Authors:
Seira Hidano
;
Yuto Nakano
and
Shinsaku Kiyomoto
Affiliation:
KDDI Research and Inc., Japan
Keyword(s):
Memory Access Pattern, Oblivious RAM, Average Min-Entropy, Collision Entropy.
Abstract:
Oblivious RAM (ORAM) is security provable approach for memory access pattern hiding. However, since
ORAM incurs high computational overheads due to repeated shuffles of data blocks in a memory, numerous
constructions have been proposed to reduce it. While the computational cost has been improved by these
constructions as compared to early ones, it is still expensive from the practical point of view. Specifically, in
its application to IoT devices, less computational cost is expected for avoiding high energy consumption. We
thus focus on an ORAM construction proposed by Nakano et al. in 2012, which we call the fastest ORAM.
The computational cost of this construction is much less than any other conventional ORAM constructions.
However, the security has not been analyzed sufficiently, due to the lack of practical security definitions.
Therefore, we formulate a new security definition for the fastest ORAM on the basis of the average min-entropy,
and propose a framework for eval
uating the security.
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