Enabling interoperable and rights-aware DRM using the Semantic Web Roberto García rgarcia@diei.udl.cat 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 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

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

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

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

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

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 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

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 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

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

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

? 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

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

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

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

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

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 http://music.org /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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Implementation Description Logic notation for the commercial copy pattern: Pattern ≡ Copy ⊓ ∀pointInTime.≥ 2007-01-01,≤ 2007-06-30 ⊓ ∀agent.PublisherSubscribers ⊓ (≥ 1 agent) ⊓ ∃theme.{urn:doi.10.1032/…} ⊓ (≤ 1 theme) Enabling interoperable and rights-aware DRM using the Semantic Web – © Roberto García 2007

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Implementation Scenario Pattern ⊑ Copy Pattern ≡ ∀pointInTime.≥2006-01-01, ≤ 2006-06-30 ⊓ ∃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

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

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

Implementation Scenario Pattern’ ⊑ Copy Pattern’ ≡ ∀pointInTime.≥2006-01-01, ≤ 2006-06-30 ⊓ ∃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

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