Cryptology ePrint Archive: Report 2017/358

Almost Optimal Oblivious Transfer from QA-NIZK

Olivier Blazy and CÚline Chevalier and Paul Germouty

Abstract: We show how to build a UC-Secure Oblivious Transfer in the presence of Adaptive Corruptions from Quasi-Adaptive Non-Interactive Zero-Knowledge proofs. Our result is based on the work of Jutla and Roy at Asiacrypt 2015, where the authors proposed a constant-size very efficient PAKE scheme. As a stepping stone, we first show how a two-flow PAKE scheme can be generically transformed in an optimized way, in order to achieve an efficient three-flow Oblivious-Transfer scheme. We then compare our generic transformations to existing OT constructions and see that we manage to gain at least a factor 2 to the best known constructions. To the best of our knowledge, our scheme is the first UC-secure Oblivious Transfer with a constant size flow from the receiver, and nearly optimal size for the server.

Category / Keywords: public-key cryptography / Oblivious Transfer, Universal Composability, QA-NIZK, Pairing

Original Publication (with major differences): ACNS 2017

Date: received 20 Apr 2017, last revised 20 Apr 2017

Contact author: olivier at blazy eu

Available format(s): PDF | BibTeX Citation

Note: Full version of the ACNS 2017 paper

Version: 20170426:173046 (All versions of this report)

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