A novel efficient m-out-of-n oblivious transfer scheme

Oblivious Transfer is an important cryptographic protocol in various security applications. In this paper, we propose an efficient two-pass m-out-of-n Oblivious Transfer protocol in which the sender S initializes the system with n public messages, the receiver R sends j messages to S, where j is strictly less than m, and S sends j messages back to R. The protocol provides unconditional security for R. The computational security for S is based on the RSA assumption. Analyses show that the proposed protocol is most efficient in terms of the communication cost either in number of passes of information exchange or in the number of messages, and in terms of the computational cost number of modular exponentiations. (4 pages)