1. 07/05/2003Brian Matthews 1 Trust Management and the Semantic Web Brian Matthews

2. 07/05/2003Brian Matthews 2 Council for Central Laboratory of the Research Councils 1700 staff - supporting 12000 scientists and engineers from universities and industry Based at 3 sites: –Daresbury Laboratory –Rutherford Appleton Laboratory –Chilbolton Observatory A Multidisciplinary Laboratory CCLRC

3. 07/05/2003Brian Matthews 3 A Multidisciplinary Laboratory Spallation Neutron and Muon Source (ISIS) Synchrotron Radiation Source (SRS) Central Laser Facility Microstructures Space Science and Technology Molecular Spectroscopy Earth Observation Atmospheric Science Computational Science Energy Research Particle Physics Radio Communications Surfaces Transforms and Interfaces I am head of the Information Science and Engineering Group within the Business and Information Technology Department. Advanced Information Systems development R&D in IT

4. 07/05/2003Brian Matthews 4 Why are we interested in Trust? The emerging information and data GRID  e-Science.  e-Science. Meta-data and formal resource description play a fundamental role in the effective co-ordination and delivery of resources to enable science. This further requires the assurance of security modelling across a diverse user base.  e-Government.  e-Government. The current initiative to provide open access to government information uses models of information; for this to be further advanced, more sophisticated models need to be developed.  Semantic Web.  Semantic Web. This initiative from the World Wide Web Consortium recognises that automated web services require information modelling and the machine-mediated analysis of those models to be communicated between agents.  Trusted e-Services.  Trusted e-Services. Consumer confidence is recognised as the key barrier to the predicted growth in e-Business. This requires the trusted transmission of information on products, services, and service provision, as well as information on the agents involved in transactions.  Ambient Computing.  Ambient Computing. The predicted emergence of computing devices distributed throughout the environment requires the modelling, transmission and analysis of information on the environment, the agents involved, and the service required, again within a framework of trust

5. 07/05/2003Brian Matthews 5 Building Trust into e-Services: Why? e- Services are now central for European business and in daily life Marked expansion in: Electronic services based on the Internet, Web and mobile networks However, there is still major concern about the trustworthiness of e- Services: "While internet penetration is growing rapidly, all the evidence shows that consumer confidence in the e-commerce medium itself and in cross-border transactions remains low. E-commerce, therefore, is an insignificant part of final consumption within the European Union – significantly below 1% of total retail sales." [David Byrne, European Commissioner for Health and Consumer Protection] managed efficiently “Despite the presence of effective base technologies, there remains a need for further innovation before trust can be managed efficiently at the service level. ” Patricia Hewitt - UK minister for e-commerce

6. 07/05/2003Brian Matthews 6 Building Trust into e-Services: Why? For e-services to achieve the same levels of acceptance as their conventional counterpart trust management has to become an intrinsic part of e-service provision. managed efficiently “Despite the presence of effective base technologies, there remains a need for further innovation before trust can be managed efficiently at the service level. ” Patricia Hewitt - UK minister for e-commerce

7. 07/05/2003Brian Matthews 7 Example 1: e-Services vendor Ford offers £10000 price http://www.rustycars.com buyer card number 935783468 limit £20000 guarantees Bank Which rates bargain value Broker Usage Privacy

8. 07/05/2003Brian Matthews 8 Example 2: Virtual Organisations Transient Virtual organisations. Need to be mediated via policies, on the fly SLAs, and Trust valuations –See Trustcom An engineer within organisation A wants to perform an analysis on a material. By accessing a data portal at site B, she discovers a suitable data set held by a data archive C. The analytical tools are provided at university D within her Virtual Organisation. She initiates the analysis by passing the reference to the data set from B to D, which is then accessed by the analysis tools. D then determines that it does not have enough computational resource available, and determines that a computer is available at different institution E and delegates part of the job there. Finally, D completes the job and return the results to A. D also caches the results of the analysis locally and registers the fact that the precomputed results are available with the portal B and the data provider C. However, the analysis has taken several hours, so the engineer has established a user proxy agent to represent her, collect the results, make payments as appropriate and close down the collaboration. A E D C B

