1. Technical Aspects of Digital Rights Management
Emilija Arsenova
MI, RWTH-Aachen

2. 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?

3. 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

4. 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

5. Digital Rights Management II
DRM = digital restriction management ?

6. 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’ ( )

7. 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

8. DRM Architecture

9. DRM Goals Protection of digital content Secure distribution
Content authenticity
Transaction non-repudiation (digital signature)
Market participant identification (digital certificates)

10. DRM Techniques Encryption Public / private keys Digital certificates
Watermarking
Access control
Secure communications protocols
Fingerprinting
Rights specification language
Trust infrastructure
Hashing

11. Security goals

12. Protection of digital content
Encryption
scramble data to make it unreadable to everyone except the recipient
Decryption
recovering the original bits

13. 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

14. Watermarking
Steganography (covered writing)
Digital Watermarking

15. Why Use Watermarking? Ease of replication
Ease of transmission and multiple use
Exact copies of digital data
Permanently mark the data

16. 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

17. Watermark Applications
Copy Control
Prevention of illegal copying
Classification/Filtering
Classification of content
Authentication

18. Types of watermarks Visible, invisible Fragile, robust
Blind, semi-blind, non-blind

19. Visibly watermarked ‘Lena’
Original
picture
Watermark
images
Smaller
watermark
Bigger
watermark
M. Kankanahalli, et. al., ”Adaptive Visible Watermarking of Images”

20. Embedding and detecting systemsP P
Chun-Shien Lu, Multimedia security: Steganography and digital watermarking techniques for protection of intellectual property

21. Ideal watermarking system
perceptibility
robust
image compression
protection of malicious attacks
capacity
speed

22. Digital Watermarking Techniques
choice of watermark object
spatial domain
transform domain
fractal domain

23. Choice of watermark object
what form should the embedded message take?

24. 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

25. Example:LSB Encoding (R,G,B) = (00000000, 11111111, 00000000)

26. 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

27. Robustness
How robust
are watermarking
algorithms?

28. Testing watermarking algorithms
Image watermarking algorithms must survive robustness attacks
Geometric distortions
Combinations of geometric distortions

29. 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

30. Applying StirMark to images I
Before StirMark
After StirMark
Copyright image courtesy of Kevin Odhner

31. Applying StirMark to images II
Underlying grid
Grid after StirMark
Fabien A. P. Petitcolas and Ross J. Anderson, Evaluation of copyright marking systems

32. Questions?

33. THANK YOU!