Game Theoretic Model of Censorship Resistance

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Game Theoretic Model of Censorship Resistance

• Andrei Serjantov
• University of Cambridge
• Computer Laboratory

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Scenario

• P2P censorship resistant network
• Traditional model secure or insecure
• Does not explain the fact that holiday photos are
  not censored
• Hence, build an economic model Attacker derives
  utility from censoring, publisher derives utility
  from the fact that his document is available
• The conflict between the publisher and the
  cesnsor

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Model

• Network of size n
• Publisher publishes to number of nodes d, at a
  cost c(d)
• Attacker attacks x nodes, at a cost c(x)
• If no copies are available, attacker get U
• If one or more copies is available, publisher
  gets U

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Results

• If attackers cost is linear, no Nash Equilibria
  in pure strategies.
• If the cost is c(x) xa , then there are Nash
  equilibria at dlta
• Meaning publisher publishes to some nodes, some
  nodes get attacked.
• This challenges the traditional model of insecure