9. 07/05/2003Brian Matthews 9 Specialised standards Secure MIME (S/MIME) Open PGP (OpenPGP) XML digital signatures (XMLDSIG) XML encryption (XMLENC) X.509 Public Key Certificates Internet X.509 Public Key Infrastructure (PKIX) XML Key Management Services Kerberos ticket issuing systems Security Assertions Markup Language (SAML) Extensible Access Control Markup Language (XACML) Web Services Security (WSS) Platform for Internet Content Selection (PICS) Platform for Privacy Preferences (P3P) Many existing approaches to managing aspects. Inflexible, do not evolve over time, not context or person sensitive Reliability criteria poorly covered Looking for a common model

10. 07/05/2003Brian Matthews 10 Problem Characterisation Across open distributed systems (Web, Grid) Establish relationships with agents with no prior knowledge. Accessing semi-closed resources. Context based decision making –What is being done –Who they are –Experience –Context Need to be underpinned by Trust TRUST +: Ensure that Good things do happen (reliability, QoS,) -: Ensure that Bad things don’t happen (security, fraud, privacy).

11. 07/05/2003Brian Matthews 11 A Working Definition of Trust This period may be in the past (history), the duration of the service (from now and until end of service), future (a scheduled or forecasted critical time slot), or always Dependability is deliberately understood broadly to include security, safety, reliability, timeliness, maintainability The measurement may be absolute (e.g. probability) or relative (e.g. dense order) Trust is relative to a specific service. Different trust relationships appear in different business contexts Trust of a party A to a party B for a service X is the measurable belief of A in that B behaves dependably for a specified period within a specified context (in relation to service X )

12. 07/05/2003Brian Matthews 12 A Working Definition of Distrust Distrust of a party A to a party B for a service X is A ’s measurable belief in that B behaves non-dependably for a specified period within a specified context (in relation to service X ) We need distrust in order: revoke previously agreed trust when entities are trusted, by default, to capture “being blacklisted’’ for a class of potential business transactions. etc..

13. 07/05/2003Brian Matthews 13 Building Trust into e-Services: How? Incorporate trust elements in e-service technology  analyse trust requirements for e-services  model trust in the development of e-services subject of the next section of this talk Thanks to Theo Dimitrakos  integrate trust management in the deployment of e-services Especially, how do we integrate trust management into established open distributed systems WWW, Grid This is the subject of the rest of this talk Ideas and work in progress

14. 07/05/2003Brian Matthews 14 A Working Model of Trust Structural Properties of Trust Relationships –Its measurement is based on evidence, experience and perception. Sally Rob John John trusts Sally to keep his savings more than he trusts Rob Trust is a measurable belief Trust exists and evolves in time –Trust relationships expire. –The level of trust may change over time John trusted Sally to ride a bike 30 years ago. He does not trust her any more. TIME 30 years

15. 07/05/2003Brian Matthews 15 Trust is relativised to a service Trust between collectives does not necessarily distribute to trust between their members John trust her tutees to do well in their group project but he does not trust Mary to do well in her part (John thinks Mary does most of the work) Mary trusts Sally to baby-sit but not to drive her car. A Working Model of Trust Structural Properties of Trust Relationships

16. 07/05/2003Brian Matthews 16 A Working Model of Trust Structural Properties of Trust Relationships Measuring self-trust facilitates delegation Measuring self-trust facilitates delegation Trust is reflexive - yet trust to oneself is measurable Trust is not necessarily transitive Mary trusts her lawyer to win her case in court more than she trust herself to do so – John trust Bob to be his barber – Bob trusts Nick to be his barber – John does not trust Nick to be his barber (John has had bad experience with Nick and he is able to chose between Bob and Nick -- Bob cannot cut his own hair )

