1. Enabling interoperable and rights-aware DRM using the Semantic Web
Roberto García
Universitat de Lleida, Spain
September 20, 2007
Sophia Antipolis, France

2. Where did you say you come from?
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

3. Table of Contents Introduction Objectives Specification
Semantic Web
Objectives
Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

4. Introduction Digital media: easy production and copy
Digital Rights Management (DRM)
Windows Media DRM, iTunes FairPlay, RealNetworks Helix, Sony MagicGate…
DRM
copy
play …
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

5. Introduction Internet: easy distribution DRM interoperability REL DRM
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

6. Introduction Need for a standard REL (Rights Expression Language)
Some efforts:
XML-based RELs
Formal syntax XML Schema for standard grammar
Informal semantics Rights Data Dictionaries
Creative Commons simple predefined licenses
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

7. Introduction XML-based RELs: Creative Commons: Limited expressivity
No interoperability mechanisms
Informal semantics, re-implement for each tool
Creative Commons:
Predefined and closed set of licenses
Non-commercial purposes
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

8. Introduction DRM Watch: “2005 Year in Review: DRM Standards” 1
“…consumer complaints have moved beyond overly restrictive DRMs to lack of interoperability among them…”
“…we see no production implementations…”
“…ContentGuards asserts its patents apply to any REL implementation in DRM…”
Electronic Frontier Foundation 2
“…fail to accommodate… copyright regimes.”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

9. Introduction DRM standardisation difficulties
Internet/Web open and heterogeneous
Copyright complex domain
High level of abstraction (not bits or pixels)
Concentrate on the roots, formalise SEMANTICS
Copyright
MPEG-21 “Adapt”
Reproduction Right
ODRL “Duplicate”
Copy
CC “Reproduction”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

10. Introduction Semantic Web Why semantics are needed?
Common scenario: web search and language ambiguity
Computers get confused because… …though we “see”:
"Smart University" (3rd edition) is an educational program dedicated to advanced technologies of Smart Card, e-ID,...
SMART (Sisterhood Mobilized for AIDS/HIV Research and Treatment) was founded in
SMART University welcomes all women infected or affected by HIV/AIDS who...
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

11. Introduction Semantic Web Computers “see”:
"Smart University" (3rd edition) is an educational program dedicated to advanced technologies of Smart Card, e-ID,...
SMART (Sisterhood Mobilized for AIDS/HIV Research and Treatment) was founded in
SMART University welcomes all women infected or affected by HIV/AIDS who...
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

12. Introduction Semantic Web XML allows some degree of automation
Data Interface: set of specific tags and grammar (DTD, XMLSchema)
<music>
<album format=“mp3”>
<author type=“group”>Faithless</author>
<title>Insomnia</title>
...
</album>
</music>
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

13. Introduction Semantic Web With XML computers “see”: <music>
<album format=“mp3”>
<author type=“group”>Faithless</author>
<title>Insomnia</title>
...
</album>
</music>
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

14. ? Introduction Semantic Web Interoperability problem
Global agreement required
Just formal syntax, no semantic interoperability tools
<music>
<album format=“mp3”>
<author tipo=“group”> ...</author>
<title>...</title>
...
</album>
</music>
<song>
<group>...</group>
<title>...</title>
<album>...</album>
<file>...</file>
...
</song> ?
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

15. Introduction Semantic Web
If the previous tool is presented a piece of data based on a new schema:
<song>
<group>Garbage</group>
<title>Version 2.0</title>
<album>Version 2.0</album>
<file>...</file>
...
</song>
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

16. Introduction Semantic Web That tool “sees”:
<song>
<group>Garbage</group>
<title>Version 2.0</title>
<album>Version 2.0</album>
<file>...</file>
...
</song>
Code interoperability rules case by case
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

17. Introduction Semantic Web Semantic Web proposal
Web + Knowledge Representation
Web wide formal semantics
RDF: semantic net, graph model
RDF Schema: classes, inheritance,…
Web Ontology Language (OWL)
OWL-DL: scalable (decidable and tractable)
Semantic Web Rules
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

18. Introduction Semantic Web RDF provides graph model: Graph can model:
trees (XML)
tables (DBs)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

