DogFish: Decentralized Optimistic Game-theoretic FIle SHaring

  • Seny Kamara
  • Alptekin Küpçü
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10892)


Peer-to-peer (p2p) file sharing accounts for the most uplink bandwidth use in the Internet. Therefore, in the past few decades, many solutions tried to come up with better proposals to increase the social welfare of the participants. Social welfare in such systems are categorized generally as average download time or uplink bandwidth utilization. One of the most influential proposals was the BitTorrent. Yet, soonafter studies showed that BitTorrent has several problems that incentivize selfish users to game the system and hence decrease social welfare.

Previous work, unfortunately, did not develop a system that maximizes social welfare in a decentralized manner (without a trusted party getting involved in every exchange), while the proposed strategy and honest piece revelation being the only equilibrium for the rational players. This is what we achieve, by modeling a general class of p2p file sharing systems theoretically, then showing honest piece revelation will help achieve social welfare, and then introducing a new cryptographic primitive, called randomized fair exchange, to instantiate our solution.


Peer-to-peer file sharing Optimistic fair exchange Proof of storage Cryptographic protocol Game theory 



The authors acknowledge the support of TÜBİTAK, the Scientific and Technological Research Council of Turkey, under project number 111E019, as well as European Union COST Action IC1306.


  1. 1.
    Aiyer, A.S., Alvisi, L., Clement, A., Dahlin, M., Martin, J.-P., Porth, C.: Bar fault tolerance for cooperative services. ACM SIGOPS Oper. Syst. Rev. 39(5), 45–58 (2005)CrossRefGoogle Scholar
  2. 2.
    Arteconi, S., Hales, D., Babaoglu, O.: Greedy cheating liars and the fools who believe them. In: Brueckner, S.A., Hassas, S., Jelasity, M., Yamins, D. (eds.) ESOA 2006. LNCS (LNAI), vol. 4335, pp. 161–175. Springer, Heidelberg (2007). Scholar
  3. 3.
    Asokan, N., Shoup, V., Waidner, M.: Optimistic fair exchange of digital signatures. IEEE Sel. Areas Commun. 18, 591–610 (2000)CrossRefGoogle Scholar
  4. 4.
    Ateniese, G., Burns, R., Curtmola, R., Herring, J., Khan, O., Kissner, L., Peterson, Z., Song, D.: Remote data checking using provable data possession. ACM Trans. Inf. Syst. Secur. 14(1), 12:1–12:34 (2011)CrossRefGoogle Scholar
  5. 5.
    Ateniese, G., Kamara, S., Katz, J.: Proofs of storage from homomorphic identification protocols. In: Matsui, M. (ed.) ASIACRYPT 2009. LNCS, vol. 5912, pp. 319–333. Springer, Heidelberg (2009). Scholar
  6. 6.
    Axelrod, R.: Effective choice in the Prisoner’s Dilemma. J. Conflict Resolut. 24(1), 3–25 (1980)CrossRefGoogle Scholar
  7. 7.
    Axelrod, R.: More effective choice in the Prisoner’s Dilemma. J. Conflict Resolut. 24(3), 379–403 (1980)CrossRefGoogle Scholar
  8. 8.
    Backes, M., Ciobotaru, O., Krohmer, A.: RatFish: a file sharing protocol provably secure against rational users. In: Gritzalis, D., Preneel, B., Theoharidou, M. (eds.) ESORICS 2010. LNCS, vol. 6345, pp. 607–625. Springer, Heidelberg (2010). Scholar
  9. 9.
    Barak, B.: Constant-round coin-tossing with a man in the middle or realizing the shared random string model. In: IEEE FOCS (2002)Google Scholar
  10. 10.
    Belenkiy, M., Chase, M., Erway, C., Jannotti, J., Küpçü, A., Lysyanskaya, A., Rachlin, E.: Making P2P accountable without losing privacy. In: ACM WPES (2007)Google Scholar
  11. 11.
    Berciu, R.M.: Designing incentives in P2P systems. Master’s thesis, Baylor University (2013)Google Scholar