17. 07/05/2003Brian Matthews 17 A Working Model of Trust Transference of Trust Guarantor offers a formal promise or assurance, that all obligations of the parties she guarantees for will be fulfilled in the context of a transaction and will be of a specified quality and durability. Intermediate intervenes between other parties in a business transaction and mediates so that they establish a business relationship with or without their knowledge. Adviser offers recommendations about the credibility of another party. Trust is (unintentionally) transitively transferred along certain mediating parties. Dimitrakos IFIP I3E 2001

18. 07/05/2003Brian Matthews 18 A Working Model of Trust Transference of Trust: A Working Model of Trust Transference of Trust: Guarantors All parties involved have to exhibit sufficient trust in each other or in a guarantor in order to be engaged in a business transaction. Trust established through a guarantor is not necessarily (directly) transferable. AB G BC G  AC G Indirect ways to transfer trust via hierarchies of guarantors may be feasible. AB G BC G  AC G’;G G’

19. 07/05/2003Brian Matthews 19 A Working Model of Trust Transference of Trust: A Working Model of Trust Transference of Trust: Intermediates Intermediate is a party that intervenes between other parties in a business transaction and mediates so that they establish a business relationship with or without their knowledge. – Transparent: an intermediate who identifies the parties she is mediating between to each other. – Translucent: an intermediate who identifies the existence of the parties she is mediating between to each other but not their identity. – Opaque: an intermediate who hides the existence of the parties she is mediating between from each other. –Proxy: an intermediate who is authorised to act as a substitute of another entity.

20. 07/05/2003Brian Matthews 20 A Working Model of Trust Transference of Trust: A Working Model of Trust Transference of Trust: Intermediates (Dis)trust is not transferred along an opaque intermediary Mary trusts John’s cooking - she likes the meals John prepares for her. Mary trusts John’s cooking - she likes the meals John prepares for her. John buys off the self precooked meals but he doesn’t tell Mary. John buys off the self precooked meals but he doesn’t tell Mary. Trust is transferred along transparent intermediaries – distrust is not. John sends his products via Royal Mail. John sends his products via Royal Mail. Mary decides to purchase John’s products. She expects the products to be delivered as agreed. Mary decides to purchase John’s products. She expects the products to be delivered as agreed. Mary places her trust on the Royal Mail delivery service. Mary places her trust on the Royal Mail delivery service.

21. 07/05/2003Brian Matthews 21 A Working Model of Trust Transference of Trust: A Working Model of Trust Transference of Trust: Intermediates (Dis)trust in a subcontractor of a transparent intermediary is transferred to (dis)trust in the intermediary. Trust is transferred anonymously along translucent intermediaries – distrust is not. Mary considers changing health insurance because she does not trust the private hospital she is being referred to. Mary considers changing health insurance because she does not trust the private hospital she is being referred to. John sends his products via courier. John sends his products via courier. Mary decides to purchase John’s products. She expects the products to be delivered as agreed. Mary decides to purchase John’s products. She expects the products to be delivered as agreed. Mary places her trust on the John’s choice of delivery service. Mary places her trust on the John’s choice of delivery service.

22. 07/05/2003Brian Matthews 22 A Working Model of Trust Transference of Trust: A Working Model of Trust Transference of Trust: Advisors Trust in an advisor is transferred to the recommended party - distrust is not. – The more A trusts T the more she relies on her recommendation. Distrust in a recommended party is transferred to the advisor – trust is not. – A’s distrust in a party B recommended by T for a service X prompts A to question T’s competence as an advisor for X. Advisors distinguish between recommendations based on “first hand” and “second hand” evidence. In the latter case they ought to identify their sources. – If T 1 and T 2 pass to A advise by T as their own observations then T gains an unfair advantage in influencing A.  

