reduction of 1 out of n oblivious transfers in random oracle model

We first present a protocol which reduces 1-out-of-n oblivious transfer OT m to 1out-of-n oblivious transfer OT k for n > 2 in random oracle model, and show that the protocol is secure against malicious sender and semi-honest receiver. Then, by employing a cut-and-choose technique, we obtain a variant of the basic protocol which is secure against a malicious receiver.