Abstract
Vehicular communications have become an increasingly important communication technique worldwide. The current limitations of vehicular communications are not determined by capability or authentication but by security infrastructure. In 2005, a proposal for vehicular network security was discussed by Raya and Hubaux. However, such protocol is not practical and is unsafe for use in VANETs. In addition, handoff has become a relevant issue for vehicles moving from one region to another. For these reasons, we propose a secure communication and handoff protocol. In our protocol, a vehicle can enjoy seamless service between heterogeneous vehicular networks. Furthermore, vehicular communication is made more secure and ubiquitous.