Efficiently from Semi-honest to Malicious OT via OLFE


A combiner securely implements a functionality out of a set implementations of another functionality from which some may be insecure. We present two efficient combiners for oblivious linear function evaluation (OLFE). The first is a constant-rate OLFE combiner in the semihonest model, the second combiner implements Rabin string oblivious transfer (RabinOT) from OLFE in the malicious model. As an application, we show a very efficient reductions in the malicious model of RabinOT over strings to one-out-of-two oblivious transfer over bits (OT) that is only secure in the semihonest model. For string of size ` = ω(k), our reductions uses only 4`+ o(`) instances of OT, while previous results required Ω(`k). Our new reduction leads to an efficiency improvement for general multi-party computation (MPC) based on semi-honest OT, and makes it almost as efficient as MPC based on malicious OT. All reductions are unconditionally secure, black-box, universally composable and secure against adaptive adversaries.

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@article{Wullschleger2009EfficientlyFS, title={Efficiently from Semi-honest to Malicious OT via OLFE}, author={J{\"{u}rg Wullschleger}, journal={IACR Cryptology ePrint Archive}, year={2009}, volume={2009}, pages={428} }