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RatFish: A File Sharing Protocol Provably Secure against Rational Users (BibTeX)

  author    = {Michael Backes and Oana Ciobotaru and Anton Krohmer},
  title     = {{RatFish: A File Sharing Protocol Provably Secure against Rational Users}},
  booktitle = {Computer Security - ESORICS 2010, 15th European Symposium on Research in Computer Security, Proceedings},
  editor    = {Dimitris Gritzalis and Bart Preneel and Marianthi Theoharidou},
  series    = {Lecture Notes in Computer Science},
  volume    = {6345},
  year      = {2010},
  publisher = {Springer},
  abstract = {The proliferation of P2P computing has recently been propelled by popular applications, most notably file sharing protocols such  as BitTorrent. These protocols provide remarkable efficiency and scalability, as well as adaptivity to dynamic situations. However, none of them is secure against attacks from rational users, i.e., users that misuse the protocol if doing so increases their benefits (e.g., reduces download time  or amount of upload capacity).  We propose a rigorous model of rational file sharing for both seeders and leechers, building upon the concept of rational cryptography. We design a novel file sharing protocol called RatFish, and we formally prove that no rational party has an incentive to deviate from RatFish; i.e., RatFish constitutes a Nash equilibrium. Compared to existing file sharing protocols such as BitTorrent, the tracker in RatFish is assigned additional tasks while the communication overhead of a RatFish client is kept to a minimum. We demonstrate by means of a prototype implementation that RatFish is practical and efficient.}