Vehicular Ad-hoc NETwork (VANET) offers a large number of new potential applications. Drivers may benefit from collision warning, road sign alarms and in-place traffic view, and others. This network tends to operate without any infra-structure or legacy client and server communication. However, due to some special properties such as high mobility, network partitioning, and constrained topology, situations in which the network topology changes dynamically are tempting to attackers for various reasons, e.g. faked location and malicious information.