1. Safety in Numbers: Crowds
By Bao-Hoi Nguyen
CS265 Spring 2003

2. Surfing the Web Cookies Anonymizer  How it works, Profiling
 Abacus Direct for $1.7B
 Edit->Preferences->Privacy & Security (Netscape); Tools->Internet Options, then Security & Privacy tabs
Anonymizer
  Disadvantages: TTP, Path btw user and anonymizer

3. Crowds
Lost in a Crowd
Like distributed, linked, and encrypted Anonymizer
Jondo (“John Doe”)
Biased coin = pf

5. Security Local Eavesdropper End Server Collaborating Jondos
 Protects Server not Client
End Server
 Protects Client
Collaborating Jondos
 Probable Innocence
 Timing Attacks

6. Theorem of Probable Innocence

7. Blender TTP Has all keys, names, passwords, IP address
Distributes messages, keys, warnings
Does not increase vulnerability
Not like Anonymizer
Diffie-Hellman