23. 07/05/2003Brian Matthews 23 A Working Model of Trust Transference of Trust The opposite initial values affect each other and the final decision depends on the resulting balance between trust and distrust in each party, and the tendencies of the trustor. This would not have been possible, had trust been viewed as a binary operator, because transitivity of trust would have lead to inconsistency Trust and distrust are allowed to be transferred in opposite directions This does not necessarily result in a conflict Distrust propagates through trust. Distrust obstructs the propagation of trust. If A distrusts an intermediary T for a service X then A will ignore T's mediation to the extent of the distrust.

24. 07/05/2003Brian Matthews 24 Formal Presentation of Trust Subjective logic ( Jøsang) Addresses the problems of forming a measurable belief about the truth or falsity of an atomic proposition denoting a state, event or identifying an agent, in the presence of uncertainty. Integrates classical logic and a theory of subjective probabilities based on an extension of the Dempster-Shafer theory of evidence. An opinion is a triple where:  b measures belief, represented as the subjective probability that the proposition is true;  d measures disbelief, represented as the subjective probability that the proposition is false;  u measures uncertainty, represented as the subjective probability that the proposition is either true or false;  b+d+u=1 A strong correlation between this opinion model and the probability density functions associated with the beta distribution ensures that opinions can be deterministically established if all available evidence can be analysed statistically. An opinion is a triple where:  b measures belief, represented as the subjective probability that the proposition is true;  d measures disbelief, represented as the subjective probability that the proposition is false;  u measures uncertainty, represented as the subjective probability that the proposition is either true or false;  b+d+u=1 A strong correlation between this opinion model and the probability density functions associated with the beta distribution ensures that opinions can be deterministically established if all available evidence can be analysed statistically.

25. 07/05/2003Brian Matthews 25 Formal Presentation of Trust Subjective logic ( Jøsang) Daskalopulu, Dimitrakos, Maibaum 2001

26. 07/05/2003Brian Matthews 26 Analyse Trust: Trust Management It is the total process of identifying, controlling and minimising the impact of deception and failure in trust. It analyses threats and trust inclinations while supporting the formation of dependable intentions and controlling dependable behaviour. Trust management subsumes and relies on risk analysis and risk management.BehaviourIntentions Inclinations Trust Management aims to maximise trust while minimising risk.

27. 07/05/2003Brian Matthews 27 Analyse Trust: Overview Intentions Intentions capture the extent to which a party is willing to depend on other parties (including themselves) within a specified context and in relation to a specific service. Inclinations Inclinations refer to the tendencies of an agent towards a particular aspect, state, character or action. Behaviour Behaviour captures the extent to which a party behaves dependably including the act and effects of trusting. It implies acceptance or treatment of risks and their impact Management Management: controls the conception, evaluation,and endorsement of trusting intentions DependableBehaviourDependableBehaviour Dependable DependableIntentions Intentions TrustInclinationsTrustInclinations Dimitrakos IFIP I3E 2001 Dimitrakos & Bicarregui ICECR-4, 2001

28. 07/05/2003Brian Matthews 28 Analyse Trust: OverviewDependableBehaviourDependableBehaviour Dependable DependableIntentions Intentions TrustInclinationsTrustInclinations Situational Trust Trusting Beliefs System Trust Resource Access Trust Service Provision Trust Certification Trust Reputation Trust Delegation Trust Underwriting Trust Infrastructure Trust Enactment Trust Enablement Trust Regulatory Trust Reputation Trust Competence Honesty Predictability Benevolence Dispositional Trust Dispositional Trust Security Risk Analysis Safety Risk Analysis Reliability Risk Analysis Timeliness Risk Analysis Maintainability Risk Analysis Dimitrakos IFIP I3E 2001 Dimitrakos & Bicarregui ICECR-4, 2001

29. 07/05/2003Brian Matthews 29 Analyse Trust: Trust Management Influences Exposes To Owners RISK Assets Value Identify To TRUSTMETRICS TRUSTEDENTITIES UTILITYCOST Expect USED BYINVOLVE MUST BE LESS THAN TO PERMIT About Trusting Beliefs Make FORMS Have Influences TrustingBehaviour SituationalDecision to Trust to Trust Trusting Intentions BeliefFormationProcess Dispositional Trust System Trust Lead To Influences

