Hiding instances in multioracle queries

  • Donald Beaver
  • Joan Feigenbaum
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 415)


Abadi, Feigenbaum, and Kilian have considered instance-hiding schemes [1]. Let f be a function for which no randomized polynomial-time algorithm is known; randomized polynomial-time machine A wants to query an oracle B for f to obtain f(x), without telling B exactly what x is. It is shown in [1] that, if f is an NP-hard function, A cannot query a single oracle B while hiding all but the size of the instance, assuming that the polynomial hierarchy does not collapse. This negative result holds for all oracles B, including those that are non-r.e.

In this paper, we generalize the definition of instance-hiding schemes to allow A to query several oracles B1,..., Bm that are not allowed to communicate. We show that every function f does have a multioracle instance-hiding scheme, thus settling a question of Rivest.


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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Donald Beaver
    • 1
  • Joan Feigenbaum
    • 2
  1. 1.Aiken Computation LaboratoryHarvard UniversityCambridgeUSA
  2. 2.AT&T Bell Labs, Rm 2C473Murray HillUSA

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