Paper 2014/997
Constants Count: Practical Improvements to Oblivious RAM
Ling Ren and Christopher W. Fletcher and Albert Kwon and Emil Stefanov and Elaine Shi and Marten van Dijk and Srinivas Devadas
Abstract
Oblivious RAM (ORAM) is a cryptographic primitive that hides memory access patterns as seen by untrusted storage. This paper proposes Ring ORAM, the most bandwidth-efficient ORAM scheme for the small client storage setting in both theory and practice. Ring ORAM is the first tree-based ORAM whose bandwidth is independent of the ORAM bucket size, a property that unlocks multiple performance improvements. First, Ring ORAM’s overall bandwidth is 2.3x to 4x better than Path ORAM, the prior-art scheme for small client storage. Second, if memory can perform simple untrusted computation, Ring ORAM achieves constant online bandwidth (~60x improvement over Path ORAM for practical parameters). As a case study, we show Ring ORAM speeds up program completion time in a secure processor by 1.5x relative to Path ORAM. On the theory side, Ring ORAM features a tighter and significantly simpler analysis than Path ORAM.
Metadata
- Available format(s)
- Category
- Cryptographic protocols
- Publication info
- Published elsewhere. usenix 2015
- Contact author(s)
- renling @ mit edu
- History
- 2015-07-07: revised
- 2014-12-18: received
- See all versions
- Short URL
- https://ia.cr/2014/997
- License
-
CC BY