30. 07/05/2003Brian Matthews 30 A Working Model of Trust: Highlights Analysis –Assess Dependability –Assess Risk –Measure Divergence from prescribed behaviour –Assess recommendations Analysis –Assess Dependability –Assess Risk –Measure Divergence from prescribed behaviour –Assess recommendations Modelling –Intentional modelling –Policy specification –Business Process Modelling –System Modelling Modelling –Intentional modelling –Policy specification –Business Process Modelling –System Modelling Logic –Belief Formation –Subjective Reasoning –Legal & Deontic Reasoning –Conflict Resolution Logic –Belief Formation –Subjective Reasoning –Legal & Deontic Reasoning –Conflict Resolution Management –Policy Oriented Management –Contract Management –Risk Management Management –Policy Oriented Management –Contract Management –Risk Management TRUST MODEL What about the deployment?

31. 07/05/2003Brian Matthews 31 Supporting Trust: Web Services? Increasingly popular standards-based framework for accessing network applications WSDL, SOAP, WS-Inspection, UDDI etc However for Trust we need to be able to –Specify what actors want to do –Specify in what contexts actions take place –Specify recommendations and trust valuations about resources –Need to share vocabularies and agree common meaning of terms –Capture Experience –Provide reasoning about trust statements The Semantic Web offers a set of tools which can support the implementation of Trust

32. 07/05/2003Brian Matthews 32 The Semantic Web The Web is chaotic - why are resources are linked? –Imagine a library where all the books have the same text on the cover, and the only catalogues are compiled by photocopying the books, cutting up the copies, and arranging the words in the order of frequency. –Johan Hjelm Thus Google is great at returning all the pages on the web that mention "Tim Berners-Lee“ – –But what about returning those pages written by Tim Berners-Lee? The Semantic Web adds well-defined meaning to describe the Web (Metadata).

33. 07/05/2003Brian Matthews 33 Semantic Web: Add Meaning to Resources

34. 07/05/2003Brian Matthews 34 Semantic Web: Layered Architecture “The Web of Trust”

35. 07/05/2003Brian Matthews 35 Web of Trust? Trusted statements through proofs over signed statements and rules. - This is not really what I mean by trusted!

36. 07/05/2003Brian Matthews 36 Resource Description Framework (RDF) Knowledge representation Designed to make statements about web resources. Statements in form of triples –(Subject, Predicate, object) For metadata descriptions Has an XML Syntax http://www.cms.brookes.ac.uk/modules/P08775/RDFMS.xml http://www.bitd.clrc.ac.uk/People/B.M.Matthews http://purl.org/dc/elements/1.1/creator Brian Matthewsb.m.matthews@rl.ac.uk http://www.examples.org/terms/email http://www.examples.org/terms/name

37. 07/05/2003Brian Matthews 37 RDF Schemas Allow simple Ontologies to be constructed –Define new classes of concepts –Define new properties –Define sub-classes and sub-properties –Define source and target of properties.

38. 07/05/2003Brian Matthews 38 RDF(S) Example

39. 07/05/2003Brian Matthews 39 Allows user to add comments to other web sites And make comments on the comments Uses RDF Metadata Annotation: a Semantic Web Application

40. 07/05/2003Brian Matthews 40 Semantic Web: Current Status The Semantic Web has been around several years: –Base technologies well-established –Gone through several iterations –Lots of academic interest –Industrial 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.

41. 07/05/2003Brian Matthews 41 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.

