1. Routing Through the Mist: Privacy Preserving Communication in Ubiquitous Computing Environments
Jalal Al-Muhtadi, Roy Campbell, Apu Kapadia, M. Dennis Mickunas, Seung Yi
University of Illinois at Urbana-Champaign
Presented by: Wayland Ni

2. Outline Introduction Related Work System Design Implementation
Future Work
Conclusion

3. Problem Ubiquitous computing prevalent User privacy threatened
Proliferation of embedded devices, sensors, etc…
User privacy threatened
Physical locations compromised
Eavesdroppers

4. Solution Privacy protocol Overlay network Gaia
Communicate freely while preserving privacy
Overlay network
Mist Router hierarchy
Handle-based routing
Gaia

5. Privacy Goals
Location privacy
Anonymous connections
Confidentiality

6. Related Work Lesson User anonymity Anonymous communication
Consider privacy from beginning
User anonymity
Anonymizer
SafeWeb
Anonymous communication
Crowds
Lack authentication
Cricket

7. System Design Overview
Router hierarchy
Mist Circuits
Locating users
Communication setup
Security

8. Mist Router Hierarchy Domains Portals Lighthouse Physical spaces
Leaves
Lighthouse
Representative

9. User Registration Mobile device, portal Lighthouse designation
Tradeoff: privacy vs. performance
Migration

10. Mist Circuits Hop-to-hop, handle-based routing Public-key encryption
Virtual circuit built upon registration
Router, certificate pair
Packet format
Message payload

11. Mist Circuits (cont.) Presence Table Mist Routing Table
Portals
Mist Routing Table
Intermediate routers
User Binding Table
Lighthouses
Failures

12. Locating Users Register and lookup <user, lighthouse> pairs
Lightweight Directory Access Protocol
Register attributes and distinguished names
Enables user lookups
Security
Signed special tokens

13. Communication Setup Between lighthouses
Asymmetric key encryption to exchange handles
Mist Communication Binding
src_handle, dest_handle
Send handles back to users

14. Implementation Mist incorporated into Gaia OS
Overlay network over TCP/IP
Java instant messaging application

15. Future Work Optimize communication Lowest common ancestor lighthouse
Get rid of extra “hops”
Lowest common ancestor lighthouse