Collusion-Preserving Computation

  • Joël AlwenEmail author
  • Jonathan Katz
  • Ueli Maurer
  • Vassilis Zikas
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7417)


In collusion-free protocols, subliminal communication is impossible and parties are thus unable to communicate any information “beyond what the protocol allows.” Collusion-free protocols are interesting for several reasons, but have specifically attracted attention because they can be used to reduce trust in game-theoretic mechanisms. Collusion-free protocols are impossible to achieve (in general) when all parties are connected by point-to-point channels, but exist under certain physical assumptions (Lepinksi et al., STOC 2005) or when parties are connected in specific network topologies (Alwen et al., Crypto 2008).

We provide a “clean-slate” definition of the stronger notion of collusion preservation. Our goals in revisiting the definition are:
  • To give a definition with respect to arbitrary communication resources (including as special cases the communication models from prior work). We can then, in particular, better understand what types of resources enable collusion-preserving protocols.

  • To construct protocols that allow no additional subliminal communication when parties can communicate via other means. (This property is not implied by collusion-freeness.)

  • To support composition, so protocols can be designed in a modular fashion using sub-protocols run among subsets of the parties.

In addition to proposing the definition, we explore implications of our model and show a general feasibility result for collusion-preserving computation of arbitrary functionalities. We formalize a model for concurrently playing multiple extensive-form, mediated games while preserving many important equilibrium notions.


Full Version Ideal Functionality Star Network Security Notion Corrupted Party 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© International Association for Cryptologic Research 2012 2012

Authors and Affiliations

  • Joël Alwen
    • 1
    Email author
  • Jonathan Katz
    • 2
  • Ueli Maurer
    • 1
  • Vassilis Zikas
    • 2
  1. 1.ETH ZürichZürichSwitzerland
  2. 2.University of MarylandCollege ParkUSA

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