Efficient k-out-of-n oblivious transfer scheme with the ideal communication cost

In this paper, we propose a two-round k-out-of-n oblivious transfer scheme with the minimum communication cost. In our proposed scheme, the messages sent by the receiver R to the sender S consist of only three elements, which is independent of n and k, while the messages from S to R are (n+1) elements when the sender holds n secrets. Our scheme features a nice property of universal parameter, where the system parameter can be used by all senders and receivers. The proposed k-out-of-n oblivious transfer scheme is the most efficient two-round scheme in terms of the number of messages transferred between two communicating parties in known constructions. The scheme preserves the privacy of receiver's choice and sender's security.