Generation of shared RSA keys by two parties

Abstract

At Crypto’97 Boneh and Franklin proposed a protocol to efficiently generate shared RSA keys. In the case of two parties, the drawback of their scheme is the need of an independent third party. Furthermore, the security is guaranteed only if the three players follow the protocol. In this paper, we propose a protocol that enables two parties to evaluate any algebraic expression, including an RSA modulus, along the same lines as in the Boneh-Franklin protocol. Our solution does not need the help of a third party and the only assumption we make is the existence of an oblivious transfer protocol. Furthermore, it remains robust even if one of the two players deviates from the protocol.