Paper 2018/851

More is Less: Perfectly Secure Oblivious Algorithms in the Multi-Server Setting

T-H. Hubert Chan, Jonathan Katz, Kartik Nayak, Antigoni Polychroniadou, and Elaine Shi


The problem of Oblivious RAM (ORAM) has traditionally been studied in the single-server setting, but more recently the multi-server setting has also been considered. Yet it is still unclear whether the multi-server setting has any inherent advantages, e.g., whether the multi-server setting can be used to achieve stronger security goals or provably better efficiency than is possible in the single-server case. In this work, we construct a perfectly secure 3-server ORAM scheme that outperforms the best known single-server scheme by a logarithmic factor. In the process we also show, for the first time, that there exist specific algorithms for which multiple servers can overcome known lower bounds in the single-server setting.

Available format(s)
Publication info
Published by the IACR in ASIACRYPT 2018
oblivious RAMmuli-serverperfect security
Contact author(s)
hubert @ cs hku hk
jkatz @ cs umd edu
nkartik @ vmware com
antigoni @ cornell edu
runting @ gmail com
2018-09-20: received
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Creative Commons Attribution


      author = {T-H.  Hubert Chan and Jonathan Katz and Kartik Nayak and Antigoni Polychroniadou and Elaine Shi},
      title = {More is Less: Perfectly Secure Oblivious Algorithms in the Multi-Server Setting},
      howpublished = {Cryptology ePrint Archive, Paper 2018/851},
      year = {2018},
      note = {\url{}},
      url = {}
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