Paper 2002/182

Oblivious Keyword Search

Wakaha Ogata and Kaoru Kurosawa

Abstract

In this paper, we introduce a notion of Oblivious Keyword Search ($OKS$). Let $W$ be the set of possible keywords. In the commit phase, a database supplier $T$ commits $n$ data. In each transfer subphase, a user $U$ can choose a keyword $w \in W$ adaptively and find $Search(w)$ without revealing $w$ to $T$, where $Search(w)$ is the set of all data which includes $w$ as a keyword. We then show two efficient protocols such that the size of the commitments is only $(nB)$ regardless of the size of $W$, where $B$ is the size of each data. It is formally proved that $U$ learns nothing more and $T$ gains no information on the keywords which $U$ searched. We further present a more efficient adaptive $OT_k^n$ protocol than the previous one as an application of our first $OKS$ protocol.

Metadata
Available format(s)
PDF PS
Category
Cryptographic protocols
Publication info
Published elsewhere. Journal of Complexity, Vol.20 [2-3], pp. 356-371 (2004)
Keywords
oblivious transfer
Contact author(s)
kurosawa @ cis ibaraki ac jp
History
2004-03-09: revised
2002-12-01: received
See all versions
Short URL
https://ia.cr/2002/182
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2002/182,
      author = {Wakaha Ogata and Kaoru Kurosawa},
      title = {Oblivious Keyword Search},
      howpublished = {Cryptology {ePrint} Archive, Paper 2002/182},
      year = {2002},
      url = {https://eprint.iacr.org/2002/182}
}
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