Paper 2014/185

Oblivious Data Structures

Xiao Shaun Wang, Kartik Nayak, Chang Liu, T-H. Hubert Chan, Elaine Shi, Emil Stefanov, and Yan Huang


Oblivious RAMs (ORAMs) have traditionally been measured by their bandwidth overhead and client storage. We observe that when using ORAMs to build secure computation protocols for RAM programs, the size of the ORAM circuits is more relevant to the performance. We therefore embark on a study of the circuit-complexity of several recently proposed ORAM constructions. Our careful implementation and experiments show that asymptotic analysis is not indicative of the true performance of ORAM in secure computation protocols with practical data sizes. We then present SCORAM, a heuristic compact ORAM design optimized for secure computation protocols. Our new design is almost 10x smaller in circuit size and also faster than all other designs we have tested for realistic settings (i.e., memory sizes between 4MB and 2GB, constrained by 2^{-80} failure probability). SCORAM makes it feasible to perform secure computations on gigabyte-sized data sets.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Major revision. CCS 2014
oblivious RAMORAMsecure computation
Contact author(s)
wangxiao @ cs umd edu
2015-01-24: last of 5 revisions
2014-03-09: received
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Creative Commons Attribution


      author = {Xiao Shaun Wang and Kartik Nayak and Chang Liu and T-H.  Hubert Chan and Elaine Shi and Emil Stefanov and Yan Huang},
      title = {Oblivious Data Structures},
      howpublished = {Cryptology ePrint Archive, Paper 2014/185},
      year = {2014},
      doi = {10.1145/2660267.2660314},
      note = {\url{}},
      url = {}
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