An efficient COT protocol

Abstract

Committed oblivious transfer is the natural fusion of one-out-of-two oblivious transfer and bit commitment. Unfortunately, the protocols proposed before are not only complicated but also very inefficient. This paper describes a new committed oblivious transfer protocol based on a first two round string oblivious transfer and bit commitment with XOR. With a first two round string oblivious transfer, the protocol can avoid performing a large number of bit oblivious transfers. And with bit commitment with XOR, zero knowledge proofs are very easy. The protocol is conceptually simple and more efficient. The security and complexity of the protocol are also discussed in this paper.