Information-theoretic Private Information Retrieval: A unified construction (extended abstract)

Amos Beimel, Yuval Ishai

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

72 Scopus citations


A Private Information Retrieval (PIR) protocol enables a user to retrieve a data item from a database while hiding the identity of the item being retrieved. In a t-private, k-server PIR protocol the database is replicated among k servers, and the user's privacy is protected from any collusion of up to t servers. The main cost-measure of such protocols is the communication complexity of retrieving a single bit of data. This work addresses the information-theoretic setting for PIR, in which the user's privacy should be unconditionally protected from collusions of servers. We present a unified general construction, whose abstract components can be instantiated to yield both old and new families of PIR protocols. A main ingredient in the new protocols is a generalization of a solution by Babai, Kimmel, and Lokam to a communication complexity problem in the so-called simultaneous messages model. Our construction strictly improves upon previous constructions and resolves some previous anomalies. In particular, we obtain: (1) t-private k-server PIR protocols with O(n1/b(2k-1)/t) communication bits, where n is the database size. For t < 1, this is a substantial asymptotic improvement over the previous state of the art; (2) a constant-factor improvement in the communication complexity of 1-private PIR, providing the first improvement to the 2-server case since PIR protocols were introduced; (3) effcient PIR protocols with logarithmic query length. The latter protocols have applications to the construction of effcient families of locally decodable codes over large alphabets and to PIR protocols with reduced work by the servers.

Original languageEnglish
Title of host publicationAutomata, Languages and Programming - 28th International Colloquium, ICALP 2001, Proceedings
EditorsFernando Orejas, Paul G. Spirakis, Jan van Leeuwen
PublisherSpringer Verlag
Number of pages15
ISBN (Print)3540422870, 9783540422877
StatePublished - 1 Jan 2001
Event28th International Colloquium on Automata, Languages and Programming, ICALP 2001 - Crete, Greece
Duration: 8 Jul 200112 Jul 2001

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume2076 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference28th International Colloquium on Automata, Languages and Programming, ICALP 2001

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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