Enabling interoperable and rights-aware DRM using the Semantic Web

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

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

Table of Contents

Introduction

Semantic Web

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

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

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

Introduction

Internet: easy distribution

DRM interoperability

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

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

XML-based RELs:

Limited expressivity

No interoperability mechanisms

Informal semantics, re-implement for each tool

Creative Commons:

Predefined and closed set of licenses

Non-commercial purposes

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

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.”

1 http://www.drmwatch.com 2 http://www.eff.org Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

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

ODRL “ Duplicate ” Reproduction Right Copy MPEG-21 “ Adapt ” CC “ Reproduction ” Copyright Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

Introduction

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 1998...

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 Semantic Web

Introduction

Computers “see”:

 Smart University   



SMART University 

Introduction

XML allows some degree of automation

Data Interface: set of specific tags and grammar ( DTD , XMLSchem a)

< music >

< album format=“ mp3 ”>

< author type=“ group ”>Faithless</ author >

< title >Insomnia</ title >

...

</ album >

</ music >

Introduction

With XML computers “see”:

< music >

< author type=“ group ”>  </ author >

< title >  </ title >

...

</ album >

</ music >

Introduction

Interoperability problem

Global agreement required

Just formal syntax, no semantic interoperability tools

< music >

< 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 Semantic Web

Introduction

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 >

Introduction

That tool “sees”:

<  >

<  >  </  >

<  >    </  >

<  >    </  >

<  >...</  >

...

</  >

Code interoperability rules case by case

Introduction

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

Introduction

RDF provides graph model:

Graph can model:

trees (XML)

tables (DBs)

Introduction

RDFSchema : OOP-like primitives

type

class, property

subclass, subproperty

domain, range

Song Class Audio Class subClassOf http:// music .org / song1 type title Property attribute Property subPropertyOf Literal Class “ ...” title type domain range RDFSchema RDF type Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Semantic Web

Introduction

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

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

Objectives

Semantic Web approach to DRM:

Knowledge Representation tools

Web Wide applicability

Benefits:

Formalise semantics

Facilitate interoperability and implementation

Overcome REL patent ?

Include copyright

Support full value chain

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)

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

Specification

Copyright domain analysis

Generic Ontology

WIPO 1 worldwide harmonisation

Literary, artistic and scientific works (not ideas)

Maybe derived, but always original

Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 1 World Intellectual Property Organisation Copyright Treaty, 1996

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

Specification

Applicable to the

“ Controlled P2P metadata diffusion scenario”

Peer A Peer B <rdf:RDF> <rdf:RDF> <rdf:RDF> <rdf:RDF> Make Available Right <rdf:RDF> Reproduction Right Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Creation, Rights and Action Model

Implementation

Evaluation

Conclusions

Future Work

Conceptualisation

Complex domain, build model in three steps:

Creation Model

Rights Model

Action Model

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

Conceptualisation

Work

“ 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

 has Derivation ┙

 has Manifestation ┙

 has Performance ┙

 ha sFixation ┙

 ha sCommunication ┙

 ha sInstance ┙

Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Creation Model

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

End-users do not hold rights

Usage licenses

Special permissions:

Quotation

Education

Information

Official Act

Private Copy

Parody

Temporary Reproduction

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

Actions, the building blocks

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

Conceptualisation

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 Action Model

Altogether: model copyright value chains

E.g. “serials adapted from literary works”

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

…

Case roles (linguistics): relate actions to involved entities

License building primitives:

Event Patterns : to state what is obliged, permitted or prohibited

Built from actions and case roles

Conceptualisation 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 “ 2007-06-01 ” Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model

Agree : model permissions

theme points to the permitted event pattern

Conceptualisation Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model

consequence : model obligations

Points to the obliged event pattern

Conceptualisation Scenario Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007 Action Model

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

...

Rules, examples:

First sale exhaustion: ∀ s:Sell, ∀ i:Instance theme(s,i) -> ¬ ∃ s’:Sell theme(s’,i) ∧ s≠s’

Assign author rights on Manifest:

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

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

OWL Full OWL DL OWL Lite + expressivity - complexity Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

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

Reproduction Right Copy Copyright Copy Pattern u ? Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

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)

Implementation

Copy pattern restricted to:

digital object ( theme )

group of users ( agent )

or

non-commercial ( aim )

depending on

time range ( pointInTime )

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

Implementation

Description Logic notation for the commercial copy pattern:

Pattern ≡ Copy ⊓ ∀ pointInTime .≥ 2007-01-01,≤ 2007-06-30 ⊓ ∀ agen t.PublisherSubscribers ⊓ (≥ 1 agent ) ⊓ ∃ theme .{urn:doi.10.1032/…} ⊓ (≤ 1 theme )

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)

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

Implementation

OWL-DL limitations:

No explicit variables

Difficult to model rules (if … then …)

Semantic Web rules

Variables

Classical rules

Built-ins (math, comparisons, date/time ops,...)

Integrates OWL

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

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

Evaluation

ODRL 1.1 (OMA V1.0 DRM REL)

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

…

Evaluation

Build SemDRMS Semantic Digital Rights Management System

Controlled P2P metadata diffusion

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

Evaluation

Quote scenario

Right exception model:

Evaluation

Concrete quote action:

Tim wants to quote 10 seconds of a work by John

Evaluation

Checking:

Result:

Evaluation

Private Copy scenario

Right exception model:

Evaluation

Concrete private copy action:

Peter wants to produce a personal copy of “My best quote of the year”

Evaluation

Checking:

Result

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

Conclusions

Concentrate on semantics

Ontology , more expressivity

Include copyright

Facilitate implementation and interoperability

Reuse DL reasoners for license checking

RELs ontologies, XML Semantics Reuse

Table of Contents

Introduction

Objectives

Specification

Conceptualisation

Implementation

Evaluation

Conclusions

Future Work

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

More details: http://rhizomik.net/ontologies/copyrightonto http://rhizomik.net/semdrms http://rhizomik.net/~roberto/thesis Smart University DRM, from research to implementations Thank you for your attention Roberto García [email_address] Universitat de Lleida, Spain

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

Implementation

Pattern ⊑ Copy

Pattern ≡ ∀ pointInTime.≥ 2006-01-01, ≤ 2006-06-30 ⊓ ∃ agent.{granted} ⊓ ∃ origin.{peerA} ⊓ ∃ theme.{fragment01} ⊓ (≤ 2 recipient) ⊓ ∀ recipient.{peerB, peerC, peerD}

Implementation

Problem : Open World Assumption (OWA)

OWA sensible constructs:

m ax Cardinality (≤ n): new facts can make cardinality ≥ n

allValuesFrom ( ∀ R.C): new facts where R.(¬C)

…

OWA insensible constructs:

m in Cardinality (≥ n): once ≥ n, new facts cannot make cardinality ≤ n

someValuesFrom ( ∃ R.C): once R.C, new facts cannot make ¬( ∃ R.C)

…

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)

Implementation

Pattern’ ⊑ Copy

Pattern’ ≡ ∀ pointInTime.≥ 2006-01-01, ≤ 2006-06-30 ⊓ ∃ agent.{granted} ⊓ ∃ origin.{peerA} ⊓ ∃ theme.{fragment0001}

Pattern’’ ≡ Pattern’ ⊓ ( ( ≥ 3 recipient) ⊔ ∃ recipient.( ¬ {peerC, peerD, peerB}) )

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