19. http://music.org /song1
Introduction
Semantic Web
RDFSchema: OOP-like primitives
type
class, property
subclass, subproperty
domain, range
RDFSchema
RDF
Audio
Class
subClassOf
Song
Class
type
/song1
domain
attribute
Property
title
Property
type
title
subPropertyOf
range
Literal
Class
type
“...”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

20. Introduction Semantic Web Web Ontology Language (OWL) Logic reasoning
Primitives for semantic interoperability
Equivalent classes and properties equivalentClass, equivalentProperty
Disjoint classes disjointWith
Inverse, transitive, symmetric properties inverseOf, TransitiveProperty, SymmetricProperty
Cardinality maxCardinality, minCardinality
Unique value properties FunctionalProperty
Identificative properties InverseFunctionalProperty
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

21. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

22. Objectives Semantic Web approach to DRM: Benefits: Formalise semantics
Knowledge Representation tools
Web Wide applicability
Benefits:
Formalise semantics
Facilitate interoperability and implementation
Overcome REL patent?
Include copyright
Support full value chain
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

23. Objectives Ontology development based on Methontology:
Specification
Conceptualisation (and formalisation)
Implementation
Evaluation
XML Semantics Reuse
Profit from existing XML Schema based RELs
Formalise implicit semantics
XML Schema to Web Ontology
XML data to semantic data (RDF)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

24. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

25. Specification Copyright domain analysis Generic Ontology
WIPO1 worldwide harmonisation
Literary, artistic and scientific works (not ideas)
Maybe derived, but always original
1 World Intellectual Property Organisation Copyright Treaty, 1996
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

26. Specification
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

27. Specification Scenario Applicable to the
“Controlled P2P metadata diffusion scenario”
Reproduction Right
Peer B
Peer A
<rdf:RDF>
<rdf:RDF>
<rdf:RDF>
<rdf:RDF>
<rdf:RDF>
Make Available Right
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

28. Table of Contents Introduction Objectives Specification
Conceptualisation
Creation, Rights and Action Model
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

29. Conceptualisation Complex domain, build model in three steps:
Creation Model
Rights Model
Action Model
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

30. Victor Hugo’s Les Misérables
Conceptualisation
Creation Model
Victor Hugo’s Les Misérables
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

31. Conceptualisation Creation Model Work Manifestation Performance
“Mozart's The Magic Flute”. ISWC
Manifestation
“The printed scores”. ISBN
Performance
“A scenic play”.
Fixation
“A sound recording”. ISRC
Communication
“An Internet stream”.
Instance
“A CD”. UPC
hasDerivation┙
hasManifestation┙
hasPerformance┙
hasFixation┙
hasCommunication┙
hasInstance┙
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

32. Conceptualisation Rights Model
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

33. Conceptualisation Rights Model End-users do not hold rights
Usage licenses
Special permissions:
Quotation
Education
Information
Official Act
Private Copy
Parody
Temporary Reproduction
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

34. Conceptualisation Action Model Actions, the building blocks
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

35. Conceptualisation Action Model Actions governed by Economic Rights:
Reproduction Right: copy
Distribution Right: distribute; sell, rent, lend
Public Performance Right: perform
Fixation Right: record
Communication Right: communicate; retransmit, broadcast, make available
Transformation Right: transform; adapt, translate
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

36. Conceptualisation Action Model End-user actions, to use a…
manifestation: buy
instance: buy
performance: attend
communication: access
broadcast: tune
something made available: access
picture, sculpture
book, CD, DVD
projection, recital, exhibition
TV channel, radio station
web page, stream
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

37. Conceptualisation Action Model
Altogether: model copyright value chains
E.g. “serials adapted from literary works”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

38. Conceptualisation Action Model Actions for users’ special permissions:
Quotation Right: quote, limited extent copy, usually requiring an attribute action
Private Copy Right: copy producing a reproduction for private consumption
Education Right: educational act, any copy, communicate or perform with educational or research purposes
Temporary Reproduction Right: a copy that produces a temporal reproduction …
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

39. Conceptualisation Action Model
Case roles (linguistics): relate actions to involved entities
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