  12. 12.
    Blum, M.: Coin flipping by telephone a protocol for solving impossible problems. SIGACT News 15(1), 23–27 (1983). Scholar
  13. 13.
    Brito, I., Meseguer, P.: Distributed stable matching problems. In: van Beek, P. (ed.) CP 2005. LNCS, vol. 3709, pp. 152–166. Springer, Heidelberg (2005). Scholar
  14. 14.
    Brito, I., Meseguer, P.: Distributed stable matching problems with ties and incomplete lists. In: Benhamou, F. (ed.) CP 2006. LNCS, vol. 4204, pp. 675–679. Springer, Heidelberg (2006). Scholar
  15. 15.
    Cash, D., Küpçü, A., Wichs, D.: Dynamic proofs of retrievability via oblivious RAM. J. Cryptol. 30(1), 22–57 (2017)MathSciNetCrossRefGoogle Scholar
  16. 16.
    Chen, K., Shen, H., Sapra, K., Liu, G.: A social network based reputation system for cooperative P2P file sharing. IEEE Trans. Parallel Distrib. Syst. 26(8), 2140–2153 (2015)CrossRefGoogle Scholar
  17. 17.
    Ciccarelli, G., Cigno, R.L.: Collusion in peer-to-peer systems. Comput. Netw. 55(15), 3517–3532 (2011)CrossRefGoogle Scholar
  18. 18.
    Cohen, B.: Incentives build robustness in BitTorrent. In: WEPS (2003)Google Scholar
  19. 19.
    Dodis, Y., Vadhan, S., Wichs, D.: Proofs of retrievability via hardness amplification. In: Reingold, O. (ed.) TCC 2009. LNCS, vol. 5444, pp. 109–127. Springer, Heidelberg (2009). Scholar
  20. 20.
    Ellison, G.: Cooperation in the Prisoner’s Dilemma with anonymous random matching. Rev. Econ. Stud. 61(3), 567–588 (1994)MathSciNetCrossRefGoogle Scholar
  21. 21.
    Erway, C.C., Küpçü, A., Papamanthou, C., Tamassia, R.: Dynamic provable data possession. ACM Trans. Inf. Syst. Secur. 17(4), 15:1–15:29 (2015). Article no. 15CrossRefGoogle Scholar
  22. 22.
    Fader, P.S., Hauser, J.R.: Implicit coalitions in a generalized Prisoner’s Dilemma. J. Conflict Resolut. 32(3), 553–582 (1988)CrossRefGoogle Scholar
  23. 23.
    Fan, B., Chiu, D., Lui, J.: The delicate tradeoffs in BitTorrent-like file sharing protocol design. Technical report, The Chinese University of Hong Kong (2006)Google Scholar
  24. 24.
    Fan, B., Chiu, D., Lui, J.C.: The delicate tradeoffs in BitTorrent-like file sharing protocol design. In: IEEE ICNP (2006)Google Scholar
  25. 25.
    Feldman, M., Lai, K., Stoica, I., Chuang, J.: Robust incentive techniques for peer-to-peer networks. In: ACM EC (2004)Google Scholar
  26. 26.
    Guo, D., Kwok, Y.-K., Jin, X.: Valuation of information and the associated overpayment problem in peer-to-peer systems. Comput. Commun. 80, 59–71 (2016)CrossRefGoogle Scholar
  27. 27.
    Halpern, J.Y.: Beyond Nash equilibrium: solution concepts for the 21st century. In: ACM PODC (2008)Google Scholar
  28. 28.
    Juels, A., Kaliski, B.S.: PORs: proofs of retrievability for large files. In: ACM CCS (2007)Google Scholar
  29. 29.
    Kash, I.A., Friedman, E.J., Halpern, J.Y.: An equilibrium analysis of scrip systems. ACM Trans. Econ. Comput. 3(3), 13:1–13:32 (2015)MathSciNetCrossRefGoogle Scholar
  30. 30.
    Keidar, I., Melamed, R., Orda, A.: Equicast: scalable multicast with selfish users. Comput. Netw. 53(13), 2373–2386 (2009)CrossRefGoogle Scholar
  31. 31.
    Kılınç, H., Küpçü, A.: Optimally efficient multi-party fair exchange and fair secure multi-party computation. In: Nyberg, K. (ed.) CT-RSA 2015. LNCS, vol. 9048, pp. 330–349. Springer, Cham (2015). Scholar
  32. 32.
    Kipnis, A., Patt-Shamir, B.: A note on distributed stable matching. In: IEEE ICDCS (2009)Google Scholar
  33. 33.
    Kumar, R., Ross, K.W.: Peer-assisted file distribution: the minimum distribution time. In: IEEE HOTWEB (2006)Google Scholar
