Using BDH for the Message Authentication in VANET

The transport message security provided by vehicles in VANETs is quite important; vehicle message should be real-time and it will be not complicated to validate message calculation. The method proposed in the essay is mainly to validate the identity by means of Bilinear Diffie-Hellman method, and make vehicles validate the authenticity of RSU and TA’s identity and the effectiveness of key. RSU and TA only need to validate vehicle identity, without helping vehicles produce any key. When vehicle identity validation is completed, vehicles will produce public value and transmit it to other RSU and vehicles, while other vehicles could validate the identity through the message from the sender and public value from RSU. The advantages of the method proposed in this essay are listed as follows. (1) Vehicles, RSU, and TA can validate mutual identities and the effectiveness of keys. (2) Vehicles can produce public value functions automatically, thus reducing key control risks. (3) Vehicles do not need to show certificates to validate their identities, preventing the certificates from attacking because of long-term exposure. (4) Vehicles adopt a pseudonym ID challenge to validate their own identities during the process of handoff. (5) Vehicle messages can be validated using the Bilinear Diffie-Hellman (BDH) method without waiting for the RSU to validate messages, thus improving the instantaneity of messaging. The method proposed in the essay can satisfy source authentication, message integrity, nonrepudiation, privacy, and conditional untraceability requirements.