Cryptology ePrint Archive: Report 2008/182

Restricted Adaptive Oblivious Transfer

Javier Herranz

Abstract: In this work we consider the following primitive, that we call {\it restricted adaptive oblivious transfer}. On the one hand, the owner of a database wants to restrict the access of users to this data according to some policy, in such a way that a user can only obtain information satisfying the restrictions imposed by the owner. On the other hand, a legitimate user wants to privately retrieve allowed parts of the data, in a sequential and adaptive way, without letting the owner know which part of the data is being obtained.

After having formally described the components and required properties of a protocol for restricted adaptive oblivious transfer, we propose two generic ways to realize this primitive. The first one uses a cryptographic tool which has received a lot of attention from the literature in the last years: cryptosystems which are both multiplicatively and additively homomorphic. Our second generic construction is based on secret sharing schemes.

Category / Keywords: cryptographic protocols / Oblivious transfer, homomorphic encryption, secret sharing

Publication Info: Theoretical Computer Science, Vol. 412, pp. 64986506 (2011)

Date: received 18 Apr 2008, last revised 27 Sep 2011

Contact author: jherranz at ma4 upc edu

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Note: Some updates and publication info

Version: 20110927:111143 (All versions of this report)

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