A Distributed Context-Aware Trust Management Architecture

1. A Distributed Context-AwareTrust Management Architecture Architecture and Services of Network Applications (ASNA) Group Ricardo Neisse – R.Neisse@ewi.utwente.nl

2. Outline • Introduction • Problem statement • Related Work • Goal Statement • Approach • Q&A Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

3. Trust in Context-Awareness Is the service provider following my privacy policies? Is the identity provider trustworthy? Identity provider Trust relationships Verify identity Authenticate Trust relationships Is the context-source providing my correct context-information? Access Service Provider Get user context info Context source Is the context source providing the correct user location? Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

4. Problem Statement • Security challenges in context-aware systems: • Context is privacy sensitive data • Dynamic management of trust relationships • Security opportunities: • Context information can be used for dynamic access control • … but for this you need trust in the context information Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

5. Position of this work – Trust Aspects • “Trust is not defined and therefore means whatever the subscriber desires most” • “Trust should be used for a particular purpose”or policy • “Trust is that thing you lose if the cryptography is broken” • Social • How do users perceive trust? • Information • What are the trust concepts/semantics? • Technical • How secure are the encryption keys? Q&A Introduction Problem Related Work Goal Statement Approach ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

6. Related Work • Available trust solutions do not fit: • Trustworthiness of identities, privacy policies and context information • Centralized solutions versus dynamic ad-hoc characteristics of context-awareness • Trust is no integrated with policy languages: • SAML, P3P, EPAL, XACML Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

7. Goal Statements • Define a trust model for context-awareness • Scope: identity, privacy and context trustworthiness • Integrate trust as a parameter in security policies • Design a distributed context-aware trust management architecture: • The role of trust in context-aware services • The role of context-information in trust management • Implement a prototype and make field tests in the scope of the AWARENESS project Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

8. Approach (1 of 3) Define a trust model for context-awareness based on available trust and policy solutions: • E.g. Sultan trust model, SAML and P3P Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

9. Trust Model A trusts B for: • Privacy enforcement (P3P) • Indentity provisioning (SAML) • Context provisioning (?) Distrust Trust High Medium Low Low Medium High 0 100 -100 Ignorance value A B Trust degree Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

10. Context Provisioning Trustworthiness Access Service Provider • Trust relationships • Honesty • Reliability • Competence • Arbitrary Get user context info What is resulting trust here? Context source Context source (reasoner) Sensor (80% accuracy) Context source Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

11. Approach (2 of 3) • Trust values should support security policy decisions • Extend policy languages to include trust as a parameter • Trust will be integrated in: • Access control (XACML) • Privacy decisions (EPAL) Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

12. Approach (3 of 3) • Dynamic trust management: • Bootstrapping protocol • Recommendations/reputation: user experience • Low user interaction • Use the concept of management domains to define context-aware trust domains Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

13. Context-Aware Trust Domains • “Domains are means of grouping objects to which a common management policy applies” • Define context aware trust domains and group objects/entities based on context information and trust values • E.g.: • Home domain (trust = high) • Work domain (trust = medium) Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

14. Domains Examples Trust Personal devices Work Policies Context-Aware Trust Domains Context Finance Unknown domain Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl

15. Thanks for your attention! Contact information: Ricardo Neisse - R.Neisse@ewi.utwente.nl http://www.cs.utwente.nl/~neisser Introduction Problem Related Work Goal Statement Approach Q&A ASNA PhD day | Ricardo Neisse - r.neisse@ewi.utwente.nl