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

Outline Introduction Related Work System Design Implementation Future Work Conclusion

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

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

Privacy Goals Location privacy Anonymous connections Confidentiality

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

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

Mist Router Hierarchy Domains Portals Lighthouse Physical spaces Leaves Lighthouse Representative

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

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

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

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

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

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

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