Sequences II pp 345-359 | Cite as

Privacy of Dense Symmetric Functions

extended abstract
  • Benny Chor
  • Netta Shani
Conference paper


An n argument function, f, is called t — private if there exists a distributed protocol for computing f, so that no coalition of ≤ t processors can infer any additional information from the execution of the protocol. It is known that every function defined over a finite domain is \( \left[ {\frac{{n - 1}}{2}} \right] \)-private. The general question of t — privacy (for t\( \left[ {\frac{n}{2}} \right] \)) is still unresolved.

In this work we relate the question of \( \left[ {\frac{n}{2}} \right] \)-privacy for the class of symmetric functions of Boolean arguments f: {0,1} n → {0,1,..., n} to the structure of weights in f -1(b) (b ∈ {0,1,..., n}). We show that if f is \( \left[ {\frac{n}{2}} \right] \)-private, then every set of weights f -1(b) must be an arithmetic progression. For the class of dense symmetric functions (defined in the sequel), we refine this to the following necessary and sufficient condition for \( \left[ {\frac{n}{2}} \right] \) — privacy of f: Every collection of such arithmetic progressions must yield distinct remainders, when computed modulo the greatest common divisor of their differences. This condition is used to show that for dense symmetric functions, \( \left[ {\frac{n}{2}} \right] \)-privacy implies n-privacy.


Boolean Function Symmetric Function Arithmetic Progression Boolean Variable Great Common Divisor 
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

© Springer-Verlag New York, Inc. 1993

Authors and Affiliations

  • Benny Chor
    • 1
  • Netta Shani
    • 1
  1. 1.Department of Computer Science TechnionHaifaIsrael

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