computational complexity

, Volume 15, Issue 1, pp 82–91

A tight lower bound for restricted pir protocols

Authors

    • Department of Computer and Information SciencesTemple University
  • Lance Fortnow
    • Department of Computer ScienceUniversity of Chicago
  • William Gasarch
    • Department of Computer Science and Institute for Advanced Computer StudiesUniversity of Maryland
Original Paper

DOI: 10.1007/s00037-006-0208-3

Cite this article as:
Beigel, R., Fortnow, L. & Gasarch, W. comput. complex. (2006) 15: 82. doi:10.1007/s00037-006-0208-3

Abstract.

We show that any 1-round 2-server Private Information Retrieval Protocol where the answers are one bit long must ask questions that are at least n−2 bits long, which is nearly equal to the known n−1 upper bound. This improves upon the approximately 0.25n lower bound of Kerenidis and deWolf while avoiding their use of quantum techniques.

Keywords.

Private information retrievallower boundsprivacy

Subject classification.

68Q17

Copyright information

© Birkhäuser Verlag, Basel 2006