  Secure routing protocols are proposed for the vehicular ad hoc networks. The
protocols integrate the security authentication process with the Location-Aided
Routing (LAR) protocol to support Wi-Fi Direct communications between the
vehicles. The methods are robust against various security threats. The security
authentication process adopts a modified Diffie-Hellman key agreement protocol.
The Diffie-Hellman protocol is used with a short authentication string
(SAS)-based key agreement over Wi-Fi Direct out-of-band communication channels.
It protects the communication from any man-in-the-middle security threats. In
particular, the security process is integrated into two LAR routing schemes,
i.e., the request-zone LAR scheme and the distance-based LAR scheme. We conduct
extensive simulations with different network parameters such as the vehicular
node density, the number of the malicious nodes, and the speed of the nodes.
Simulation results show that the proposed routing protocols provide superior
performance in secure data delivery and average total packet delay. Also, the
secure distance-based LAR protocol outperforms the secure request-zone LAR
protocol.
