technical aspects of digital rights management emilija arsenova mi, rwth-aachen
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Technical Aspects of Digital Rights Management
Emilija ArsenovaMI, 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
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
USERS CONTENT
OVEROWN
CREATE/USE
http://lib.colostate.edu/lingo/d.html
What Does DRM Really Mean?
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 on-screen 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
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
Protection of digital content
Secure distribution Content authenticity Transaction non-
repudiation (digital signature)
Market participant identification (digital certificates)
DRM Techniques
Encryption Public / private keys Digital certificates Watermarking Access control Secure communications protocols Fingerprinting Rights specification language Trust infrastructure Hashing
Security goals
INTEGRITY PROTECTION
SECURITY GOAL
CONDITIONAL ACCESS COPY
PREVENTION
DETECTION
PROTECTION OFOWNERSHIP
ENCRYPTION
TAMPERRESISTANT
HW DEVICES
FINGERPRINTING
WATERMARKING
TECHNIQUES
http://www.inf.tu-dresden.de/~hf2/
Protection of digital content
Encryption scramble data to make it unreadable to everyone
except the recipient
Decryption recovering the original bits
Encrypting the file – is it enough?
Managing the decryption key: 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
Why Use Watermarking?
Ease of replication Ease of transmission and multiple use Exact copies of digital data Permanently mark the data
Watermark Applications
Proof of ownership Prove ownership in a court of law
Broadcast monitoring Keep track of when and where a clip is played
Owner identification Transactional watermarks (Fingerprinting)
Identifying the source of an illegal copy
www.digimarc.com
Watermark Applications
Copy Control Prevention of illegal copying
Classification/Filtering Classification of content
Authentication
www.digimarc.com
Types of watermarks
Visible, invisible Fragile, robust Blind, semi-blind, non-blind
Visibly watermarked ‘Lena’
Smaller
watermark
Watermark
images
Original
picture
Bigger
watermark
M. Kankanahalli, et. al., ”Adaptive Visible Watermarking of Images”
Embedding and detecting systems
P
P
ORIGINALMEDIASIGNAL
WATERMARKEDMEDIA SIGNAL
ENCODER
KEY
WATERMARK
PIRATEPRODUCT
ATTACKEDCONTENT
DECODER
KEY
DECODERRESPONSE
Chun-Shien Lu, Multimedia security: Steganography and digital watermarking techniques for protection of intellectual property
Ideal watermarking system
perceptibility robust image compression protection of malicious attacks capacity speed
Digital Watermarking Techniques
choice of watermark object
spatial domain
transform domain
fractal domain
Choice of watermark object
what form should the embedded message take?
Spatial Domain Techniques
Addition of pseudo-random noise LSB modification
Replace the LSB of each pixel with the secret message
Pixels may be chosen randomly according to a key
Drawbacks highly sensitive to signal processing operations easily corrupted
Example:LSB Encoding
(R,G,B) = (00000000, 11111111, 00000000) (R,G,B) = (00000001, 11111111, 00000000)
Transform Domain Techniques
Wavelet based watermarking Most efficient domain for watermark embedding HVS
DCT-based watermarking Fractal domain watermarking
Computational expense Not suitable for general use
Robustness
How robust
are watermarking
algorithms?
W
LOSSYCOMPRESSION
GEOMETRICDISTORTIONS
SIGNALPROCESSINGOPERATIONS
WATERMARKEDIMAGE OR SOUND
W
CORRUPTEDWATERMARKED
IMAGE OR SOUND
Testing watermarking algorithms
Image watermarking algorithms must survive robustness attacks
Geometric distortions Combinations of geometric distortions
Example – StirMark Tool
Applies: 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
Applying StirMark to images I
Before StirMark After StirMarkCopyright image courtesy of Kevin Odhner ([email protected])
Applying StirMark to images II
Underlying grid Grid after StirMarkFabien A. P. Petitcolas and Ross J. Anderson, Evaluation of copyright marking systems
Questions?
THANK YOU!