TY - GEN
T1 - Can we access a database both locally and privately?
AU - Boyle, Elette
AU - Ishai, Yuval
AU - Pass, Rafael
AU - Wootters, Mary
N1 - Publisher Copyright:
© 2017, International Association for Cryptologic Research.
PY - 2017
Y1 - 2017
N2 - We consider the following strong variant of private information retrieval (PIR). There is a large database x that we want to make publicly available. To this end, we post an encoding X of x together with a short public key pk in a publicly accessible repository. The goal is to allow any client who comes along to retrieve a chosen bit xi by reading a small number of bits from X, whose positions may be randomly chosen based on i and pk, such that even an adversary who can fully observe the access to X does not learn information about i. Towards solving this problem, we study a weaker secret key variant where the data is encoded and accessed by the same party. This primitive, that we call an oblivious locally decodable code (OLDC), is independently motivated by applications such as searchable symmetric encryption. We reduce the public-key variant of PIR to OLDC using an ideal form of obfuscation that can be instantiated heuristically with existing indistinguishability obfuscation candidates, or alternatively implemented with small and stateless tamper-proof hardware. Finally, a central contribution of our work is the first proposal of an OLDC candidate. Our candidate is based on a secretly permuted Reed-Muller code. We analyze the security of this candidate against several natural attacks and leave its further study to future work.
AB - We consider the following strong variant of private information retrieval (PIR). There is a large database x that we want to make publicly available. To this end, we post an encoding X of x together with a short public key pk in a publicly accessible repository. The goal is to allow any client who comes along to retrieve a chosen bit xi by reading a small number of bits from X, whose positions may be randomly chosen based on i and pk, such that even an adversary who can fully observe the access to X does not learn information about i. Towards solving this problem, we study a weaker secret key variant where the data is encoded and accessed by the same party. This primitive, that we call an oblivious locally decodable code (OLDC), is independently motivated by applications such as searchable symmetric encryption. We reduce the public-key variant of PIR to OLDC using an ideal form of obfuscation that can be instantiated heuristically with existing indistinguishability obfuscation candidates, or alternatively implemented with small and stateless tamper-proof hardware. Finally, a central contribution of our work is the first proposal of an OLDC candidate. Our candidate is based on a secretly permuted Reed-Muller code. We analyze the security of this candidate against several natural attacks and leave its further study to future work.
UR - http://www.scopus.com/inward/record.url?scp=85033774555&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-70503-3_22
DO - 10.1007/978-3-319-70503-3_22
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AN - SCOPUS:85033774555
SN - 9783319705026
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 662
EP - 693
BT - Theory of Cryptography - 15th International Conference, TCC 2017, Proceedings
A2 - Kalai, Yael
A2 - Reyzin, Leonid
T2 - 15th International Conference on Theory of Cryptography, TCC 2017
Y2 - 12 November 2017 through 15 November 2017
ER -