JISE

   Now the vehicular ad hoc networks (VANETs) are extremely inhomogeneous because the vehicles come from different manufacturers around the world. It is difficult to realize secure communications between two heterogeneous vehicles. And confidentiality and authentication are the main security goals of secure communications. In order to achieve above two security goals simultaneously in such a heterogeneous vehicular ad hoc network, two efficient signcryption schemes are proposed in this paper. The first scheme allows a vehicle registered in a public key infrastructure (PKI) to send a message to another vehicle registered in an identity-based cryptosystem (IBC). And the second scheme allows a vehicle registered in the IBC to send a message to a vehicle registered in the PKI system. Two vehicles from different public key cryptosystems can freely communicate any authenticated and encrypted message in our proposed schemes. Finally, we prove that both schemes have indistinguishability against adaptive chosen ciphertext attacks and existential unforgeability against adaptive chosen messages attacks under the hardness assumption of decisional Diffie-Hellman problem in the random oracle model. Performance analyses demonstrate our schemes have great advantages in computation, ciphertext length, communication cost and storage.