42. 07/05/2003Brian Matthews 42 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 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 –prevent the growth of future wide area distributed systems Trust on the Web

43. 07/05/2003Brian Matthews 43 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 Partners: –Univ. of Bristol, W3C-INRIA, CCLRC, HP Labs, Stilo

44. 07/05/2003Brian Matthews 44 SWAD-Europe: WPs Thesuari Queries Trust Semantic Portals SW + WS Semantic Blogging XML + RDF Accessibility Scaleability Annotations Databases Visualisation

45. 07/05/2003Brian Matthews 45 What we want to do? Survey of Web and trust methods –Those already in Semantic Web: PICS, P3P, CC/PP –Other Web trust initiatives: XSig, XEncrypt, XACML, SAML, –Other distributed trust work: e.g. Ponder, trust evaluation. Usage scenarios of trust on the Web –E-Commerce, access control, … Framework for Trust within the Semantic Web. –Ontologies for trust statements –Applying trust policies Develop tools for processing RDF statements against policies. Relate general trust values across all the applications –A general trust framework for the Semantic Web

46. 07/05/2003Brian Matthews 46 Towards a Framework for Trust using the Semantic Web A representation of trust statements in RDF E.g. “A has trust in B to do X in context Y in time period (T1, T2) to value 0.8” A T2 X 0.8 B T2 trusts trustee value action Y context end begin

47. 07/05/2003Brian Matthews 47 Towards a Framework for Trust using the Semantic Web Or use Classes to represent general rules E.g. “A has trust in members of Class C to do X in context Y in time period (T1, T2) to value 0.8” With WebOnt gives the possibility of more complex rules for trust valuations. A T2 X 0.8 C T2 trusts trusteeClass value action Y context end begin

48. 07/05/2003Brian Matthews 48 Propagation of Trust through Semantic Networks The Semantic Web provides a semantically rich network of resources Add trust valuations to links (from 1-9) Calculated the propagation of trust via the rules in the above framework FOAF is a candidate for adding trust values to links between people Golbeck, Hendler and Parsla 2002 A B 6 8 9 2 8 9 3 6 6 7 6 5

49. 07/05/2003Brian Matthews 49 Platform for Internet Content Selection (PICS) - quite an early Recommendation from the W3C (October 96). Labels, Filters, Rating – a set of categories on a rating system PICS Rules - Defining a filtering policy Ratings Services

50. 07/05/2003Brian Matthews 50 PICS and Trust One of the aims of the RDF effort was to provide a generalised way of doing rating. –Now a proposed RDF format and under reconsideration PICS is about Third parties providing additional properties about resources –its ideal for trust! –Use RDF/PICS vocabulary to define recommendations. –PICS services become recommendations services Generalise this method to provide a trust recommendation service <rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf- syntax-ns#" xmlns:p="http://www.w3.org/TR/WD-pics2.0#" xmlns:gcf="http://www.gcf.org/v2.5#" about=""> John Doe 1995.12.31T23:59-0000 <rdf:Description about="http://w3.org/PICS/Overview.html"> "1995.12.31T23:59-0000" 0.5 0 1 <rdf:Description about="http://w3.org/PICS/Underview.html"> Jane Doe 2 1

51. 07/05/2003Brian Matthews 51 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. RuleML etc Edit_form s hasPolic y FRSPolic y Policy type positiv e subject Liz type Employee Project Manager jobtitle target type PolicyStatemen t /Finance/FrS Web/Lookup action Bag _1 load _2 displa y _3 fill _4 submi t type

52. 07/05/2003Brian Matthews 52 Trusted Web Architecture Trust enabled web gateway resources Policy store TrustBase Trust reasoning engine Accessing agent Recommending agent RDF trust Statements Behaviour Intentions Inclinations risk Trust Management System Intranet Internet RDF Store (Jena) PICS RDF Net API Rules (RuleML, CWM)

53. 07/05/2003Brian Matthews 53 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.

