Safety in Numbers: Crowds

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Safety in Numbers Crowds

• By Bao-Hoi Nguyen
• CS265 Spring 2003

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Surfing the Web

• Cookies
• ? How it works, Profiling
• ? Abacus Direct for 1.7B
• ? Edit-gtPreferences-gtPrivacy
  Security (Netscape) Tools-gtInternet
  Options, then Security Privacy tabs
• Anonymizer
• ? http/www.anonymizer.com8080/www.google.com
  ? Disadvantages TTP, Path btw user and
  anonymizer

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Crowds

• Lost in a Crowd
• Like distributed, linked, and encrypted
  Anonymizer
• Jondo (John Doe)
• Biased coin pf

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Security

• Local Eavesdropper
• ? Protects Server not Client
• End Server
• ? Protects Client
• Collaborating Jondos
• ? Probable Innocence
• ? Timing Attacks

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Theorem of Probable Innocence
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Blender

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