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Copy Control
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Classification/Filtering
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Prevention of illegal copying
Classification of content
Authentication
www.digimarc.com
Types of watermarks
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Visible, invisible
Fragile, robust
Blind, semi-blind, non-blind
Visibly watermarked ‘Lena’
Original
Watermark
picture
images
Smaller
Bigger
watermark
watermark
M. Kankanahalli, et. al., ”Adaptive Visible Watermarking of Images”
Embedding and detecting systems
WATERMARK
P
ORIGINAL
MEDIA
SIGNAL
ENCODER
WATERMARKED
MEDIA SIGNAL
KEY
P
PIRATE
PRODUCT
ATTACKED
CONTENT
DECODER
DECODER
RESPONSE
KEY
Chun-Shien Lu, Multimedia security: Steganography and digital watermarking techniques for protection of intellectual property
Ideal watermarking system
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perceptibility
robust
image compression
protection of malicious attacks
capacity
speed
Digital Watermarking Techniques
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choice of watermark object
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spatial domain
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transform domain
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fractal domain
Choice of watermark object
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what form should the embedded message take?
Spatial Domain Techniques
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Addition of pseudo-random noise
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LSB modification
Replace the LSB of each pixel with the secret
message
 Pixels may be chosen randomly according to a key
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Drawbacks
highly sensitive to signal processing operations
 easily corrupted
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Example:LSB Encoding
(R,G,B) = (00000000, 11111111, 00000000)
(R,G,B) = (00000001, 11111111, 00000000)
Transform Domain Techniques
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Wavelet based watermarking
Most efficient domain for watermark embedding
 HVS
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DCT-based watermarking
Fractal domain watermarking
Computational expense
 Not suitable for general use
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Robustness
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WATERMARKED
IMAGE OR SOUND
How robust
are watermarking
algorithms?
W
LOSSY
COMPRESSION
GEOMETRIC
DISTORTIONS
W
CORRUPTED
WATERMARKED
IMAGE OR SOUND
SIGNAL
PROCESSING
OPERATIONS
Testing watermarking algorithms
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Image watermarking algorithms must survive
robustness attacks
Geometric distortions
Combinations of geometric distortions
Example – StirMark Tool
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Applies:
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Large set of different geometric distortions
 The image is slightly stretched, shifted, bent and
rotated by an unnoticeable random amount
Frequency displacement and deviation
 Embeds a small error in each sample value
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Applying StirMark to images I
Before StirMark
After StirMark
Copyright image courtesy of Kevin Odhner ([email protected])
Applying StirMark to images II
Underlying grid
Grid after StirMark
Fabien A. P. Petitcolas and Ross J. Anderson, Evaluation of copyright marking systems
Questions?
THANK YOU!