  34. 34.
    Küpçü, A.: Official arbitration with secure cloud storage application. Comput. J. 58(4), 831–852 (2015)CrossRefGoogle Scholar
  35. 35.
    Küpçü, A., Lysyanskaya, A.: Optimistic fair exchange with multiple arbiters. In: Gritzalis, D., Preneel, B., Theoharidou, M. (eds.) ESORICS 2010. LNCS, vol. 6345, pp. 488–507. Springer, Heidelberg (2010). Scholar
  36. 36.
    Küpçü, A., Lysyanskaya, A.: Usable optimistic fair exchange. Comput. Netw. 56, 50–63 (2012)CrossRefGoogle Scholar
  37. 37.
    Levin, D., LaCurts, K., Spring, N., Bhattacharjee, B.: BitTorrent is an auction: analyzing and improving BitTorrent’s incentives. ACM SIGCOMM Comput. Commun. Rev. 38(4), 243–254 (2008)CrossRefGoogle Scholar
  38. 38.
    Levin, D., Sherwood, R., Bhattacharjee, B.: Fair file swarming with fox. In: IPTPS (2006)Google Scholar
  39. 39.
    Lindell, Y.: Parallel coin-tossing and constant-round secure two-party computation. J. Cryptol. 16(3), 143–184 (2003)MathSciNetCrossRefGoogle Scholar
  40. 40.
    Locher, T., Moor, P., Schmid, S., Wattenhofer, R.: Free riding in BitTorrent is cheap. In: HotNets (2006)Google Scholar
  41. 41.
    Luo, J., Xiao, B., Bu, K., Zhou, S.: Understanding and improving piece-related algorithms in the BitTorrent protocol. IEEE Trans. Parallel Distrib. Syst. 24(12), 2526–2537 (2013)CrossRefGoogle Scholar
  42. 42.
    Meng, X., Tsang, P.-S., Lui, K.-S.: Analysis of distribution time of multiple files in a P2P network. Comput. Netw. 57(15), 2900–2915 (2013)CrossRefGoogle Scholar
  43. 43.
    Neyman, A.: Bounded complexity justifies cooperation in the finitely repeated Prisoners’ Dilemma. Econ. Lett. 19(3), 227–229 (1985)MathSciNetCrossRefGoogle Scholar
  44. 44.
    Okumuşoğlu, O., Bayraktar, M.F., Küpçü, A.: JustTorrent: value based-fairer and faster protocols for P2P file sharing. Int. J. Eng. Sci. Appl. 1(1), 1–10 (2017)Google Scholar
  45. 45.
    Pagnia, H., Gartner, F.C.: On the impossibility of fair exchange without a trusted third party. Technical report, Darmstadt University of Technology TUD-BS-1999-02 (1999)Google Scholar
  46. 46.
    Piatek, M., Isdal, T., Anderson, T., Krishnamurthy, A., Venkataramani, A.: Do incentives build robustness in BitTorrent. In: NSDI (2007)Google Scholar
  47. 47.
    Rabin, M.O.: How to exchange secrets by oblivious transfer. Technical report, Harvard Aiken Computation Laboratory Technical report TR-81 (1981)Google Scholar
  48. 48.
    Radner, R.: Can bounded rationality resolve the Prisoner’s Dilemma? In: Essays in Honor of Gerard Debreu, pp. 387–399 (1986)Google Scholar
  49. 49.
    Roy, S.D., Zeng, W.: prTorrent: on establishment of piece rarity in the BitTorrent unchoking algorithm. In: IEEE P2P (2009)Google Scholar
  50. 50.
    Sandvine. Global Internet Phenemona, December 2015Google Scholar
  51. 51.
    Shacham, H., Waters, B.: Compact proofs of retrievability. J. Cryptol. 26(3), 442–483 (2013)MathSciNetCrossRefGoogle Scholar
  52. 52.
    Sirivianos, M., Yang, X., Jarecki, S.: Robust and efficient incentives for cooperative content distribution. IEEE/ACM Trans. Netw. 17(6), 1766–1779 (2009)CrossRefGoogle Scholar
  53. 53.
    Vilaça, X., Rodrigues, L.: On the range of equilibria utilities of a repeated epidemic dissemination game with a mediator. In: ACM ICDCN (2015)Google Scholar
  54. 54.
    Vishnumurthy, V., Chandrakumar, S., Sirer, E.G.: Karma: a secure economic framework for peer-to-peer resource sharing. In: P2PECON (2003)Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Brown UniversityProvidenceUSA
  2. 2.Koç UniversityİstanbulTurkey

Personalised recommendations