Brian Matthews, DeFINE, Pisa 26/11/02

Trust and the Semantic Web

Brian Matthews,Business & Information Technology Dept, CLRC

b.m.matthews@rl.ac.uk

Brian Matthews, DeFINE, Pisa 26/11/02

Who are we?

• Multidisciplinary Science Laboratory• Information Science & Engineering, Business &

Information Technology Department – Advanced development of Business Information Systems– Research programme in information technology and

distributed systems– Metadata, Trust, Grids, Workflow, Risk Analysis, Ambients

….

• Deputy Manager, W3C Office for the UK and Ireland

Brian Matthews, DeFINE, Pisa 26/11/02

Trust

• Working Definition:Trust of a party A in a party B for a service X is the measurable

belief of A that B will behave dependably for a specified period within a specified context

• A property of intelligent agents• A measure of the Dependability of others (including

self)– can be used to determine behaviour

• Can be influenced by the – Recommendations of others (trust propagation)– Behaviour over time of other agents (experience)– The environment (regulatory, legal, benevolence etc).

Brian Matthews, DeFINE, Pisa 26/11/02

iTrust

• FP5 WG• Looking at all aspects of Trust in open distributed

systems– Policy management– Contract management– Risk Management– Links to security, dependability,privacy, ratings etc.

• Multidisciplinary– Computer science– Lawyers– Psychology– Philosophers– Management consultancy

Brian Matthews, DeFINE, Pisa 26/11/02

• Establishing that the interactions between actors on the Web are trustworthy– Security: access control, authentication and authorisation and policies– Reliability and dependability– Quality ratings– Personalisation: Privacy, confidentiality, user preferences, accessibility – IPR

• Dynamic virtual organisations over Trusted Web Services– Transferring trust from third parties– Establishing service-level agreements which can be relied upon

• Establishing trust between agents that have no prior knowledge of each other

Could prevent the growth of future wide area distributed systems

Trust on the Web

Brian Matthews, DeFINE, Pisa 26/11/02

Semantic Web:Add Meaning to Resources

Brian Matthews, DeFINE, Pisa 26/11/02

A Layered Architecture

Brian Matthews, DeFINE, Pisa 26/11/02

Semantic Web – current status

• The Semantic Web has been around several years:– Base technologies well-established– Gone through several iterations– Lots of academic interest– Convincing applications are still missing

• However, many demonstrators and interesting applications.– CC/PP, P3P, PICS – applications of great significance to the

trust domain.– Need to demonstrate the benefit of a common framework.

Brian Matthews, DeFINE, Pisa 26/11/02

SWAD-Europe

• Semantic Web Advanced Development in Europe• Purpose is to encourage the use of Semantic Web

tools and techniques now:– By an outreach programme– By developing practical demonstrators– By providing tools and standards

• Many application and demonstration areas– Annotations, querying, scalability, knowledge management,

accessibility, web service integration– Developing tools and techniques for representing and

processing Trust relationships in the Semantic Web.

• Partners:– Univ. of Bristol, W3C-INRIA, CCLRC, HP Labs, Stilo

Brian Matthews, DeFINE, Pisa 26/11/02

CLRC in SWAD-Europe

• Three major areas– Developing XML Schemas from the Semantic Web– Developing tools and techniques for representing thesauri in

the Semantic Web• Especially Multilingual Thesauri

– Developing tools and techniques for representing and processing Trust relationships in the Semantic Web.

Brian Matthews, DeFINE, Pisa 26/11/02

Trust Policies and Statements in RDF

• Express policy in RDF

• Present a trust statement to the Policy in RDF

• Proof satisfaction of one to other

• Problems: e.g. representing free variables.

Edit_forms hasPolicy FRSPolicy Policytype

positive

subject Liztype

Employee

Project Manager

jobtitletarget

type

PolicyStatement

/Finance/FrSWeb/Lookup

action

Bag

_1load

_2display

_3fill

_4submit

type

Brian Matthews, DeFINE, Pisa 26/11/02

Architecture

Trust enabled web gateway

resource

Policy store

TrustBase

Trust reasoning

engineAccessing

agent

Recommending agent

RDF Statements

Brian Matthews, DeFINE, Pisa 26/11/02

Trust, Ontologies and Proof

• Use Web Ontologies work to: – Provide web accessible description of trust properties and

policy frameworks– Add domain ontologies to customise to applications – role

based trust management– Proof to demonstrate satisfaction of policy

• Initial Case study:– Frank Dale: Oxford Brookes Univ. MSc student – RDF formats for Access Control policies and – Added domain ontologies for role based access control.– Using XSLT to prove satisfaction of policies.

Brian Matthews, DeFINE, Pisa 26/11/02

What we want to do?

• Take a look at the existing methods related to trust on the Web – Those already in Semantic Web: PICS, P3P, CC/PP– Other Web trust initiatives: XSig, XEncrypt, XACML, SAML,

• Develop usage scenarios of trust on the Web• Develop a Framework for Trust Modelling within the Semantic

Web.– Ontologies for trust statements– Web based trust management– For trust policies

• Develop and implement a Web based architecture for trust usage.• Develop tools for processing RDF statements against policies. • Relate general trust values across all the applications

– A general trust framework for the Semantic Web