Simpósio Brasileiro de Cibersegurança (SBSeg)

Universally Composable Committed Oblivious Transfer With A Trusted Initializer

Adriana C. B. Pinto, Bernardo David, Jeroen van de Graaf, Anderson C. A. Nascimento

Published Nov 19, 2012• 0 citations

Abstract

Committed Oblivious Transfer (COT) is a two-party primitive that combines one-out-of-two oblivious transfer with bit commitment. In the beginning of COT, a sender is committed to bits b0, b1 and a receiver to a choice bit c. In the end, the receiver is committed to bc without learning anything about b1-c, while the sender learns nothing about c. This primitive implies secure multi-party computation assuming that a broadcast channel is available. In this paper, we introduce the first universally composable unconditionally secure committed oblivious transfer protocol based on a Trusted Initializer (TI), which pre-distributes data to the parties. Our protocol builds on simple bit commitment and oblivious transfer protocols, using XOR commitments to prove simple relations in zero-knowledge. Besides providing very high security guarantees, our protocols are significantly simpler and more efficient than previous results, since they rely on pre-computed operations distributed by the TI.

DOI: 10.5753/sbseg.2012.20541

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