40. Conceptualisation Action Model Scenario License building primitives:
Event Patterns: to state what is obliged, permitted or prohibited
Built from actions and case roles
Scenario
All copy events performed by agent “granted” who copies “content01” from “PeerA” to two peers from the set “PeerB, PeerC, PeerD” at any time point six months after “ ”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

41. Conceptualisation Action Model Scenario License building primitives:
Agree: model permissions
theme points to the permitted event pattern
Scenario
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

42. Conceptualisation Action Model Scenario License building primitives:
consequence: model obligations
Points to the obliged event pattern
Scenario
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

43. Conceptualisation Action Model License building primitives:
condition: model a priori conditions
Points to the condition event pattern
Disagree: model prohibitions
theme points to the prohibited event pattern
Other concepts:
Transfer: model interchanges, commercial or not.
Time
Location
...
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

44. Conceptualisation Action Model Rules, examples:
First sale exhaustion: ∀s:Sell,∀i:Instance theme(s,i)→¬∃s’:Sell theme(s’,i)∧s≠s’
Assign author rights on Manifest:
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

45. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

46. Implementation One conceptual model, many implementations
Semantic Web implementation with OWL
OWL-DL variant
enables tractable and decidable reasoning for use-license checking, scalability
Additionally, Semantic Web rules
+ expressivity
OWL Full
OWL DL
OWL Lite
- complexity
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

47. Implementation Rights and License Patterns implemented as Classes
Copyright, Reproduction Right, Copy, CopyPattern,...
Uses implemented as Instances u
if u ∈ Copy Pattern then license pattern authorises u
Copyright
Reproduction Right
Copy
Copy Pattern ? u
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

48. Implementation
License Pattern Class built from constraints on kind of actions, agents, time points, locations, etc.
OWL Building Blocks
Classes for actions (e.g. Copy)
Logical operators (AND, OR, NOT)
OWL Restrictions, constraints on case roles (e.g. agent all values from PublisherSubscribers)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

49. Implementation Scenario Copy pattern restricted to: or depending on
digital object (theme)
group of users (agent) or
non-commercial (aim)
depending on
time range (pointInTime)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

50. Implementation
Description Logic notation for the commercial copy pattern:
Pattern ≡ Copy ⊓ ∀pointInTime.≥ ,≤ ⊓ ∀agent.PublisherSubscribers ⊓ (≥ 1 agent) ⊓ ∃theme.{urn:doi /…} ⊓ (≤ 1 theme)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

51. Implementation
Patterns permitted by Agree actions and prohibited by Disagree ones.
Algorithm:
If disagreed  not allowed
If agreed and not disagreed  allowed
If not agreed  not allowed
Disagree precedence allows:
Revocation
More complex patterns
Avoid DL reasoners limitations (details Annex A)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

52. Implementation Agree Agree Disagree Copy Pattern 2 Pattern 1
all copy actions
Disagree
Pattern 2
Pattern 2’
Pattern 1
Allowed
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

53. Implementation OWL-DL reasoners services:
Satisfiability: consistency, license verification
Subsumption: compute subclasses
License interactions
License search
Instance Checking: class an individual belongs to
Check uses against licenses
Other:
Debugging, justifications for conclusions
Pattern A
Pattern B
Pattern
Use
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

54. Implementation OWL-DL limitations: Semantic Web rules
No explicit variables
Difficult to model rules (if … then …)
Semantic Web rules
Variables
Classical rules
Built-ins (math, comparisons, date/time ops,...)
Integrates OWL
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

55. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

56. Evaluation Map MPEG-21 and ODRL ontologies to Copyright Ontology
Based on XML Semantics Reuse Methodology
XML Schemas  OWL Ontologies
XML instances  RDF metadata
MPEG-21, ISO/IEC 21000
Part 5 – REL, XML Schemas:
Core  RELOnto-R
Standard Extensions  RELOnto-SX
Multimedia Extensions  RELOnto-MX
Part 6 – RDD, informal ontology  RDDOnto
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

