Path ORAM: An extremely simple oblivious RAM protocol

Emil Stefanov, Marten V.A.N. Dijk, S. H.I. Elaine, T. H.Hubert Chan, Christopher Wardlaw Fletcher, Ling Ren, Xiangyao Yu, Srinivas Devadas

Research output: Contribution to journalArticlepeer-review


We present Path ORAM, an extremely simple Oblivious RAM protocol with a small amount of client storage. Partly due to its simplicity, Path ORAM is the most practical ORAM scheme known to date with small client storage. We formally prove that Path ORAM has a O(log N) bandwidth cost for blocks of size B = Ω(log2 N) bits. For such block sizes, Path ORAM is asymptotically better than the best-known ORAM schemes with small client storage. Due to its practicality, Path ORAM has been adopted in the design of secure processors since its proposal.

Original languageEnglish (US)
Article number18
JournalJournal of the ACM
Issue number4
StatePublished - Apr 2018


  • Access pattern
  • ORAM
  • Oblivious RAM
  • Path ORAM

ASJC Scopus subject areas

  • Software
  • Control and Systems Engineering
  • Information Systems
  • Hardware and Architecture
  • Artificial Intelligence


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