Locality-preserving oblivious RAM

Gilad Asharov, T. H. Hubert Chan, Kartik Nayak, Rafael Pass, Ling Ren, Elaine Shi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Oblivious RAMs, introduced by Goldreich and Ostrovsky [JACM’96], compile any RAM program into one that is “memory oblivious”, i.e., the access pattern to the memory is independent of the input. All previous ORAM schemes, however, completely break the locality of data accesses (for instance, by shuffling the data to pseudorandom positions in memory). In this work, we initiate the study of locality-preserving ORAMs—ORAMs that preserve locality of the accessed memory regions, while leaking only the lengths of contiguous memory regions accessed. Our main results demonstrate the existence of a locality-preserving ORAM with poly-logarithmic overhead both in terms of bandwidth and locality. We also study the tradeoff between locality, bandwidth and leakage, and show that any scheme that preserves locality and does not leak the lengths of the contiguous memory regions accessed, suffers from prohibitive bandwidth. To the best of our knowledge, before our work, the only works combining locality and obliviousness were for symmetric searchable encryption [e.g., Cash and Tessaro (EUROCRYPT’14), Asharov et al. (STOC’16)]. Symmetric search encryption ensures obliviousness if each keyword is searched only once, whereas ORAM provides obliviousness to any input program. Thus, our work generalizes that line of work to the much more challenging task of preserving locality in ORAMs.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology – EUROCRYPT 2019 - 38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings
EditorsYuval Ishai, Vincent Rijmen
PublisherSpringer-Verlag
Pages214-243
Number of pages30
ISBN (Print)9783030176556
DOIs
StatePublished - Jan 1 2019
Externally publishedYes
Event38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Eurocrypt 2019 - Darmstadt, Germany
Duration: May 19 2019May 23 2019

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume11477 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference38th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Eurocrypt 2019
CountryGermany
CityDarmstadt
Period5/19/195/23/19

Keywords

  • Locality
  • Oblivious RAM
  • Randomized algorithms

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

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