In vehicular ad hoc networks, evaluating trustworthiness of data is utmost necessary for the receiver to make reliable decisions that are very crucial in safety and traffic-efficiency related applications. Existing trust management schemes that have been proposed so far for the vehicular networks has suffered from various limitations. For example, some schemes build trust based on the history of interactions. However, vehicular networks are ephemeral in nature, which makes that approach infeasible. Furthermore, in most of the existing approaches, unique identities of each vehicle must be known. This violates user privacy. In order to overcome these limitations, we have proposed a novel trust management scheme for the vehicular networks. The proposed method is simple and completely decentralized, which makes it easy to implement in the vehicular networks. We have analytically proved its robustness with respect to various security threats. Furthermore, it introduces linear time complexity, which makes it suitable to use in real-time.