54. 07/05/2003Brian Matthews 54 Ontology enabled role-based access control Frank Arild Dale’s work (MSc Oxford Brookes) OBU course3 Access control statements in RDF Using vocabulary from domain ontology course3 Wheatley Computer Science Statements about individuals in domain ontology RDF reasoning tool to determine access

55. 07/05/2003Brian Matthews 55 Ontology-based access control

56. 07/05/2003Brian Matthews 56 So to do? Establish the vocabulary of Trust in the Semantic Web –Through the trust propagation framework –Rethink PICS Implement the architecture! Trials! –E-commerce –Virtual Organisations How trust affects those associated techs –Security, privacy, QoS etc Policy and Contract management

57. 07/05/2003Brian Matthews 57 The Home Network Manager Graham’s work

58. 07/05/2003Brian Matthews 58 Some observations Trust valuations on the Web would be an extremely valuable commodity. –Part of a company’s commercial property –Would they want to reveal it? Trust on the Web could become a tradable commodity –“trust-rating agencies” (like credit rating agencies Legal implications? –Would you get sued for down-rating? –Need to provide reasons (“Proof” in Web of Trust) “Accurate” valuation of Goodwill –Your goodwill asset is everybody else’s trust in you! –Business in collecting such information!

59. 07/05/2003Brian Matthews 59 Will Trust work? Will automatic trust management be used as a practical means to enable the use of e- services? NO: –Too conceptual an approach –Relies on humans –Open to abuse –People won’t trust the trust mechanism –Rely on traditional security measures and “word of mouth” YES: –There is at least one example where trust works

60. 07/05/2003Brian Matthews 60 Ebay: a success story for trust …the company philosophy remains pretty much the same: trust in human nature. … Fraud is a concern to the company, concedes Donlay [ebay spokesman]. 'But it is not a massive problem. Of the 195 million items listed for auction last year, less than one hundredth of one percent of the transactions ended in some kind of fraud. We are taking every step we can to protect people and make sure their eBay experience is a good one,' he says. Observer, 2 March 2003

61. 07/05/2003Brian Matthews 61 Why does ebay work? Trusts its customers Buyers and sellers accumulate reputation Trust propagation through trusted sources Underpinned by a “guarantor of last resort” and punitive sanction Community Values eBay is a community where we encourage open and honest communication between all of our members. We believe in the following five basic values. We believe people are basically good. We believe everyone has something to contribute. We believe that an honest, open environment can bring out the best in people. We recognise and respect everyone as a unique individual. We encourage you to treat others the way that you want to be treated. eBay is committed to these values. And we believe that our community members should also honour these values -- whether buying, selling, or chatting. We hope these community values will help you better understand the eBay community. We should try to emulate this example across the Web.

62. 07/05/2003Brian Matthews 62 Modelling Trust Future & On-going Work  Formalise and evaluate the proposed role-based model of trust in e- commerce.  Integrate modelling and risk analysis by correlating risks with trust.  how to combine suitable risk analysis methods across different areas of dependability.  Support the transition between trust inclinations, intentions and dependable behaviour.  on how to maximise trust and minimise risk in different e-service scenarios.  bring together belief theory and economic game theory.  To embody trust-based decision making in the policy-based management of decentralised open distributed systems.  enabling the dynamic evaluation of the trust associated with each transaction.  Semantic web as such as platform  To embody trust elements in contract management  legal issues concerning the status of electronic agents in contract formation. To experiment with developing a virtual marketplace from scratch, taking trust issues into account throughout the development lifecycle.

63. 07/05/2003Brian Matthews 63 Modelling Trust: Final Word Effective solutions require interdisciplinary approaches which provide a fertile ground for the application of many tools from cognitive sciences, law and economics in addition to computer science. Effective implementations over open architectures require the effective transmission of context and intention, and the Semantic Web is a strong candidate to provide that infrastructure. The iTRUST European Working Group http://www.bitd.clrc.ac.uk/Activity/iTrust 1st Int. Conf. on Trust Management, Crete, Greece, 28-30 May 2003. http://www.ebusinesscity.org/ 2nd Int. Conf. on Trust Management, Oxford, UK, 29-31 March 2004 SWAD-Europe http://www.w3.org/2001/sw/Europe Semantic Web Trust and Security Resource Guide http://www.wiwiss.fu-berlin.de/suhl/bizer/SWTSGuide/ b.m.matthews@rl.ac.uk