A Provably Secure Oblivious Transfer Protocol

The idea of the Oblivious Transfer, developed by Rabin, has been shown to have important applications in cryptography. M. Fischer pointed out that Rabin's original implementation of the Oblivious Transfer was not shown to be secure. Since then it has been an open problem to find a provably secure implementation. We present an implementation which we believe will simplify the development of secure cryptographic protocols. Our protocol is provably secure under the assumptions that factoring is hard and that the message is chosen at random from a large message space.