Inter-Vehicular Communications (IVC) are a cornerstone of the future intelligent transportation systems. A crucial enabling component of IVC is its security and privacy. Indeed, as vehicular computing systems become interconnected, there will be new venues for attackers to exploit system vulnerabilities. In addition, proper security mechanisms can assist in law enforcement and automate payment operations, such as toll collection. Leveraging on experience gained from other networks like the Internet or wireless LANs, system security for vehicular networks has to be introduced in the design phase. In the following sections, we outline several security threats encountered in IVC, then we present the obstacles needed to overcome in order to cope with these threats. Finally, we describe several tools that will be helpful in building secure IVC networks.