57. Evaluation ODRL 1.1 (OMA V1.0 DRM REL) Benefits XML Schemas:
Expression Language  ODRLOnto-EX
Data Dictionary  ODRLOnto-DD
Benefits
Check Copyright Ontology coverage
Apply semantic tools existing RELs
Validate MPEG-21 RDD standard
Implement Data Dictionary inheritance
License checking …
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

58. Evaluation Build SemDRMS Semantic Digital Rights Management System
Controlled P2P metadata diffusion
SemDRM
copy
Peer A
make available
DL Reasoner
Licenses Store
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

59. Evaluation Digital Media Project (DMP)
Traditional Rights and Usages informal descriptions, difficult to incorporate into DRM systems
Quote
Private Copy
Time Shift
...
Copyright Ontology: profit from copyright model and capture rights exceptions
No enforcing mechanisms, accountability
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

60. Evaluation Quote scenario Right exception model:
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

61. Evaluation Concrete quote action:
Tim wants to quote 10 seconds of a work by John
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

62. Evaluation Checking: Result:
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

63. Evaluation Private Copy scenario Right exception model:
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

64. Evaluation Concrete private copy action:
Peter wants to produce a personal copy of “My best quote of the year”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

65. Evaluation Checking: Result
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

66. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

67. Conclusions Concentrate on semantics Ontology, more expressivity
Include copyright
Facilitate implementation and interoperability
Reuse DL reasoners for license checking
RELs ontologies, XML Semantics Reuse
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

68. Table of Contents Introduction Objectives Specification
Conceptualisation
Implementation
Evaluation
Conclusions
Future Work
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

69. Future Work Full SemDRMS based on OWL-DL Copyright Ontology
Complete Mappings to Copyright Ontology
MPEG-21 REL Ontologies
ODRL Ontologies
Creative Commons
Security and trust through RDF signatures
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

70. Smart University Thank you for your attention
DRM, from research to implementations
Thank you for your attention
Roberto García
Universitat de Lleida, Spain
More details:

71. Smart University DRM, from research to implementations Annex A
Implementation Details
How to deal with licenses using Description Logic reasoners

72. Implementation Scenario Pattern ⊑ Copy
Pattern ≡ ∀pointInTime.≥ , ≤ ⊓ ∃agent.{granted} ⊓ ∃origin.{peerA} ⊓ ∃theme.{fragment01} ⊓ (≤ 2 recipient) ⊓ ∀recipient.{peerB, peerC, peerD}
Agree
Problem
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

73. Implementation Problem: Open World Assumption (OWA)
OWA sensible constructs:
maxCardinality (≤ n): new facts can make cardinality ≥ n
allValuesFrom (∀R.C): new facts where R.(¬C) …
OWA insensible constructs:
minCardinality (≥ n): once ≥ n, new facts cannot make cardinality ≤ n
someValuesFrom (∃R.C): once R.C, new facts cannot make ¬(∃R.C) 1 2 3
maxCardinality 2
(n ≤ 2)
minCardinality 3
(n ≥ 3)
New facts
“OPEN WORLD”
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

74. Implementation Metalevel negation to overcome OWA
Agree OWA insensible constructs
∃, ≥,…
Disagree “negated” OWL sensible constructs
∀R.C  ∃R.¬C
≤ n  ≥ n+1
Allowed(u)  Agree.theme(u) ⊓ ¬Disagree.theme(u)
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

75. Implementation Scenario Pattern’ ⊑ Copy
Pattern’ ≡ ∀pointInTime.≥ , ≤ ⊓ ∃agent.{granted} ⊓ ∃origin.{peerA} ⊓ ∃theme.{fragment0001}
Pattern’’ ≡ Pattern’ ⊓ ( ( ≥ 3 recipient) ⊔ ∃recipient.(¬{peerC, peerD, peerB}) )
Agree
Disagree
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

76. Implementation Scenario Copy Pattern’ Pattern’’ Allowed [ a Copy;
agent :granted; origin :peerA;
theme :fragment02; recipient :peerB ]
Pattern’
[ a Copy;
agent :granted; origin :peerA;
theme :fragment01; recipient :peerC, :peerD ]
Pattern’’
[ a Copy;
agent :granted; origin :peerA;
theme :fragment01; recipient :peerB, :peerC, :peerE ]
Allowed
Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007