1. Anonymity Cs5090: Advanced Computer Networks, fall 2004 Department of Computer Science Michigan Tech University Byung Choi

2. Anonymity and Population Houghton vs. New York –Murder case: Once in 10 years Once in every two hours Population of computer networks –Houghton in early ages –New York in nowadays Computer networks, everyone’s resource for everyday life –Critical resource for criminals too!

3. Anonymity and Identity Identity required vs. non-required –Many users don’t care! WWW? –Cookies! –(Unwanted,) unwarranted identification Openness of computer networks –Observe-ability at any networking devices

4. Digital Society Electronic Voting! (a best example?) –Identity required by authorities –Anonymity required by users –Deadline required by servers –Confirmation required by users –Secure delivery required by both users and authorities –Anything else?

5. Anonymity for Privacy? Who has communicated with whom? How long? How many bytes? From which location?

6. Easiest Approach Proxy –Single –Cascaded Fixed vs. Dynamic configuration Results? –User identity not known to server –Proxy, trustable? Who runs proxies?

7. Mix Networks Dedicated routers –Run by anonymity service providers –Use layered encryption technique –Users pick a path Results: –User identity known only to the first mix router Improvements: –Use same length of packets –Generate dummy traffic

8. Mixing Application: P2P? Transport: every TCP-able computer? IP: every router? MAC: every networking devices? Physical: Intelligent physical layer?