# Adaptive Oblivious Transfer with Access Control from Lattice Assumptions

2 ARIC - Arithmetic and Computing
Inria Grenoble - Rhône-Alpes, LIP - Laboratoire de l'Informatique du Parallélisme
Abstract : Adaptive oblivious transfer (OT) is a protocol where a sender initially commits to a database $\{M_i\}_{i=1}^N$. Then, a receiver can query the sender up to $k$ times with private indexes $\rho_1,\ldots,\rho_k$ so as to obtain $M_{\rho_1},\ldots , M_{\rho_k}$ and nothing else. Moreover, for each $i \in [k]$, the receiver's choice $\rho_i$ may depend on previously obtained messages. Oblivious transfer with access control (OT-AC) is a flavor of adaptive OT where database records are protected by distinct access control policies that specify which credentials a receiver should obtain in order to access each $M_i$. So far, all known OT-AC protocols only support access policies made of conjunctions or rely on {\it ad hoc} assumptions in pairing-friendly groups (or both). In this paper, we provide an OT-AC protocol where access policies may consist of any branching program of polynomial length, which is sufficient to realize any access policy in NC1. The security of our protocol is proved under the Learning-with-Errors (LWE) and Short-Integer-Solution (SIS) assumptions. As a result of independent interest, we provide protocols for proving the correct evaluation of a committed branching program on a committed input.
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Type de document :
Communication dans un congrès
Tsuyoshi Takagi; Thomas Peyrin. Advances in Cryptology – ASIACRYPT 2017, Dec 2017, Hong Kong, China. Springer, Lecture Notes in Computer Science, 10624, pp.30, 2017, 〈https://asiacrypt.iacr.org/2017/〉

Littérature citée [62 références]

https://hal.inria.fr/hal-01622197
Contributeur : Benoit Libert <>
Soumis le : mercredi 25 octobre 2017 - 11:05:27
Dernière modification le : jeudi 8 février 2018 - 11:10:03
Document(s) archivé(s) le : vendredi 26 janvier 2018 - 13:08:47

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OT-LWE-full-version.pdf
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• HAL Id : hal-01622197, version 2

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Benoît Libert, San Ling, Fabrice Mouhartem, Khoa Nguyen, Huaxiong Wang. Adaptive Oblivious Transfer with Access Control from Lattice Assumptions. Tsuyoshi Takagi; Thomas Peyrin. Advances in Cryptology – ASIACRYPT 2017, Dec 2017, Hong Kong, China. Springer, Lecture Notes in Computer Science, 10624, pp.30, 2017, 〈https://asiacrypt.iacr.org/2017/〉. 〈hal-01622197v2〉

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