An ORAM Scheme with Improved Worst-Case Computational Overhead

  • Nairen Cao
  • Xiaoqi Yu
  • Yufang Yang
  • Linru Zhang
  • SiuMing YiuEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9543)


We construct a statistically secure ORAM with computational overhead of \(O(\log ^2N\log \log N)\). Moreover, when accessing continuous blocks, our scheme can achieve an amortized complexity \(O(\log N\log \log N)\), which almost matches the theoretical lower bound of the ORAM problem. Our construction is based on a tree-based construction [16]. The technical novelty comes from the idea of combining \(O(\log N)\) blocks into a big block together with a more aggressive and efficient “flush” operation, which is the bottleneck of existing ORAM schemes. All in all, we can achieve better amortized overhead in our new scheme.



This work is supported in part by National High Technology Research and Development Program of China (No. 2015AA016008), NSFC/RGC Joint Research Scheme (N_HKU 729/13), and Seed Funding Programme for Basic Research of HKU (201411159142).


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Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Nairen Cao
    • 1
  • Xiaoqi Yu
    • 1
  • Yufang Yang
    • 2
  • Linru Zhang
    • 3
  • SiuMing Yiu
    • 1
    Email author
  1. 1.The University of Hong KongHong KongChina
  2. 2.Tsinghua UniversityBeijingChina
  3. 3.Sun Yat-sen UniversityGuangzhouChina

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